Stephan Gabriele, Erdjument-Bromage Hediye, Liu Wenke, Frenster Joshua D, Ravn-Boess Niklas, Bready Devin, Cai Julia, Fenyo David, Neubert Thomas, Placantonakis Dimitris G
Department of Neurosurgery, NYU Grossman School of Medicine, New York, NY 10016, USA.
Department of Cell Biology and Kimmel Center for Biology and Medicine at the Skirball Institute, NYU Grossman School of Medicine, New York, NY 10016, USA.
bioRxiv. 2023 Feb 9:2023.02.09.527921. doi: 10.1101/2023.02.09.527921.
GPR133 (ADGRD1) is an adhesion G protein-coupled receptor that signals through Gαs and is required for growth of glioblastoma (GBM), an aggressive brain malignancy. The regulation of GPR133 signaling is incompletely understood. Here, we use proximity biotinylation proteomics to identify ESYT1, a Ca-dependent mediator of endoplasmic reticulum-plasma membrane bridge formation, as an intracellular interactor of GPR133. ESYT1 knockdown or knockout increases GPR133 signaling, while its overexpression has the opposite effect, without altering GPR133 levels in the plasma membrane. The GPR133-ESYT1 interaction requires the Ca-sensing C2C domain of ESYT1. Thapsigargin-mediated increases in cytosolic Ca relieve signaling-suppressive effects of ESYT1 by promoting ESYT1-GPR133 dissociation. ESYT1 knockdown or knockout in GBM impairs tumor growth , suggesting functions of ESYT1 beyond the interaction with GPR133. Our findings suggest a novel mechanism for modulation of GPR133 signaling by increased cytosolic Ca, which reduces the signaling-suppressive interaction between GPR133 and ESYT1 to raise cAMP levels.
GPR133（ADGRD1）是一种粘附性G蛋白偶联受体，通过Gαs发出信号，是侵袭性脑恶性肿瘤胶质母细胞瘤（GBM）生长所必需的。对GPR133信号传导的调节尚未完全了解。在这里，我们使用邻近生物素化蛋白质组学来鉴定ESYT1，一种内质网-质膜桥形成的钙依赖性介质，作为GPR133的细胞内相互作用因子。ESYT1的敲低或敲除会增加GPR133信号传导，而其过表达则具有相反的效果，且不会改变质膜中GPR133的水平。GPR133与ESYT1的相互作用需要ESYT1的钙感应C2C结构域。毒胡萝卜素介导的胞质钙增加通过促进ESYT1与GPR133的解离来减轻ESYT1的信号抑制作用。在GBM中敲低或敲除ESYT1会损害肿瘤生长，这表明ESYT1的功能不仅仅局限于与GPR133的相互作用。我们的研究结果表明了一种通过增加胞质钙来调节GPR133信号传导的新机制，即减少GPR133与ESYT1之间的信号抑制相互作用以提高cAMP水平。
