Rabbit Anti-Human S6 monoclonal antibody for IF. Ribosomal protein 6 (RPS6) is a component of the 40S ribosomal subunit belonging to S6E family of ribosomal proteins. RPS6 is a key substrate for kinases, and is phosphorylated by growth factors and mitogens during in cell growth and cell division. Phosporylation in RPS6 is well regulated, and the different phosphorylation sites are highly conserved. Major phosphorylation sites of RPS6 include Ser 235, 236, 240, and 244.