The protein encoded by this gene is a member of the serine/threonine protein kinase family. This kinase was shown to be activated rapidly during Fas mediated apoptosis in Jurkat cells. In response to Fas receptor ligation, it phosphorylates TIA1, an apoptosis promoting nuclear RNA binding protein. The encoded protein is a strong inducer of lymphocyte apoptosis. Two transcript variants encoding different isoforms have been found for this gene. Other variants exist, but their full length natures have not yet been determined.