Palmitylation of the glycoprotein IIb-IIIa complex in human blood platelets
- Medical School, Lodz (Poland)
The presence of covalently bound palmitic acid in fibrinogen receptors, glycoproteins (GP) IIb and IIIa, has been explored in human blood platelets. Membrane fractions were isolated from fresh blood platelets labeled with (9,10-3H)palmitic acid and then analyzed for radioactive proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Protein bands were visualized by staining with Coomassie Brilliant Blue, excised, and counted in a liquid scintillation counter. The results indicate that membrane proteins with electrophoretic mobility corresponding to glycoproteins IIb and IIIa incorporate (9,10-3H)palmitic acid. The palmitylated glycoproteins IIb and IIIa were immunoprecipitated by specific anti-GP IIb and GP IIIa antisera. It is interesting to note that the palmitylation of these glycoproteins occurred rapidly in platelets activated with 0.5 unit of thrombin or 30 microM ADP. At the concentration used (100 micrograms/ml), cycloheximide did not inhibit incorporation of (3H)palmitate into the glycoproteins showing that this process is not dependent upon protein synthesis. The acyl moiety was resistant to denaturating detergents, delipidation with organic solvents, and hydrolyzable with hydroxylamine. In the case of membrane protein with the electrophoretic mobility of GP IIb, the radioactive label was significantly decreased after reduction with 2-mercaptoethanol. Final identification of GP IIIa as an acylated product in human platelets incubated with (9,10-3H)palmitic acid was provided by two-dimensional polyacrylamide gel electrophoresis. In contrast to GP IIb alpha, GP IIIa isolated by this method showed the presence of attached radioactive palmitic acid residues. Analysis by high performance liquid chromatography after methanolysis of the (3H)palmitate-labeled glycoproteins confirmed the fatty acid nature of the label.
- OSTI ID:
- 5517213
- Journal Information:
- Journal of Biological Chemistry; (USA), Journal Name: Journal of Biological Chemistry; (USA) Vol. 264:21; ISSN JBCHA; ISSN 0021-9258
- Country of Publication:
- United States
- Language:
- English
Similar Records
Covalent modification of platelet proteins by palmitate
Rh polypeptide is a major fatty acid-acylated erythrocyte membrane protein
Related Subjects
59 BASIC BIOLOGICAL SCIENCES
AMINES
ANIMALS
ANTI-INFECTIVE AGENTS
ANTIBIOTICS
BIOASSAY
BIOLOGICAL MATERIALS
BIOSYNTHESIS
BLOOD
BLOOD CELLS
BLOOD PLATELETS
BODY FLUIDS
CARBOXYLIC ACIDS
COAGULANTS
COMPLEXES
COUNTING TECHNIQUES
CYCLOHEXIMIDE
DRUGS
ENZYMES
FUNGICIDES
GLYCOPROTEINS
HEMATOLOGIC AGENTS
HEMOSTATICS
HEXADECANOIC ACID
HYDROGEN COMPOUNDS
HYDROLASES
HYDROXYLAMINE
IMMUNOASSAY
IN VITRO
ISOTOPE APPLICATIONS
MAMMALS
MAN
MATERIALS
METABOLISM
MONOCARBOXYLIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
PEPTIDE HYDROLASES
PESTICIDES
PRIMATES
PROTEINS
SCINTILLATION COUNTING
SERINE PROTEINASES
SYNTHESIS
THROMBIN
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES