title: Regulation of Gic2 localization and function by phosphatidylinositol 4,5-bisphosphate during the establishment of cell polarity in budding yeast.
abstract: Establishment of cell polarity is important for a wide range of biological processes, from asymmetric cell growth in budding yeast to neurite formation in neurons. In the yeast Saccharomyces cerevisiae, the small GTPase Cdc42 controls polarized actin organization and exocytosis toward the bud. Gic2, a Cdc42 effector, is targeted to the bud tip and plays an important role in early bud formation. The GTP-bound Cdc42 interacts with Gic2 through the Cdc42/Rac interactive binding domain located at the N terminus of Gic2 and activates Gic2 during bud emergence. Here we identify a polybasic region in Gic2 adjacent to the Cdc42/Rac interactive binding domain that directly interacts with phosphatidylinositol 4,5-bisphosphate in the plasma membrane. We demonstrate that this interaction is necessary for the polarized localization of Gic2 to the bud tip and is important for the function of Gic2 in cell polarization. We propose that phosphatidylinositol 4,5-bisphosphate and Cdc42 act in concert to regulate polarized localization and function of Gic2 during polarized cell growth in the budding yeast.
authors.affiliation: Department of Biology, University of Pennsylvania, Philadelphia, PA 19104-6018, USA.
authors.forename: Kelly
authors.initials: K
authors.lastname: Orlando
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Zhang
authors.forename: Peng
authors.initials: P
authors.lastname: Yue
authors.forename: Teresa
authors.initials: T
authors.lastname: Chiang
authors.forename: Erfei
authors.initials: E
authors.lastname: Bi
authors.forename: Wei
authors.initials: W
authors.lastname: Guo
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D016764:Cell Polarity; D015966:Gene Expression Regulation, Fungal / Q000235:genetics; D009154:Mutation / Q000235:genetics; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism*; D010770:Phosphotransferases / Q000235:genetics / Q000378:metabolism; D017853:Phosphotransferases (Alcohol Group Acceptor); D011485:Protein Binding; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; C109253:GIC2 protein, S cerevisiae; D019269:Phosphatidylinositol 4,5-Diphosphate; D029701:Saccharomyces cerevisiae Proteins; D010770:Phosphotransferases; D017853:Phosphotransferases (Alcohol Group Acceptor); C489795:MSS4 protein, S cerevisiae