Available structures
PDBOrtholog search: PDBe RCSB
AliasesRPS6KA3, CLS, HU-3, ISPK-1, MAPKAPK1B, MRX19, RSK, RSK2, S6K-alpha3, p90-RSK2, pp90RSK2, ribosomal protein S6 kinase A3, XLID19
External IDsOMIM: 300075 MGI: 104557 HomoloGene: 37940 GeneCards: RPS6KA3
RefSeq (mRNA)



RefSeq (protein)



Location (UCSC)Chr X: 20.15 – 20.27 MbChr X: 157.99 – 158.15 Mb
PubMed search[3][4]
View/Edit HumanView/Edit Mouse

protein S6 kinase, 90kDa, polypeptide 3, also s RPS6KA3, is an enzyme that in humans is encoded by the RPS6KA3 gene.[5][6]


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 members of the mitogen-activated kinase (MAPK) signalling pathway. The activity of this protein has been implicated in controlling cell growth and differentiation.[5]

Clinical significance

Mutations in this gene have been associated with Coffin–Lowry syndrome (CLS).[7]


RPS6KA3 has been shown to interact with CREB-binding protein,[8] MAPK1[9][10] and PEA15.[11]


  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000177189 - Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000031309 - Ensembl, May 2017
  3. ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. ^ a b "Entrez Gene: RPS6KA3 ribosomal protein S6 kinase, 90kDa, polypeptide 3".
  6. ^ Moller DE, Xia CH, Tang W, Zhu AX, Jakubowski M (February 1994). "Human rsk isoforms: cloning and characterization of tissue-specific expression". The American Journal of Physiology. 266 (2 Pt 1): C351–9. doi:10.1152/ajpcell.1994.266.2.C351. PMID 8141249.
  7. ^ Jacquot S, Zeniou M, Touraine R, Hanauer A (January 2002). "X-linked Coffin-Lowry syndrome (CLS, MIM 303600, RPS6KA3 gene, protein product known under various names: pp90(rsk2), RSK2, ISPK, MAPKAP1)". European Journal of Human Genetics. 10 (1): 2–5. doi:10.1038/sj.ejhg.5200738. PMID 11896450.
  8. ^ Merienne K, Pannetier S, Harel-Bellan A, Sassone-Corsi P (October 2001). "Mitogen-regulated RSK2-CBP interaction controls their kinase and acetylase activities". Molecular and Cellular Biology. 21 (20): 7089–96. doi:10.1128/MCB.21.20.7089-7096.2001. PMC 99884. PMID 11564891.
  9. ^ Zhao Y, Bjorbaek C, Moller DE (November 1996). "Regulation and interaction of pp90(rsk) isoforms with mitogen-activated protein kinases". The Journal of Biological Chemistry. 271 (47): 29773–9. doi:10.1074/jbc.271.47.29773. PMID 8939914.
  10. ^ Smith JA, Poteet-Smith CE, Malarkey K, Sturgill TW (January 1999). "Identification of an extracellular signal-regulated kinase (ERK) docking site in ribosomal S6 kinase, a sequence critical for activation by ERK in vivo". The Journal of Biological Chemistry. 274 (5): 2893–8. doi:10.1074/jbc.274.5.2893. PMID 9915826.
  11. ^ Vaidyanathan H, Ramos JW (August 2003). "RSK2 activity is regulated by its interaction with PEA-15". The Journal of Biological Chemistry. 278 (34): 32367–72. doi:10.1074/jbc.M303988200. PMID 12796492.

Further reading