title: Ist2 in the yeast cortical endoplasmic reticulum promotes trafficking of the amino acid transporter Bap2 to the plasma membrane.
abstract: The equipment of the plasma membrane in Saccharomyces cerevisiae with specific nutrient transporters is highly regulated by transcription, translation and protein trafficking allowing growth in changing environments. The activity of these transporters depends on a H(+) gradient across the plasma membrane generated by the H(+)-ATPase Pma1. We found that the polytopic membrane protein Ist2 in the cortical endoplasmic reticulum (ER) is required for efficient leucine uptake during the transition from fermentation to respiration. Experiments employing tandem fluorescence timer protein tag showed that Ist2 was necessary for efficient trafficking of newly synthesized leucine transporter Bap2 from the ER to the plasma membrane. This finding explains the growth defect of ist2Δ mutants during nutritional challenges and illustrates the important role of physical coupling between cortical ER and plasma membrane.
authors.affiliation: Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH-Allianz, Heidelberg, Germany.
authors.forename: Wendelin
authors.initials: W
authors.lastname: Wolf
authors.affiliation: Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH-Allianz, Heidelberg, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Meese
authors.affiliation: Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH-Allianz, Heidelberg, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Seedorf
mesh_terms: D026905:Amino Acid Transport Systems / Q000235:genetics* / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005285:Fermentation; D015966:Gene Expression Regulation, Fungal; D017136:Ion Transport; D010085:Oxidative Phosphorylation; D021381:Protein Transport; D006180:Proton-Translocating ATPases / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D026905:Amino Acid Transport Systems; C097094:BAP2 protein, S cerevisiae; C477782:IST2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C092477:PMA1 protein, S cerevisiae; D006180:Proton-Translocating ATPases