This gene 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 ATF1. The encoded protein can also phosphorylate histone H3 to regulate certain inflammatory genes. Several transcript variants encoding different isoforms have been found for this gene. RPS6KA4 (Ribosomal Protein S6 Kinase A4) is a Protein Coding gene. Among its related pathways are Type I Interferon Signaling Pathways and Endocytic Trafficking of EGFR. GO annotations related to this gene include transferase activity, transferring phosphorus-containing groups and protein tyrosine kinase activity. An important paralog of this gene is RPS6KA5.