ICK or intestinal cell kinase belongs to a very extensive family of proteins that share a conserved catalytic core common with both serine/threonine and tyrosine protein kinases. ICK encodes an intestinal serine/threonine kinase harboring a dual phosphorylation site found in mitogen-activating protein (MAP) kinases (1). ICK localizes to the intestinal crypt region and is thought to be important in intestinal epithelial cell proliferation and differentiation. ICK purified from transfected human embryonic kidney cells undergoes autophosphorylation and phosphorylates a test protein. ICK plays a key role in development of central nervous, skeletal, and endocrine systems (2).