Biosynthesis and intracellular transport of the receptor for platelet-derived growth factor.
The biosynthesis of the receptor for platelet-derived growth factor (PDGF) was examined in metabolically labeled human foreskin fibroblasts. The receptor was synthesized as a 145-kDa precursor, which, when incubated with endo-beta-N-acetylglucosaminidase H (endo H), underwent a 15-kDa decrease in molecular mass. This indicates that the size of the core protein is about 130 kDa and that the 145-kDa form represents a receptor precursor carrying high-mannose N-linked oligosaccharide groups. Within 15 min after synthesis, the receptor was converted to a 165-kDa form. This form was entirely resistant to endo H treatment and probably represents a receptor molecule that has undergone further posttranslational modification, including O-linked glycosylation. Subsequently, within 30 min, a molecule of 170 kDa--i.e., the size of the mature receptor--appeared. A slightly larger molecule, of 175 kDa, which could be immunoprecipitated from PDGF-stimulated 32P-labeled cells, probably represents a receptor further modified by autophosphorylation. The 170-kDa molecule had an isoelectric point of about 4.5. Addition of PDGF increased the turnover rate of the 170-kDa PDGF receptor.
Claesson-Welsh
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Ludwig Institute for Cancer Research, Biomedical Center, Uppsala, Sweden.
Rönnstrand
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Heldin
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D000118:Acetylglucosaminidase; D001692:Biological Transport; D011232:Chemical Precipitation; D006031:Glycosylation; D006801:Humans; D007158:Immunologic Techniques; D066298:In Vitro Techniques; D007526:Isoelectric Point; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008970:Molecular Weight; D010750:Phosphoproteins / Q000378:metabolism; D010982:Platelet-Derived Growth Factor / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D011956:Receptors, Cell Surface / Q000378:metabolism*; D017479:Receptors, Platelet-Derived Growth Factor
D008562:Membrane Glycoproteins; D010750:Phosphoproteins; D010982:Platelet-Derived Growth Factor; D011956:Receptors, Cell Surface; D017479:Receptors, Platelet-Derived Growth Factor; D000118:Acetylglucosaminidase; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase