Rodríguez-Liñares B, Watson S P
FEBS Lett. 1994 Oct 3;352(3):335-8. doi: 10.1016/0014-5793(94)00983-x.
We show the presence of the tyrosine kinase JAK2 in human platelets and demonstrate that it undergoes phosphorylation on tyrosine residues on challenge with the G protein receptor stimulus, thrombin, or the tyrosine phosphatase inhibitor, peroxovanadate. Thrombin-induced phosphorylation of JAK2 is inhibited by two structurally distinct inhibitors of tyrosine kinases, staurosporine and the tyrphostin ST271. The protein kinase C (PKC) inhibitor, Ro 31-8220, and intracellular Ca2+ chelator, BAPTA-AM, also inhibit thrombin-induced phosphorylation of JAK2, while the phorbol ester, phorbol dibutyrate (PDBu), and Ca2+ ionophore, A23187, induce tyrosine phosphorylation of JAK2. These results suggest that tyrosine phosphorylation of JAK2 stimulated by thrombin may be mediated downstream of phosphoinositide metabolism.
我们发现人类血小板中存在酪氨酸激酶JAK2，并证明在受到G蛋白受体刺激物凝血酶或酪氨酸磷酸酶抑制剂过氧钒酸盐刺激时，它会在酪氨酸残基上发生磷酸化。凝血酶诱导的JAK2磷酸化受到两种结构不同的酪氨酸激酶抑制剂（星形孢菌素和酪氨酸磷酸化抑制剂ST271）的抑制。蛋白激酶C（PKC）抑制剂Ro 31-8220和细胞内Ca2+螯合剂BAPTA-AM也抑制凝血酶诱导的JAK2磷酸化，而佛波酯佛波醇二丁酸酯（PDBu）和Ca2+离子载体A23187则诱导JAK2的酪氨酸磷酸化。这些结果表明，凝血酶刺激引起的JAK2酪氨酸磷酸化可能在磷酸肌醇代谢的下游介导。
