Activity of pp60c-src and association of pp60c-src, pp54/58lyn, pp60fyn, and pp72syk with the cytoskeleton in platelets activated by collagen.
Collagen stimulation of platelets induced an increase in the specific activity of pp60c-src immunoprecipitated from the Triton-soluble fraction. The earliest time after collagen stimulation that an increase in pp60c-src activity was observed was 30 s. However, the maximum activity of pp60c-src in the Triton-soluble fraction was observed 60 s after collagen stimulation. At this time an approximately twofold increase of pp60c-src activity towards phosphorylation of KVEKIGEGTYGVVKK specific peptide and enolase and a 4.5-fold increase towards phosphorylation of pp60c-src itself was measured. Furthermore, the majority of pp60c-src as well as pp54/58lyn, pp60fyn, and pp72syk were found in the Triton-soluble fraction in resting platelets. Collagen induced, to different extents and velocities, translocation of all of these proteins from the Triton-soluble fraction to the Triton-insoluble, cytoskeleton-rich, platelets fraction. These results provide direct evidence that collagen stimulation of platelets increases the tyrosine kinase activity of pp60c-src and suggest that the platelet cytoskeleton plays an important role in collagen-induced signal transduction by localizing signaling molecules.
Kralisz
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Department of Biophysics, Institute of Physiology and Biochemistry, Medical University of Lodz, Poland. ulakr@yahoo.com
Cierniewski
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D001792:Blood Platelets / Q000378:metabolism*; D003094:Collagen / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism*; D003902:Detergents / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004792:Enzyme Precursors / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D047908:Intracellular Signaling Peptides and Proteins; D017830:Octoxynol / Q000494:pharmacology; D015539:Platelet Activation; D010974:Platelet Aggregation; D011233:Precipitin Tests; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051076:Proto-Oncogene Proteins c-fyn; D051575:Proto-Oncogene Proteins c-yes; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000378:metabolism*; D015398:Signal Transduction; D000072377:Syk Kinase; D013997:Time Factors; D019061:src-Family Kinases / Q000378:metabolism*
D003902:Detergents; D004792:Enzyme Precursors; D047908:Intracellular Signaling Peptides and Proteins; D011518:Proto-Oncogene Proteins; D017830:Octoxynol; D003094:Collagen; D011505:Protein-Tyrosine Kinases; C494957:FYN protein, human; D051076:Proto-Oncogene Proteins c-fyn; D051575:Proto-Oncogene Proteins c-yes; D016392:Proto-Oncogene Proteins pp60(c-src); C000606896:SYK protein, human; D000072377:Syk Kinase; D019061:src-Family Kinases