title: Fission yeast Msp1 is a mitochondrial dynamin-related protein.
abstract: We recently identified Msp1p, a fission yeast Schizosaccharomyces pombe dynamin-related protein, which is essential for the maintenance of mitochondrial DNA. The Msp1p sequence displays typical features of a mitochondrial protein. Here we report in vitro and in vivo data that validate that prediction. We demonstrate that the targeting sequence of Msp1p is processed by recombinant mitochondrial processing peptidase and that Msp1p is imported into S. pombe mitochondria in vitro in the presence of cellular extracts. We show that the first 109 residues of Msp1p encompass a functional peptide signal that is sufficient to direct chimera to mitochondria. Immunofluorescence studies indicate that Msp1p staining colocalises with a mitochondrial marker and electron microscopy shows that the protein is located inside the mitochondria. Mitochondrial enrichment and fractionation further confirm that localisation and show that Msp1p is anchored to the matrix side of the mitochondrial inner membrane. Finally, we report that overexpression of the Msp1 protein results in gross alteration of the mitochondrial structure and function. All together our results suggest that Msp1p is an essential component for mitochondrial maintenance.
authors.affiliation: Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération, Université Paul Sabatier, CNRS EP2079, 31062 Toulouse cedex, France.
authors.forename: L
authors.initials: L
authors.lastname: Pelloquin
authors.forename: P
authors.initials: P
authors.lastname: Belenguer
authors.forename: Y
authors.initials: Y
authors.lastname: Menon
authors.forename: N
authors.initials: N
authors.lastname: Gas
authors.forename: B
authors.initials: B
authors.lastname: Ducommun
mesh_terms: D000595:Amino Acid Sequence; D001692:Biological Transport; D034281:Dynamins; D004579:Electron Transport / Q000502:physiology; D020558:GTP Phosphohydrolases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal / Q000502:physiology; D007425:Intracellular Membranes / Q000378:metabolism / Q000648:ultrastructure; D008666:Metalloendopeptidases / Q000378:metabolism; D016253:Microscopy, Immunoelectron; D008928:Mitochondria / Q000378:metabolism* / Q000648:ultrastructure; D008969:Molecular Sequence Data; D021382:Protein Sorting Signals / Q000737:chemistry / Q000502:physiology; D012568:Schizosaccharomyces / Q000378:metabolism* / Q000648:ultrastructure; D029702:Schizosaccharomyces pombe Proteins; D000096122:Mitochondrial Processing Peptidase
chemical_list: D034281:Dynamins; D020558:GTP Phosphohydrolases; D008666:Metalloendopeptidases; D021382:Protein Sorting Signals; D029702:Schizosaccharomyces pombe Proteins; D000096122:Mitochondrial Processing Peptidase; C498344:Msp1 protein, S pombe