Serine/threonine-protein kinase that acts downstream of ERK (MAPK1/ERK2 and MAPK3/ERK1) signaling and mediates mitogenic and stress-induced activation of transcription factors, regulates translation, and mediates cellular proliferation, survival, and differentiation. May function as tumor suppressor in epithelial ovarian cancer cells. {ECO:0000269|PubMed:16878154, ECO:0000269|PubMed:7623830}. This is the function of Ensembl gene identifier ENSG00000071242 (RPS6KA2, ribosomal protein S6 kinase A2).