Endocytosis and Physiology: Insights from Disabled-2 Deficient Mice

In the paper

“Dab2 null mice are produced at an expected ratio and the mice are essentially phenotypically normal in unchallenged conditions (Moore et al., 2013).”

What the sources say

• Disputed

  The Results section on constitutive null embryos reports that dab2 (-/-) embryos die around E5.5 and none survived to E9.5. The expected Mendelian ratio and absence of obvious developmental defects are reported instead for conditional Sox2-Cre mutants, in which Dab2 deletion was restricted to the embryo proper. (LLM, conf=0.88)

  Checked by a reasoning model — may be wrong.

  cites Moore et al., 2013 sourceExperimental — accuracy not yet measured

In the paper

“The rapid cell death and tissue regression during mammary involution is a tightly controlled process (Furth et al., 1997; Furth, 1999), and TGF-beta signaling is known to play a crucial role (Bierie et al., 2009).”

What the sources say

• ?Not checked — no full text of the sourcecites Furth et al., 1997 source
• ?Not checked — no full text of the sourcecites Furth, 1999 source
• Supported

  The section “TGF-β Signaling Promotes Cell Death and Suppresses Lactation During the Second Stage of Mammary Involution” reports that TGF-β signaling promotes commitment to cell death during involution. Bierie et al. is cited for the TGF-β clause, not the preceding description of involution as tightly controlled. (LLM, conf=0.92)

  cites Bierie et al., 2009 source

In the paper

“In the dab2-deficient embryos, extra-embryonic endoderm cells are present but fail to sort and form primitive and subsequent visceral endoderm epithelia. Rather, the extra-embryonic endoderm cells intermingle with the ectoderm cells”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Yang et al., 2002a, 2007, 2009
• Supported

  The Discussion reports that extraembryonic endoderm cells are present in Dab2-deficient embryos but intermingle with epiblast cells instead of forming a surface epithelial layer. The Results describe failure to organize primitive endoderm at E4.5 and disorganization of visceral endoderm at E5.5. The paper calls the intermixed cells “epiblast,” rather than “ectoderm.” (LLM, conf=0.91)

  cites Moore et al., 2013 source

In the paper

“Also, participation in the clathrin-mediated endocytosis and trafficking of E-cadherin explains its affects on epithelial organization (Yang et al., 2007).”

What the sources say

• Partly supported

  The Discussion says Dab2 is important for E-cadherin distribution and suggests that Dab2-mediated clathrin-coated endocytosis removes E-cadherin from the apical surface. The Abstract proposes loss of polarity as the mechanism behind defective epithelial surface positioning. The citing sentence presents that proposed explanation as established. (LLM, conf=0.82)

  cites Yang et al., 2007 sourceExperimental — accuracy not yet measured

In the paper

“Dab2 proteins also contain clathrin binding, NPF, and DPF motifs, which bind components of endocytic vesicles such as clathrin, alpha-adaptin, and EPS-15, respectively (Traub, 2003).”

What the sources say

• Partly supported

  The “ARH, Disabled-2, and numb” section says Dab2 has clathrin-box and/or AP-2 appendage-binding sequences and describes PTB adaptors as binding clathrin and AP-2. It does not identify NPF or DPF motifs in Dab2, or establish the claimed respective binding of those motifs to alpha-adaptin and EPS-15. (LLM, conf=0.86)

  cites Traub, 2003 sourceExperimental — accuracy not yet measured

In the paper

“its expression was found to be absent or very low in virgin mammary epithelial cells, but is greatly induced in mammary glands during pregnancy and lactation (Tao et al., 2014).”

What the sources say

• Partly supported

  The Results section, “Induction of Dab2 expression in mammary glands during pregnancy and lactation,” reports that Dab2 was essentially undetectable in virgin mammary epithelial cells and was massively induced during lactation. It reports only a low level during pregnancy, so “greatly induced” overstates the pregnancy finding. (LLM, conf=0.86)

  cites Tao et al., 2014 sourceExperimental — accuracy not yet measured

In the paper

“Dab2 is essential for mouse embryonic development and gene deletion in mice causes early embryonic lethality at a stage prior to gastrulation (Morris et al., 2002b; Yang et al., 2002a, 2007).”

