Anti-I-4 antibodies enable researchers to detect and measure the I-4 antigen in biological samples. This target is a reported synonym of the PPP1R2C gene, which encodes PPP1R2C family member C. This protein is known to function as a protein phosphatase inhibitor. The human version of I-4 has a canonical amino acid length of 202 residues and a protein mass of 22.7 kilodaltons. I-4 is a member of the Protein phosphatase inhibitor 2 protein family.