Platelet basic protein

Chemokines are produced as propeptides and are cleaved to yield the active secreted form. N-terminal proteolysis is necessary to produce the active mature protein and further N-terminal proteolysis inactivates mature chemokines. The peptidases that clip the proform, yielding the functionally mature form, have not been fully characterized. Perhaps one of the most complicated posttranslational modifications is the sequential processing of platelet basic protein (PBP) to produce connective tissue-activating protein (CTAPIII), /3-thromboglobin (/3TG), and neutrophil... 

Walz, A., Dewald, B., von Tscharner, V., and Baggiolini, M. (1989). Effects of the neutrophil-activating peptide NAP-2, platelet basic protein, connective tissue-activating peptide III and platelet factor 4 on human neutrophils. J. Exp. Med. 170, 1745-1750. 

Holt, J. C., Rabellino, E. M., Gewirtz, A. M., Gunkel, L. M., Rucinski, B., and Niewiarowski, S. (1988). Occurrence of platelet basic protein, a precursor of low affinity platelet factor 4 and beta-thromboglobulin, in human platelets and megakaryocytes. Exp. Hematol. 16, 302-306. 

Walsh PN. Platelet-coagulant protein interactions. In Colman RW, Hirdi J, Marder VI, Salzman EW eds Hemostasis and Thrombosis Basic principles and clinical practice. Philadelphia J.B. Li] incott 1994 629-51. 

Basic aspects of the proteins of the blood coagulation system and of fibrinolysis are described in this chapter. Some fundamental aspects of platelet biology are also presented. Hemorrhagic and thrombotic states can cause serious medical emergencies, and thromboses in the coronary and cerebral arteries are major causes of death in many parts of the world. Rational management of these conditions requires a clear understanding of the bases of blood clotting and fibrinolysis. 

Niewiarowski S, Holt JC. Biochemistry and physiology of secreted platelet proteins. In Colman RW, Hirsh J, MarderVJ, Salzman EW, eds. Hemostasis and Thrombosis. Basic Principles and Clinical Practice. 2nd ed. Philadelphia Lippincott, 1987 618-630. 

Parallel-plate perfusion system have been also useful to evaluate the relative roles of purified plasma adhesive proteins or isolated components of the vessel wall. Receptors for all fiiese proteins are present in the membrane of platelets. Potentially, platelets can adhere to all of them, although this ability does not depend exclusively on the recognition of the q>ecific proteins by its receptor but also on rheological factors. In fact, there may be more one receptor for each of the adhesive proteins. Recognition by one or another receptor may also be affected by the presence of divalent cations and by the degree of platelet activation. The use of the parallel-plate perfusion chamber together with manipulation of the perfusates and variations in experimental conditions allow the detailed study of basic pathophysiological mechanisms involved in platelet-vessel interactions. 

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