The thrombin receptor, PAR-1, causes transformation by activation of Rho-mediated signaling pathways
The thrombin receptor, PAR-1, causes transformation by activation of Rho-mediated signaling pathways
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DOI：
10.1038/sj.onc.1204281
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发表时间：
2001-04-12
期刊：
影响因子：
8
通讯作者：
Whitehead, IP
中科院分区：
文献类型：
--
作者：
Martin, CB;Mahon, GM;Whitehead, IP
我们利用来自B6SutA(1)小鼠髓系祖细胞系的cDNA表达文库，寻找促进NIH3T3细胞生长转化的新癌基因。一个2.2 kb的转化cDNA编码野生型凝血酶刺激的G蛋白偶联受体PAR-1，除了其强大的焦点形成活性外，PAR-1在NIH3T3细胞中的组成性过表达促进锚定和血清依赖性生长的丧失。虽然凝血酶抑制剂不能阻断PAR-1的转化活性，但不能被凝血酶切割的PAR-1突变体是不转化的。由于PAR-1诱导的转化细胞的焦点与活化的RhoA诱导的细胞具有惊人的相似性，我们确定PAR-1转化是否由于特定Rho家族成员的异常激活。与RhoA一样，PAR-1与活化的raf -1协同增强转化活性，微注射猪主动脉内皮细胞诱导应激纤维，刺激血清反应因子和NF-kappaB转录因子活性，并通过共表达优势阴性RhoA阻断PAR-1的转化。最后，百日毒和Lsc RGS结构域的共表达阻断PAR-1的转化活性。表明G α (i)和G α (12)/G α(13)亚基分别是PAR-I转化的介质。综上所述，这些观察结果表明PAR-1的生长转化在一定程度上是由RhoA的激活介导的。
We utilized a cDNA expression library derived from the B6SutA(1) mouse myeloid progenitor cell line to search for novel oncogenes that promote growth transformation of NIH3T3 cells. A 2.2 kb transforming cDNA was recovered that encodes the wild type thrombin-stimulated G protein-coupled receptor PAR-I, In addition to its potent focus forming activity, constitutive overexpression of PAR-1 in NIH3T3 cells promoted the loss of anchorage- and serum-dependent growth. Although inhibitors of thrombin failed to block PAR-I transforming activity, a PAR-1 mutant that cannot be cleaved by thrombin was nontransforming. Since the foci of transformed cells induced by PAR-1 bear a striking resemblance to those induced by activated RhoA, we determined if PAR-1 transformation was due to the aberrant activation of a specific Rho family member. Like RhoA, PAR-I cooperated with activated Raf-l and caused synergistic enhancement of transforming activity, induced stress fibers when microinjected into porcine aortic endothelial cells, stimulated the activity of the serum response factor and NF-kappaB transcription factors, and PAR-1 transformation was blocked by co-expression of dominant negative RhoA, Finally, PAR-I transforming activity was blocked by pertussis toxin and by coexpression of the RGS domain of Lsc, implicating G alpha (i) and G alpha (12)/G alpha (13) subunits, respectively, as mediators of PAR-I transformation. Taken together, these observations suggest that PAR-1 growth transformation is mediated, in part, by activation of RhoA.