Using siRNA to define functional interactions between melanopsin and multiple G Protein partners
Using siRNA to define functional interactions between melanopsin and multiple G Protein partners
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DOI：
10.1007/s00018-014-1664-6
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发表时间：
2015-01-01
影响因子：
8
通讯作者：
Hankins, Mark W.
中科院分区：
文献类型：
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作者：
Hughes, Steven;Jagannath, Aarti;Hankins, Mark W.
表达黑视素的光敏视网膜神经节细胞（pRGC）代表第三类眼光感受器，并介导一系列对光的非成像反应。黑视素是一种G蛋白偶联受体（GPCR），现有数据表明它采用涉及Gnaq/11型G蛋白的膜结合信号级联。然而，迄今为止，黑视素光转导中涉及的G α亚基的精确身份仍然不清楚。在这里，我们表明Gnaq，Gna 11和Gna 14在小鼠视网膜的pRGC中高度共表达。此外，使用基于RNAi的基因沉默，我们表明黑视蛋白可以通过Gnaq，Gna 11或Gna 14在体外发出信号，并证明Gnaq/11亚家族的多个成员，包括Gna 14和至少Gnaq或Gna 11，可以参与体内黑视蛋白光转导，并有助于缺乏视杆细胞和视锥细胞的小鼠的瞳孔光反应。这种G蛋白相互作用的多样性表明黑视蛋白光转导级联中的额外复杂性，并且可以为产生从pRGC亚型观察到的光响应的多样性提供基础。
Melanopsin expressing photosensitive retinal ganglion cells (pRGCs) represent a third class of ocular photoreceptors and mediate a range of non-image forming responses to light. Melanopsin is a G protein coupled receptor (GPCR) and existing data suggest that it employs a membrane bound signalling cascade involving Gnaq/11 type G proteins. However, to date the precise identity of the G alpha subunits involved in melanopsin phototransduction remains poorly defined. Here we show that Gnaq, Gna11 and Gna14 are highly co-expressed in pRGCs of the mouse retina. Furthermore, using RNAi based gene silencing we show that melanopsin can signal via Gnaq, Gna11 or Gna14 in vitro, and demonstrate that multiple members of the Gnaq/11 subfamily, including Gna14 and at least Gnaq or Gna11, can participate in melanopsin phototransduction in vivo and contribute to the pupillary light responses of mice lacking rod and cone photoreceptors. This diversity of G protein interactions suggests additional complexity in the melanopsin phototransduction cascade and may provide a basis for generating the diversity of light responses observed from pRGC subtypes.