Differential Phosphorylation of the Rhodopsin Cytoplasmic Tail Mediates the Binding of Arrestin and Its Splice Variant, p44

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• 作者：Maria Ascano and Phyllis R. Robinson
• 刊名：Biochemistry
• 出版年：2006
• 出版时间：February 21, 2006
• 年：2006
• 卷：45
• 期：7
• 页码：2398 - 2407
• 全文大小：224K
• 年卷期：v.45,no.7(February 21, 2006)
• ISSN：1520-4995

文摘

Deactivation of the vertebrate photopigment rhodopsin is achieved through a two-step process.Rhodopsin is first phosphorylated by rhodopsin kinase and subsequently deactivated by the binding ofthe regulatory protein arrestin or its splice variant, p44. Although much is known about the overalldifferences between arrestin and p44 binding to different rhodopsin species (photolyzed versus unphotolyzedand/or phosphorylated versus unphosphorylated), the exact role of p44 during phototransduction remainsto be fully elucidated. Our current study addresses this question by identifying structural differences betweenarrestin and p44 and characterizing the interaction between the negatively charged rhodopsin tail andeither p44 or arrestin. Our results demonstrate that arrestin and p44 bind differently to differentphosphorylated rhodopsin species and that this may be due to a structural difference between p44's andarrestin's basal states. This difference offers a potential regulatory mechanism that could regulate p44and arrestin binding and, as a result, regulate the kinetics of the rod's light response.