title: Mitochondrial association, protein phosphorylation, and degradation regulate the availability of the active Rab GTPase Ypt11 for mitochondrial inheritance.
abstract: The Rab GTPase Ypt11 is a Myo2-binding protein implicated in mother-to-bud transport of the cortical endoplasmic reticulum (ER), late Golgi, and mitochondria during yeast division. However, its reported subcellular localization does not reflect all of these functions. Here we show that Ypt11 is normally a low-abundance protein whose ER localization is only detected when the protein is highly overexpressed. Although it has been suggested that ER-localized Ypt11 and ER-mitochondrial contact sites might mediate passive transport of mitochondria into the bud, we found that mitochondrial, but not ER, association is essential for Ypt11 function in mitochondrial inheritance. Our studies also reveal that Ypt11 function is regulated at multiple levels. In addition to membrane targeting and GTPase domain-dependent effector interactions, the abundance of active Ypt11 forms is controlled by phosphorylation status and degradation. We present a model that synthesizes these new features of Ypt11 function and regulation in mitochondrial inheritance.
authors: Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA.
authors: Agnieszka
authors: A
authors: Lewandowska
authors: Jane
authors: J
authors: Macfarlane
authors: Janet M
authors: JM
authors: Shaw
mesh_terms: D000595:Amino Acid Sequence; D017124:Conserved Sequence; D004721:Endoplasmic Reticulum / Q000201:enzymology; D004795:Enzyme Stability; D015870:Gene Expression; D015966:Gene Expression Regulation, Fungal; D050259:Genes, Mitochondrial; D008928:Mitochondria / Q000201:enzymology*; D024101:Mitochondrial Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D059748:Proteolysis; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D020691:rab GTP-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D024101:Mitochondrial Proteins; C571177:Mmr1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C468556:Ypt11 protein, S cerevisiae; D020691:rab GTP-Binding Proteins