Structural basis for Rab6 activation by the Ric1-Rgp1 complex.

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, indi

SUBMITTER: Feathers JR 

PROVIDER: S-EPMC11618376 | biostudies-literature | 2024 Dec

REPOSITORIES: biostudies-literature