title: Yeast cell wall integrity sensors form specific plasma membrane microdomains important for signalling.
abstract: The cell wall integrity (CWI) pathway of the yeast Saccharomyces cerevisiae relies on the detection of cell surface stress by five sensors (Wsc1, Wsc2, Wsc3, Mid2, Mtl1). Each sensor contains a single transmembrane domain and a highly mannosylated extracellular region, and probably detects mechanical stress in the cell wall or the plasma membrane. We here studied the distribution of the five sensors at the cell surface by using fluorescently tagged variants in conjunction with marker proteins for established membrane compartments. We find that each of the sensors occupies a specific microdomain at the plasma membrane. The novel punctate 'membrane compartment occupied by Wsc1' (MCW) shows moderate overlap with other Wsc-type sensors, but not with those of the Mid-type sensors or other established plasma membrane domains. We further observed that sensor density and formation of the MCW compartment depends on the cysteine-rich head group near the N-terminus of Wsc1. Yet, signalling capacity depends more on the sensor density in the plasma membrane than on clustering within its microcompartment. We propose that the MCW microcompartment provides a quality control mechanism for retaining functional sensors at the plasma membrane to prevent them from endocytosis.
authors.affiliation: Universität Osnabrück, Fachbereich Biologie/Chemie, AG Genetik, 49076, Osnabrück, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Kock
authors.affiliation: Universität Osnabrück, Fachbereich Biologie/Chemie, AG Biochemie, 49076, Osnabrück, Germany.
authors.forename: Henning
authors.initials: H
authors.lastname: Arlt
authors.affiliation: Universität Osnabrück, Fachbereich Biologie/Chemie, AG Biochemie, 49076, Osnabrück, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Ungermann
authors.affiliation: Universität Osnabrück, Fachbereich Biologie/Chemie, AG Genetik, 49076, Osnabrück, Germany.
authors.forename: Jürgen J
authors.initials: JJ
authors.lastname: Heinisch
mesh_terms: D000595:Amino Acid Sequence; D002473:Cell Wall / Q000378:metabolism; D004705:Endocytosis; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000378:metabolism*; D021962:Membrane Microdomains / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000378:metabolism* / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; C091625:MID2 protein, S cerevisiae; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; C119383:SLG1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins