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The GAP Domain and the SNARE, Coatomer and Cargo Interaction Region of the ArfGAP2/3 Glo3 are Sufficient for Glo3 Function
Author(s) -
Schindler Christina,
Rodriguez Fernanda,
Poon Pak P.,
Singer Richard A.,
Johnston Gerald C.,
Spang Anne
Publication year - 2009
Publication title -
traffic
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.677
H-Index - 130
eISSN - 1600-0854
pISSN - 1398-9219
DOI - 10.1111/j.1600-0854.2009.00952.x
Subject(s) - golgi apparatus , biology , microbiology and biotechnology , endoplasmic reticulum , vesicular transport proteins , gtpase , small gtpase , gtpase activating protein , transport protein , phenotype , signal transduction , endosome , genetics , g protein , gene , intracellular , vacuolar protein sorting
The ArfGAP Glo3 is required for coat protein I vesicle generation in the Golgi–endoplasmic reticulum (ER) shuttle. The best‐understood role of Glo3 is the stimulation of the GTPase activity of Arf1. In this study, we characterized functional domains of the ArfGAP Glo3 and identified an interaction interface for coatomer, SNAREs and cargo in the central region of Glo3 (BoCCS region). The GAP domain together with the BoCCS region is necessary and sufficient for all vital Glo3 functions. Expression of a truncated Glo3 lacking the GAP domain results in a dominant negative growth phenotype in glo3 Δ cells at 37°C. This phenotype was alleviated by mutating either the BoCCS region or the Glo3 regulatory motif (GRM), or by overexpression of ER–Golgi SNAREs or the ArfGAP Gcs1. The GRM is not essential for Glo3 function; it may act as an intrinsic sensor coupling GAP activity to SNARE binding to avoid dead‐end complex formation at the Golgi membrane. Our data suggest that membrane‐interaction modules and cargo‐sensing regions have evolved independently in ArfGAP1s versus ArfGAP2/3s.