What the sources say

• Supported

  The 'Targeting of the Dab2 locus' section reports that homozygous Dab2 mutation is lethal in early development and that null embryos implant but fail to undergo gastrulation. This supports the claim about gene deletion in mice; the paper separately notes that deletion limited to the embryo proper does not cause this lethality. Page numbers were not provided in the supplied passages. (LLM, conf=0.93)

  cites Morris et al., 2002b source
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Yang et al., 2002a, 2007

In the paper

“For mammary morphology, the impact of Dab2 deletion is most obvious at day 3 of forced involution; however, no permanent changes in mammary glands of Dab2 null mice are noted.”

What the sources say

• Supported

  The Results section on delayed mammary involution says the differences were most noticeable on day 3 of forced involution. It reports that they became minimal by day 5 and describes the effect as transient, supporting the statement that no permanent morphological change was noted. (LLM, conf=0.91)

  cites Tao et al., 2014 source

In the paper

“Analyses in embryoid bodies and cultured cells support that Dab2 is critical for the surface targeting and restriction of cell adhesion molecules and the establishment and maintenance of epithelial polarity”

What the sources say

• ?Not checked — no full text of the sourcecites Rula et al., 2007 source
• Supported

  The Background describes Dab2-mediated polarized trafficking of adhesion molecules, including integrins and E-cadherin. The Discussion (mechanism of epithelial organization; loss of Dab2 in epithelial disorganization and cancer) links reduced trafficking to failure to establish polarity and loss of Dab2 to epithelial depolarization in embryos and embryoid bodies. These passages support the claim as a summary of the cell and embryoid-body findings, rather than a claim that Dab2 is required for polarity in every tissue. (LLM, conf=0.86)

  cites Moore et al., 2013 source

In the paper

“Dab2 is able to recruit LDL receptor into clathrin-coated pits and facilitate endocytosis”

What the sources say

• ?Not checked — no full text of the sourcecites Maurer and Cooper, 2006 source
• Supported

  The Introduction says Dab2 recruits cargo to clathrin-coated pits and identifies LDLR as a receptor bound by this adaptor family. It also describes a Dab2-dependent pathway for LDLR internalization; the Results report that depleting Dab2 inhibited LDLR endocytosis and that wild-type Dab2 rescued it. (LLM, conf=0.93)

  cites Mulkearns and Cooper, 2012 source

In the paper

“It was reported that Dab2 serves as an adaptor linking the transforming growth factor beta (TGF-beta) receptors with the Smad family proteins, facilitating TGF-beta signal transduction pathway (Hocevar et al., 2001).”

What the sources say

• Supported

  The Introduction states that Dab2 functions as an adaptor bridging the TGF-β receptor complex to the Smad pathway. It also reports that Dab2 restores TGF-β-induced Smad responses in a signaling-mutant cell line. (LLM, conf=0.94)

  cites Hocevar et al., 2001 source

In the paper

“Indeed, endocytosis and trafficking of cell surface receptors and signaling components have been suggested to account for its activities in modulating multiple cellular signaling pathways, including Ras/MAPK”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Xu et al., 1998
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites He et al., 2001
• Partly supported

  The Abstract and Discussion (pages unavailable) support Dab2’s modulation of the Ras/MAPK pathway through binding Grb2 and interrupting its interaction with SOS. They do not support endocytosis or trafficking as the mechanism, or address Dab2’s modulation of TGF-beta and Wnt pathways. (LLM, conf=0.85)

  cites Zhou and Hsieh, 2001 sourceExperimental — accuracy not yet measured

In the paper

“Nevertheless, a surprising finding is that Dab2 is not expressed in hepatocytes, but rather in the sinusoidal endothelial cells in liver (Tao et al., 2016a).”

