Role of MMM1 in maintaining mitochondrial morphology in Neurospora crassa.
Mmm1p is a protein required for maintenance of mitochondrial morphology in budding yeast. It was proposed that it is required to mediate the interaction of the mitochondrial outer membrane with the actin cytoskeleton. We report the cloning and characterization of MMM1 of the filamentous fungus Neurospora crassa, an organism that uses microtubules for mitochondrial transport. Mutation of the mmm-1 gene leads to a temperature-sensitive slow growth phenotype and female sterility. Mutant cells harbor abnormal giant mitochondria at all stages of the asexual life cycle, whereas actin filament-depolymerizing drugs have no effect on mitochondrial morphology. The MMM1 protein has a single transmembrane domain near the N terminus and exposes a large C-terminal domain to the cytosol. The protein can be imported into the outer membrane in a receptor-dependent manner. Our findings suggest that MMM1 is a factor of general importance for mitochondrial morphology independent of the cytoskeletal system used for mitochondrial transport.
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Institut für Physiologische Chemie der Universität München, Goethestrasse 33, 80336 München, Germany.
Neupert
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Westermann
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D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D017124:Conserved Sequence; D003599:Cytoskeleton / Q000502:physiology / Q000648:ultrastructure; D003600:Cytosol / Q000648:ultrastructure; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007425:Intracellular Membranes / Q000648:ultrastructure; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000502:physiology / Q000648:ultrastructure; D008928:Mitochondria / Q000502:physiology / Q000648:ultrastructure*; D008969:Molecular Sequence Data; D009492:Neurospora crassa / Q000235:genetics* / Q000648:ultrastructure*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D012568:Schizosaccharomyces / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D005656:Fungal Proteins; C089418:MMM1 protein, S cerevisiae; D008565:Membrane Proteins; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins