| Modification Notes |
The major translational product of the v-Fms oncogene, originally isolated from the McDonough strain of feline sarcoma virus, has been identified as a glycoprotein with intrinsic tyrosine kinase activity. The v-Fms human cellular homolog, c-Fms, has been molecularly cloned and mapped to band q34 on chromosome 5 and identified as the receptor for hematopoietic ligand, CSF-1. Ligand-induced activation of the intrinsic CSF-1R protein tyrosine kinase triggers its interaction with cytoplasmic effector molecules, whose enzymatic activities in part determine the specificity of the CSF-1 response. A series of novel cyclin-like (CYL) genes have been identified in mouse macrophages; the genes are regulated by CSF-1, inducible in G1 and only distantly related to mammalian cyclins A and B or to yeast CLN genes. Tyrosine 809 of CSF-1R lies in a highly-conserved region of the PTK domain which has proven to be a major in-vivo phosphorylation site in many family members. Mutation analysis for Tyrosine 809 shows decreased ability to transduce ligand-dependent mitogenic signals, suggesting that the residue is necessary for interaction with growth factors such as CSF-1. |
