RRC ID 36220
著者 Obara K, Yamamoto H, Kihara A.
タイトル Membrane protein Rim21 plays a central role in sensing ambient pH in Saccharomyces cerevisiae.
ジャーナル J Biol Chem
Abstract External alkalization activates the Rim101 pathway in Saccharomyces cerevisiae. In this pathway, three integral membrane proteins, Rim21, Dfg16, and Rim9, are considered to be the components of the pH sensor machinery. However, how these proteins are involved in pH sensing is totally unknown. In this work, we investigated the localization, physical interaction, and interrelationship of Rim21, Dfg16, and Rim9. These proteins were found to form a complex and to localize to the plasma membrane in a patchy and mutually dependent manner. Their cellular level was also mutually dependent. In particular, the Rim21 level was significantly decreased in dfg16Δ and rim9Δ cells. Upon external alkalization, the proteins were internalized and degraded. We also demonstrate that the transient degradation of Rim21 completely suppressed the Rim101 pathway but that the degradation of Dfg16 or Rim9 did not. This finding strongly suggests that Rim21 is the pH sensor protein and that Dfg16 and Rim9 play auxiliary functions through maintaining the level of Rim21 and assisting in its plasma membrane localization. Even without external alkalization, the Rim101 pathway was activated in a Rim21-dependent manner by either protonophore treatment or depletion of phosphatidylserine in the inner leaflet of the plasma membrane, both of which caused plasma membrane depolarization like the external alkalization. Therefore, plasma membrane depolarization seems to be one of the key signals for the pH sensor molecule Rim21.
巻・号 287(46)
ページ 38473-81
公開日 2012-11-9
DOI 10.1074/jbc.M112.394205
PII S0021-9258(20)62313-4
PMID 23019326
PMC PMC3493892
MeSH Amino Acid Motifs Cell Membrane / metabolism F-Box Proteins / metabolism Gene Deletion Glycosylation Green Fluorescent Proteins / metabolism Hydrogen-Ion Concentration Lipid Bilayers / chemistry Lipids / chemistry Membrane Proteins / chemistry Membrane Proteins / metabolism Phosphorylation Plasmids / metabolism Protein Processing, Post-Translational Receptors, Cell Surface / metabolism* Saccharomyces cerevisiae / metabolism* Saccharomyces cerevisiae Proteins / metabolism* Ubiquitin-Protein Ligase Complexes / metabolism
IF 4.238
引用数 36
WOS 分野 BIOCHEMISTRY & MOLECULAR BIOLOGY
リソース情報
酵母 BY25598 BYP6739 BYP6740