c-kit protein, a transmembrane kinase: identification in tissues and characterization.

Abstract

The proto-oncogene c-kit encodes a transmembrane kinase which is related to the receptors for colony-stimulating factor type 1 and platelet-derived growth factor, as well as to the immunoglobulin superfamily. Antibodies specific for the kinase domain of the P80 gag-kit protein of the Hardy-Zuckerman 4 feline sarcoma virus were prepared. These kit-specific antibodies were used to identify and characterize the c-kit protein in cat brain tissue. The c-kit protein product displays an autophosphorylating activity in immune complex kinase assays, and, in turn, this activity was used to identify the c-kit protein in different tissues. In cat brain, a single 145-kilodalton (kDa) glycoprotein was detected. Its N-linked carbohydrates were found to be sensitive to digestion with the endoglycosidases (neuraminidase, endoglycosidase F, and endoglycosidase H), indicating hybrid and/or complex and high-mannose structures. A partial purification of the c-kit protein was achieved by wheat germ agglutinin affinity chromatography, and the autophosphorylating activity of the partially purified c-kit protein was characterized and found to be specific for tyrosine. The kit antibodies cross-react with the murine c-kit protein product, and variant c-kit proteins in different mouse tissues were identified, with sizes of about 145 kDa (brain), 160 kDa (spleen), and 150 kDa (testis).

The Stem Cell Factor–c-kit System and Mast Cells in Human Pancreatic Cancer

“…Analysis of c-kit by Western blotting failed to detect the reported 145-kDa band (Yarden et al, 1987). The size of the c-kit protein varies between human tissues and cell lines (Hassan et al, 1998;Majumder et al, 1988;Sandlow et al, 1997). This may be due to the existence of different splicing isoforms or to differential glycosylation (Lyman and Jacobsen, 1998).…”

Identification of mutations in the coding sequence of the proto-oncogene c-kit in a human mast cell leukemia cell line causing ligand-independent activation of c-kit product.

“…A murine mAb (YB5.B8) that reacts with the extracellular domain of human c-kit protein was originally raised against human AML blast cells (21,35). The rabbit antiserum against the whole murine c-kit protein (36) was generously donated by Dr. P. Besmer (Cor-nell University Graduate School of Medical Science, New York). A rat mAb (ACK-2) against the extracellular domain of murine c-kit product ( 19) and the full length of murine c-kit cDNA clone were generously donated by Dr. S-I.…”

Expression of c-kit and p53 in Non-small Cell Lung Cancers

“…The kit receptor is a 145~165 kd transmembrane protein that exhibits protein tyrosine kinase activity (1). Its ligand, stem cell factor (SCF), is an early hematopoietic growth factor that, in conjunction with other hematopoietic growth factors, supports the proliferation and differentiation of multiple hematopoietic cell lineages, and has an effect on the control of gametogenesis and melanogenesis through the interaction between c-kit and SCF.…”