Protein kinase activation is a frequent response of cells to treatment with growth factors, chemicals, heat shock, or apoptosisinducing agents. This protein kinase activation presumably allows cells to resist unfavorable environmental conditions. The yeast 'sterile 20' (Ste20) kinase acts upstream of the mitogen-activated protein kinase (MAPK) cascade that is activated under a variety of stress conditions. MST2 was identified as a kinase that is activated by the proapoptotic agents straurosporine and FAS ligand. Synonyms: Monoclonal STK3 antibody, Anti-STK3 antibody, Serine/threonine-protein kinase 3 antibody, KRS1 antibody, MST2 antibody, FLJ90748 antibody.