RSK

Ribosomal S6 protein kinases (RSKs) are a family of protein serine/threonine kinases that regulate diverse cellular processes such as cell growth, motility, survival and proliferation. The RSK family can be divided into two subfamilies: p90 RSK and p70 S6K.

p90 RSKs phosphorylate numerous cytosolic and nuclear targets and act as downstream effectors of the ERK/MAPK signaling cascade. The four isoforms of this enzyme are expressed ubiquitously in human tissues and exist in multiple subcellular compartments. p90 RSKs are activated in response to growth factors, many polypeptide hormones, neurotransmitters and chemokines. Aberrant activation of p90 RSKs has been linked to many human diseases, including breast and prostate cancers.

p70 ribosomal S6 kinase (S6K) exists as two isoforms − S6K1 and S6K2 − which are activated by mitogenic stimuli such as growth factors, insulin and cytokines. In turn, p70 S6K phosphorylates the ribosomal protein S6. The S6K1 isoform also phosphorylates other proteins involved in the cell's translational machinery, including elF4B (initiation factor); eEF2K (elongation factor 2 kinase); and SKAR (RNA binding protein). As such, it is thought that S6K1 may be directly involved in cell growth and when considered alongside its position downstream of the PI3K and mTOR pathways, this activity makes S6K1 a potential target for cancer therapy.

External sources of pharmacological information for RSK :

• BJP Guide

Ribosomal S6 Kinase Gene Data