Identification of cell surface binding sites for PC-cell-derived growth factor, PCDGF, (epithelin/granulin precursor) on epithelial cells and fibroblasts.
PC cell derived growth factor (PCDGF) is an 88-kDa glycoprotein purified from the culture medium of the highly tumorigenic mouse teratoma-derived cell line PC. PCDGF was shown to stimulate the proliferation of 3T3 fibroblasts and PC cells. Amino acid sequencing of PCDGF indicated its identity to the precursor for the 6-kDa polypeptides epithelins and granulins. In this paper, we investigated the binding of PCDGF to the mink lung epithelial cell line CCL64. Scatchard analysis indicates that 125I-PCDGF binding to CCL64 cells is curvilinear, corresponding to the existence of two classes of binding sites: high affinity binding sites (560 +/- 170 sites/cell) with a Kd1 of 43 +/- 15 pM and low affinity binding sites (16,350 +/- 5900 sites/cell) with a Kd2 of 3.9 +/- 1.9 nM. 125I-PCDGF was chemically crosslinked to cell surface receptors on CCL64 cells with disuccinimidyl suberate. A major crosslinked band of about 190 kDa with radiolabeled PCDGF was detected after SDS-PAGE, suggesting the presence of PCDGF binding sites with molecular weight of about 120 kDa. 125I. PCDGF crosslinking studies indicate the presence of PCDGF binding sites with a molecular weight similar to those of binding sites on CCL64 cells on the surface of two other PCDGF-responsive cell lines, 3T3 fibroblasts and PC cells. These data suggest that the receptors for PCDGF are widely distributed on cells of distinct embryonic origin.
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Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore 21201-1180, USA.
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D000345:Affinity Labels / Q000737:chemistry; D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D003432:Cross-Linking Reagents / Q000378:metabolism; D005786:Gene Expression Regulation / Q000235:genetics; D006023:Glycoproteins / Q000378:metabolism*; D006133:Growth Substances / Q000378:metabolism*; D036341:Intercellular Signaling Peptides and Proteins; D007457:Iodine Radioisotopes / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D008907:Mink; D000077153:Progranulins; D011956:Receptors, Cell Surface / Q000737:chemistry*; D011994:Recombinant Proteins / Q000378:metabolism; D013388:Succinimides / Q000378:metabolism
D000345:Affinity Labels; D003432:Cross-Linking Reagents; D006023:Glycoproteins; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D007457:Iodine Radioisotopes; D000077153:Progranulins; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; D013388:Succinimides; C019358:disuccinimidyl suberate