Analysis of functional domains of rat mitochondrial Fis1, the mitochondrial fission-stimulating protein.
In yeast, mitochondrial-fission is regulated by the cytosolic dynamin-like GTPase (Dnm1p) in conjunction with a peripheral protein, Mdv1p, and a C-tail-anchored outer membrane protein, Fis1p. In mammals, a dynamin-related protein (Drp1) and Fis1 are involved in the mitochondrial-fission reaction as Dnm1 and Fis1 orthologues, respectively. The involvement of other component(s), such as the Mdv1 homologue, and the mechanisms regulating mitochondrial-fission remain unclear. Here, we identified rat Fis1 (rFis1) and analyzed its structure-function relationship. Blue-native-polyacrylamide gel electrophoresis revealed that rFis1 formed a approximately 200-kDa complex in the outer mitochondrial membrane. Its expression in HeLa cells promoted extensive mitochondrial fragmentation, and gene knock-down by RNAi induced extension of the mitochondrial networks. Taking advantage of these properties, we analyzed functional domains of rFis1. These experiments revealed that the N-terminal and C-terminal segments are both essential for oligomeric rFis1 interaction, and the middle TPR-like domains regulate proper oligomer assembly. Any mutations that disturb the proper oligomeric assembly compromise mitochondrial division-stimulating activity of rFis1.
Jofuku
Akihiro
A
Department of Molecular Biology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan.
Ishihara
Naotada
N
Mihara
Katsuyoshi
K
D000595:Amino Acid Sequence; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008930:Mitochondria, Liver / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016297:Mutagenesis, Site-Directed; D009928:Organ Specificity; D017434:Protein Structure, Tertiary; D051381:Rats; D013329:Structure-Activity Relationship; D014018:Tissue Distribution
C503403:Fis1 protein, rat; D024101:Mitochondrial Proteins