Dual cell wall/mitochondria localization of the 'SUN' family proteins.
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.
Velours
Gisèle
G
Institut de Biochimie et Génétique Cellulaires, CNRS, UMR 5095, 1 rue Camille Saint Saëns, 33077, Bordeaux Cedex, France.
Boucheron
Catherine
C
Manon
Stéphen
S
Camougrand
Nadine
N
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
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