Msp1p is an intermembrane space dynamin-related protein that mediates mitochondrial fusion in a Dnm1p-dependent manner in S. pombe

• Published in: FEBS letters Vol. 579; no. 5; pp. 1109 - 1116
• Main Authors: Guillou, Emmanuelle, Bousquet, Céline, Daloyau, Marlène, Emorine, Laurent J., Belenguer, Pascale
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 14.02.2005
• Subjects: 4′,6′-diamino-2-phenylindole; Adenosine Triphosphatases - chemistry; Adenosine Triphosphatases - genetics; Adenosine Triphosphatases - metabolism; ADOA; Amino Acid Motifs; autosomal dominant optic atrophy; CAT; chloroamphenicol-acetyl-transferase; DAPI; DNA, Mitochondrial - metabolism; Dynamin; Dynamins - chemistry; Dynamins - genetics; Dynamins - metabolism; Fungal Proteins - chemistry; Fungal Proteins - genetics; Fungal Proteins - metabolism; Gene Expression Regulation, Fungal; GTP Phosphohydrolases - chemistry; GTP Phosphohydrolases - metabolism; GTPase; IMS; inner membrane; intermembrane space; Intracellular Membranes - metabolism; matrix; Mito-GFP; Mitochondria; Mitochondria - metabolism; mitochondrial DNA; mitochondrial-targeted green fluorescent protein; mtDNA; Optic atrophy; outer membrane; Protein Structure, Tertiary; Schizosaccharomyces - cytology; Schizosaccharomyces - metabolism; Schizosaccharomyces pombe Proteins - chemistry; Schizosaccharomyces pombe Proteins - genetics; Schizosaccharomyces pombe Proteins - metabolism; TEV; tobacco etch virus; Yeast; Yeast; IM; TEV; mtDNA; DAPI; ADOA; IMS; Mitochondria; Optic atrophy; MA; Mito-GFP; CAT; Dynamin; GTPase; OM
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/j.febslet.2004.12.083

Mitochondrial morphology is controlled by large GTPases, such as Msp1p, whose action on mitochondrial membranes is not yet understood. The sub-mitochondrial localization of Msp1p, the subject of ongoing controversies, was found to be within the intermembrane space. Overexpression of Msp1p led to aggregation of the mitochondrial network, while its downregulation resulted in fragmentation of this network. Mutations affecting the integrity of the Msp1p GTPase function had a dominant phenotype and induced mitochondrial fragmentation followed by mitochondrial DNA loss and cell death. These effects were not observed in cells deleted for Dnm1p, an actor in mitochondrial fission, suggesting that Msp1p is involved in the fusion of mitochondria.