Anti-CLS antibodies are protein reagents that detect specific antigens. The CLS antigen is another term for the human protein ribosomal protein S6 kinase A3, encoded by the RPS6KA3 gene. The protein is known to function in the cell cycle and nervous system development, among other biological roles. Canonically, it has an amino acid length of 740 residues and a mass of 83.7 kilodaltons. Its subcellular localization is in the nucleus and cytoplasm and it is reported to be expressed in many tissues, highest levels in skeletal muscle. The CLS protein is a member of the AGC Ser/Thr protein kinase protein family. Other alias names for CLS include HU-3.