Rac1 Regulation of Surface Expression of Protease-Activated Receptor-1 and Responsiveness to Thrombin in Vascular Smooth Muscle Cells
Rac1 Regulation of Surface Expression of Protease-Activated Receptor-1 and Responsiveness to Thrombin in Vascular Smooth Muscle Cells
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DOI：
10.1161/01.atv.0000168418.10276.f0
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发表时间：
2005-07
期刊：
影响因子：
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通讯作者：
Tatsuya Yufu;K. Hirano;Dan Bi;M. Hirano;J. Nishimura;Y. Iwamoto;H. Kanaide
中科院分区：
文献类型：
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作者：
Tatsuya Yufu;K. Hirano;Dan Bi;M. Hirano;J. Nishimura;Y. Iwamoto;H. Kanaide
凝血酶-蛋白酶激活受体1（PAR 1）介导凝血酶诱导的血管平滑肌细胞增殖和肥大。研究了Rac 1在PAR 1表达调节中的作用。方法和结果-辛伐他汀，一种羟基-3-甲基-戊二酰辅酶A还原酶抑制剂，治疗24小时，减弱凝血酶诱导的短暂[Ca 2 +]i升高。免疫荧光染色显示，辛伐他汀降低PAR 1的表面表达的方式依赖于蛋白质香叶基香叶基化。使用细胞穿透肽引入Rac 1/Cdc 42抑制片段而不是RhoA抑制片段也减弱了对凝血酶的反应并降低了PAR 1的表面表达。最后，下调Rac 1，但不是RhoA，使用RNA干扰技术减弱凝血酶诱导的[Ca 2 +]i升高。然而，PAR 1 mRNA水平和PAR 1蛋白总量保持不变。结论-在这里，我们首次提供了3条证据，证明Rac 1在维持血管平滑肌细胞PAR 1的表面表达和对凝血酶的反应性中起着关键作用。Rac 1被认为调节PAR 1的组成性运输，从而调节PAR 1的表面表达。
Objective—Protease-activated receptor-1 (PAR1) mediates the thrombin-induced proliferation and hypertrophy of vascular smooth muscle cells. A role of Rac1 in the regulation of PAR1 expression was investigated. Methods and Results—Treatment with simvastatin, a hydroxy-3-methyl-glutaryl coenzyme A reductase inhibitor, for 24 hours attenuated the transient [Ca2+]i elevation induced by thrombin. Immunofluorescence staining revealed that simvastatin decreased the surface expression of PAR1 in a manner dependent on protein geranylgeranylation. Introduction of a Rac1/Cdc42 inhibitory fragment but not a RhoA inhibitory fragment using a cell-penetrating peptide also attenuated the response to thrombin and decreased the surface expression of PAR1. Finally, downregulation of Rac1, but not RhoA, using an RNA interference technique attenuated the thrombin-induced [Ca2+]i elevation. However, the level of PAR1 mRNA and the total amount of PAR1 protein remained unchanged. Conclusions—Here, we provide for the first time 3 lines of evidence that Rac1 plays a critical role in maintaining the surface expression of PAR1 and the responsiveness to thrombin in vascular smooth muscle cells. Rac1 is suggested to regulate the constitutive trafficking of PAR1 and thereby regulate the surface expression of PAR1.