title: Dual cell wall/mitochondria localization of the 'SUN' family proteins.
abstract: The Saccharomyces cerevisiae SUN family gene products, namely Sim1p, Uth1p, Nca3p and Sun4p, show a high degree of homology among themselves and are closely related to beta-glucosidase of Candida wickerhamii; however, these proteins do not bear such an activity. Dithiothreitol-treatment of intact cells induces the release of Uth1p, Sun4p and Sim1p from the cell wall. These highly glycosylated proteins are thus non-covalently bound to the cell wall. Two of them, Uth1p and Sun4p, have also been found in mitochondria. Sub-localization experiments show that Uth1p is inserted in the outer mitochondrial membrane and that Sun4p is preferentially a matrix protein. The physiological significance of this double localization is discussed in relation to the roles of these proteins in different cellular processes, namely mitochondrial biogenesis and cell septation.
authors.affiliation: Institut de Biochimie et Génétique Cellulaires, CNRS, UMR 5095, 1 rue Camille Saint Saëns, 33077, Bordeaux Cedex, France.
authors.forename: Gisèle
authors.initials: G
authors.lastname: Velours
authors.forename: Catherine
authors.initials: C
authors.lastname: Boucheron
authors.forename: Stéphen
authors.initials: S
authors.lastname: Manon
authors.forename: Nadine
authors.initials: N
authors.lastname: Camougrand
mesh_terms: D051792:Basic Helix-Loop-Helix Proteins; D002473:Cell Wall / Q000378:metabolism; D004229:Dithiothreitol; D005656:Fungal Proteins / Q000302:isolation & purification / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000378:metabolism; D018257:Helix-Loop-Helix Motifs; D015151:Immunoblotting; D008565:Membrane Proteins; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins; D012097:Repressor Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D004229:Dithiothreitol; D005656:Fungal Proteins; D006360:Heat-Shock Proteins; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; C491093:SIM1 protein, S cerevisiae; C116477:UTH1 protein, S cerevisiae