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.
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.
Authors: Shuang Wu; Sophia R Majeed; Timothy M Evans; Marine D Camus; Nicole M L Wong; Yvette Schollmeier; Minjong Park; Jagan R Muppidi; Andrea Reboldi; Peter Parham; Jason G Cyster; Frances M Brodsky Journal: Proc Natl Acad Sci U S A Date: 2016-08-18 Impact factor: 11.205
Authors: Sophia R Majeed; Lavanya Vasudevan; Chih-Ying Chen; Yi Luo; Jorge A Torres; Timothy M Evans; Andrew Sharkey; Amy B Foraker; Nicole M L Wong; Christopher Esk; Theresa A Freeman; Ashley Moffett; James H Keen; Frances M Brodsky Journal: Nat Commun Date: 2014-05-23 Impact factor: 14.919
Authors: Anna Young; Svetla Stoilova-McPhie; Alice Rothnie; Yvonne Vallis; Phillip Harvey-Smith; Neil Ranson; Helen Kent; Frances M Brodsky; Barbara M F Pearse; Alan Roseman; Corinne J Smith Journal: Traffic Date: 2013-06-20 Impact factor: 6.215