Probable transmembrane GTPase (By similarity). Mediates mitochondrial fusion (PubMed:21248201, PubMed:25190516). Fusion of mitochondria occurs in many cell types and constitutes an important step in mitochondria morphology, which is balanced between fusion and fission (By similarity). GTP + H2O = GDP + H(+) + phosphate RNAi-mediated knockdown results in fragmented mitochondria, most likely due to lack of fusion activity (PubMed:25190516). RNAi-mediated knockdown in a moma-1 mutant background results in mitochondrial fragmentation. Belongs to the TRAFAC class dynamin-like GTPase superfamily. Dynamin/Fzo/YdjA family. Mitofusin subfamily.