Photoreceptor specific guanylate cyclases in vertebrate phototransduction
Photoreceptor specific guanylate cyclases in vertebrate phototransduction
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DOI：
10.1023/a:1014209711793
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发表时间：
2002-01-01
影响因子：
4.3
通讯作者：
Sharma, RK
中科院分区：
文献类型：
--
作者：
Koch, KW;Duda, T;Sharma, RK
两种膜结合鸟苷酸环化酶在脊椎动物感光细胞中表达。它们在光感受器生理学中起关键作用，因为它们合成光激发鸟苷3 '，5'-环一磷酸（cGMP）的细胞内递质。两种名为ROS-GC 1和ROS-GC 2的环化酶形成膜结合环化酶的亚类，并且在许多方面不同于激素肽受体鸟苷酸环化酶。一个独特的特征是它们由三种称为GCAP的小Ca 2+结合蛋白调节。这些调节蛋白在光照期间感测胞质Ca 2+浓度[Ca 2 +]的变化，并且当[Ca 2 +]降低到低于暗适应细胞中500-600 nM的值时激活ROS-GC。最近的工作已经确定了ROS-GC 1中GCAP-1的靶区域。除了GCAPs，还发现其他几种蛋白质，包括aktin，微管蛋白，富含谷氨酸的蛋白质和GT3加速蛋白（RGS 9）与ROS-GC 1相互作用，并可能形成多蛋白复合物。
Two membrane bound guanylate cyclases are expressed in vertebrate photoreceptor cells. They serve a key function in photoreceptor physiology as they synthesize the intracellular transmitter of photoexcitation guanosine 3',5'-cyclic monophosphate (cGMP). Both cyclases named ROS-GC1 and ROS-GC2 form a subclass of membrane bound cyclases and differ in many aspects from hormone peptide receptor guanylate cyclases. One unique feature is their regulation by three small Ca2+-binding proteins called GCAPs. These regulatory proteins sense changes in the cytoplasmic Ca2+-concentration [Ca2+] during illumination and activate ROS-GCs when the [Ca2+] decreases below the value in a dark adapted cell of 500-600 nM. Recent work has identified the target regions of GCAP-1 in ROS-GC1. In addition to GCAPs several other proteins including aktin, tubulin, a glutamic-acid-rich protein and a GTPase accelerating protein (RGS9) were found to interact with ROS-GC1 and probably form a multiprotein complex.