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Titolo:
TYROSINE PHOSPHORYLATION OF THE NOVEL PROTEIN-TYROSINE KINASE RAFTK DURING AN EARLY PHASE OF PLATELET ACTIVATION BY AN INTEGRIN GLYCOPROTEIN IIB-IIIA-INDEPENDENT MECHANISM
Autore:
RAJA S; AVRAHAM S; AVRAHAM H;
Indirizzi:
HARVARD UNIV,BETH ISRAEL DEACONESS MED CTR,DIV EXPT MED,W CAMPUS,1 DEACONESS RD BOSTON MA 02215 HARVARD UNIV,BETH ISRAEL DEACONESS MED CTR,DIV EXPT MED BOSTON MA 02215 HARVARD UNIV,BETH ISRAEL DEACONESS MED CTR,DIV HEMATOL ONCOL BOSTON MA 02215
Titolo Testata:
The Journal of biological chemistry
fascicolo: 16, volume: 272, anno: 1997,
pagine: 10941 - 10947
SICI:
0021-9258(1997)272:16<10941:TPOTNP>2.0.ZU;2-S
Fonte:
ISI
Lingua:
ENG
Soggetto:
FOCAL ADHESION KINASE; SIGNAL-TRANSDUCTION; ACTIN-FILAMENTS; CALPAIN; ASSOCIATION; ALPHA(IIB)BETA(3); IDENTIFICATION; AGGREGATION; PP125(FAK); MEMBRANE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
45
Recensione:
Indirizzi per estratti:
Citazione:
S. Raja et al., "TYROSINE PHOSPHORYLATION OF THE NOVEL PROTEIN-TYROSINE KINASE RAFTK DURING AN EARLY PHASE OF PLATELET ACTIVATION BY AN INTEGRIN GLYCOPROTEIN IIB-IIIA-INDEPENDENT MECHANISM", The Journal of biological chemistry, 272(16), 1997, pp. 10941-10947

Abstract

A key regulatory event controlling platelet activation is mediated through the phosphorylation of several cellular proteins by protein-tyrosine kinases, The related adhesion focal tyrosine kinase (RAFTK) is a novel cytoplasmic tyrosine kinase and a member of the focal adhesion kinase (FAR) gene family, FAK, phosphorylation in platelets is integrin-dependent, occurs in a late stage of platelet activation, and is dependent on platelet aggregation, In this study, we have investigated theinvolvement of RAFTK phosphorylation during different stages of platelet activation, Treatment of platelets with thrombin induced, in as early as 10 s, a rapid tyrosine phosphorylation of RAFTK:in a time- and concentration-dependent manner, Treatment of platelets with thrombin in the absence of stirring or pretreatment of platelets with RGDS peptide prevented platelet aggregation, but not RAFTK phosphorylation, Furthermore, phosphorylation of RAFTK did not require integrin engagement since platelets treated with the 7E3 inhibitory antibodies that block fibrinogen binding to glycoprotein IIb-IIIa did not inhibit RAFTK phosphorylation. Similarly, platelets treated with LIBS6 antibodies, whichspecifically activate glycoprotein IIb-IIIa, did not induce RAFTK phosphorylation. Stimulation of platelets by several agonists such as collagen, ADP, epinephrine, and calcium ionophore A23187 induced RAFTK phosphorylation, Tyrosine phosphorylation of RAFTK in platelets is regulated by calcium and is mediated through the protein kinase C pathway. Phosphorylation of RAFTK is dependent upon the formation of actin cytoskeleton as disruption of actin polymerization by cytochalasin D significantly inhibited this phosphorylation, The RAFTK protein appears to be proteolytically cleaved by calpain in an aggregation dependent manner upon thrombin stimulation, These results demonstrate that RAFTK is tyrosine-phosphorylated during an early phase of platelet activation by an integrin- independent mechanism and is not dependent on platelet aggregation, suggesting different mechanisms of regulation for FAK andRAFTK phosphorylation during platelet activation.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 06/07/20 alle ore 05:53:10