Anti-Optineurin antibodies are directed against the protein encoded by the gene OPTN in humans. The Optineurin protein has an expected mass of 65.9 kDa. The protein may also be known as FIP2, HIP7, ALS12, GLC1E, E3-14.7K-interacting protein, and FIP-2. Variants of this antigen may also be found in other species, including canine, porcine, monkey, mouse and rat.