Specific Recognition of Rac2 and Cdc42 by DOCK2 and DOCK9 Guanine Nucleotide Exchange Factors
Open accessAbstract
Recognition of cognate Rho GTPases by guanine-nucleotide exchange factors (GEF) is fundamental to Rho GTPase signaling specificity. Two main GEF families use either the Dbl homology (DH) or the DOCK homology region 2 (DHR-2) catalytic domain. How DHR-2-containing GEFs distinguish between the GTPases Rac and Cdc42 is not known. To determine how these GEFs specifically recognize the two Rho GTPases, we studied the amino acid sequences in Rac2 and Cdc42 that are crucial for activation by DOCK2, a Rac-specific GEF, and DOCK9, a distantly related Cdc42-specific GEF. Two elements in the N-terminal regions of Rac2 and Cdc42 were found to be essential for specific interactions with DOCK2 and DOCK9. One element consists of divergent amino acid residues in the switch 1 regions of the GTPases. Significantly, these residues were also found to be important for GTPase recognition by Rac-specific DOCK180, DOCK3, and DOCK4 GEFs. These findings were unexpected because the same residues were shown previously to interact with GTPase effectors rather than GEFs. The other element comprises divergent residues in the beta3 strand that are known to mediate specific recognition by DH domain containing GEFs. Remarkably, Rac2-to-Cdc42 substitutions of four of these residues were sufficient for Rac2 to be specifically activated by DOCK9. Thus, DOCK2 and DOCK9 specifically recognize Rac2 and Cdc42 through their switch 1 as well as beta2-beta3 regions and the mode of recognition via switch 1 appears to be conserved among diverse Rac-specific DHR-2 GEFs.
AI snapshot
Written from the paper’s full text.
TL;DR
DOCK2 and DOCK9 recognize Rac2 and Cdc42 through divergent residues in switch 1 and the β2–β3 region, not solely through the β3 strand used by DH-domain GEFs. Four Rac2-to-Cdc42 substitutions in switch 1 and β3 were sufficient to switch Rac2 to specific activation by DOCK9.
Key findings
- Two N-terminal elements in Rac2/Cdc42 mediate specific activation by DOCK2-ELMO1 and DOCK9: divergent residues at positions 27 and 30 in switch 1, and residues at positions 51, 52, and 56 in the β3 strand.
- Rac2-to-Cdc42 substitutions at Ala-27, Gly-30, or Trp-56 severely compromised DOCK2-ELMO1 binding and activation; Val-51 and Asn-52 substitutions modestly decreased activation without detectably affecting DOCK2-ELMO1 binding.
- A Rac2 mutant with four substitutions—A27K, VN51YT, and W56F—was specifically activated by DOCK9 instead of DOCK2-ELMO1; a five-substitution mutant was activated by DOCK9 to ~30% of wild-type Cdc42, and omitting G30A modestly increased DOCK9 binding and activation.
- Switch 1 residues were also important for Rac recognition by diverse DHR-2 GEFs: Rac2-(A3T,A27K,G30S,I33V) was almost completely unresponsive to DOCK180, DOCK2, and DOCK3, and only somewhat responsive to DOCK4; restoring Rac2-specific Ala-27 and Gly-30 largely restored activation.
Methods
- Chimeric and point-mutated Rac2/Cdc42 GTPases were expressed in HEK 293T cells alone or with DOCK2 plus ELMO1, DOCK9, or DHR-2 domains of DOCK180, DOCK2, DOCK3, and DOCK4; activation was measured by PBD-GST pull-down and immunoblotting for the myc epitope.
- Binding was assayed by GST-myc-GTPase pull-down from HEK 293T extracts expressing DOCK9, DOCK2, and ELMO1.
- In vitro guanine nucleotide exchange was measured by [3H]GDP dissociation using recombinant GST-myc-GTPases and His7-myc-DHR-2 domains, including DOCK2-(1115-1645) and DOCK9-(1358-2068).
Limitations
- The paper does not state a limitations section.
- Evident: the study relies on mutational, chimeric, and GDP-dissociation assays rather than structures of DHR-2–GTPase complexes, so direct contacts are inferred.
- Evident: most mutant GTPases showed little to no interaction with full-length DOCK9 in GST pull-downs even when activation was detected, and mutants interacted with the DOCK9 DHR-2 domain in data not shown; full-length binding versus activation remains unresolved. DOCK9 physiological roles are also noted as not defined.
Model-written summary. Check it against the paper before relying on it.
Integrity signals
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Cites
Statistics
Claims the paper makes
10 of 29 cited sources checked · 3 supported · 0 flagged · accuracy not yet measured
- Interpretationcitation
The side chains of the critical amino acid residues, except for those at positions 51, are surface accessible and thus may contact the cognate CDM GEFs directly.
“The side chains of these critical amino acid residues, except for those at positions 51, are surface accessible and thus may contact the cognate CDM GEFs directly (28,29,45).”
Quote in the paperSubstantial claim1 of 3 sources checked- cites [28] Rossman, 2002, EMBO J. source
In “The interface between the PH domain of Dbs and Cdc42” (page unavailable), the paper describes direct contacts between Cdc42 side chains and the GEF Dbs, supporting the proposed contact mechanism. It does not identify the citing sentence’s critical residues, establish that their side chains are surface accessible, or discuss the exception at position 51 or cognate CDM GEFs. (LLM, conf=0.82)
Experimental — accuracy not yet measured - cites [29] Worthylake, 2000, Nature source
- cites [45] Snyder, 2002, Nat. Struct. Biol. source
- Premisecitation
The reciprocal substitution in Cdc42 allows Cdc42-(F56W) to be specifically activated by Tiam1.
“Conversely, the reciprocal substitution in Cdc42 allows Cdc42-(F56W) to be specifically activated by Tiam1 (47).”
Quote in the paperNot a substantial claim1 of 1 sources checked- cites [47] Gao, 2001, J. Biol. Chem. source
- Premisecitation
Previous studies demonstrated that DH domain GEFs distinguish between Rac and Cdc42 mainly via an aromatic residue at position 56.
“For example, previous studies demonstrated that the DH domain GEFs distinguish between Rac and Cdc42 mainly via an aromatic residue at position 56 (47,48).”
Quote in the paperSubstantial claim1 of 2 sources checked- cites [47] Gao, 2001, J. Biol. Chem. source
The Results section identifies Rac1 Trp56 as necessary and sufficient for discrimination from Cdc42 by the tested GEFs, TrioN, GEF-H1, and Tiam1. The Discussion cautions that this mechanism may not generalize to other GEFs, so the claim is too broad in referring to DH-domain GEFs generally. The source also specifies tryptophan, rather than an aromatic residue generically. (LLM, conf=0.88)
Experimental — accuracy not yet measured - cites [48] Karnoub, 2001, Nat. Struct. Biol. source
- Premisecitation
Crystal structures of DH domain GEFs such as Tiam1, ITSN1, and Dbs in complex with their cognate GTPases show that positions 27 and 30 of the Rho GTPases remain accessible in the complexes.
“Also, the crystal structures of DH domain GEFs such as Tiam1, ITSN1, and Dbs in complex with their cognate GTPases show that positions 27 and 30 of the Rho GTPases remain accessible in the complexes (28,29,45).”
Quote in the paperSubstantial claim1 of 3 sources checked- cites [28] Rossman, 2002, EMBO J. source
The Structural overview (page unavailable) describes the Dbs–Cdc42 structure and compares it with Tiam1–Rac1. It says the nucleotide-binding pocket is exposed to solvent, but explicitly excludes the switch regions from that description; positions 27 and 30 lie within switch 1. Our copy therefore does not establish that those specific positions remain accessible, and it does not discuss an ITSN1 complex. (LLM, conf=0.82)
Experimental — accuracy not yet measured - cites [29] Worthylake, 2000, Nature source
- cites [45] Snyder, 2002, Nat. Struct. Biol. source
- Findingown data
Additional Cdc42-to-Rac2 substitutions in the β2 strand (AVT41SAN) and the loop connecting β2 and β3 (IGGE46VDSK) revealed that at least some of these changes are required to further suppress activation by DOCK9.
“Analysis of mutant GTPases with additional Cdc42-to-Rac2 substitutions in the 2 strand (AVT41SAN) and the loop connecting the 2 and 3 strands (IGGE46VDSK) revealed that at least some of these changes are required to further suppress activation by DOCK9 (panel B, compare lanes 3 with 2 and 4 -9).”
Quote in the paperSubstantial claim
- Findingown data
A chimeric GTPase comprising amino acids 1 to 58 of Cdc42 joined to amino acids 59 to 192 of Rac2 (C58R) is activated by DOCK9 almost as well as wild-type Cdc42.
