Human Misato regulates mitochondrial distribution and morphology.
Misato of Drosophila melanogaster and Saccharomyces cerevisiae DML1 are conserved proteins having a homologous region with a part of the GTPase family that includes eukaryotic tubulin and prokaryotic FtsZ. We characterized human Misato sharing homology with Misato of D. melanogaster and S. cerevisiae DML1. Tissue distribution of Misato exhibited ubiquitous distribution. Subcellular localization of the protein studied using anti-Misato antibody suggested that it is localized to the mitochondria. Further experiments of fractionating mitochondria revealed that Misato was localized to the outer membrane. The transfection of Misato siRNA led to growth deficiencies compared with control siRNA transfected HeLa cells, and the Misato-depleted HeLa cells showed apoptotic nuclear fragmentation resulting in cell death. After silencing of Misato, the filamentous mitochondrial network disappeared and fragmented mitochondria were observed, indicating human Misato has a role in mitochondrial fusion. To examine the effects of overexpression, COS-7 cells were transfected with cDNA encoding EGFP-Misato. Its overexpression resulted in the formation of perinuclear aggregations of mitochondria in these cells. The Misato-overexpressing cells showed low viability and had no nuclei or a small and structurally unusual ones. These results indicated that human Misato has a role(s) in mitochondrial distribution and morphology and that its unregulated expression leads to cell death.
Kimura
Masashi
M
Department of Molecular Pathobiochemistry, Division of Disease Control, Gifu University Graduate School of Medicine, Yanagido 1-1, Gifu 501-1194, Japan. yo@gifu-u.ac.jp
Okano
Yukio
Y
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002470:Cell Survival; D002522:Chlorocebus aethiops; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics; D005111:Extrachromosomal Inheritance; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D007150:Immunohistochemistry; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D051336:Mitochondrial Membranes / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D034622:RNA Interference; D017386:Sequence Homology, Amino Acid; D014162:Transfection
D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D029721:Drosophila Proteins; C519909:MSTO1 protein, human; D024101:Mitochondrial Proteins; C105947:mst protein, Drosophila