Thrombin-induced protein phosphorylation in resting platelets and fibroblasts: evidence for common post-receptor molecular events.
We have investigated the thrombin-stimulated protein phosphorylation associated with the activation of two cellular processes: 1) reinitiation of DNA synthesis in G0-arrested hamster fibroblasts and 2) stimulation of serotonin release in platelets. We found a rapid 4- to 6-fold increased phosphorylation of a peptide with apparent Mr = 27,000 in SDS-PAGE. In both cell systems, the 27,000 dalton phosphopeptide is cytosolic, is resolved by isoelectric focusing as multiple variants (pHi 5 to 6), and thrombin stimulation generates the most acidic phosphorylated forms. This result and the fact that the 27,000 dalton peptide is also stimulated by a variety of growth factors in fibroblasts, strongly suggests that thrombin action in platelets and growth factor-induced mitogenesis, share common post-receptor molecular events.
D000818:Animals; D001792:Blood Platelets / Q000378:metabolism*; D006224:Cricetinae; D003412:Cricetulus; D004261:DNA Replication / Q000187:drug effects*; D005347:Fibroblasts / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D008168:Lung / Q000378:metabolism; D010750:Phosphoproteins / Q000097:blood / Q000378:metabolism*; D010766:Phosphorylation; D010974:Platelet Aggregation / Q000187:drug effects; D011956:Receptors, Cell Surface / Q000378:metabolism; D018179:Receptors, Thrombin; D012701:Serotonin / Q000097:blood; D013917:Thrombin / Q000494:pharmacology*
D010750:Phosphoproteins; D011956:Receptors, Cell Surface; D018179:Receptors, Thrombin; D012701:Serotonin; D013917:Thrombin