title: Charged flanking residues control the efficiency of membrane insertion of the first transmembrane segment in yeast mitochondrial Mgm1p.
abstract: Mgm1p is a nuclearly encoded GTPase important for mitochondrial fusion. Long and short isoforms of the protein are generated in a unique "alternative topogenesis" process in which the most N-terminal of two hydrophobic segments in the protein is inserted into the inner mitochondrial membrane in about half of the molecules and translocated across the inner membrane in the other half. In the latter population, the second hydrophobic segment is cleaved by the inner membrane protease Pcp1p, generating the short isoform. Here, we show that charged residues in the regions flanking the first segment critically affect the ratio between the two isoforms, providing new insight into the importance of charged residues in the insertion of proteins into the mitochondrial inner membrane.
authors: Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.
authors: Marie
authors: M
authors: Osterberg
authors: Salomé
authors: S
authors: Calado Botelho
authors: Gunnar
authors: G
authors: von Heijne
authors: Hyun
authors: H
authors: Kim
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D019204:GTP-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D057927:Hydrophobic and Hydrophilic Interactions; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D051336:Mitochondrial Membranes / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D021381:Protein Transport; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012697:Serine Endopeptidases / Q000378:metabolism
chemical_list: D000596:Amino Acids; D007527:Isoenzymes; C082883:MGM1 protein, S cerevisiae; D024101:Mitochondrial Proteins; D029701:Saccharomyces cerevisiae Proteins; C490256:Pcp1 protein, S cerevisiae; D012697:Serine Endopeptidases; D019204:GTP-Binding Proteins