THE EFFECT OF RECOVERIN-LIKE CALCIUM-BINDING PROTEINS ON THE PHOTORESPONSE OF RETINAL RODS
THE EFFECT OF RECOVERIN-LIKE CALCIUM-BINDING PROTEINS ON THE PHOTORESPONSE OF RETINAL RODS
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DOI：
10.1016/0896-6273(93)90339-s
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发表时间：
1993-03-01
期刊：
影响因子：
16.2
通讯作者：
DETWILER, PB
中科院分区：
文献类型：
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作者：
GRAYKELLER, MP;POLANS, AS;DETWILER, PB
视杆细胞的光反应是由刺激 cGMP 水解的酶级联触发的。由此导致的 cGMP 下降导致 Ca2+ 减少，从而通过激活鸟苷酸环化酶促进光响应恢复，引起 cGMP 再合成。体外生化研究表明，鸟苷酸环化酶的 Ca2+ 激活是由恢复蛋白（一种 26 kd Ca2+ 结合蛋白）介导的。为了评估这一点，使用全细胞记录将外源牛恢复蛋白和另外两种来自鸡和壁虎视网膜的同源 Ca2+ 结合蛋白透析成功能完整的壁虎杆。所有三种蛋白质都延长了光响应的上升阶段，而不影响响应恢复的动力学。这些结果表明恢复蛋白样蛋白影响转导级联的终止，而不是介导鸟苷酸环化酶的Ca2+敏感性激活。
The rod photoresponse is triggered by an enzyme cascade that stimulates cGMP hydrolysis. The resulting fall in cGMP leads to a decrease in Ca2+, which promotes photoresponse recovery by activating guanylate cyclase, causing cGMP resynthesis. In vitro biochemical studies suggest that Ca2+ activation of guanylate cyclase is mediated by recoverin, a 26 kd Ca2+-binding protein. To evaluate this, exogenous bovine recoverin and two other homologous Ca2+-binding proteins from chicken and Gecko retina were dialyzed into functionally intact Gecko rods using whole-cell recording. All three proteins prolonged the rising phase of the photoresponse without affecting the kinetics of response recovery. These results suggest that recoverin-like proteins affect termination of the transduction cascade, rather than mediate Ca2+-sensitive activation of guanylate cyclase.