What the sources say

• Supported

  The Results section states that Dab2 is not expressed in hepatocytes and concludes that it is expressed in liver sinusoidal endothelial cells. The Discussion repeats this finding. (LLM, conf=0.95)

  cites Tao et al., 2016a source

In the paper

“Another study indicates that Dab2 facilitates the cellular endocytosis and trafficking of TGF-beta receptor (Penheiter et al., 2010).”

What the sources say

• Partly supported

  The Introduction reports that Dab2 knockdown disrupts TGF-β receptor recycling and endosomal trafficking, supporting the trafficking part of the claim. It also states that knockdown does not affect receptor internalization; the Discussion likewise reports no effect on TGF-β receptor internalization. Thus the paper does not support saying Dab2 facilitates the receptor's initial endocytosis. (LLM, conf=0.92)

  cites Penheiter et al., 2010 sourceExperimental — accuracy not yet measured

In the paper

“Therefore, Dab2 functions in endocytic trafficking to sustain cell polarity and thus epithelial organization, and hence loss of Dab2 leads to endoderm epithelial disorganization and failure of the embryos”

What the sources say

• ?Not checked — no full text of the sourcecites Rula et al., 2007 source
• Supported

  The Discussion proposes that Dab2-mediated trafficking establishes and maintains epithelial polarity, which supports epithelial organization. Figure 6 states that Dab2-deficient endoderm cells lose polarity and surface positioning, mix with inner-cell-mass cells, and cause embryo failure; the section on early mouse embryos reports disorganized knockout embryos lacking a recognizable endoderm layer by E5.5. (LLM, conf=0.92)

  cites Yang et al., 2007 source
• Supported

  The Discussion section on epithelial organization describes Dab2-mediated endocytic trafficking as a mechanism for establishing endoderm cell polarity and reports disorganization when Dab2 is lost (page unavailable). The Conclusion reports early embryonic lethality following dab2 deletion (page unavailable). (LLM, conf=0.92)

  cites Moore et al., 2013 source

In the paper

“However, despite rigorous investigation, these phenotypes were not found, and only subtle differences were observed between control and Dab2-deficient mice (Tao et al., 2014).”

What the sources say

• Partly supported

  The Discussion says that only subtle differences in mammary functions were observed, and the Results report minimal effects on milk production and nursing. But the Results section on delayed mammary involution reports delayed cell clearance and differences in apoptosis and survival markers, so the claim that cell-survival phenotypes were not found is too broad. (LLM, conf=0.84)

  cites Tao et al., 2014 sourceExperimental — accuracy not yet measured

In the paper

“The most prominent phenotype of Dab2 knockout mice was their striking lean body composition under a high fat and high caloric diet, although the weight of the mutant mice was indistinguishable from wild-type littermates on a regular chow.”

What the sources say

• Partly supported

  The Results section reports that Dab2-null mice were leaner on a high-fat diet and had weights similar to wild-type mice on normal chow. But it also says the lean phenotype occurred when the high-fat diet began in juvenile mice and was absent when it began after six months of age. The claim omits that age qualification. (LLM, conf=0.86)

  cites Tao et al., 2016b sourceExperimental — accuracy not yet measured

In the paper

“The preliminary result suggests that Dab2 suppresses MAPK and allows the unsuppressed activity of PPARγ to induce adipocyte differentiation.”

What the sources say

• Supported

  The Discussion describes a model in which Dab2 suppresses Ras/Erk1/2 signaling, allowing PPARγ to enter the nucleus and promote adipogenic differentiation. The Results further report that inhibiting Erk1/2 increased PPARγ levels and partially restored differentiation in Dab2-null cells. (LLM, conf=0.94)

  cites Tao et al., 2016b source

In the paper

“Sox2-Cre is expressed in the inner cell mass and delete Dab2 gene in a mosaic fashion, and the embryo proper is essentially depleted of Dab2 allele by E9.5 (Moore et al., 2013).”

