Protein-tyrosine kinase p72syk is activated by wheat germ agglutinin in platelets.
We previously reported a molecular cloning of porcine gene syk encoding a non-receptor type 72-kDa protein-tyrosine kinase (Taniguchi et al. (1991) J. Biol. Chem. 266, 15790-15796). In this study, we have demonstrated that p72syk is expressed in porcine platelets at 0.1-0.2% of total protein and that the lectin wheat germ agglutinin induces an activation of p72syk against both auto- and exogenous-substrate-phosphorylation in porcine platelets. The activation of p72syk was abrogated by the coexistence of N-acetyl-D-glucosamine with wheat germ agglutinin. These data suggest that p72syk is a candidate of responsible protein-tyrosine kinase for platelet activation and that cell surface glycoprotein is involved in the activation of p72syk in platelets.
Ohta
S
S
Department of Biochemistry, Fukui Medical School, Japan.
Taniguchi
T
T
Asahi
M
M
Kato
Y
Y
Nakagawara
G
G
Yamamura
H
H
D000117:Acetylglucosamine / Q000494:pharmacology; D000596:Amino Acids / Q000302:isolation & purification; D000818:Animals; D001792:Blood Platelets / Q000201:enzymology*; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D015151:Immunoblotting; D008214:Lymphocytes / Q000201:enzymology; D008970:Molecular Weight; D010750:Phosphoproteins / Q000097:blood; D011505:Protein-Tyrosine Kinases / Q000097:blood*; D013347:Subcellular Fractions / Q000201:enzymology; D013552:Swine; D014909:Wheat Germ Agglutinins
D000596:Amino Acids; D010750:Phosphoproteins; D014909:Wheat Germ Agglutinins; D011505:Protein-Tyrosine Kinases; D000117:Acetylglucosamine