OPA3 (outer mitochondrial membrane lipid metabolism regulator OPA3) is a mitochondrial protein that plays critical roles in mitochondrial function and cellular metabolism. The protein consists of 179 amino acids and is ubiquitously expressed, with highest levels in skeletal muscle and kidney 1. OPA3 localizes to the outer mitochondrial membrane where it regulates lipid metabolism and mitochondrial dynamics 2. Functionally, OPA3 maintains mitochondrial structural integrity and prevents ferroptosis by interacting with NFS1, a key iron-sulfur cluster biogenesis protein 2. The protein also influences the cGAS-STING innate immune pathway by preventing mitochondrial DNA stress 3. Mutations in OPA3 cause autosomal dominant optic atrophy type 3 and 3-methylglutaconic aciduria type 3 (Costeff syndrome), conditions characterized by bilateral optic nerve degeneration, visual impairment, and in severe cases, multi-systemic features including cardiomyopathy and neurological dysfunction 45. OPA3 deficiency leads to retinal ganglion cell death and increased mitochondrial activity as a compensatory mechanism 5. The protein has also been implicated in cancer progression, with high expression associated with poor prognosis in ovarian and colorectal cancers 63.