What the sources say

• Partly supported

  The Results (Characterization of dab2 conditional mutant mice; page unavailable) report that Sox2-Cre produced mosaic mutants and that the undeleted Dab2 allele was undetectable in the embryo proper by E9.5. The paper describes Sox2 expression in the epiblast, but does not establish the claim that Sox2-Cre is expressed in the inner cell mass specifically. (LLM, conf=0.84)

  cites Moore et al., 2013 sourceExperimental — accuracy not yet measured

In the paper

“However, mice with Dab2 deletion in Treg cells are healthy in appearance and do not show phenotypes related to autoimmunity defects even at 1 year of age, indicating that the Dab2 is dispensable for Treg cells in maintaining T cell tolerance (Jain et al., 2009).”

What the sources say

• Partly supported

  The Results and Discussion section reports that Dab2-deficient mice appeared healthy and had no overt autoimmunity at 10–12 months, suggesting that their Treg cells maintained naïve T cell tolerance. The claim omits that qualifier: the same section reports that Dab2-deficient Treg cells failed to control established colitis, so the paper does not establish that Dab2 is dispensable for Treg-mediated tolerance generally. Page numbers are not provided in our copy. (LLM, conf=0.88)

  cites Jain et al., 2009 sourceExperimental — accuracy not yet measured

In the paper

“In adults, Dab2 mRNA is present in most tissues at a low level, but is noticeably higher in macrophages, kidney, white adipose tissues, adrenal, and lactating mammary glands”

In the paper

“Disabled-2 (Dab2) is a clathrin and cargo binding endocytic adaptor protein”

In the paper

“Dab2 conditional knockout mice mediated through a Sox2-Cre transgene have no obvious developmental defects and have a normal life span”

In the paper

“Although, Dab2 constitutive knockout mice are early embryonic lethal, cre-lox approach enables the study of its functions in physiology.”

In the paper

“Dab2 is also considered a tumor suppressor, as loss or reduced expression is found in several cancer types.”

In the paper

“A PTB/PID domain located in the N-terminus of Dab2 binds the NPXY motif(s) present at the cytoplasmic tails of certain transmembrane proteins/receptors.”

In the paper

“Dab2 facilitates the endocytosis of the Ras activating Grb2/Sos1 signaling complex, controls its disassembly, and thereby regulates the Ras/MAPK signaling pathway.”

In the paper

“The membrane receptors reported to bind directly to Dab2 include LDL receptor and its family members LRP1 and LRP2 (megalin), growth factor receptors EGFR and FGFR, and the cell adhesion receptor beta1 integrin.”

In the paper

“In primary cultures of mammary epithelial cells isolated from either virgin or pregnant mice, Dab2 expression can be induced by estrogen, progesterone, and prolactin, individually and also synergistically.”

In the paper

“Characterization of Dab2 null mice revealed several phenotypes, both expected and surprised, and verified the links between cellular functions in endocytosis and signaling to the identified physiological functions”

In the paper

“Thus, a scenario is presented that Dab2 also mediates the endocytosis and trafficking of components of various signaling pathways. By doing so, Dab2 acts to modulate cellular signalings.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Xu et al., 1998

In the paper

“while Arh mutation significantly elevates serum LDL and cholesterol levels in mice (Jones et al., 2003, 2007; Harada-Shiba et al., 2004) and also human (Garcia et al., 2001)”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Jones et al., 2003, 2007
• ?Not checked — no full text of the sourcecites Harada-Shiba et al., 2004 source
• ?Not checked — no full text of the sourcecites Garcia et al., 2001 source

In the paper

“mammalian Dab2 is most similar to Dab1, Numb, Numbl, and Arh, which are all endocytic adaptor proteins”

In the paper

“Several spliced isoforms including p96, p93, and p67 were identified as the protein products of the Dab2 gene (Xu et al., 1995; Sheng et al., 2000a, 2001).”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Xu et al., 1995
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Sheng et al., 2000a, 2001

In the paper

“No redundancy between Dab1 and Dab2 activity has been found or reported, likely because of their divergent tissue expression.”

