This gene encodes a member of the RSK (ribosomal S6 kinase) family of serine/threonine kinases. This kinase contains a kinase catalytic domain and phosphorylates the S6 ribosomal protein and eukaryotic translation initiation factor 4B (eIF4B). Phosphorylation of S6 leads to an increase in protein synthesis and cell proliferation. [provided by RefSeq, Jan 2015].