Structural basis of the interaction between RalA and Sec5, a subunit of the sec6/8 complex
Open accessAbstract
The sec6/8 complex or exocyst is an octameric protein complex that functions during cell polarization by regulating the site of exocytic vesicle docking to the plasma membrane, in concert with small GTP-binding proteins. The Sec5 subunit of the mammalian sec6/8 complex binds Ral in a GTP-dependent manner. Here we report the crystal structure of the complex between the Ral-binding domain of Sec5 and RalA bound to a non-hydrolyzable GTP analog (GppNHp) at 2.1 A resolution, providing the first structural insights into the mechanism and specificity of sec6/8 regulation. The Sec5 Ral-binding domain folds into an immunoglobulin-like beta-sandwich structure, which represents a novel fold for an effector of a GTP-binding protein. The interface between the two proteins involves a continuous antiparallel beta-sheet, similar to that found in other effector/G-protein complexes, such as Ras and Rap1A. Specific interactions unique to the RalA.Sec5 complex include Sec5 Thr11 and Arg27, and RalA Glu38, which we show are required for complex formation by isothermal titration calorimetry. Comparison of the structures of GppNHp- and GDP-bound RalA suggests a nucleotide-dependent switch mechanism for Sec5 binding.
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Integrity signals
Registry
Cites
Statistics
Claims the paper makes
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
The interaction of RalA with Sec5 and Exo84 is thought to promote complex assembly, vesicle exocytosis, and membrane addition.
“this interaction is thought to promote complex assembly, vesicle exocytosis, and membrane addition (Moskalenko et al, 2002(Moskalenko et al, , 2003;;Sugihara et al, 2002;Fukai et al, 2003;Mott et al, 2003;Wang et al, 2004;Jin et al, 2005;Hase et al, 2009).”
From Ral mediates activity‐dependent growth of postsynaptic membranes via recruitment of the exocyst (2013) · cites this paper as Fukai et al, 2003
The ‘Implications of the Sec5–Ral interaction’ section proposes that RalA–Sec5 contact may regulate sec6/8 complex assembly and initiate vesicle tethering before membrane fusion. The Introduction links the exocyst to exocytosis and sites of plasma-membrane expansion. The paper identifies Exo84 as an exocyst component, but does not say that RalA interacts with Exo84 or that the RalA interaction itself promotes membrane addition. (LLM, conf=0.87)
Experimental — accuracy not yet measuredSurface levels of membrane proteins are determined by the dynamic balance of exocytosis-mediated delivery and endocytosis-dependent retrieval.
“The surface level of a protein is determined by the dynamic balance of its delivery to the plasma membrane through exocytic pathways (including recycling exocytosis) and removal from the plasma membrane by endocytic pathways (4–6).”
From Regulation of cargo exocytosis by a Reps1-Ralbp1-RalA module (2023) · cites this paper as [4]
The Introduction describes the exocyst as a tethering complex for exocytosis at the plasma membrane and discusses protein transport to that membrane, supporting the delivery side of the claim. Our copy does not address endocytic removal, recycling exocytosis, or the assertion that their balance determines surface protein levels. (LLM, conf=0.84)
Experimental — accuracy not yet measuredSubsequent dissociation of Ralbp1 from RalA is expected to result from direct competition from exocyst as Ralbp1 and exocyst recognize the same domain of GTP-bound Ral GTPases.
“Subsequent dissociation of Ralbp1 from RalA, on the other hand, is expected to result from direct competition from exocyst as Ralbp1 and exocyst recognize the same domain of GTP-bound Ral GTPases (4, 9, 45).”
From Regulation of cargo exocytosis by a Reps1-Ralbp1-RalA module (2023) · cites this paper as [4]
The introduction describes a GTP-dependent association between Ral and RalBP1, while the Abstract and Specificity section establish that the exocyst subunit Sec5 binds GTP-analog-bound RalA. Our copy does not establish that RalBP1 and Sec5 recognize the same RalA domain or that Sec5 directly competes with and displaces RalBP1. Passage-specific page numbers are unavailable. (LLM, conf=0.84)
Experimental — accuracy not yet measured
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
The self-check needs the paper’s full text.
Cites
No references could be resolved yet.
Research works printed but not linked: 4
- Adams,P.D., Pannu,N.S., Read,R.J. and Brunger,A.T. (1997) Cross- validated maximum likelihood enhances crystallographic simulated annealing re®nement. Proc. Natl Acad. Sci. USA, 94, 5018±5023.
