Membrane Biology
RUTBC1 Functions as a GTPase-activating Protein for Rab32/38 and Regulates Melanogenic Enzyme Trafficking in Melanocytes
Two cell type-specific Rab proteins, Rab32 and Rab38 (Rab32/38), have been proposed as regulating the trafficking of melanogenic enzymes, including tyrosinase and tyrosinase-related protein 1 (Tyrp1), to melanosomes in melanocytes. Like other GTPases, Rab32/38 function as switch molecules that cycle between a GDP-bound inactive form and a GTP-bound active form; the cycle is thought to be regulated by an activating enzyme, guanine nucleotide exchange factor (GEF), and an inactivating enzyme, GTPase-activating protein (GAP), which stimulates the GTPase activity of Rab32/38.Small GTPase Rab2B and Its Specific Binding Protein Golgi-associated Rab2B Interactor-like 4 (GARI-L4) Regulate Golgi Morphology
Background: Rab small GTPases are membrane trafficking proteins in eukaryotes.Results: Comprehensive knockdown screening identified six Rab isoforms that are involved in regulating Golgi morphology in HeLa-S3 cells.Conclusion: Five of the six Rabs, including Rab2A and Rab2B, non-redundantly regulate Golgi morphology. A Rab2B-specific effector, GARI-L4, also regulates it.Significance: This is the first study to systematically analyze all human Rabs in the Golgi.
