Endocytosis of G Protein-Coupled Receptors Is Regulated by Clathrin Light Chain Phosphorylation
Endocytosis of G Protein-Coupled Receptors Is Regulated by Clathrin Light Chain Phosphorylation
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DOI：
10.1016/j.cub.2012.05.034
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发表时间：
2012-08-07
期刊：
影响因子：
9.2
通讯作者：
Smythe, Elizabeth
中科院分区：
文献类型：
--
作者：
Ferreira, Filipe;Foley, Matthew;Smythe, Elizabeth
背景资料：跨膜受体如G蛋白偶联受体（GPCR）的信号传导发生在细胞表面和整个内吞途径中，并且来自细胞表面的信号传导可能在幅度和下游输出上与胞内信号传导不同。因此，信号分子穿过内吞途径的速率对下游输出做出显著贡献。核心内吞机制的调节促进个体货物的差异摄取。网格蛋白包被的凹坑是一个主要的入口，其中组装的网格蛋白在已捕获内吞货物的内陷芽周围形成网格。网格蛋白组装成由三条网格蛋白重链和相关的网格蛋白轻链（CLC）组成的三链体。尽管在30多年前的细胞表面的网格蛋白包被的小坑的识别，CLC在endocytosis.Results的功能一直难以捉摸：在这项工作中，我们确定了一个新的作用CLC在特定货物的调节内吞。CLCa或CLCb的小干扰RNA介导的敲低抑制GPCR的摄取。此外，我们证明，Ser 204的磷酸化CLCb的GPCR的一个子集的有效内吞作用是必需的，并确定G蛋白偶联受体激酶2（GRK 2）作为一种激酶，可以磷酸化CLCb Ser 204。CLCbS 204 A的过表达特异性地抑制了那些GPCR的内吞作用，这些GPCR的内吞作用是GRK 2-dependent.Conclusions：总之，这些结果表明，CLCb磷酸化作为一种抑制剂，用于特定GPCR的内吞作用。
Background: Signaling by transmembrane receptors such as G protein-coupled receptors (GPCRs) occurs at the cell surface and throughout the endocytic pathway, and signaling from the cell surface may differ in magnitude and downstream output from intracellular signaling. As a result, the rate at which signaling molecules traverse the endocytic pathway makes a significant contribution to downstream output. Modulation of the core endocytic machinery facilitates differential uptake of individual cargoes. Clathrin-coated pits are a major entry portal where assembled clathrin forms a lattice around invaginating buds that have captured endocytic cargo. Clathrin assembles into triskelia composed of three clathrin heavy chains and associated clathrin light chains (CLCs). Despite the identification of clathrin-coated pits at the cell surface over 30 years ago, the functions of CLCs in endocytosis have been elusive.Results: In this work, we identify a novel role for CLCs in the regulated endocytosis of specific cargoes. Small interfering RNA-mediated knockdown of either CLCa or CLCb inhibits the uptake of GPCRs. Moreover, we demonstrate that phosphorylation of Ser204 in CLCb is required for efficient endocytosis of a subset of GPCRs and identify G protein-coupled receptor kinase 2 (GRK2) as a kinase that can phosphorylate CLCb on Ser204. Overexpression of CLCbS204A specifically inhibits the endocytosis of those GPCRs whose endocytosis is GRK2-dependent.Conclusions: Together, these results indicate that CLCb phosphorylation acts as a discriminator for the endocytosis of specific GPCRs.