What the sources say

• ?Not checked — no full text of the sourcecites Howell et al., 1997 source

In the paper

“Thus, Grb2 recruits Sos1 to membrane receptors to mediate Ras activation (McCormick, 1993).”

What the sources say

• ?Not checked — no full text of the sourcecites McCormick, 1993 source

In the paper

“another study found that Dab2 dose not impact the canonical TGF-beta pathway but Dab2 loss in head and neck cancer compromised the tumor suppressor function of TGF-beta, while enabling its tumor-promoting activities, and concluded that Dab2 is a molecular switch for TGF-beta from a tumor suppressor to a promoter (Hannigan et al., 2010).”

What the sources say

• Not checked yet

  Checked before — its earlier verdict is held back until a new check runs.

  cites Hannigan et al., 2010 source

In the paper

“In the studies of primary mammary epithelial cells in cultures, Dab2 deletion appears to influence Grb2-mediated TGF-beta Ras/MAPK activation, but does not alter the phosphorylation and activation of the Smad family proteins, which is the canonical pathway of TGF-beta signaling (Tao et al., 2014).”

What the sources say

• Not checked yet

  Checked before — its earlier verdict is held back until a new check runs.

  cites Tao et al., 2014 source

In the paper

“An initial survey indicated that Dab2 is expressed widely in most tissues and particularly abundantly in the kidney (Fazili et al., 1999)”

What the sources say

• ?Not checked — no full text of the sourcecites Fazili et al., 1999 source

In the paper

“kidney was confirmed to be one of the highest expressing tissues profiled from a large public expression database (Figure 2), and the expressing cells was found later to be the kidney epithelial cells lining the proximal convoluted tubule (Moore et al., 2013).”

What the sources say

• Not checked yet

  Checked before — its earlier verdict is held back until a new check runs.

  cites Moore et al., 2013 source

In the paper

“In mammals, Dab2 is widely expressed (Xu et al., 1998; Fazili et al., 1999), but Dab1 is restricted to brain (Howell et al., 1997; Sheldon et al., 1997).”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Xu et al., 1998
• ?Not checked — no full text of the sourcecites Fazili et al., 1999 source
• ?Not checked — no full text of the sourcecites Howell et al., 1997 source

In the paper

“was first isolated from a murine macrophage cell line as a phospho-protein, p96, involved in CSF-1 signal transduction (Xu et al., 1995)”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Xu et al., 1995

In the paper

“An interest to examine a potential role of Dab2 in mammary glands was prompted by the findings that Dab2 expression is lost in breast cancer (Sheng et al., 2000b) and in carcinogen-induced rodent mammary tumors (Schwahn and Medina, 1998; Medina, 2002).”

What the sources say

• ?Not checked — no full text of the sourcecites Sheng et al., 2000b source
• ?Not checked — no full text of the sourcecites Schwahn and Medina, 1998 source
• ?Not checked — no full text of the sourcecites Medina, 2002 source

In the paper

“Through the PRD, Sos1 binds strongly to the two SH3 domains of the signaling adaptor Grb2, which associates with phosphorylated and activated transmembrane signaling receptors through the SH2 domain of Grb2.”

What the sources say

• ?Not checked — no full text of the sourcecites McCormick, 1993 source

In the paper

“Sequence alignment indicated that mammalian Dab2 and a neuron specific isoform Dab1 are orthologs of the Drosophila Disabled gene”

What the sources say

• ?Not checked — no full text of the sourcecites Gertler et al., 1989 source

In the paper

“The model suggests a role for Dab2 in mediating the endocytosis of signaling complexes and regulating signaling at the endosomes”

What the sources say

• ?Not checked — no full text of the sourcecites Vieira et al., 1996 source

In the paper

“and likely loss of Dab2 contributes but is not sufficiently to cause tumorigenesis.”

