title: Specific cleavage of the fibroblast receptor for platelet-derived growth factor by an endogenous Ca2+-dependent thiol protease.
abstract: Previous studies have shown that platelet-derived growth factor (PDGF) stimulates the phosphorylation of two components in membranes prepared from human fibroblasts in the presence of Ca2+. One of these represents the 185-kDa PDGF receptor, which undergoes autophosphorylation, and the other has an Mr of 130 000. We show in this communication that the 130-kDa component is derived from the 185-kDa receptor via proteolysis by an endogenous Ca2+-dependent protease, which is dependent on a reduced -SH group for its activity. The 130-kDa fragment contains several of the characteristics of the receptor, such as the PDGF-binding site and the major autophosphorylation sites. Furthermore, the cleaved receptor retains tyrosine kinase activity.
mesh_terms: D002118:Calcium / Q000494:pharmacology*; D003546:Cysteine Endopeptidases; D010450:Endopeptidases / Q000502:physiology*; D066246:ErbB Receptors; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D007457:Iodine Radioisotopes; D008970:Molecular Weight; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000032:analysis; D011956:Receptors, Cell Surface / Q000378:metabolism*; D017479:Receptors, Platelet-Derived Growth Factor
chemical_list: D007457:Iodine Radioisotopes; D010982:Platelet-Derived Growth Factor; D011956:Receptors, Cell Surface; D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases; D017479:Receptors, Platelet-Derived Growth Factor; D010450:Endopeptidases; D003546:Cysteine Endopeptidases; D002118:Calcium