Polans A, Baehr W, Palczewski K
Dept of Ophthalmology and Visual Sciences, University of Wisconsin-Madison Medical School 53792-4673, USA.
Trends Neurosci. 1996 Dec;19(12):547-54. doi: 10.1016/s0166-2236(96)10059-x.
Vertebrate photoreceptor cells can signal the absorption of a single photon and then modulate their response as the intensity of the light and the intensity of the background illumination vary, and it has long been recognized that Ca2+ ions contribute to the underlying processes. Recently, several Ca(2+)-binding proteins of the EF-hand family were identified that mediate the actions of Ca2+ during the response to light. Molecular interactions between these Ca(2+)-binding proteins and their cellular targets are amenable to study owing in part to the unique features of phototransduction. In addition, two of the proteins, recoverin and guanylate cyclase activating protein (GCAP), appear to be involved in separate degenerative diseases of the retina that arise in humans and in animal models of human disease. Information obtained from these studies should also be relevant to the growing number of homologous proteins found in other neural tissues.
脊椎动物的光感受器细胞能够对单个光子的吸收发出信号，并随着光强度和背景光照强度的变化调节其反应，长期以来人们一直认识到钙离子参与了这些基本过程。最近，人们鉴定出了几种EF手型家族的钙结合蛋白，它们在对光的反应过程中介导钙离子的作用。这些钙结合蛋白与其细胞靶点之间的分子相互作用便于研究，部分原因是光转导的独特特性。此外，其中两种蛋白，恢复蛋白和鸟苷酸环化酶激活蛋白（GCAP），似乎与人类以及人类疾病动物模型中出现的视网膜的不同退行性疾病有关。从这些研究中获得的信息也应该与在其他神经组织中发现的越来越多的同源蛋白相关。
