Microtubule-associated force-producing protein that mediates mitochondrial fission during interphasic growth and at cell division. Fission of mitochondria occurs in many cell types and constitutes an important step in mitochondria morphology, which is balanced between fusion and fission. With vps1, acts redundantly in peroxisome biogenesis, which is under cell cycle control. GTP + H2O = GDP + H(+) + phosphate Localizes at sites of mitochondrial constriction. Belongs to the TRAFAC class dynamin-like GTPase superfamily. Dynamin/Fzo/YdjA family.