Platelet-derived growth factor stimulates phosphorylation of the 25 kDa mRNA cap binding protein (eIF-4E) in human lung fibroblasts.
Platelet-derived growth factor exerts rapid effects on protein synthesis and polysome formation in cultured cells. We report that platelet-derived growth factor stimulates a rapid phosphorylation of eIF-4E in WI-38 human lung fibroblasts. The effect was dependent on both time and PDGF concentrations. Phosphoserine was the sole phosphoamino acid identified and tryptic phosphopeptide maps showed a single phosphopeptide under both control and PDGF conditions. Phosphorylation of eIF-4E may be of the events required for initiating entry into G1 and commitment into S phase of the cell cycle.
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Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232.
Hagedorn
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D000596:Amino Acids / Q000032:analysis; D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002460:Cell Line; D039561:Eukaryotic Initiation Factor-4E; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008168:Lung; D008970:Molecular Weight; D010448:Peptide Initiation Factors / Q000302:isolation & purification / Q000378:metabolism*; D010449:Peptide Mapping; D010748:Phosphopeptides / Q000302:isolation & purification; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D039381:RNA Cap-Binding Proteins
D000596:Amino Acids; D002352:Carrier Proteins; D039561:Eukaryotic Initiation Factor-4E; D010448:Peptide Initiation Factors; D010748:Phosphopeptides; D010982:Platelet-Derived Growth Factor; D039381:RNA Cap-Binding Proteins