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Biochim Biophys Acta

Title:		The yeast Arf-GAP Glo3p is required for the endocytic recycling of cell surface proteins
Author(s):		Kawada D; Kobayashi H; Tomita T; Nakata E; Nagano M; Siekhaus DE; Toshima JY; Toshima J;
Address:		"Department of Biological Science and Technology, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585, Japan. Department of Biological Science and Technology, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585, Japan; Research Center for RNA Science, RIST, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585, Japan. Institute of Science and Technology Austria, Am Campus 1, A-3400 Klosterneuburg, Austria. Research Center for RNA Science, RIST, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585, Japan; Faculty of Science and Engineering, Waseda University, Wakamatsu-cho 2-2, Shinjuku-ku, Tokyo 162-8480, Japan. Electronic address: yama_jun@aoni.waseda.jp. Department of Biological Science and Technology, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585, Japan; Research Center for RNA Science, RIST, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585, Japan. Electronic address: jtosiscb@rs.noda.tus.ac.jp"
Journal Title:		Biochim Biophys Acta
Year:		2015
Volume:		20141018
Issue:		1
Page Number:		144 - 156
DOI:		10.1016/j.bbamcr.2014.10.009
ISSN/ISBN:		0006-3002 (Print) 0006-3002 (Linking)
Abstract:		"Small GTP-binding proteins of the Ras superfamily play diverse roles in intracellular trafficking. Among them, the Rab, Arf, and Rho families function in successive steps of vesicle transport, in forming vesicles from donor membranes, directing vesicle trafficking toward target membranes and docking vesicles onto target membranes. These proteins act as molecular switches that are controlled by a cycle of GTP binding and hydrolysis regulated by guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). In this study we explored the role of GAPs in the regulation of the endocytic pathway using fluorescently labeled yeast mating pheromone alpha-factor. Among 25 non-essential GAP mutants, we found that deletion of the GLO3 gene, encoding Arf-GAP protein, caused defective internalization of fluorescently labeled alpha-factor. Quantitative analysis revealed that glo3Delta cells show defective alpha-factor binding to the cell surface. Interestingly, Ste2p, the alpha-factor receptor, was mis-localized from the plasma membrane to the vacuole in glo3Delta cells. Domain deletion mutants of Glo3p revealed that a GAP-independent function, as well as the GAP activity, of Glo3p is important for both alpha-factor binding and Ste2p localization at the cell surface. Additionally, we found that deletion of the GLO3 gene affects the size and number of Arf1p-residing Golgi compartments and causes a defect in transport from the TGN to the plasma membrane. Furthermore, we demonstrated that glo3Delta cells were defective in the late endosome-to-TGN transport pathway, but not in the early endosome-to-TGN transport pathway. These findings suggest novel roles for Arf-GAP Glo3p in endocytic recycling of cell surface proteins"
Keywords:		"*Endocytosis GTPase-Activating Proteins/genetics/*physiology Golgi Apparatus/metabolism Membrane Proteins/*metabolism Protein Transport R-SNARE Proteins/metabolism Receptors, Mating Factor/metabolism Saccharomyces cerevisiae Proteins/genetics/metabolism/*;"
Notes:		"MedlineKawada, Daiki Kobayashi, Hiromu Tomita, Tsuyoshi Nakata, Eisuke Nagano, Makoto Siekhaus, Daria Elisabeth Toshima, Junko Y Toshima, Jiro eng Research Support, Non-U.S. Gov't Netherlands 2014/11/21 Biochim Biophys Acta. 2015 Jan; 1853(1):144-56. doi: 10.1016/j.bbamcr.2014.10.009. Epub 2014 Oct 18"