- Fasshauer,D., Sutton,R.B., Brunger,A.T. and Jahn,R. (1998) Conserved structural features of the synaptic fusion complex: SNARE proteins reclassi®ed as Q-and R-SNAREs. Proc. Natl Acad. Sci. USA, 95, 15781±15786.
- Kee,Y., Yoo,J.S., Hazuka,C.D., Peterson,K.E., Hsu,S.C. and Scheller,R.H. (1997) Subunit structure of the mammalian exocyst complex. Proc. Natl Acad. Sci. USA, 94, 14438±14443.
- Matern,H.T., Yeaman,C., Nelson,W.J. and Scheller,R.H. (2001) The Sec6/8 complex in mammalian cells: characterization of mammalian Sec3, subunit interactions and expression of subunits in polarized cells. Proc. Natl Acad. Sci. USA, 98, 9648±9653.
Cited by
Sorted by citations
Cryo-EM structure of the exocyst complex
Mei, K., Li, Y., Wang, S., Shao, G., Wang, J., Ding, Y., Luo, G., Yue, P., Liu, J.-J., Wang, X., et al. (2018) · Nature Structural & Molecular Biology · doi:10.1038/s41594-017-0016-2 · Cited by 156 · see citing works
Discovery and characterization of small molecules that target the GTPase Ral
Yan, C., Liu, D., Li, L., Wempe, M. F., Guin, S., Khanna, M., Meier, J., Hoffman, B., Owens, C., Wysoczynski, C. L., et al. (2014) · Nature · doi:10.1038/nature13713 · Cited by 150 · see citing works
Ral mediates activity‐dependent growth of postsynaptic membranes via recruitment of the exocyst
Teodoro, R. O., Pekkurnaz, G., Nasser, A., Higashi‐Kovtun, M. E., Balakireva, M., McLachlan, I. G., Camonis, J., & Schwarz, T. L. (2013) · The EMBO Journal · doi:10.1038/emboj.2013.147 · Cited by 61 · see citing works
Regulation of cargo exocytosis by a Reps1-Ralbp1-RalA module
Wang, S., Chen, X., Crisman, L., Dou, X., Winborn, C. S., Wan, C., Puscher, H., Yin, Q., Kennedy, M. J., & Shen, J. (2023) · Science Advances · doi:10.1126/sciadv.ade2540 · Cited by 14 · see citing works
- Authors
- Fukai, S., Matern, H. T., Jagath, J. R., Scheller, R. H., & Brunger, A. T.
- Affiliations
- Howard Hughes Medical Institute (US)
- Genentech (US)
- ORCID
- Fukai, Shuya
- Venue
- The EMBO Journal
- Published
- 2003-07-01
- Volume
- 22
- Issue
- 13
- Pages
- 3267-3278
- ISSN
- 0261-4189 (ISSN-L)
- 1460-2075
- PMC
- PMC165653
- OpenAlex
- W2005768432
- Cited by
- 126
- References
- 0
- Citations by year
- 2026: 1 · 2025: 5 · 2024: 4 · 2023: 1 · 2022: 3 · 2021: 3 · 2020: 3 · 2019: 5 · 2018: 5 · 2017: 6 · 2016: 5 · 2015: 9 · 2014: 6 · 2013: 6 · 2012: 9
- FWCI
- 2.15
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Locations
- The EMBO Journal (publishedVersion)
- Europe PMC (PubMed Central) (publishedVersion)
- PubMed Central (publishedVersion)
- PubMed (publishedVersion)
- Institutional Repositories DataBase (IRDB) (submittedVersion)
- Tokyo Tech Research Repository (Tokyo Institute of Technology) (submittedVersion)
- Funders
- U.S. Department of Energy
- National Institutes of Health
- Japan Society for the Promotion of Science
- National Institute of General Medical Sciences
- National Center for Research Resources
- Basic Energy Sciences
- Biological and Environmental Research
- Topics
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Cellular transport and secretion
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Protein Kinase Regulation and GTPase Signaling
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Receptor Mechanisms and Signaling
- Keywords
- RalA, Sec5, exocyst, antiparallel beta-sheet, cell polarization, protein-protein interfaces
- MeSH terms
- Amino Acid Sequence, Animals, Carrier Proteins, Humans, Membrane Proteins, Models, Molecular, Molecular Sequence Data, Protein Conformation, Recombinant Proteins, Mutagenesis, Site-Directed, Sequence Homology, Amino Acid, GTP Phosphohydrolases, ral GTP-Binding Proteins, Vesicular Transport Proteins
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