“Interestingly, a chimeric GTPase comprising amino acids 1 to 58 of Cdc42 joined to amino acids 59 to 192 of Rac2 (C58R) was activated by DOCK9 almost as well as wild-type Cdc42 (Fig. 2A, histogram, compare lanes 7 with 8).”
Quote in the paperSubstantial claim - Findingown data
The DOCK2 and DOCK9 DHR-2 domains specifically enhanced GDP dissociation from their cognate GTPases in vitro.
“As shown in Fig. 5, the DOCK2 and DOCK9 DHR-2 domains specifically enhanced GDP dissociation from their cognate GTPases (compare panel 6 with 1 and 2 with 7).”
Quote in the paperSubstantial claim - Findingown data
Rac2 GTPases with amino acid substitutions in switch 1 region are not responsive to DOCK9.
“As shown in Fig. 3C, Rac2 GTPases with amino acid substitutions in the switch 1 region were not responsive to DOCK9.”
Quote in the paperSubstantial claim - Findingown data
The R39C and C39R58C chimeras are severely defective for activation by DOCK2-ELMO1.
“Notably, the R39C and C39R58C chimeras were severely defective for activation by DOCK2-ELMO1 (compare lanes 2 and 5 with 1 and 6).”
Quote in the paperSubstantial claim - Findingown data
Rac2, but not Cdc42, is strongly activated by co-expression of DOCK2 and ELMO1 in HEK 293T cells.
“As shown in Fig. 2B, Rac2, but not Cdc42, was strongly activated by co-expression of DOCK2 and ELMO1.”
Quote in the paperSubstantial claim - Findingown data
The mutant GTPases formed readily detectable interactions with the DOCK9 DHR-2 domain in GST pull-down assays.
“Of note, the mutants formed readily detectable interactions with the DOCK9 DHR-2 domain in GST pull-down assays (data not shown).”
Quote in the paperSubstantial claim - Findingown data
Divergent residues in switch 1 regions of Rac2 and Cdc42 are also important for GTPase recognition by Rac-specific DOCK180, DOCK3, and DOCK4 GEFs.
“Significantly, these residues were also found to be important for GTPase recognition by Rac-specific DOCK180, DOCK3, and DOCK4 GEFs.”
Quote in the paperSubstantial claim - Findingown data
The other element comprises divergent residues in the β3 strand.
“The other element comprises divergent residues in the 3 strand”
Quote in the paperSubstantial claim - Findingown data
Two elements in the N-terminal regions of Rac2 and Cdc42 are essential for specific interactions with DOCK2 and DOCK9.
“Two elements in the N-terminal regions of Rac2 and Cdc42 were found to be essential for specific interactions with DOCK2 and DOCK9.”
Quote in the paperSubstantial claim - Findingown data
Additional Cdc42-to-Rac2 substitutions in the β2 strand and the loop connecting β2 and β3 allowed specific binding and activation of the mutant GTPase by DOCK2-ELMO1, but not DOCK9.
“Significantly, additional Cdc42-to-Rac2 substitutions in the 2 strand and the loop connecting the 2 and 3 strands allowed specific binding and activation of the mutant GTPase by DOCK2-ELMO1, but not DOCK9 (panels A-C, compare lanes 3 with 2 and 4 -9).”
Quote in the paperSubstantial claim - Findingown data
Rac2-to-Cdc42 substitution of Ala-27 or Gly-30 in switch 1, or Trp-56 in β3 strand, severely compromises the ability of Rac2 to precipitate DOCK2 and ELMO1.
“Rac2-to-Cdc42 substitution of alanine 27 (Ala-27) or glycine 30 (Gly-30), located in the N-proximal region of switch 1, or of tryptophan 56 (Trp-56), located in the 3 strand, severely compromised the ability of Rac2 to precipitate DOCK2 and ELMO1 (compare lanes 2, 3, and 7 with lane 1).”
Quote in the paperSubstantial claim - Findingown data
The reciprocal chimera C58R is not responsive to DOCK2-ELMO1.
“whereas the reciprocal chimera C58R was not responsive (compare lanes 7 with 6 and 8).”
Quote in the paperSubstantial claim - Findingown data
All four DHR-2 domains (DOCK180, DOCK2, DOCK3, and DOCK4) activated Rac2 without having a detectable effect on Cdc42.
“As shown in Fig. 8, all four DHR-2 domains activated Rac2 without having a detectable effect on Cdc42.”
Quote in the paperSubstantial claim - Findingown data
Substitutions of Val-51 and Asn-52 in β3 strand have little if any detectable effect on the ability of Rac2 to bind DOCK2-ELMO1.
“However, these changes had little if any detectable effect on the ability of Rac2 to bind DOCK2-ELMO1 (compare lanes 5 and 6 with lane 1).”
Quote in the paperSubstantial claim - Findingown data
Rac2-(W56F) and Rac2-(VN51YT,W56F) with changes in β3 strand are modestly activated by DOCK9 as well as by DOCK2-ELMO1.
“In contrast, Rac2-(W56F) and Rac2-(VN51YT,W56F) with changes in the 3 strand were modestly activated by DOCK9 as well as by DOCK2-ELMO1 (panels B and C, compare lanes 7 and 8 with 1 and 9).”
Quote in the paperSubstantial claim - Findingown data
Mutating both Ala-27 and Gly-30 in switch 1 renders Rac2 essentially unresponsive to DOCK2-ELMO1.
“Strikingly, mutating both Ala-27 and Gly-30 in the switch 1 region rendered Rac2 essentially unresponsive to DOCK2-ELMO1 (compare lane 4 with 1-3).”
Quote in the paperSubstantial claim - Findingown data
The specific binding of Rac2 and Cdc42 to their cognate CDM family GEFs is reproduced in pull-down assay.
“Thus, these data demonstrate that the specific binding of Rac2 and Cdc42 to their cognate CDM family GEFs is reproduced in pull-down assay.”
Quote in the paperSubstantial claim - Findingown data
The Rac2-(A27K,VN51YT,W56F) and other mutant Rac2 proteins, except those lacking W56F or A27K substitutions, were not detectably activated by DOCK2-ELMO1.
“The Rac2-(A27K,VN51YT,W56F) and other mutant Rac2 proteins, except those lacking the W56F or A27K substitutions, were not detectably activated by DOCK2-ELMO1 (compare lanes 2-6 with 1 and 7-9).”
Quote in the paperSubstantial claim - Findingown data
Rac2-(A27K,VN51YT) lacking the W56F change was not detectably activated by the DOCK9 DHR-2 domain.
“Notably, Rac2-(A27K,VN51YT) that lacked the W56F change was not detectably activated by the DOCK9 DHR-2 domain (panel 4), thus underscoring the crucial role of phenylalanine at position 56.”
Quote in the paperSubstantial claim - Findingown data
The R58C chimera is activated by DOCK2-ELMO1 to about 50% of the level seen with wild-type Rac2.
“Significantly, the R58C chimera was activated by DOCK2-ELMO1 to about 50% of the level seen with the wild-type Rac2 (histogram, compare lanes 6 with 1 and 8)”
Quote in the paperSubstantial claim - Findingown data
The negative effects of V51Y and N52T changes on Rac2 activation are more clearly seen when combined with W56F in Rac2-(VN51YT,W56F).
“The negative effects of the V51Y and N52T changes on Rac2 activation were more clearly seen when these substitutions were combined with the W56F change in Rac2-(VN51YT,W56F) (Fig. 3B histogram, compare lane 8 with 5-7).”
Quote in the paperNot a substantial claim - Findingown data
Chimeric proteins with Rac2 and Cdc42 sequences swapped at positions 39, such as C39R and R39C58R, are severely defective for activation by DOCK9.
“Interestingly, chimeric proteins with Rac2 and Cdc42 sequences swapped at positions 39, such as C39R and R39C58R, were severely defective for activation by DOCK9 (compare lanes 3 and 4 with 7 and 8).”
Quote in the paperSubstantial claim - Findingown data
One element consists of divergent amino acid residues in the switch 1 regions of the GTPases.
“One element consists of divergent amino acid residues in the switch 1 regions of the GTPases.”
Quote in the paperSubstantial claim - Findingown data
The reciprocal R58C chimera is severely defective for activation by DOCK9.
“In contrast, the reciprocal R58C chimera was severely defective for activation by DOCK9 (compare lanes 6 with 7 and 8).”
Quote in the paperSubstantial claim - Findingown data
Rac2-(W56F) was also activated by the DOCK2 DHR-2 domain.
“However, Rac2-(W56F) was also activated by the DOCK2 DHR-2 domain (panel 10), consistent with observations from activation assays in HEK 293T cells (see Figs. 3, B and C).”
Quote in the paperSubstantial claim - Findingown data
The W56F substitution alone allowed modest activation of the mutant Rac2-(W56F) GTPase by the DOCK9 DHR-2 domain.
