Serine/threonine-protein kinase that acts downstream ofERK (MAPK1/ERK2 and MAPK3/ERK1) signaling and mediates mitogenicand stress-induced activation of the transcription factors CREB1,ETV1/ER81 and NR4A1/NUR77, regulates translation through RPS6 andEIF4B phosphorylation, and mediates cellular proliferation,survival, and differentiation by modulating mTOR signaling andrepressing pro-apoptotic function of BAD and DAPK1. In fibroblast,is required for EGF-stimulated phosphorylation of CREB1, whichresults in the subsequent transcriptional activation of severalimmediate-early genes. In response to mitogenic stimulation (EGFand PMA), phosphorylates and activates NR4A1/NUR77 and ETV1/ER81transcription factors and the cofactor CREBBP. Upon insulin-derived signal, acts indirectly on the transcription regulation ofseveral genes by phosphorylating GSK3B at 'Ser-9' and inhibitingits activity. Phosphorylates RPS6 in response to serum or EGF viaan mTOR-independent mechanism and promotes translation initiationby facilitating assembly of the pre-initiation complex. Inresponse to insulin, phosphorylates EIF4B, enhancing EIF4Baffinity for the EIF3 complex and stimulating cap-dependenttranslation. Is involved in the mTOR nutrient-sensing pathway bydirectly phosphorylating TSC2 at 'Ser-1798', which potentlyinhibits TSC2 ability to suppress mTOR signaling, and mediatesphosphorylation of RPTOR, which regulates mTORC1 activity and maypromote rapamycin-sensitive signaling independently of thePI3K/AKT pathway. Mediates cell survival by phosphorylating thepro-apoptotic proteins BAD and DAPK1 and suppressing their pro-apoptotic function. Promotes the survival of hepatic stellatecells by phosphorylating CEBPB in response to the hepatotoxincarbon tetrachloride (CCl4). Mediates induction of hepatocyteprolifration by TGFA through phosphorylation of CEBPB (Bysimilarity). Is involved in cell cycle regulation byphosphorylating the CDK inhibitor CDKN1B, which promotes CDKN1Bassociation with 14-3-3 proteins and prevents its translocation tothe nucleus and inhibition of G1 progression..
RPS6KA1(Ribosomal Protein S6 Kinase, 90-KD, 1), also called RSK1, is an enzyme that in humans is encoded by the RPS6KA1 gene. The RSK(ribosomal S6 kinase) family comprises growth factor-regulated serine/threonine kinases, known also as p90(rsk). Homologs of RSK exist in several species. By analysis of somatic cell hybrids, Moller et al.(1994) mapped the RPS6KA1 gene to chromosome 3.Bonni et al.(1999) characterized the mechanism by which the RAS-MAPK signaling pathway mediates growth factor-dependent cell survival. Inoue et al.(2007) demonstrated that p90rsk, the kinase immediately downstream from Mos-MAPK, directly targets Erp1 for CSF arrest in Xenopus oocytes.
[list_product_images]Western blot analysis of p90 RSK1 expression in immunoprecipitated negative control (lane A) and mouse brain extract (lane B). p90 RSK1 at 88KD was detected using rabbit anti-p90 RSK1 Antigen Affinity purified polyclonal antibody (Catalog # A01058). The blot was developed using chemiluminescence (ECL) method (Catalog # EK1002).[/list_product_images]