Ribosomal Protein S6 Kinase Alpha 4 (RPS6Ka4)

RPS6Ka4 encodes a member of the RSK (ribosomal S6 kinase) family of serine/threonine kinases. This kinase contains 2 non-identical kinase catalytic domains and phosphorylates various substrates, including CREB1 and c-fos. Alternate transcriptional splice variants of this gene have been observed but have not been thoroughly characterized.

The predicted 772-amino acid protein contains 2 complete catalytic ser/thr kinase domains, both of which include 11 consensus kinase subdomains and conserved ATP-binding and activation domains. The N-terminal and C-terminal kinase domains of RSKB and ribosomal protein kinase 1 share 53% and 43% identity, respectively.