Double knockouts reveal that protein tyrosine phosphatase 1B is a physiological target of calpain-1 in platelets
Double knockouts reveal that protein tyrosine phosphatase 1B is a physiological target of calpain-1 in platelets
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DOI：
10.1128/mcb.00522-07
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发表时间：
2007-09-01
影响因子：
5.3
通讯作者：
Chishti, Athar H.
中科院分区：
文献类型：
--
作者：
Kuchay, Shafi M.;Kim, Nayoung;Chishti, Athar H.
钙蛋白酶是一种普遍存在的钙调节半胱氨酸蛋白酶，与细胞骨架组织、细胞增殖、细胞凋亡、细胞运动和止血有关。我们利用基因靶向技术评估了小鼠calpain-1的生理功能，并证实其失活可能通过引起血小板蛋白的去磷酸化导致血小板聚集和凝块缩回减少。在这里，我们报道了calpain-1缺失（Capni(-/-)）血小板积累蛋白酪氨酸磷酸酶1B (PTP1B)，这与酪氨酸磷酸酶活性增强和多种底物的去磷酸化有关。用酪氨酸磷酸酶抑制剂双（N，N-二甲基羟胺）羟xovanadate治疗Capn1（-/-）血小板，可纠正聚集缺陷并恢复受损的凝块缩回。更重要的是，在缺乏calpain-1和PTP1B的双敲除小鼠中，血小板聚集、凝块缩回和酪氨酸去磷酸化缺陷得以恢复。通过氯化铁诱导的动脉损伤模型对突变小鼠进行进一步评估，表明Capn1（-/-）小鼠体内对血栓形成具有相对的抗性。综上所述，我们的研究结果表明，PTP1B是calpain-1的生理靶点，并表明在其他细胞中，类似的机制可能调节calpain-1介导的酪氨酸去磷酸化。
Calpains are ubiquitous calcium-regulated cysteine proteases that have been implicated in cytoskeletal organization, cell proliferation, apoptosis, cell motility, and hemostasis. Gene targeting was used to evaluate the physiological function of mouse calpain-1 and establish that its inactivation results in reduced platelet aggregation and clot retraction potentially by causing dephosphorylation of platelet proteins. Here, we report that calpain-1 null (Capni(-/-)) platelets accumulate protein tyrosine phosphatase 1B (PTP1B), which correlates with enhanced tyrosine phosphatase activity and dephosphorylation of multiple substrates. Treatment of Capn1(-/-) platelets with bis(N,N-dimethylhydroxamido)hydroxooxovanadate, an inhibitor of tyrosine phosphatases, corrected the aggregation defect and recovered impaired clot retraction. More importantly, platelet aggregation, clot retraction, and tyrosine dephosphorylation defects were rescued in the double knockout mice lacking both calpain-1 and PTP1B. Further evaluation of mutant mice by the ferric chloride-induced arterial injury model suggests that the Capn1(-/-) mice are relatively resistant to thrombosis in vivo. Together, our results demonstrate that PTP1B is a physiological target of calpain-1 and suggest that a similar mechanism may regulate calpain-1-mediated tyrosine dephosphorylation in other cells.