Gαq and Gβγ regulate PAR-1 signaling of thrombin-induced NF-κB activation and ICAM-1 transcription in endothelial cells
Gαq and Gβγ regulate PAR-1 signaling of thrombin-induced NF-κB activation and ICAM-1 transcription in endothelial cells
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DOI：
10.1161/01.res.0000033520.95242.a2
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发表时间：
2002-09-06
影响因子：
20.1
通讯作者：
Malik, AB
中科院分区：
文献类型：
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作者：
Rahman, A;True, AL;Malik, AB
由于凝血酶与 G 蛋白偶联蛋白酶激活受体 1 (PAR-1) 结合，通过 NF-kappaB 激活和细胞间粘附分子 1 (ICAM-1) 表达诱导内皮细胞粘附，因此我们确定了介导该反应的信号通路。研究表明，异三聚体 G 蛋白、Galpha(q) 和 Gbetagamma 二聚体是 PAR-1 激动剂肽 (TFLLRNPNDK) 诱导的内皮细胞中 NF-κB 激活和 ICAM-1 表达的关键决定因素。 RGS3T 是一种 G 蛋白信号转导调节剂，可抑制 Galpha(q) 或 α-转导蛋白 (Galpha(t))（Gbetagamma 的清除剂），共转染可显着降低 PAR-1 激活诱导的 NF-kappaB 活性。我们确定了由介导 NF-kappaB 激活的 Galpha(q) 和 Gbetagamma 激活的下游信号传导靶标。激酶缺陷型蛋白激酶 C (PKC)-delta 突变体的表达抑制了由组成型活性 Galpha(q) 突变体诱导的 NF-kappaB 激活，但对 Gbeta(1)gamma(2) 诱导的 NF-kappaB 活性没有影响。 在相关实验中，NF-kappaB 以及 Gbeta(1)gamma(1) 诱导的 ICAM-1 启动子激活均受到显性失活突变体的表达的抑制。 PI 3-激酶的 85-kDa 调节亚基；然而，该突变体的表达对激活的 Galpha(q) 诱导的反应没有影响。催化失活的 Akt 突变体的共转染抑制了由组成型活性 PI 3-激酶突变体以及激活形式的 Galpha(q) 和 PKC-delta 诱导的 NF-κB 激活。这些结果支持这样一种模型，其中 PAR-1 的连接通过汇聚于 Akt 的平行 Galphaq/PKC-delta 和 Gbetagamma/P13 激酶途径的参与诱导 NF-kappaB 激活和 ICAM-1 转录。
As thrombin binding to the G protein-coupled proteinase activated receptor-1 (PAR-1) induces endothelial adhesivity to leukocytes through NF-kappaB activation and intercellular adhesion molecule-1 (ICAM-1) expression, we determined the signaling pathways mediating the response. Studies showed that the heterotrimeric G proteins, Galpha(q), and the Gbetagamma dimer were key determinants of the PAR-1 agonist peptide (TFLLRNPNDK)-induced NF-kappaB activation and ICAM-1 expression in endothelial cells. Cotransfection of RGS3T, a regulator of G-protein signaling that inhibits Galpha(q), or alpha-transducin (Galpha(t)), a scavenger of the Gbetagamma, markedly decreased NF-kappaB activity induced by PAR-1 activation. We determined the downstream signaling targets activated by Galpha(q) and Gbetagamma that mediate NF-kappaB activation. Expression of the kinase-defective protein kinase C (PKC)-delta mutant inhibited NF-kappaB activation induced by the constitutively active Galpha(q) mutant, but had no effect on NF-kappaB activity induced by Gbeta(1)gamma(2) In related experiments, NF-kappaB as well as ICAM-1 promoter activation induced by Gbeta(1)gamma(1), were inhibited by the expression of the dominant-negative mutant of 85-kDa regulatory subunit of PI 3-kinase; however, the expression of this mutant had no effect on the response induced by activated Galpha(q). Cotransfection of the catalytically inactive Akt mutant inhibited the NF-kappaB activation induced by the constitutively active PI 3-kinase mutant as well as that by the activated forms of Galpha(q) and PKC-delta. These results support a model in which ligation of PAR-1 induces NF-kappaB activation and ICAM-1 transcription by the engagement of parallel Galphaq/PKC-delta and Gbetagamma/P13-kinase pathways that converge at Akt.