Dominant negative actions of human prostacyclin receptor variant through dimerization: implications for cardiovascular disease.
Dominant negative actions of human prostacyclin receptor variant through dimerization: implications for cardiovascular disease.
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DOI：
10.1161/atvbaha.110.208900
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发表时间：
2010-09
期刊：
影响因子：
--
通讯作者：
Smyth EM
中科院分区：
文献类型：
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作者：
Ibrahim S;Tetruashvily M;Frey AJ;Wilson SJ;Stitham J;Hwa J;Smyth EM
前列环素和凝血素分别通过其受体IP和TP介导相反的心血管作用。IP变体IPR212C杂合的个体表现出血小板IP反应性的严重丧失和心血管疾病的加速。我们研究了IPR212C与同质和异质二聚体受体复合物的关联以及对前列环素和凝血素生物学的影响。用生物荧光共振能量转移法检测转染HEK293细胞中IP、IPR212C和TPα的二聚化。我们观察到IPIP同二聚体和IPTPα异二聚体形成的倾向相同。与单独的IP相比，IPR212C显示cAMP生成减少，内质网定位增加，但正常的同源和异质二聚化。当IPR212C和IP共表达时，变体的显性负作用很明显，增强了野生型IP对内质网的定位，减少了激动剂依赖的信号传导。此外，当TPα与IPR212C二聚化时，TPα的激活反应从肌醇磷酸转移到cAMP生成，这一反应被正常化了。IPR212C通过二聚化作用对野生型IP和TPα发挥主导作用。这可能会加速携带一个变异等位基因的个体的心血管疾病。
Prostacyclin and thromboxane mediate opposing cardiovascular effects through their receptors, the IP and TP, respectively. Individuals heterozygous for an IP variant, IPR212C, displayed exaggerated loss of platelet IP responsiveness and accelerated cardiovascular disease. We examined association of IPR212C into homo- and hetero- dimeric receptor complexes and the impact on prostacyclin and thromboxane biology. Dimerization of the IP, IPR212C and TPα and was examined by Bioluminescent Resonance Energy Transfer in transfected HEK293 cells. We observed an equal propensity for formation of IPIP homo- and IPTPα hetero- dimers. Compared to the IP alone, IPR212C displayed reduced cAMP generation and increased ER localization, but underwent normal homo- and hetero- dimerization. When the IPR212C and IP were co-expressed a dominant negative action of variant was evident with enhanced wild type IP localization to the ER and reduced agonist-dependent signaling. Further, the TPα activation response, which was shifted from inositol phosphate to cAMP generation following IPTPα heterodimerization, was normalized when the TPα instead dimerized with IPR212C. IPR212C exerts a dominant action on the wild type IP and TPα through dimerization. This likely contributes to accelerated cardiovascular disease in individuals carrying one copy of the variant allele.