Sustains mitochondrial morphology probably through maintaining cristae morphology (PubMed:20578245, PubMed:21248201). May act as a component of the MICOS complex, a large protein complex of the mitochondria (By similarity). Component of the mitochondrial contact site and cristae organizing system (MICOS) complex. Localized to cytoplasmic foci in embryos and gonads. Evenly distributed between the periphery and the cristae regions of the mitochondrion inner membrane. Expressed in the gonads and muscle cells. Expressed in embryos. Egg-laying defects, defective oogenesis in 30% of mutants, reduced brood size and increased resistance to oxidative stress inducer paraquat (PubMed:20578245). Abnormal mitochondrial morphology with mitochondria appearing larger and as localized swellings and tubular extensions (PubMed:20578245, PubMed:21248201). Mitochondria also have elongated and curved cristae that are stacked with a reduced number of junctions (PubMed:20578245, PubMed:21248201). Double knockout with immt-2 results in a more reduced brood size and enhanced resistance to paraquat-induced oxidative stress as compared to the single mutant, and in addition, mutants are slower swimmers, have increased hydrogen peroxide-induced reactive oxygen species (ROS), and reduced mitochondrial mass accompanied by reduced superoxide anion oxidation (PubMed:20578245). Double knockout with chch-3 RNAi results in reduced or no brood, poor growth and withered gonads (PubMed:21248201). Belongs to the MICOS complex subunit Mic60 family.