In the paper

“In sum, although Dab2 null mice are largely normal, slight challenges were able to reveal several physiological changes.”

In the paper

“Systematic analysis of a large panel of ovarian carcinomas showed that loss of Dab2 expression occurs in about 90% of ovarian cancer, and is an early event in ovarian tumorigenicity (Fazili et al., 1999).”

What the sources say

• ?Not checked — no full text of the sourcecites Fazili et al., 1999 source

In the paper

“A suggestive observation is that the loss of Dab2 expression occurs in an epithelial layer, and correlates closely with morphological transformation from a benign monolayer to malignant multiple layered ovarian cancer (Yang et al., 2002b).”

What the sources say

• ?Not checked — no full text of the sourcecites Yang et al., 2002b source

In the paper

“and also Dab2 is not required for normal function and turnover of adipocytes.”

In the paper

“which were observed to have frequent uterine hyperproliferation and atypia, and increased ovarian epithelial growth and changes (Yang et al., 2006)”

What the sources say

• ?Not checked — no full text of the sourcecites Yang et al., 2006 source

In the paper

“A mechanism was suggested that the Dab2-deficient Treg cells are poor suppressors in vitro due to a deficiency in gap junctions for transferring cAMP to effector T cells, because of a role for Dab2 in endocytic trafficking of connexins, components of the gap junctions (Jain et al., 2009).”

What the sources say

• Not checked yet

  Checked before — its earlier verdict is held back until a new check runs.

  cites Jain et al., 2009 source

In the paper

“Thus, unsuppressed Ras/MAPK activation in pre-adipocytes that inhibits the differentiation accounts for the phenotype of resistance to high fat diet-induced weight gain in Dab2 null mice.”

In the paper

“Dab2 cDNA was first cloned from a macrophage cDNA library (Xu et al., 1995), and macrophages are one of the cell types with highest Dab2 expressing (Figure 3).”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Xu et al., 1995

In the paper

“Studies of cultured cells suggested that Dab2 acts in macrophage spreading and adhesion (Rosenbauer et al., 2002).”

What the sources say

• ?Not checked — no full text of the sourcecites Rosenbauer et al., 2002 source

In the paper

“the absence of the endocytosis adaptor protein impacts diverse physiological functions in whole mice, including cholesterol homeostasis, kidney function, mammary involution, tumor risk, and high calorie-induced adipose expansion, to name the most noticeable few (Table 1).”

In the paper

“Also, some speculated cellular functions may not be physiological due to low expression in the tissues and cell types and the phenotypes observed in cultured cells do not present in the whole animals.”

In the paper

“Follow up studies corroborated the loss of Dab2 expression in ovarian and breast cancer and its cell growth suppressive activity, and substantiated the proposal for Dab2 as a tumor suppressor (Mok et al., 1998; Fazili et al., 1999).”

What the sources say

• ?Not checked — no full text of the sourcecites Mok et al., 1998 source
• ?Not checked — no full text of the sourcecites Fazili et al., 1999 source

In the paper

“Induction of Dab2 expression likely acts as a feedback loop for the hormonal induction of mammary gland expansion during pregnancy and lactation, and the presence of Dab2 allows efficient cell death and clearance in mammary involution.”

What the sources say

• Not checked yet

  Checked before — its earlier verdict is held back until a new check runs.

  cites Tao et al., 2014 source

In the paper

“Dab2 is initially expressed and mediates endocytosis in the blastocyst stages”

In the paper

“In additional analysis, it was observed that Dab2-deficient Treg cells failed to alleviate established colitis, suggesting a role of Dab2 in regulating lymphocyte infiltration and accumulation in the colon.”

What the sources say

• Not checked yet

  Checked before — its earlier verdict is held back until a new check runs.

  cites Jain et al., 2009 source