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Tyrosine‐specific phosphorylation of gpIIIa in platelet membranes
Author(s) -
Elmore Moira A.,
Anand Radhika,
Horvath Andrea R.,
Kellie Stuart
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)81177-p
Subject(s) - phosphorylation , phosphoprotein , tyrosine phosphorylation , tyrosine , proto oncogene tyrosine protein kinase src , platelet , chemistry , biochemistry , protein phosphorylation , microbiology and biotechnology , sh2 domain , biology , protein kinase a , immunology
In vitro phosphorylation of platelet subcellular fractions revealed that most of the alkali‐resistant phosphoproteins and the majority of pp60 c‐src were in the surface membrane fraction. An alkali‐resistant phosphoprotein of about 100 kDa was also immune precipitated by an anti‐phosphotyrosine antibody and comigrated with gpIIIa. The phosphorylation of gpIIIa, but not gpIIb, was confirmed by the comparison of reduced and non‐reduced gels, and this protein was phosphorylated exclusively on tyrosine. In contrast, both gpIIb and gpIIIa were phosphorylated when the purified complex was added to immunopurified, immobilised pp60 c‐src . A synthetic peptide with partial homology to a putative tyrosine phosphorylation site in the cytoplasmic domain of gpIIIa was phosphorylated by antibody‐purified pp60 c‐src . Our results indicate that tyrosine‐specific phosphorylation of gpIIIa by pp60 c‐src may play a role in the regulation of platelet function.