Ribosomal S6 Kinase (RSK)

Ribosomal S6 Kinase (RSK) is a family of serine/threonine protein kinases involved in the regulation of cell viability. RSK is phosphorylated in response to mitogens by activation of one or more protein kinase cascades. Phosphorylation of S6 in vivo is catalyzed by (at least) two distinct mitogen-activated S6 kinase families distinguishable by size, the 70 kDa and 90 kDa S6 kinases. Both S6 kinases are activated by serine/threonine phosphorylation.

The p90 ribosomal s6 kinase family (1-4) is a group of highly conserved Ser/Thr kinases that act as downstream effectors of the Ras/Raf/MEK/ERK signaling pathway. They regulate diverse cellular processes, such as cell growth, cell motility, cell survival and cell proliferation. The p70 ribosomal protein S6 kinase, an important member of AGC family, is a kind of multifunctional Ser/Thr kinases, which plays an important role in mTOR signaling cascade. The p70 ribosomal protein S6 kinase is closely associated with diverse cellular processes such as protein synthesis, mRNA processing, glucose homeostasis, cell growth and apoptosis.