Characterization of GMP-140 (P-selectin) as a circulating plasma protein
| Autor: | Lindsay Dunlop, Emmanuel J. Favaloro, Michael P. Skinner, J J Gorman, Michael C. Berndt, Linda J. Bendall, Mathew Vadas, Jennifer R. Gamble, P. A. Castaldi |
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| Jazyk: | angličtina |
| Rok vydání: | 1992 |
| Předmět: |
Blood Platelets
P-selectin Chemistry Immunology Molecular Sequence Data Articles Blood Proteins Platelet Membrane Glycoproteins Platelet Activation Blood proteins Peptide Fragments Respiratory burst P-Selectin Secretory protein Biochemistry Membrane protein Solubility Antigens CD Immunology and Allergy Humans Platelet Platelet activation Amino Acid Sequence Cell activation |
| Zdroj: | The Journal of Experimental Medicine |
| ISSN: | 1540-9538 0022-1007 |
| Popis: | GMP-140 is a 140-kD granule membrane protein, found in the alpha granules of platelets and the Weibel-Palade bodies of endothelial cells, that is surface expressed on cell activation and mediates neutrophil attachment. Cloning data for GMP-140 from an endothelial library predict a soluble form of the protein, the transcription message for which is also found in platelets. In this study, we report the detection by enzyme-linked immunosorbent assay of soluble GMP-140 in plasma centrifuged for 3 h at 100,000 g (to remove platelet microparticles) and confirm its identity by purification from plasma. Plasma concentrations were found to be 0.251 +/- 0.043 micrograms/ml (means +/- SD, n = 10) in normal male controls and 0.175 +/- 0.063 micrograms/ml (means +/- SD, n = 10) in normal female controls. The purified protein had an identical molecular mass (nonreduced) to platelet membrane GMP-140 (approximately 3 kD lower, reduced) and was immunoblotted by polyclonal anti-GMP-140, and the anti-GMP-140 monoclonal antibodies AK4 and AK6. Analytical gel filtration studies indicated that the plasma GMP-140 eluted as a monomer whereas detergent-free, platelet membrane GMP-140 eluted as a tetramer consistent with plasma GMP-140 lacking a transmembrane domain. Purified plasma GMP-140 bound to the same neutrophil receptor as the membrane-bound form, and when immobilized on plastic, bound neutrophils equivalently to immobilized platelet membrane GMP-140. Since it has been shown that fluid-phase GMP-140 is antiinflammatory and downregulates CD18-dependent neutrophil adhesion and respiratory burst, its presence in plasma may be of major importance in preventing the inadvertent activation of neutrophils in the circulation. |
| Databáze: | OpenAIRE |
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