Extracellular Factors Influencing the In Vitro Protein Synthesis of Platelets

Summary

Regulation of platelet protein synthesis by selected extracellular factors and events have been examined. Protein synthetic function was assessed by the incorporation of ³H-leucine into trichloroacetic acid-precipitable protein and was characterized by: a) incorporation of 0.1 μ moles leucine/hr/10⁸8 platelets; b) sensitivity to puromycin but not actinomycin D; and c) synthesis of multiple size species. Inhibition and potentiation of the rate of protein synthesis by extracellular factors was demonstrable. Plasma and serum both inhibited protein synthesis, and the inhibitory effect appeared to be dependent upon a cooperative effect of two distinct plasma factors. The inhibitory effect may reflect a decrease in the rate of protein synthesis and/or an increase in the rate of protein catabolism. Fibrinogen and its plasmic cleavage products X, Y and E did not affect platelet protein synthesis; but the D: E complex and D fragment produced approximately 50% increases in the rate of synthesis. Protein synthesis and the release reaction appeared to be independent cellular functions as ADP, thrombin, AMP, ATP, adenosine and dibutyryl derivatives of cyclic AMP and GMP did not influence protein synthesis. Epinephrine at 1 mM inhibited the initial rate of protein synthesis by 45%; however, this effect appeared to be independent of the release reaction. It is concluded that platelet protein synthesis in vitro is independent of selected platelet hemostatic functions such as the release reaction but is susceptible to regulation by agents which occur in vivo.

• References

• 1 Agam G, Bessler H, Djaldetti M. 1976; In vitro DNA and RNA synthesis by human platelets. Biochimica et Biophysica Acta 425: 41
• 2 Bocci V, Conti T, Muscettola M, Pacini A, Pessina GP. 1974; Factors regulating plasma protein synthesis. IV. Influence of fragments D and E on plasma fibrinogen concentration. Thrombosis et Diathesis Haemorrhagica 31: 395
• 3 Booyse FM, Rafelson Jr ME. 1967; a Stable messenger RNA in the synthesis of contractile protein in human platelets. Biochimica et Biophysica Acta 145: 188
• 4 Booyse FM, Rafelson Jr ME. 1967; b In vitro incorporation of amino acids into the contractile protein of human blood platelets. Nature 215: 283
• 5 Booyse FM, Rafelson Jr ME. 1968; a Studies of human platelets. I. Synthesis of platelet protein in a cell-free system. Biochimica et Biophysica Acta 166: 689
• 6 Booyse FM, Hoveke TP, Rafelson Jr ME. 1968; b Studies of human platelets. II. Protein synthetic activity of various platelet populations. Biochimica et Biophysica Acta 157: 660
• 7 Booyse FM, Zschocke D, Hoveke TP, Rafelson Jr ME. 1971; Studies of human platelets IV. Protein synthesis in maturing human platelets Thrombosis et Diathesis Haemorrhagica 26: 167
• 8 Born GV R, Haslam RJ, Goldman M, Lowe RD. 1965; Comparative effectiveness of adenosine analogues as inhibitors of blood platelet aggregation and as vasodilators in man. Nature 205: 678
• 9 Doolittle RF, Schubert D, Schwartz SA. 1967; Amino acid sequence studies on autiodactyl fibrinopeptides. I. Dromedary camel, mule deer, and cape buffalo. Archives of Biochemistry and Biophysics 118: 456
• 10 Haslam RJ. 1967; Mechanisms of blood platelet aggregation. Physiology of Hemostasis and Thrombosis Thomas, Springfield, IL, p 88
• 11 Humphrey JH. 1955; Origin of blood platelets. Nature 176: 38
• 12 Jerushalmy Z, Zucker MB. 1966; Some effects of fibrinogen degradation products (fDP) on blood platelets. Thrombosis et Diathesis Haemorrhagica 75: 413
• 13 Knutt AA, Gardner FH. 1958; Survival of blood platelets labeled with chromium51. Journal of Clinical Investigation 37: 1257
• 14 Luganova IS, Seits IF, Teodorovich VI. 1958; Metabolism in human thrombocytes. Biochemistry (Eng. Trans.) 23: 379
• 15 Nachman RL, Ferris B. 1968; Studies on human platelet protease activity. Journal of Clinical Investigation 47: 2530
• 16 Nilehn JE. 1967; Split products of fibrinogen after prolonged interaction with plasmin. Thrombosis et Diathesis Haemorrhagica 18: 89
• 17 Packham MA, Ardlie NG, Mustard JF. 1969; The effect of adenine compounds on platelet aggregation. American Journal of Physiology 217: 1009
• 18 Plow E, Edgington TS. 1973; Immunobiology of fibrinogen. Emergence of neoantigenic expressions during physiologic cleavage in vitro and in vivo Journal of Clinical Investigation 52: 273
• 19 Reich E, Franklin RM, Shatkin AJ, Tatum EL. 1962; Action of actinomycin D on animal cells and viruses. Proceedings of the National Academy of Sciences USA 98: 1238
• 20 Robison GA, Butcher RW, Sutherland EW. 1971. Some actions of cyclic AMP. Cyclic AMP. Academic Press; New York: p 138
• 21 Rosier O, Wegrzynowicz. Sawicki Z, Kopec M. 1969; Fibrinogensynthese in Blutplättchen. Folia Hematologica 92: 553
• 22 Salzman EW. 1972; Cyclic AMP and platelet function. New England Journal of Medicine 286: 358
• 23 Steiner M, Baldini M. 1969; Protein synthesis in aging blood platelets. Blood 33: 628
• 24 Warshaw AL, Laster L, Shulman NR. 1966; Oxidation in human platelets. Journal of Clinical Investigation 45: 1923
• 25 Warshaw AL, Laster L, Shulman NR. 1967; Protein synthesis by human platelets. Journal of Biological Chemistry 242: 2094
• 26 Weber K, Osborn M. 1969; The reliability of molecular weight determinations by dodecylsul- fate-polyacrylamide gel electrophoresis. Journal of Biological Chemistry 244: 4406
• 27 WICKS WD. 1974; Regulation of protein synthesis by cyclic AMP. Advances in Cyclic Nucleotide Research 4: 335
• 28 Yarmolinsky MB, De La Haba GL. 1959; Inhibition by puromycin of amino acid incorporation into protein. Proceedings of the National Academy of Sciences USA 45: 1721