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ATP Augments von Willebrand Factor-dependent Shear-induced Platelet Aggregation through Ca2+-Calmodulin and Myosin Light Chain Kinase Activation
- Source :
- Journal of Biological Chemistry. 279:26266-26273
- Publication Year :
- 2004
- Publisher :
- Elsevier BV, 2004.
-
Abstract
- Shear stress triggers von Willebrand factor (VWF) binding to platelet glycoprotein Ibalpha and subsequent integrin alpha(IIb)beta(3)-dependent platelet aggregation. Concomitantly, nucleotides are released from plateletdense granules, and ADP is known to contribute to shear-induced platelet aggregation (SIPA). We found that the impaired SIPA of platelets from a Hermansky-Pudlak patient lacking dense granules was restored by exogenous l-beta,gamma-methylene ATP, a stable P2X(1) agonist, as well as by ADP, confirming that in addition to ADP (via P2Y(1) and P2Y(12)), ATP (via P2X(1)) also contributes to SIPA. Likewise, SIPA of apyrase-treated platelets was restored upon P2X(1) activation with l-beta,gamma-methylene ATP, which promoted granule centralization within platelets and stimulated P-selectin expression, which is a marker of alpha-granule release. In addition, during SIPA, platelet degranulation required both extracellular Ca(2+) and VWF-glycoprotein Ibalpha interactions without involving alpha(IIb)beta(3). Neither platelet release nor SIPA was affected by protein kinase C inactivation, even though protein kinase C blockade inhibits platelet responses to collagen and thrombin in stirring conditions. In contrast, inhibiting myosin light chain (MLC) kinase with ML-7 reduced platelet release and SIPA by 30%. Accordingly, the potentiating effect of P2X(1) stimulation on the aggregation of apyrase-treated platelets coincided with intensified phosphorylation of MLC and was abrogated by ML-7. SIPA-induced MLC phosphorylation occurred exclusively through released nucleotides and selective antagonism of P2X(1) with MRS2159-reduced SIPA, ATP release, and potently inhibited MLC phosphorylation. We conclude that the P2X(1) ion channel induces MLC-mediated cytoskeletal rearrangements, thus contributing to SIPA and degranulation during VWF-triggered platelet activation.
- Subjects :
- Blood Platelets
Time Factors
Myosin light-chain kinase
Platelet Aggregation
Blotting, Western
Immunoblotting
Platelet Membrane Glycoproteins
Platelet membrane glycoprotein
Models, Biological
Biochemistry
chemistry.chemical_compound
Adenosine Triphosphate
Calmodulin
Platelet degranulation
von Willebrand Factor
Humans
Platelet
Platelet activation
Phosphorylation
Myosin-Light-Chain Kinase
Molecular Biology
Cytoskeleton
Ions
Receptors, Purinergic P2
Thrombin
Platelet Glycoprotein GPIb-IX Complex
Cell Biology
Flow Cytometry
Platelet Activation
Molecular biology
Cell biology
Adenosine Diphosphate
Enzyme Activation
Microscopy, Electron
P-Selectin
Adenosine diphosphate
chemistry
Receptors, Purinergic P2X
Pyridoxal Phosphate
Calcium
Collagen
Azo Compounds
Adenosine triphosphate
Protein Binding
Subjects
Details
- ISSN :
- 00219258
- Volume :
- 279
- Database :
- OpenAIRE
- Journal :
- Journal of Biological Chemistry
- Accession number :
- edsair.doi.dedup.....5fb279760af4c1e7cd003872c061f406