“Indeed, the W56F substitution alone allowed a modest activation of the mutant Rac2-(W56F) GTPase by DOCK9 DHR-2 (panel 5).”
Quote in the paperSubstantial claim - Findingown data
Rac2-to-Cdc42 substitutions of four of these residues were sufficient for Rac2 to be specifically activated by DOCK9.
“Remarkably, Rac2-to-Cdc42 substitutions of four of these residues were sufficient for Rac2 to be specifically activated by DOCK9.”
Quote in the paperSubstantial claim - Findingown data
Individual Rac2-to-Cdc42 substitutions for Ala-27, Gly-30, or Trp-56 significantly diminish Rac2 activation by DOCK2-ELMO1.
“As shown in Fig. 3B, individual Rac2-to-Cdc42 substitutions for Ala-27, Gly-30, or Trp-56 significantly diminished Rac2 activation by DOCK2-ELMO1 (Fig. 3B, histogram, compare lanes 2, 3, and 7 with 1).”
Quote in the paperSubstantial claim - Findingown data
Wild-type GST-myc-Rac2 precipitates DOCK2 and ELMO1 but not DOCK9.
“As shown in Fig. 3A, wild-type GST-myc-Rac2 precipitated DOCK2 and ELMO1 but not DOCK9 (lane 1).”
Quote in the paperSubstantial claim - Findingown data
Rac2-to-Cdc42 substitution of Val-51 or Asn-52 in β3 region modestly decreases activation by DOCK2-ELMO1.
“Interestingly, Rac2-to-Cdc42 substitution of Val-51 or Asn-52 in the 3 region modestly decreased activation by DOCK2-ELMO1, even though neither of these changes detectably affected Rac2 binding to DOCK2-ELMO1 in pull-down assays (compare lanes 5 and 6 with 1; see Fig. 3A).”
Quote in the paperSubstantial claim - Interpretationown data
Divergent amino acid residues located in the 58-amino acid long N-proximal region of Rac2 are instrumental for activation by DOCK2-ELMO1.
“These observations suggested that divergent amino acid residues located in the 58-amino acid long N-proximal region of Rac2 are instrumental for activation by DOCK2-ELMO1.”
Quote in the paperSubstantial claim - Premisecitation
DOCK9 specifically activates Cdc42.
“Another distantly related subfamily of CDM GEFs includes DOCK9, also called Zizimin1, which specifically activates Cdc42.”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [35] Meller, 2002, Nat. Cell Biol. source
- Interpretationown data
DOCK2 and DOCK9 specifically recognize Rac2 and Cdc42 through their switch 1 as well as β2-β3 regions.
“Thus, DOCK2 and DOCK9 specifically recognize Rac2 and Cdc42 through their switch 1 as well as 2-3 regions”
Quote in the paperSubstantial claim - Interpretationown data
Divergent amino acids in the N-proximal 58 residues of Cdc42 are instrumental for its activation by DOCK9.
“These observations indicated that divergent amino acids in the N-proximal 58 residues of Cdc42 are instrumental for its activation by DOCK9.”
Quote in the paperSubstantial claim - Interpretationown data
These observations underscore the importance of the divergent amino acids in the switch 1 region for Rac recognition by DHR-2 GEFs.
“These observations underscore the importance of the divergent amino acids in the switch 1 region for Rac recognition by DHR-2 GEFs.”
Quote in the paperSubstantial claim - Interpretationown data
Divergent residues at positions 27 and 30 in switch 1 region and those at positions 51, 52, and 56 in β3 strand of Rac2 are critical for specific activation of Rac2 by DOCK2-ELMO1.
“These observations indicated that divergent residues at positions 27 and 30 in the switch 1 region and those at positions 51, 52, and 56 in the 3 strand of Rac2 are critical for the specific activation of Rac2 by DOCK2-ELMO1.”
Quote in the paperSubstantial claim - Interpretationreasoning
The mode of recognition via switch 1 appears to be conserved among diverse Rac-specific DHR-2 GEFs.
“and the mode of recognition via switch 1 appears to be conserved among diverse Rac-specific DHR-2 GEFs.”
Quote in the paperSubstantial claim - Interpretationown data
The combination of four Rac2-to-Cdc42 substitutions comprising A27K in switch 1 and VN51YT and W56F changes in β3 region appears optimal for activation of the GTPase by DOCK9.
“Thus the combination of four Rac2-to-Cdc42 substitutions comprising the A27K substitution in the switch 1 region and the VN51YT and W56F changes in the 3 region appeared to be optimal for activation of the GTPase by DOCK9 (panel B, compare lanes 4 -8 with 3).”
Quote in the paperSubstantial claim - Interpretationreasoning
The mutant GTPases probably still interacted with full-length DOCK9, albeit weakly.
“Thus, the mutant GTPases probably still interacted with the full-length DOCK9, albeit weakly.”
Quote in the paperNot a substantial claim - Interpretationown data
Four Rac2-to-Cdc42 substitutions at positions 27, 51, 52, and 56 are sufficient to direct specific activation of the mutant Rac2-(A27K,VN51YT,W56F) GTPase by DOCK9 but not DOCK2.
“In summary, we conclude that four Rac2-to-Cdc42 substitutions of divergent amino acid residues at position 27 in the switch 1 region and 51, 52, and 56 in the 3 sheet are sufficient to direct specific activation of the mutant Rac2-(A27K,VN51YT,W56F) GTPase by DOCK9 but not DOCK2.”
Quote in the paperSubstantial claim - Interpretationown data
Evidence from both in vitro and in vivo assays indicates that Cdc42-to-Rac2 substitutions in the N-proximal region of switch 1 and the β2-β3 region of Cdc42 allow specific activation by DOCK2 instead of DOCK9.
“Thus, evidence from both in vitro and in vivo assays indicates that Cdc42-to-Rac2 substitutions in the N-proximal region of switch 1 and the 2-3 region of Cdc42 allow specific activation by DOCK2 instead of DOCK9.”
Quote in the paperSubstantial claim - Interpretationown data
Divergent amino acid residues Ala-27 and Gly-30 in switch 1 region and Trp-56 in β3 strand of Rac2 are required for specific binding to DOCK2-ELMO1.
“We concluded that divergent amino acid residues Ala-27 and Gly-30 in the switch 1 region and Trp-56 in the 3 strand of Rac2 are required for specific binding to DOCK2-ELMO1.”
Quote in the paperSubstantial claim - Interpretationown data
The combination of Rac2-to-Cdc42 substitutions of residues Ala-27 in switch 1 and Val-51, Asn-52, and Trp-56 in β3 strand of Rac2 directs optimal and specific activation in vivo by DOCK9 instead of DOCK2-ELMO1.
“We concluded that the combination of Rac2-to-Cdc42 substitutions of residues Ala-27 in the switch 1 region and Val-51, Asn-52, and Trp-56 in the 3 strand of Rac2 directs optimal and specific activation in vivo by DOCK9 instead of DOCK2-ELMO1.”
Quote in the paperSubstantial claim - Interpretationown data
The finding that both DOCK2 and DOCK9 recognize their cognate GTPases via divergent amino acid residues in their switch 1 regions suggested that alanine 27 and glycine 30 play a larger role in specific recognition of Rac by DHR-2 GEFs.
“Our finding that both DOCK2 and DOCK9 recognize their cognate GTPases via divergent amino acid residues in their switch 1 regions suggested that alanine 27 and glycine 30 play a larger role in specific recognition of Rac by DHR-2 GEFs.”
Quote in the paperSubstantial claim - Interpretationown data
The mutant Cdc42 with combined substitutions probably retained a residual interaction with DOCK9 sufficient to catalyze nucleotide exchange, even though it was not readily detectable in GST pull-down assays.
“Thus, the mutant GTPase probably retained a residual interaction with the GEF that was sufficient to catalyze nucleotide exchange, even though it was not readily detectable in GST pull-down assays.”
Quote in the paperSubstantial claim - Interpretationown data
The W56F substitution in β3 strand of Rac2 allows modest activation by both DOCK9 and DOCK2-ELMO1 GEFs.
“We concluded that the W56F substitution in the 3 strand of Rac2 allows modest activation by both DOCK9 and DOCK2-ELMO1 GEFs.”
Quote in the paperSubstantial claim - Interpretationreasoning
CDM family GEFs and DH family GEFs use different elements to specifically recognize and activate cognate GTPases.
“These observations suggest that CDM family GEFs and DH family GEFs use different elements to specifically recognize and activate cognate GTPases.”
Quote in the paperSubstantial claim - Interpretationreasoning
CDM GEFs may influence the recruitment of specific downstream effectors by restricting their access to the cognate GTPase.
“also suggests that CDM GEFs may influence the recruitment of specific downstream effectors by restricting their access to the cognate GTPase.”
Quote in the paperNot a substantial claim - Interpretationreasoning
CDM/DHR-2 and DH domain GEFs use both common and distinct structural elements in Rac and Cdc42 to discriminate between the GTPases.
“Thus, CDM/DHR-2 and DH domain GEFs use both common and distinct structural elements in Rac and Cdc42 to discriminate between the GTPases.”
Quote in the paperSubstantial claim - Premisecitation
A Rac-to-Cdc42 substitution of tryptophan at position 56 of Rac1 with phenylalanine (W56F) allows Rac1-(W56F) to be specifically activated by the otherwise Cdc42-specific DH domain GEF ITSN1, but not the Rac-specific DH domain GEF Tiam1.
“This is best illustrated by the observation that a Rac-to-Cdc42 substitution of the tryptophan residue at position 56 of Rac1 with phenylalanine (W56F) allows Rac1-(W56F) to be specifically activated by the otherwise Cdc42specific DH domain GEF ITSN1, but not the Rac-specific DH domain GEF Tiam1 (48).”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [48] Karnoub, 2001, Nat. Struct. Biol. source
- Interpretationown data
Even though both DOCK9/DOCK2 and previously studied DH domain GEFs recognize GTPases through β3 strands, they probably do so differently.
“Even though both the DOCK9/DOCK2 and the previously studied DH domain GEFs recognize GTPases through their 3 strands, they probably do so differently.”
Quote in the paperSubstantial claim - Interpretationown data
Both DOCK9 and DOCK2 recognize cognate GTPases through their β3 strands.
“Similar to DH domain GEFs, our findings indicate that both DOCK9 and DOCK2 recognize cognate GTPases through their 3 strands.”
Quote in the paperSubstantial claim - Interpretationreasoning
This evidence and our findings together indicate that divergent amino acid residues at positions 27 and 30 in the switch 1 regions of Rac and Cdc42 can mediate functional interactions with both downstream effectors and upstream regulators.
“This evidence and our findings together indicate that the divergent amino acid residues at positions 27 and 30 in the switch 1 regions of Rac and Cdc42 can mediate functional interactions with both downstream effectors (e.g.p67 phox ) as well as upstream regulators (e.g.DOCK2 and DOCK9), and”
Quote in the paperSubstantial claim - Interpretationreasoning
DH and DHR-2 GEFs evolved to probe distinct regions to discriminate between small GTPases such as Rac and Cdc42.
“it seems that DH and DHR-2 GEFs evolved to probe distinct regions to discriminate between small GTPases such as Rac and Cdc42.”
Quote in the paperSubstantial claim- Rests on an assumption: Divergent residues at positions 27 and 30 in the switch 1 regions have not been implicated in specific recognition of these GTPases by any of the studied DH domain GEFs.
- Interpretationreasoning
Both CDM GEFs also recognize divergent residues in switch 1 regions, which are usually not utilized by DH family GEFs.
“In contrast, both CDM GEFs also recognize divergent residues in switch 1 regions, which are usually not utilized by DH family GEFs.”
Quote in the paperSubstantial claim
- Classified as probably not a substantial claim. 8
- May combine two claims. 16
Probably not a substantial claim: may not pass S3 (load-bearing).
PremisecitationDivergent amino acid residues in the β2-β3 regions of Rac and Cdc42 are the major determinants of specific interactions with DH-domain containing GEFs.
“These structural studies have also revealed that divergent amino acid residues in the 2-3 regions of Rac and Cdc42 are the major determinants of specific interactions with DH-domain containing GEFs (26 -29).”
Quote in the paperNot a substantial claim1 of 4 sources checked- cites [26] Aghazadeh, 1998, Nat. Struct. Biol. source
- cites [27] Didsbury, 1989, J. Biol. Chem. source
- cites [28] Rossman, 2002, EMBO J. source
The Structural overview and the section on the Dbs–Cdc42 interface describe contacts between Rho GTPases and DH-domain GEFs, including a comparison with Tiam1–Rac1. They do not identify divergent residues in the β2–β3 regions of Rac and Cdc42 as the major determinants of interaction specificity; the Structural overview instead notes a DH-domain region implicated in binding specificity. Page numbers were not available in our copy. (LLM, conf=0.81)
Experimental — accuracy not yet measured - cites [29] Worthylake, 2000, Nature source
Probably not a substantial claim: may not pass S3 (load-bearing).
PremisecitationThe physiological activation of Rac by DOCK2 and DOCK180 requires their association with a regulatory protein ELMO1.
“Interestingly, the physiological activation of Rac by these GEFs requires their association with a regulatory protein ELMO1 (Engulfment and Motility) (6,33,34).”
Quote in the paperNot a substantial claim2 of 3 sources checked- cites [6] Fukui, 2001, Nature source
- cites [33] Gumienny, 2001, Cell source
The Rac-GEF activity section reports that ELMO1 associates with Dock180 and increases Dock180-dependent Rac-GTP loading in transfected cells. It also reports Rac-GTP loading with Dock180 alone, so it does not establish that ELMO1 association is required for physiological activation. The CED-12/ELMO and CED-5/Dock180 Connection section says interaction between Dock-2 and ELMO proteins remains to be tested. (LLM, conf=0.90)
Experimental — accuracy not yet measured - cites [34] Sanui, 2003, Blood source
The Results and discussion section says DOCK2’s interaction with ELMO1 is required for Rac activation in the tested cells. The Introduction says ELMO1 associates with DOCK180 and cooperatively regulates Rac activation, but does not establish that the association is required for DOCK180. No page numbers are provided in our copy. (LLM, conf=0.85)
Experimental — accuracy not yet measured
Classified as probably not a substantial claim.
PremisecitationELMO1 enhances the ability of DOCK2 to activate Rac through binding to DOCK2 and thereby relieving the inhibition of its catalytic domain function.
“ELMO1 was included in these experiments because this protein was reported to enhance the ability of DOCK2 to activate Rac through binding to DOCK2 and thereby relieving the inhibition of its catalytic domain function (39).”
Quote in the paperSubstantial claim1 of 1 sources checked- cites [39] Lu, 2005, Curr. Biol. source
The paper reports that ELMO interaction with Dock2 enhanced binding to nucleotide-free Rac (p. 3), and its discussion includes Dock2 in a proposed steric-inhibition model (p. 6). But the direct demonstration that ELMO relieves inhibition and increases GEF activity is for Dock180, not Dock2; the claim states that mechanism for Dock2 more firmly than the paper establishes it. (LLM, conf=0.82)
Experimental — accuracy not yet measured
Classified as probably not a substantial claim.
PremisecitationPrevious structural and biochemical studies indicated that divergent amino acids at positions 27 and 30 in the switch 1 region of Rac are important for specific recognition and recruitment of its downstream effector p67phox.
“Moreover, previous structural and biochemical studies indicated that divergent amino acids at positions 27 and 30 in the switch 1 region of Rac are important for specific recognition and recruitment of its downstream effector p67 phox , a component of the NADPH oxidase (49,50).”
Quote in the paperSubstantial claim1 of 2 sources checkedMay combine two claims.
Premisecitationp67phox is not a downstream effector of wildtype Cdc42, but Cdc42-to-Rac substitutions at positions 27 and 30 (K27A and S30G) in Cdc42 allow p67phox to serve as an effector of the resulting mutant Cdc42.
“p67 phox is not a downstream effector of wildtype Cdc42, however, Cdc42-to-Rac substitutions at positions 27 and 30 (K27A and S30G) in Cdc42 allows p67 phox to serve as an effector of the resulting mutant Cdc42 (49,50).”
Quote in the paperSubstantial claim1 of 2 sources checkedClassified as probably not a substantial claim.
Findingnone givenThe catalytic DHR-2 domains of DOCK2 and DOCK9 share 19% amino acid identity.
“The amino acid sequences of the catalytic DHR-2 domains of DOCK2 and DOCK9 share 19% amino acid identity.”
Quote in the paperSubstantial claimMay combine two claims.
Findingown dataCombined Cdc42-to-Rac2 substitutions at positions 27, 30, 51, 52, and 56 disrupted the ability of Cdc42 to bind DOCK9 in pull-down assays but did not totally abolish its ability to be activated by DOCK9.
“As shown in Fig. 6, the combined changes disrupted the ability of Cdc42 to bind DOCK9 in pull-down assays but did not totally abolish the ability to be activated by this GEF (panels A and B, for example, compare 2 with 1 and 10).”
Quote in the paperSubstantial claimMay combine two claims.
Findingown dataWild-type GST-myc-Cdc42 precipitates DOCK9 but not DOCK2 or ELMO1.
“Conversely, wild-type GST-myc-Cdc42 precipitated DOCK9 but not DOCK2 or ELMO1 (compare lanes 1 and 10).”
Quote in the paperSubstantial claimMay combine two claims.
Findingown dataThe DOCK2 DHR-2 domain modestly enhanced GDP dissociation from Cdc42-(C3R), whereas this effect was not seen with the DOCK9 DHR-2 domain.
