RRC ID 57094
Author Marubashi S, Shimada H, Fukuda M, Ohbayashi N.
Title RUTBC1 Functions as a GTPase-activating Protein for Rab32/38 and Regulates Melanogenic Enzyme Trafficking in Melanocytes.
Journal J Biol Chem
Abstract 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. Although BLOC-3 has already been identified as a Rab32/38-specific GEF that regulates the trafficking of tyrosinase and Tyrp1, no physiological GAP for Rab32/38 in melanocytes has ever been identified, and it has remained unclear whether Rab32/38 is involved in the trafficking of dopachrome tautomerase, another melanogenic enzyme, in mouse melanocytes. In this study we investigated RUTBC1, which was originally characterized as a Rab9-binding protein and GAP for Rab32 and Rab33B in vitro, and the results demonstrated that RUTBC1 functions as a physiological GAP for Rab32/38 in the trafficking of all three melanogenic enzymes in mouse melanocytes. The results of this study also demonstrated the involvement of Rab9A in the regulation of the RUTBC1 localization and in the trafficking of all three melanogenic enzymes. We discovered that either excess activation or inactivation of Rab32/38 achieved by manipulating RUTBC1 inhibits the trafficking of all three melanogenic enzymes. These results collectively indicate that proper spatiotemporal regulation of Rab32/38 is essential for the trafficking of all three melanogenic enzymes in mouse melanocytes.
Volume 291(3)
Pages 1427-40
Published 2016-1-15
DOI 10.1074/jbc.M115.684043
PII M115.684043
PMID 26620560
PMC PMC4714225
MeSH Amino Acid Substitution Animals Cell Line Enzyme Activation Humans Intracellular Signaling Peptides and Proteins / antagonists & inhibitors Intracellular Signaling Peptides and Proteins / chemistry Intracellular Signaling Peptides and Proteins / genetics Intracellular Signaling Peptides and Proteins / metabolism* Intramolecular Oxidoreductases / metabolism Melanocytes / cytology Melanocytes / enzymology* Melanocytes / metabolism Melanosomes / enzymology* Melanosomes / metabolism Membrane Glycoproteins / metabolism Mice Monophenol Monooxygenase / metabolism Mutation Oxidoreductases / metabolism Protein Transport RNA Interference Recombinant Fusion Proteins / chemistry Recombinant Fusion Proteins / metabolism Recombinant Proteins / chemistry Recombinant Proteins / metabolism Vesicular Transport Proteins / genetics Vesicular Transport Proteins / metabolism rab GTP-Binding Proteins / agonists* rab GTP-Binding Proteins / antagonists & inhibitors rab GTP-Binding Proteins / genetics rab GTP-Binding Proteins / metabolism
IF 4.106
Times Cited 21
Resource
DNA material pEF-T7-HPS4 (RDB17366) pEF-T7-GST-RBD32/38 (RDB17371)