Catalytic domain of the Serine/Threonine Kinase, STK10 (also called Lymphocyte-Oriented Kinase or LOK)
STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. STK10/LOK is also called polo-like kinase kinase 1 in Xenopus (xPlkk1). It is highly expressed in lymphocytes and is responsible in regulating leukocyte function associated antigen (LFA-1)-mediated lymphocyte adhesion. It plays a role in regulating the CD28 responsive element in T cells, and may also function as a regulator of polo-like kinase 1 (Plk1), a protein which is overexpressed in multiple tumor types. The STK10 subfamily is part of a larger superfamily that includes the catalytic domains of other protein STKs, protein tyrosine kinases, RIO kinases, aminoglycoside phosphotransferase, choline kinase, and phosphoinositide 3-kinase.