“As shown in Fig. 7, the DOCK2 DHR-2 domain modestly enhanced GDP dissociation from Cdc42-(C 3 R) (panel 3), whereas this effect was not seen with the DOCK9 DHR-2 domain (panel 6).”
Quote in the paperSubstantial claimMay combine two claims.
Findingown dataDOCK9 specifically activates Cdc42 but not Rac2 in HEK 293T cells.
“Thus the ability of DOCK9 to specifically activate Cdc42 was reproduced in a transient expression assay in HEK 293T cells.”
Quote in the paperSubstantial claimMay combine two claims.
Findingown dataA mutant Rac2 protein bearing Rac2-to-Cdc42 substitutions of all five divergent amino acid residues important for activation by DOCK2-ELMO1 is activated by DOCK9 to ~30% of wild-type Cdc42 level, even though it is unable to form stable complex with DOCK9 in pull-down assays.
“As shown in Fig. 4, the mutant GTPase was activated by DOCK9 to ϳ30% of the level seen with the wildtype Cdc42, even though it was unable to form a stable complex with DOCK9 in pull-down assays (panels A and B, compare lanes 2 with 9).”
Quote in the paperSubstantial claimMay combine two claims.
Findingown dataThe DOCK9 DHR-2 domain accelerated GDP dissociation from Rac2-(A27K,VN51YT,W56F), whereas the DOCK2 DHR-2 domain did not.
“As expected, the dissociation of GDP from Rac2-(A27K,VN51YT,W56F) was accelerated in the presence of the DOCK9 DHR-2 domain, whereas the DOCK2 DHR-2 domain did not have such an effect (compare panel 3 with 8).”
Quote in the paperSubstantial claimMay combine two claims.
Findingown dataAmino acid changes at positions 27, 30, 51, 52, and 56 allowed weak activation of the mutant Cdc42 by DOCK2-ELMO1, whereas the GTPase was unable to form a stable complex with this GEF in pull-down assay.
“As shown in Fig. 6, amino acid changes at positions 27, 30, 51, 52, and 56 allowed a weak activation of the mutant Cdc42 by DOCK2-ELMO1, whereas the GTPase was unable to form a stable complex with this GEF in pull-down assay (panels A and C, compare lanes 2 with 1 and 10).”
Quote in the paperSubstantial claimMay combine two claims.
Findingown dataSubstitutions at all four divergent N-proximal positions (3, 27, 30, and 33) rendered the GTPase almost completely unresponsive to DOCK180, DOCK2, and DOCK3, and only somewhat responsive to DOCK4.
“Notably, substitutions at all four divergent N-proximal positions rendered the GTPase almost completely unresponsive to DOCK180, DOCK2, and DOCK3, and only somewhat responsive to DOCK4.”
Quote in the paperSubstantial claimMay combine two claims.
Findingown dataRestoration of Rac2-specific alanine 27 and glycine 30 residues in switch 1 restored to a large degree activation by DOCK180, DOCK2, and DOCK3 and enhanced activation by DOCK4 to a level seen with wild type Rac2.
“Furthermore, restoration of Rac2-specific alanine 27 and glycine 30 residues in switch 1 restored to a large degree activation by DOCK180, DOCK2, and DOCK3 and enhanced the activation by DOCK4 to a level seen with wild type Rac2 (compare lanes 3 with 2).”
Quote in the paperSubstantial claimMay combine two claims.
Findingown dataOmitting the G30A substitution results in a modest increase in both binding to and activation by DOCK9.
“Unexpectedly, we found that omitting the G30A substitution resulted in a modest increase in both binding to and activation by DOCK9 (panels A and B, compare lane 3 with 2 and 9).”
Quote in the paperSubstantial claimMay combine two claims.
PremisecitationDOCK2 activates Rac but not Cdc42, whereas DOCK9 activates Cdc42 but not Rac.
“DOCK2 activates Rac but not Cdc42, whereas DOCK9 activates Cdc42 but not Rac (6,35,38).”
Quote in the paperSubstantial claim0 of 3 sources checkedClassified as probably not a substantial claim.
PremisecitationPrevious studies have revealed that DH domain GEFs discriminate between Rac and Cdc42 based on their β2 and β3 strands.
“Previous studies have revealed that DH domain GEFs discriminate between Rac and Cdc42 based on their 2 and 3 strands (45,46).”
Quote in the paperSubstantial claim0 of 2 sources checkedClassified as probably not a substantial claim. May combine two claims.
PremisecitationGEFs contribute to the specificity of Rho GTPase signaling by recognizing cognate GTPases and coupling GTPase activation to downstream signaling pathways.
“GEFs contribute to the specificity of Rho GTPase signaling by recognizing cognate GTPases and coupling GTPase activation to downstream signaling pathways (16,18,19,21,(42)(43)(44).”
Quote in the paperSubstantial claim0 of 1 sources checked- cites 16,18,19,21,(42)(43)(44)
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.
Study design and conductown dataThe in vitro GDP dissociation experiments shown in Figures 5 and 7 were performed at least twice, with a representative experiment shown.
“A representative of two independent experiments is shown.”
- Also stated in: § DISCUSSION · plain
“A representative of two independent experiments is shown.”
Quote in the paperNot a substantial claim- Also stated in: § DISCUSSION · plain
May combine two claims.
Interpretationown dataOur observations indicate that whereas hydrophobic residues at positions 56 are also important for recognition of the GTPases by DOCK2 and DOCK9, they are not sufficient to allow these GEFs to fully discriminate between Rac and Cdc42.
“In contrast, our observations indicate that whereas the hydrophobic residues at positions 56 are also important for the recognition of the GTPases by DOCK2 and DOCK9, they are not sufficient to allow these GEFs to fully discriminate between Rac and Cdc42.”
Quote in the paperSubstantial claimMay combine two claims.
Interpretationown dataThe switch 1 region is important for the recognition of Rac by diverse Rac-specific DHR-2 GEFs and Cdc42 by DOCK9.
“Our observations indicate that the switch 1 region is important for the recognition of Rac by diverse Rac-specific DHR-2 GEFs and Cdc42 by DOCK9.”
Quote in the paperSubstantial claim
The paper relies on this without support.
No information regarding elements in Rac and Cdc42 that mediate specific interactions with CDM GEFs is available.
“To date, no information regarding elements in Rac and Cdc42 that mediate specific interactions with CDM GEFs is available.”
The paper relies on this without support.
The same residues in switch 1 were shown previously to interact with GTPase effectors rather than GEFs.
“These findings were unexpected because the same residues were shown previously to interact with GTPase effectors rather than GEFs.”
The paper relies on this without support.
Divergent residues at positions 27 and 30 in the switch 1 regions have not been implicated in specific recognition of these GTPases by any of the studied DH domain GEFs.
“Since the divergent residues at positions 27 and 30 in the switch 1 regions have not been implicated in specific recognition of these GTPases by any of the studied DH domain GEFs”
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
Each contradiction between two passages listed here was confirmed by an independent check.
G30A conflicts with the stated Rac2-to-Cdc42 substitution
MinorThe omitted Rac2-to-Cdc42 change at position 30 is called G30A, but the paper identifies the corresponding Cdc42 residue as serine and elsewhere denotes the Rac2 change G30S.
“omitting the G30A substitution resulted in a modest increase in both binding to and activation by DOCK9”
“Rac2-(A3T,A27K,G30S,I33V)”
Figure 8 substitutions are described in the wrong direction
MinorThe text calls A27K and G30S in a Rac2 variant Cdc42-to-Rac2 substitutions, but elsewhere identifies changes at those Rac2 positions as Rac2-to-Cdc42 substitutions.
