title: Opt2 mediates the exposure of phospholipids during cellular adaptation to altered lipid asymmetry.
abstract: Plasma membrane lipid asymmetry is important for various membrane-associated functions and is regulated by membrane proteins termed flippases and floppases. The Rim101 pathway senses altered lipid asymmetry in the yeast plasma membrane. The mutant lem3Δ cells, in which lipid asymmetry is disturbed owing to the inactivation of the plasma membrane flippases, showed a severe growth defect when the Rim101 pathway was impaired. To identify factors involved in the Rim101-pathway-dependent adaptation to altered lipid asymmetry, we performed DNA microarray analysis and found that Opt2 induced by the Rim101 pathway plays an important role in the adaptation to altered lipid asymmetry. Biochemical investigation of Opt2 revealed its localization to the plasma membrane and the Golgi, and provided several lines of evidence for the Opt2-mediated exposure of phospholipids. In addition, Opt2 was found to be required for the maintenance of vacuolar morphology and polarized cell growth. These results suggest that Opt2 is a novel factor involved in cell homeostasis by regulating lipid asymmetry.
authors.affiliation: Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan.
authors.forename: Saori
authors.initials: S
authors.lastname: Yamauchi
authors.affiliation: Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan obarak@pharm.hokudai.ac.jp kihara@pharm.hokudai.ac.jp.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Obara
authors.affiliation: Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan.
authors.forename: Kenya
authors.initials: K
authors.lastname: Uchibori
authors.affiliation: Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Kamimura
authors.affiliation: Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Azumi
authors.affiliation: Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan obarak@pharm.hokudai.ac.jp kihara@pharm.hokudai.ac.jp.
authors.forename: Akio
authors.initials: A
authors.lastname: Kihara
mesh_terms: D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism*; D006056:Golgi Apparatus / Q000235:genetics / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D010743:Phospholipids / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: C478771:Lem3 protein, S cerevisiae; D026901:Membrane Transport Proteins; C000598906:OPT2 protein, S cerevisiae; D010743:Phospholipids; C489601:RIM101 protein, S cerevisiae; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins
keywords: Lipid asymmetry; Phospholipid; Plasma membrane; Yeast