The product of the c-fms proto-oncogene: a glycoprotein with associated tyrosine kinase activity.

The c-fms proto-oncogene is a member of a gene family that has been implicated in tumorigenesis. Glycoproteins encoded by c-fms were identified in cat spleen cells by means of an immune-complex kinase assay performed with monoclonal antibodies to v-fms-coded epitopes. The major form of the normal cellular glycoprotein has an apparent molecular weight of 170,000 and, like the product of the viral oncogene, serves as a substrate for an associated tyrosine-specific protein kinase activity in vitro. The results suggest that the transforming glycoprotein specified by v-fms is a truncated form of a c-fms-coded growth factor receptor.