RRC ID 77368
Author Saitoh A, Shin HW, Yamada A, Waguri S, Nakayama K.
Title Three homologous ArfGAPs participate in coat protein I-mediated transport.
Journal J Biol Chem
Abstract ArfGAP1 is a prototype of GTPase-activating proteins for ADP-ribosylation factors (ARFs) and has been proposed to be involved in retrograde transport from the Golgi apparatus to the endoplasmic reticulum (ER) by regulating the uncoating of coat protein I (COPI)-coated vesicles. Depletion of ArfGAP1 by RNA interference, however, causes neither a discernible phenotypic change in the COPI localization nor a change in the Golgi-to-ER retrograde transport. Therefore, we also examined ArfGAP2 and ArfGAP3, closely related homologues of ArfGAP1. Cells in which ArfGAP1, ArfGAP2, and ArfGAP3 are simultaneously knocked down show an increase in the GTP-bound ARF level. Furthermore, in these cells proteins resident in or cycling through the cis-Golgi, including ERGIC-53, beta-COP, and GM130, accumulate in the ER-Golgi intermediate compartment, and Golgi-to-ER retrograde transport is blocked. The phenotypes observed in the triple ArfGAP knockdown cells are similar to those seen in beta-COP-depleted cells. Both the triple ArfGAP- and beta-COP-depleted cells accumulate characteristic vacuolar structures that are visible under electron microscope. Furthermore, COPI is concentrated at rims of the vacuolar structures in the ArfGAP-depleted cells. On the basis of these observations, we conclude that ArfGAP1, ArfGAP2, and ArfGAP3 have overlapping roles in regulating COPI function in Golgi-to-ER retrograde transport.
Volume 284(20)
Pages 13948-13957
Published 2009-5-15
DOI 10.1074/jbc.M900749200
PII S0021-9258(20)58248-3
PMID 19299515
PMC PMC2679494
MeSH Autoantigens / genetics Autoantigens / metabolism Biological Transport / physiology COP-Coated Vesicles / genetics COP-Coated Vesicles / metabolism* Coatomer Protein / genetics Coatomer Protein / metabolism* Endoplasmic Reticulum / genetics Endoplasmic Reticulum / metabolism* GTPase-Activating Proteins / genetics GTPase-Activating Proteins / metabolism* Gene Knockdown Techniques Golgi Apparatus / genetics Golgi Apparatus / metabolism* HeLa Cells Humans Mannose-Binding Lectins / genetics Mannose-Binding Lectins / metabolism Membrane Proteins / genetics Membrane Proteins / metabolism Vacuoles / genetics Vacuoles / metabolism
IF 4.238
DNA material pcDNA3-hARFGAP1-HA (RDB20104) pcDNA3-hARFGAP2-HA (RDB20105) pcDNA3-hARFGAP3-HA (RDB20106) EGFP-VSVG-KDELR2 (RDB20107)