Receptor tyrosine kinases (RTKs) play a key role in the communication of cells with their microenvironment. These molecules are involved in the regulation of cell growth, differentiation and metabolism. The protein encoded by this gene is a RTK that is widely expressed in normal and transformed epithelial cells and is activated by various types of collagen. This protein belongs to a subfamily of tyrosine kinase receptors with a homology region to the Dictyostelium discoideum protein discoidin I in their extracellular domain. Its autophosphorylation is achieved by all collagens so far tested (type I to type VI).di Marco E., J. Biol. Chem. 268:24290-24295(1993)Johnson J.D., Proc. Natl. Acad. Sci. U.S.A. 90:5677-5681(1993)Laval S., Cell Growth Differ. 5:1173-1183(1994).