“Rac-(A3T,A27K,G30S,I33V) variant with Cdc42-to-Rac2 amino acid substitutions at positions 3, 27, 30, and 33”
“Rac2-to-Cdc42 substitution of alanine 27 (Ala-27) or glycine 30 (Gly-30)”
Cites
RHO GTPASES: Biochemistry and Biology
Jaffe, A. B., & Hall, A. (2005) · Annual Review of Cell and Developmental Biology · doi:10.1146/annurev.cellbio.21.020604.150721 · Cited by 3,009 · see citing works
Rho GTPases and signaling networksPreprint
Aelst, L. V., & D’Souza‐Schorey, C. (1997) · Genes & Development · doi:10.1101/gad.11.18.2295 · Cited by 2,358 · see citing works
The Guanine Nucleotide-Binding Switch in Three Dimensions
Vetter, I. R., & Wittinghofer, A. (2001) · Science · doi:10.1126/science.1062023 · Cited by 1,875 · see citing works
GEF means go: turning on RHO GTPases with guanine nucleotide-exchange factors
Rossman, K. L., Der, C. J., & Sondek, J. (2005) · Nature Reviews Molecular Cell Biology · doi:10.1038/nrm1587 · Cited by 1,697 · see citing works
Guanine nucleotide exchange factors for Rho GTPases: turning on the switchPreprint
Schmidt, A., & Hall, A. (2002) · Genes & Development · doi:10.1101/gad.1003302 · Cited by 1,235 · see citing works
Rho GTPases and cell migration
Ridley, A. J. (2001) · Journal of Cell Science · doi:10.1242/jcs.114.15.2713 · Cited by 1,194 · see citing works
An Essential Role for Rho, Rac, and Cdc42 GTPases in Cell Cycle Progression Through G 1
Olson, M. F., Ashworth, A., & Hall, A. (1995) · Science · doi:10.1126/science.7652575 · Cited by 1,148 · see citing works
Rho-family GTPases: it's not only Rac and Rho (and I like it)
Wennerberg, K., & Der, C. J. (2004) · Journal of Cell Science · doi:10.1242/jcs.01118 · Cited by 615 · see citing works
Unconventional Rac-GEF activity is mediated through the Dock180–ELMO complex
Brugnera, E., Haney, L., Grimsley, C., Lu, M., Walk, S. F., Tosello-Trampont, A.-C., Macara, I. G., Madhani, H., Fink, G. R., & Ravichandran, K. S. (2002) · Nature Cell Biology · doi:10.1038/ncb824 · Cited by 576 · see citing works
rac, a novel ras-related family of proteins that are botulinum toxin substrates
Didsbury, J., Weber, R. F., Bokoch, G. M., Evans, T., & Snyderman, R. (1989) · Journal of Biological Chemistry · doi:10.1016/s0021-9258(19)84716-6 · Cited by 575 · see citing works
Gumienny, T. L., Brugnera, E., Tosello-Trampont, A.-C., Kinchen, J. M., Haney, L. B., Nishiwaki, K., Walk, S. F., Nemergut, M. E., Macara, I. G., Francis, R., et al. (2001) · Cell · doi:10.1016/s0092-8674(01)00520-7 · Cited by 568 · see citing works
Cerione, R. A., & Zheng, Y. (1996) · Current Opinion in Cell Biology · doi:10.1016/s0955-0674(96)80068-8 · Cited by 492 · see citing works
Haematopoietic cell-specific CDM family protein DOCK2 is essential for lymphocyte migration
Fukui, Y., Hashimoto, O., Sanui, T., Oono, T., Koga, H., Abe, M., Inayoshi, A., Noda, M., Oike, M., Shirai, T., et al. (2001) · Nature · doi:10.1038/35090591 · Cited by 449 · see citing works
Westwick, J. K., Lambert, Q. T., Clark, G. J., Symons, M. H., Aelst, L. V., Pestell, R. G., & Der, C. J. (1997) · Molecular and Cellular Biology · doi:10.1128/mcb.17.3.1324 · Cited by 436 · see citing works
Côté, J., & Vuori, K. (2002) · Journal of Cell Science · doi:10.1242/jcs.00219 · Cited by 412 · see citing works
αvβ5 integrin recruits the CrkII–Dock180–Rac1 complex for phagocytosis of apoptotic cells
Albert, M. L., Kim, J.-I., & Birge, R. B. (2000) · Nature Cell Biology · doi:10.1038/35046549 · Cited by 377 · see citing works
Directional Sensing Requires Gβγ-Mediated PAK1 and PIXα-Dependent Activation of Cdc42
Li, Z. A., Hannigan, M. O., Mo, Z., Liu, B., Lü, W., Wu, Y., Smrcka, A. V., Wu, G., Li, L., Liu, M., et al. (2003) · Cell · doi:10.1016/s0092-8674(03)00559-2 · Cited by 373 · see citing works
Crystal structure of Rac1 in complex with the guanine nucleotide exchange region of Tiam1
Worthylake, D. K., Rossman, K. L., & Sondek, J. (2000) · Nature · doi:10.1038/35047014 · Cited by 355 · see citing works
Williams, D., Tao, W., Yang, F., Kim, C., Gu, Y., Mansfield, P. J., Levine, J. E., Petryniak, B., Derrow, C. W., Harris, C., et al. (2000) · PubMed · Cited by 334 · see citing works
Structure of the TPR Domain of p67phox in Complex with Rac·GTP
Lapouge, K., Smith, S. J. M., Walker, P. A., Gamblin, S. J., Smerdon, S. J., & Rittinger, K. (2000) · Molecular Cell · doi:10.1016/s1097-2765(05)00091-2 · Cited by 311 · see citing works
Regulation of innate immunity by Rho GTPases
Bokoch, G. (2005) · Trends in Cell Biology · doi:10.1016/j.tcb.2005.01.002 · Cited by 295 · see citing works
CZH proteins: a new family of Rho-GEFs
Meller, N., Merlot, S., & Guda, C. (2005) · Journal of Cell Science · doi:10.1242/jcs.02671 · Cited by 273 · see citing works
Differential Requirements for DOCK2 and Phosphoinositide-3-Kinase γ during T and B Lymphocyte Homing
Nombela‐Arrieta, C., Lacalle, R. A., Montoya, M. C., Kunisaki, Y., Megı́as, D., Marqués, M., Carrera, A. C., Mañes, S., Fukui, Y., Martínez‐A, C., et al. (2004) · Immunity · doi:10.1016/j.immuni.2004.07.012 · Cited by 224 · see citing works
Rossman, K. L., Worthylake, D. K., Snyder, J. T., Siderovski, D. P., Campbell, S. L., & Sondek, J. (2002) · The EMBO Journal · doi:10.1093/emboj/21.6.1315 · Cited by 222 · see citing works
Structural basis for the selective activation of Rho GTPases by Dbl exchange factors
Snyder, J. T., Worthylake, D. K., Rossman, K. L., Betts, L., Pruitt, W. M., Siderovski, D. P., Der, C. J., & Sondek, J. (2002) · Nature Structural Biology · doi:10.1038/nsb796 · Cited by 209 · see citing works
The Rac Activator DOCK7 Regulates Neuronal Polarity through Local Phosphorylation of Stathmin/Op18
Watabe-Uchida, M., John, K. A., Janas, J. A., Newey, S. E., & Van Aelst, L. (2006) · Neuron · doi:10.1016/j.neuron.2006.07.020 · Cited by 208 · see citing works
Buchsbaum, R. J., Connolly, B. A., & Feig, L. A. (2002) · Molecular and Cellular Biology · doi:10.1128/mcb.22.12.4073-4085.2002 · Cited by 198 · see citing works
Zizimin1, a novel Cdc42 activator, reveals a new GEF domain for Rho proteins
Meller, N., Irani-Tehrani, M., Kiosses, W. B., Del Pozo, M. A., & Schwartz, M. A. (2002) · Nature Cell Biology · doi:10.1038/ncb835 · Cited by 171 · see citing works
Activation of Rac1 by RhoG regulates cell migration
Katoh, H., Hiramoto, K., & Negishi, M. (2005) · Journal of Cell Science · doi:10.1242/jcs.02720 · Cited by 171 · see citing works
Multiple roles for Cdc42 in cell regulation
Erickson, J. W., & Cerione, R. A. (2001) · Current Opinion in Cell Biology · doi:10.1016/s0955-0674(00)00192-7 · Cited by 168 · see citing works
García‐Mata, R., & Burridge, K. (2006) · Trends in Cell Biology · doi:10.1016/j.tcb.2006.11.004 · Cited by 166 · see citing works
Rho GTPases as Targets of Bacterial Protein Toxins
Aktories, K., Schmidt, G., & Just, I. (2000) · Biological Chemistry · doi:10.1515/bc.2000.054 · Cited by 161 · see citing works
Structure and mutagenesis of the Dbl homology domain
Aghazadeh, B., Zhu, K., Kubiseski, T. J., Liu, G. A., Pawson, T., Zheng, Y., & Rosen, M. K. (1998) · Nature Structural Biology · doi:10.1038/4209 · Cited by 145 · see citing works
Signaling to the Rho GTPases: networking with the DH domain
Hoffman, G. R., & Cerione, R. A. (2002) · FEBS Letters · doi:10.1016/s0014-5793(01)03310-5 · Cited by 137 · see citing works
HIV-1 Nef Binds the DOCK2–ELMO1 Complex to Activate Rac and Inhibit Lymphocyte Chemotaxis
Janardhan, A. H., Swigut, T., Hill, B. T., Myers, M. P., & Skowroński, J. (2004) · PLoS Biology · doi:10.1371/journal.pbio.0020006 · Cited by 123 · see citing works
DOCK2 regulates Rac activation and cytoskeletal reorganization through interaction with ELMO1
Sanui, T., Inayoshi, A., Noda, M., Iwata, E., Stein, J. V., Sasazuki, T., & Fukui, Y. (2003) · Blood · doi:10.1182/blood-2003-01-0173 · Cited by 120 · see citing works
Erickson, J. W., & Cerione, R. A. (2003) · Biochemistry · doi:10.1021/bi036026v · Cited by 118 · see citing works
Buchsbaum, R. J., Connolly, B. A., & Feig, L. A. (2003) · Journal of Biological Chemistry · doi:10.1074/jbc.m207876200 · Cited by 117 · see citing works
Trp56 of Rac1 Specifies Interaction with a Subset of Guanine Nucleotide Exchange Factors
Gao, Y., Xing, J., Streuli, M., Leto, T. L., & Zheng, Y. (2001) · Journal of Biological Chemistry · doi:10.1074/jbc.m108865200 · Cited by 115 · see citing works
A Steric-Inhibition Model for Regulation of Nucleotide Exchange via the Dock180 Family of GEFs
Lu, M., Kinchen, J. M., Rossman, K. L., Grimsley, C., Hall, M., Sondek, J., Hengartner, M. O., Yajnik, V., & Ravichandran, K. S. (2005) · Current Biology · doi:10.1016/j.cub.2005.01.050 · Cited by 102 · see citing works
Molecular basis for Rac1 recognition by guanine nucleotide exchange factors.
