Larger inhibition of visual pigment kinase in cones than in rods
Larger inhibition of visual pigment kinase in cones than in rods
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DOI：
10.1111/j.1471-4159.2010.06925.x
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发表时间：
2010-10-01
影响因子：
4.7
通讯作者：
Kawamura, Satoru
中科院分区：
文献类型：
--
作者：
Arinobu, Daisuke;Tachibanaki, Shuji;Kawamura, Satoru
在鲤鱼视网膜中，视色素激酶GRK 1（G蛋白偶联受体激酶1）和GRK 7（视锥细胞）分别被视杆细胞中的S-调制蛋白（或recoverin）和视锥细胞中的visinin（以前称为s26）所抑制。在这里，我们比较了钙依赖性抑制GRK 1的S-调制蛋白和GRK 7的visinin。首先，估计外节中S-调制蛋白和visinin的浓度：visinin的浓度（1.2 mM）比S-调制蛋白的浓度（53 μ M）高20倍。根据测定的Ca 2 +-传感器蛋白的浓度和已知的暗Ca 2+浓度，我们估计，在原位Ca 2+依赖性抑制GRK在视锥细胞中将是2.5倍以上，在杆中的Ca 2+浓度在黑暗中。因为GRK活性在视锥细胞中比在视杆细胞中高大约100倍[Proc. Sci. USA 102（2005）21359]，视锥细胞中对GRK活性的Ca 2+依赖性抑制的范围比视杆细胞中宽100倍以上。S-调制蛋白和visinin对感光细胞GRKs的抑制作用是不可区分的，虽然这些Ca 2+传感器蛋白以细胞类型特异性的方式表达。这些Ca 2+传感器蛋白的抑制作用对GRK 7的抑制作用略高于GRK 1，这可能是因为GRK 7的特异性特征。
P>In the carp retina, visual pigment kinase, GRK1 (G-protein coupled receptor kinase 1) in rods and GRK7 in cones, is inhibited by a photoreceptor neuronal Ca2+-sensor protein, S-modulin (or recoverin) in rods and visinin (formerly named s26) in cones. Here, we compared Ca2+-dependent inhibition of GRK1 by S-modulin and that of GRK7 by visinin. First, the concentrations of S-modulin and visinin in the outer segment were estimated: the concentration of visinin (1.2 mM) was 20 times higher than that of S-modulin (53 mu M). Based on the determined concentrations of the Ca2+-sensor proteins and the known dark Ca2+ concentrations, we estimated that in situ Ca2+-dependent inhibition on GRK in cones would be 2.5 times higher than that in rods at the Ca2+ concentration in the dark. Because GRK activity is approximately 100 times higher in cones than in rods [Proc. Natl Acad. Sci. USA102 (2005) 21359], the range of Ca2+-dependent inhibition on GRK activity is more than 100 times wider in cones than in rods. The inhibitory effects of S-modulin and visinin on photoreceptor GRKs were indistinguishable, although these Ca2+-sensor proteins are expressed in a cell-type specific manner. The inhibition by these Ca2+-sensor proteins was slightly higher on GRK7 than GRK1 probably because of a characteristic specific to GRK7.