Download MendeleyStructural basis for Rab6 activation by the Ric1-Rgp1 complex.
Feathers, J.R., Vignogna, R.C., Fromme, J.C.(2024) Nat Commun 15: 10561-10561
- PubMed: 39632878 Search on PubMedSearch on PubMed Central
- DOI: https://doi.org/10.1038/s41467-024-54869-9
- Primary Citation Related Structures:
9AYR - PubMed Abstract:
Rab GTPases act as molecular switches to regulate organelle homeostasis and membrane trafficking. Rab6 plays a central role in regulating cargo flux through the Golgi and is activated via nucleotide exchange by the Ric1-Rgp1 protein complex. Ric1-Rgp1 is conserved throughout eukaryotes but the structural and mechanistic basis for its function has not been established. Here we report the cryoEM structure of a Ric1-Rgp1-Rab6 complex representing a key intermediate of the nucleotide exchange reaction. Ric1-Rgp1 interacts with the nucleotide-binding domain of Rab6 using an uncharacterized helical domain, which we establish as a RabGEF domain by identifying residues required for Rab6 activation. Unexpectedly, the complex uses an arrestin fold to interact with the Rab6 hypervariable domain, indicating that interactions with the unstructured C-terminal regions of Rab GTPases may be a common binding mechanism used by their activators. Collectively, our findings provide a detailed mechanistic understanding of regulated Rab6 activation at the Golgi.
- Department of Molecular Biology & Genetics and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, 14850, USA.
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