Presence of lipocortins I and IV, but not II and VI, in human platelets

• Published in: FEBS letters 1993-03, Vol.318 (3), p.231-234
• Main Authors: Eldering, Joyce A., Kocher, Markus, Clemetson, Jeannine M., Clemetson, Kenneth J., Frey, Felix J., Frey, Brigitte M.
• Format: Article
• Language: English
• Subjects: Analytical, structural and metabolic biochemistry; Annexin; Annexin A1 - blood; Annexin A2 - blood; Annexin A4 - blood; Annexin A6 - blood; Binding and carrier proteins; Biological and medical sciences; Blood Platelets - chemistry; Blood Platelets - drug effects; Blotting, Western; Calcium - pharmacology; Cytoplasmic Granules - chemistry; Cytoskeleton - chemistry; Cytosol - chemistry; Detergents - pharmacology; DTT, dithiothreitol; Egtazic Acid - pharmacology; Electrophoresis, Polyacrylamide Gel; Fundamental and applied biological sciences. Psychology; Humans; IEF, isoelectric focusing; LC, lipocortin; Lipocortin; mAB, monoclonal antibody; NEM, N-ethylmaleimide; PAGE, polyacrylamide gel electrophoresis; Platelet; Platelet Activation; PMSF, phenylmethylsulfonyl fluoride; Proteins; rLC, recombinant lipocortin; SDS, sodium dodecyl sulfate; Thrombin - pharmacology; Tris, trishydroxymethylaminomethane
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(93)80518-Y

The present investigation revealed the presence of lipocortins I and IV, but not lipocortins II and VI, in human platelets. Lipocortin I was found in the Triton-soluble fraction of both resting and thrombin-activated platelets and was not covalently bound to skeletal components. Without detergents, when resting platelets were lysed and fractionated in the absence of Ca 2+, lipocortin I was found only in the cytosolic fraction, whereas, in the presence of Ca 2+, lipocortin I was associated only with the crude particulate and not with the membrane nor the cytosolic fractions.