Potent and selective inhibition of angiotensin AT1 receptor signalling by RGS2: roles of its N-terminal domain
Potent and selective inhibition of angiotensin AT1 receptor signalling by RGS2: roles of its N-terminal domain
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RGS2 对血管紧张素 AT1 受体信号传导的有效和选择性抑制：其 N 末端结构域的作用
DOI：
10.1016/j.cellsig.2011.01.023
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发表时间：
2011
影响因子：
4.8
通讯作者：
Kimura S
中科院分区：
文献类型：
--
作者：
Matsuzaki N;Nishiyama M;Song D;Moroi K;Kimura S
新的证据表明，R4/B亚家族RGS蛋白在心血管系统的功能调节中发挥作用。在本研究中，我们比较了RGS2、RGS4和RGS5这三个R4/B亚家族蛋白对血管紧张素AT1受体信号转导的影响，并探讨了RGS2的N末端的作用。在稳定表达AT1受体的HEK293T细胞中，RGS2对血管紧张素II诱导的细胞内钙反应的抑制作用明显强于RGS4和RGS5。N端缺失的RGS2蛋白失去了这种有效的抑制作用。用RGS5的相应残基(1-51)取代RGS2的N-末端残基1-71，抑制作用显著降低。另一方面，用RGS2的残基1-71取代RGS5的残基1-51，抑制效果显著增强。此外，我们还研究了RGS2的N末端亚域的功能贡献，即N末端区域(残基16-55)与两亲性α螺旋结构域(N1亚域)，可能的非特异性膜靶向亚域，以及位于α螺旋和RGS盒之间的另一区域(残基56-71)(亚域N2)，可能是GPCR识别的亚域。RGS5残基为1-33或34-52的RGS2嵌合体蛋白抑制活性较弱，RGS2残基为1-55或56-71的RGS5嵌合蛋白对AT1受体信号转导有较强的抑制作用。本研究表明，在RGS2对AT1受体信号的有效抑制作用中，这两个N-末端亚区都起着重要的作用。
Emerging evidence indicates that R4/B subfamily RGS (regulator of G protein signaling) proteins play roles in functional regulation in the cardiovascular system. In this study, we compared effects of three R4/B subfamily proteins, RGS2, RGS4 and RGS5 on angiotensin AT1 receptor signaling, and investigated roles of the N-terminus of RGS2. In HEK293T cells expressing AT1 receptor stably, intracellular Ca2+responses induced by angiotensin II were much more strongly attenuated by RGS2 than by RGS4 and RGS5. N-terminally deleted RGS2 proteins lost this potent inhibitory effect. Replacement of the N-terminal residues 1–71 of RGS2 with the corresponding residues (1–51) of RGS5 decreased significantly the inhibitory effect. On the other hand, replacement of the residues 1–51 of RGS5 with the residues 1–71 of RGS2 increased the inhibitory effect dramatically. Furthermore, we investigated functional contribution of N-terminal subdomains of RGS2, namely, an N-terminal region (residues 16–55) with an amphipathic α helix domain (the subdomain N1), a probable non-specific membrane-targeting subdomain, and another region (residues 56–71) between the α helix and the RGS box (the subdomain N2), a probable GPCR-recognizing subdomain. RGS2 chimera proteins with the residues 1–33 or 34–52 of RGS5 showed weak inhibitory activity, and either of RGS5 chimera proteins with residues 1–55 or 56–71 of RGS2 showed strong inhibitory effects on AT1 receptor signaling. The present study indicates the essential roles of both N-terminal subdomains for the potent inhibitory activity of RGS2 on AT1 receptor signaling.