Anti-GSP antibodies are protein reagents that detect specific antigens. The GSP antigen is another term for the human protein GNAS complex locus, encoded by the GNAS gene. Canonically, it has an amino acid length of 245 residues and a mass of 28 kilodaltons. Its subcellular localization is in the cytoplasmic vesicles and is secreted. The GSP protein is a member of the NESP55 protein family.