(2001) · Nature Structural Biology · doi:10.1038/nsb719 · Cited by 93 · see citing works
Dock4 is regulated by RhoG and promotes Rac-dependent cell migration
Hiramoto, K., Negishi, M., & Katoh, H. (2006) · Experimental Cell Research · doi:10.1016/j.yexcr.2006.09.006 · Cited by 92 · see citing works
MOCA Induces Membrane Spreading by Activating Rac1
Namekata, K., Enokido, Y., Iwasawa, K., & Kimura, H. (2004) · Journal of Biological Chemistry · doi:10.1074/jbc.m311275200 · Cited by 84 · see citing works
Characterization of the Effector-specifying Domain of Rac Involved in NADPH Oxidase Activation
Kwong, C. H., Adams, A. G., & Leto, T. L. (1995) · Journal of Biological Chemistry · doi:10.1074/jbc.270.34.19868 · Cited by 76 · see citing works
Li, R., & Zheng, Y. (1997) · Journal of Biological Chemistry · doi:10.1074/jbc.272.8.4671 · Cited by 67 · see citing works
Horiguchi, Y. (2001) · Toxicon · doi:10.1016/s0041-0101(01)00149-0 · Cited by 55 · see citing works
In Vitro Guanine Nucleotide Exchange Activity of DHR‐2/DOCKER/CZH2 Domains
Côté, J., & Vuori, K. (2006) · Methods in Enzymology · doi:10.1016/s0076-6879(06)06004-6 · Cited by 45 · see citing works
Swigut, T., Greenberg, M. E., & Skowroński, J. (2003) · Journal of Virology · doi:10.1128/jvi.77.14.8116-8126.2003 · Cited by 42 · see citing works
García‐Bernal, D., Sotillo-Mallo, E., Nombela‐Arrieta, C., Samaniego, R., Fukui, Y., Stein, J. V., & Teixidó, J. (2006) · The Journal of Immunology · doi:10.4049/jimmunol.177.8.5215 · Cited by 41 · see citing works
DOCK2 mediates T cell receptor-induced activation of Rac2 and IL-2 transcription
Nishihara, H., Maeda, M., Tsuda, M., Makino, Y., Sawa, H., Nagashima, K., & Tanaka, S. (2002) · Biochemical and Biophysical Research Communications · doi:10.1016/s0006-291x(02)00931-2 · Cited by 33 · see citing works
Flagged first, then by citations
Research works printed but not linked: 2
- Colicelli, 2004, Sci. STKE, 250, RE13
- Williams, 2000, Blood, 96, 1646
Cited by
Sorted by citations
The Genetic and Environmental Factors for Keratoconus
Gordon‐Shaag, A., Millodot, M., Shneor, E., & Liu, Y. (2015) · BioMed Research International · doi:10.1155/2015/795738 · Cited by 430 · see citing works
“Mutation screening of 8 candidate genes in this region identified a potential mutation c.2262A>C (p. Gln754His) in DOCK9 (dedicator of cytokinesis 9) in a large EcuadorianKC family [91].DOCK9 (OMIM607325) encodes a member of the DOCK protein family with GTP/GDP exchange factor activity that specifically activates G-pr…”
BackgroundCellular signaling for activation of Rho GTPase Cdc42
Sinha, S., & Yang, W. (2008) · Cellular Signalling · doi:10.1016/j.cellsig.2008.05.002 · Cited by 133 · see citing works
Kulkarni, K., Yang, J., Zhang, Z., & Barford, D. (2011) · Journal of Biological Chemistry · doi:10.1074/jbc.m111.236455 · Cited by 97 · see citing works
Lemos, M., Chiaia, H., Berton, M. P., Feitosa, F., Aboujaoud, C., Camargo, G. M., Pereira, A. S. C., Albuquerque, L., Ferrinho, A., Mueller, L., et al. (2016) · BMC Genomics · doi:10.1186/s12864-016-2511-y · Cited by 78 · see citing works
“This gene is associated with production of kinase protein, enzymes that catalyze the phosphorylation of proteins by transferring one phosphoryl group of ATP and in exceptional cases, from GTP to threonine, serine (Ser/Thr specific kinase) or tyrosine residues (Tyr specific kinase) [39].”
BackgroundThe Genetics of Keratoconus: A Review
Hauser, J. W. M. A. (2012) · Reproductive System & Sexual Disorders · doi:10.4172/2161-038x.s6-001 · Cited by 90 · see citing works
“DOCK9 (Dedicator of Cytokinesis 9) DOCK9 (Dedicator of cytokinesis 9) (OMIM 607325) encodes a member of the DOCK protein family that possesses GTP/GDP exchange factor activity and specifically activates G-protein CDC42 [66].”
BackgroundCzugala, M., Karolak, J. A., Nowak-Malczewska, D. M., et al. (2011) · European Journal of Human Genetics · doi:10.1038/ejhg.2011.203 · Cited by 83 · see citing works
Carrascal, M., Ovelleiro, D., Casas, V., Gay, M., & Abián, J. (2008) · Journal of Proteome Research · doi:10.1021/pr800500r · Cited by 73 · see citing works
Genomic strategies to understand causes of keratoconus
Karolak, J. A., & Gajęcka, M. (2016) · Molecular Genetics and Genomics · doi:10.1007/s00438-016-1283-z · Cited by 63 · see citing works
Primary immunodeficiencies caused by mutations in actin regulatory proteins
Janssen, E., & Geha, R. S. (2018) · Immunological Reviews · doi:10.1111/imr.12716 · Cited by 52 · see citing works
Karolak, J. A., Polakowski, P., Szaflik, J., et al. (2014) · Ophthalmic Genetics · doi:10.3109/13816810.2014.926375 · Cited by 43 · see citing works
“One of the newest candidate genes for KTCN is DOCK9, which encodes a member of the DOCK protein family that possesses guanosine triphosphate/guanosine diphosphate (GTP/GDP) exchange factor activity and specifically activates G-protein CDC42 involved in intracellular signaling networks.(47) The DOCK9 gene is localized…”
BackgroundVariant c.2262A>C inDOCK9Leads to Exon Skipping in Keratoconus Family
Karolak, J. A., Rydzanicz, M., Ginter-Matuszewska, B., et al. (2015) · Investigative Ophthalmology & Visual Science · doi:10.1167/iovs.15-17538 · Cited by 42 · see citing works
Dedicator of Cytokinesis 2 in Cell Signaling Regulation and Disease Development
Guo, X., & Chen, S. (2016) · Journal of Cellular Physiology · doi:10.1002/jcp.25512 · Cited by 40 · see citing works
Wu, M. H., Li, L., Hamaker, M. C., Small, D., & Duffield, A. S. (2019) · Haematologica · doi:10.3324/haematol.2018.208843 · Cited by 35 · see citing works
“FLT3 interacts with Dedicator of Cytokinesis 2 (DOCK2), which is a guanine nucleotide exchange factor for Rac1 and Rac2.(7-10) Rac1 is widely expressed and”
BackgroundPrenylation and Membrane Localization of Cdc42 Are Essential for Activation by DOCK7
Zhou, Y., Johnson, J. L., Cerione, R. A., & Erickson, J. W. (2013) · Biochemistry · doi:10.1021/bi301688g · Cited by 34 · see citing works
Rac-maninoff and Rho-vel: The symphony of Rho-GTPase signaling at excitatory synapses
Duman, J. G., Blanco, F. A., Cronkite, C. A., Ru, Q., Erikson, K., Mulherkar, S. A., Saifullah, A. B., Firozi, K., & Tolias, K. F. (2021) · Small GTPases · doi:10.1080/21541248.2021.1885264 · Cited by 33 · see citing works
“Besides RhoG/Rac1 and RhoA GEF tandems, endothelia possess a DOCK4/ DOCK9 complex [112], whose members possess Rac1[112] and Cdc42- [113] GEF domains, respectively.”
