Anti-S3 antibodies enable researchers to detect and measure the S3 antigen in biological samples. This target is a reported synonym of the RPS3 gene, which encodes ribosomal protein S3. This protein is known to function in the apoptotic pathway and cell division, among other biological roles. The human version of S3 has a canonical amino acid length of 243 residues and a protein mass of 26.7 kilodaltons, although 2 isoforms have been identified. It is reported to be localized in the nucleus, mitochondria, and cytoplasm of cells. S3 is a member of the Universal ribosomal protein uS3 protein family.