The selectivity of visual arrestin for light-activated phosphorhodopsin is controlled by multiple nonredundant mechanisms
The selectivity of visual arrestin for light-activated phosphorhodopsin is controlled by multiple nonredundant mechanisms
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DOI：
10.1074/jbc.273.25.15501
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发表时间：
1998-06-19
影响因子：
4.8
通讯作者：
Gurevich, VV
中科院分区：
文献类型：
--
作者：
Gurevich, VV
Arrestin通过其结合视觉受体视紫红质（P-Rh*）的磷酸化光激活形式的能力在猝灭光转导中起重要作用。视觉抑制蛋白对这种功能形式的显著选择性是由一个优雅的顺序多位点结合机制决定的。先前的结构-功能研究表明，arrestin的COOP末端区域（残基356-404）不直接参与视紫红质相互作用，而是起着调节作用。该区域支持基础arrestin构象，并确保arrestin在遇到P-Rh* 时转变为高亲和力的视紫红质结合状态。总的来说，我们的研究结果证实了这一假设，并确定了三个功能亚区（残基361-368，369-378和379-404）和单个氨基酸参与控制抑制蛋白的稳定性和结合选择性。两个最有效的突变体，arrestin（1-378）和arrestin（F375 A，V376 A，F377 A）属于一类新的组成型活性arrestins，其对P-Rh*，暗P-Rh具有高亲和力。和Rh*（但不是暗Ph），这与早期构建的突变体arrestin（R175 E）和arrestin（Delta 2-16）形成对比，其仅对光激活形式具有高亲和力。最近确定的arrestin的晶体结构的arrestin，视紫红质相互作用的机制，这些研究结果的影响进行了讨论。
Arrestin plays an important role in quenching photo transduction via its ability to bind to the phosphorylated light-activated form of the visual receptor rhodopsin (P-Rh*). Remarkable selectivity of visual arrestin toward this functional form is determined by an elegant sequential multisite binding mechanism. Previous structure-function studies have suggested that the COOP-terminal region of arrestin (residues 356-404) is not directly involved in rhodopsin interaction, but instead plays a regulatory role. This region supports basal arrestin conformation and ensures arrestin's transition into a high affinity rhodopsin-binding state upon an encounter with P-Rh*. Overall, our results corroborate this hypothesis and identify three functional subregions (residues 361-368, 369-378, and 379-404) and individual amino acids involved in the control of arrestin stability and binding selectivity. Two of the most potent mutants, arrestin(1-378) and arrestin(F375A,V376A,F377A) belong to a novel class of constitutively active arrestins with high affinity for P-Rh*, dark P-Rh. and Rh* (but not dark Ph), in contrast to earlier constructed mutants arrestin(R175E) and arrestin(Delta 2-16) with high affinity for light-activated forms only. The implications of these findings for the mechanism of arrestin-rhodopsin interaction are discussed in light of the recently determined crystal structure of arrestin.