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Curr Biol. 2012 Aug 7;22(15):1361-70. doi: 10.1016/j.cub.2012.05.034. Epub 2012 Jun 14.

Endocytosis of G protein-coupled receptors is regulated by clathrin light chain phosphorylation.

Author information

1
Department of Biomedical Science, Centre for Membrane Interactions and Dynamics, University of Sheffield, Sheffield S10 2TN, UK.

Abstract

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 CLCb(S204A) 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.

PMID:
22704991
DOI:
10.1016/j.cub.2012.05.034
[Indexed for MEDLINE]
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