InfluentialKukimoto‐Niino, M., Ihara, K., Murayama, K., & Shirouzu, M. (2021) · Current Opinion in Structural Biology · doi:10.1016/j.sbi.2021.08.001 · Cited by 26 · see citing works
Structural Basis for the Dual Substrate Specificity of DOCK7 Guanine Nucleotide Exchange Factor
Kukimoto-Niino, M., Tsuda, K., Ihara, K., Mishima-Tsumagari, C., Honda, K., Ohsawa, N., & Shirouzu, M. (2019) · Structure · doi:10.1016/j.str.2019.02.001 · Cited by 25 · see citing works
Wang, Y., Huang, L., Li, D., Shao, J., Xiong, S., Wang, C., & Lu, S. (2017) · PubMed Central · Cited by 21 · see citing works
Mahankali, M., Henkels, K. M., Alter, G. M., et al. (2012) · Journal of Biological Chemistry · doi:10.1074/jbc.m112.383596 · Cited by 21 · see citing works
Mutation in GNE Downregulates Peroxiredoxin IV Altering ER Redox Homeostasis
Chanana, P., Padhy, G., Bhargava, K., & Arya, R. (2017) · NeuroMolecular Medicine · doi:10.1007/s12017-017-8467-5 · Cited by 20 · see citing works
Sampson, C. J., Valanne, S., Fauvarque, M., Hultmark, D., Rämet, M., & Williams, M. J. (2012) · Developmental & Comparative Immunology · doi:10.1016/j.dci.2012.05.004 · Cited by 19 · see citing works
García, M. J. A., Ruiz-Lafuente, N., Sebastián-Ruiz, S., Majado, M. J., González‐García, C., Bernardo, M. V., López-Álvarez, M. R., & Parrado, A. (2011) · Human Immunology · doi:10.1016/j.humimm.2011.03.024 · Cited by 17 · see citing works
Biochemical and cellular implications of a dual lipase-GEF function of phospholipase D2 (PLD2)
Gómez-Cambronero, J. (2012) · Journal of Leukocyte Biology · doi:10.1189/jlb.0212073 · Cited by 13 · see citing works
“More than one family of RhoGEFs have been identified, namely the Dbl family and the CDM/DOCK180-related family [30].”
BackgroundA Minimal Rac Activation Domain in the Unconventional Guanine Nucleotide Exchange Factor Dock180
Wu, X., Ramachandran, S., Lin, M.-C. J., Cerione, R. A., & Erickson, J. W. (2010) · Biochemistry · doi:10.1021/bi100971y · Cited by 11 · see citing works
“In addition, whether Trp(56) of Rac is equally critical forDock180 recognition is controversial, as it has been reported that the W56F mutant of Rac can still interact with theDHR-2 domain ofDock180 (19) as well as being partially activated by the DHR-2 domain of Dock2 (42).”
BackgroundHe, J., Antonyan, L., Zhu, H., Ardila, K., Li, Q., Enoma, D., Zhang, W., Liu, A., Chekouo, T., Cao, B., et al. (2023) · The American Journal of Human Genetics · doi:10.1016/j.ajhg.2023.11.006 · Cited by 11 · see citing works
Guo, Y., Ma, X., Wu, W., et al. (2017) · International Journal of Molecular Medicine · doi:10.3892/ijmm.2017.3304 · Cited by 7 · see citing works
“DOCK9 (OMIM 607325) encodes a DOCK protein family member that has GTP/GDP exchange factor activity and specifically activates G-protein cell division control protein 42 homolog (40).”
Zhang, B., Zhong, X., Sauane, M., Zhao, Y., & Zheng, Z. (2020) · Cells · doi:10.3390/cells9030621 · Cited by 7 · see citing works
Modification of the rat airway explant transcriptome by cigarette smoke
López-Boado, Y. S., Li, J. U., Clayton, C. L., et al. (2009) · Inhalation Toxicology · doi:10.3109/08958370903191437 · Cited by 7 · see citing works
“…5730590G19 gene Slc2a4 −4.99 1.59E-06 solute carrier family 2 (facilitated glucose transporter), member 4 Gdpd2 −4.97 6.00E-08 glycerophosphodiester phosphodiesterase domain containing 2 LOC364648 −4.90 1.40E-07 Shc SH2-domain binding protein 1 by the small GTPase Cdc42 (Kwofie & Skowronski, 2008).”
BackgroundInfluentialStructure analysis between the SWAP-70 RHO-GEF and the newly described PLD2-GEF
Gómez-Cambronero, J. (2012) · Small GTPases · doi:10.4161/sgtp.20887 · Cited by 6 · see citing works
“Since each mediates signaling of membrane ruffling and actin cytoskeletal architectural remodeling, these the DH domain of these two RHOGEFs.”
InfluentialHu, B., Symons, M. H., Salhia, B., Ensign, S. P. F., Tran, N. L., Rutka, J. T., & Cheng, S. (2011) · Springer eBooks · doi:10.1007/978-94-007-2558-4_6 · Cited by 3 · see citing works
Structural basis for the dual GTPase specificity of the DOCK10 guanine nucleotide exchange factor
Kukimoto‐Niino, M., Ihara, K., Mishima-Tsumagari, C., Inoue, M., Fukui, Y., Yokoyama, S., & Shirouzu, M. (2023) · Biochemical and Biophysical Research Communications · doi:10.1016/j.bbrc.2023.02.054 · Cited by 1 · see citing works
Hamel, B. (2019) · Carolina Digital Repository (University of North Carolina at Chapel Hill) · doi:10.17615/kmq6-qg97 · Cited by 1 · see citing works
The Dock Family of Atypical Guanine Nucleotide Exchange Factors: Regulation by ELMO1 and RhoG
Holley, C. P. (2019) · Carolina Digital Repository (University of North Carolina at Chapel Hill) · doi:10.17615/m95n-qm88
Genetic aspects of keratoconus development
Bikbov, M. M., Usubov, E. L., Oganisyan, K. K., Lobov, S. L., Khasanova, R. R., Dzhemileva, L. U., & Хуснутдинова, Э. К. (2017) · Russian Journal of Genetics · doi:10.1134/s1022795417040020
“This protein from the group of C DOCK proteins plays a role in reorganization of the actin cytoskeleton by activating Rho GTPases Cdc42 and Rac1, actively expressed in the cornea [68, 76].”
BackgroundHsu, A. P. (2026) · Springer eBooks · doi:10.1007/978-3-032-21135-4_20
- Authors
- Kwofie, M. A., & Skowronski, J.
- Affiliations
- Cold Spring Harbor Laboratory (US)
- ORCID
- Kwofie, Michael A.
- Venue
- Journal of Biological Chemistry
- Publisher
- Elsevier BV
- Published
- 2008-02
- Volume
- 283
- Issue
- 6
- Pages
- 3088-3096
- ISSN
- 0021-9258 (ISSN-L)
- OpenAlex
- W2069291704
- Semantic Scholar
- 7f571ca6194cabfadf33d0c29498c3e8d2294ca8
- Cited by
- 36
- References
- 50
- Citations by year
- 2026: 1 · 2023: 2 · 2021: 2 · 2020: 1 · 2019: 4 · 2018: 1 · 2017: 4 · 2016: 3 · 2015: 2 · 2014: 1 · 2013: 1 · 2012: 6
- FWCI
- 0.48
- Type
- journal article
- Language
- en
- Open access
- hybrid
- doi.org
- Licence
- Locations
- Journal of Biological Chemistry (publishedVersion, cc-by)
- PubMed (publishedVersion)
- Cold Spring Harbor Laboratory Institutional Repository (Cold Spring Harbor Laboratory) (acceptedVersion)
- Funders
- U.S. Public Health Service
- National Institute of Allergy and Infectious Diseases (AI 42561)
- Topics
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Protein Kinase Regulation and GTPase Signaling
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Cellular transport and secretion
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Receptor Mechanisms and Signaling
- Keywords
- Rac2, Cdc42, DOCK2, guanine nucleotide exchange factor, DOCK180, DOCK4, GTPase activation
- MeSH terms
- RAC2 GTP-Binding Protein, Amino Acid Sequence, Gene Expression Regulation, Humans, Molecular Sequence Data, Protein Binding, Recombinant Proteins, Guanosine 5'-O-(3-Thiotriphosphate), Point Mutation, Sequence Homology, Amino Acid, Protein Structure, Tertiary, Guanine Nucleotide Exchange Factors, GTPase-Activating Proteins, rac GTP-Binding Proteins, cdc42 GTP-Binding Protein
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