Identification of a Preassembled TRH Receptor-Gq/11 Protein Complex in HEK293 Cells

Cell Structure and Function

Zdenka Drastichova¹  Jiri Novotny¹ 

[1] Department of Physiology, Faculty of Science, Charles University

关键词: thyrotropin-releasing hormone receptor;    Gq/11 protein;    clear-native electrophoresis;    protein complex;   

DOI  :  10.1247/csf.11024

学科分类：分子生物学，细胞生物学和基因

来源: Japan Society for Cell Biology

【 摘 要 】

References(56)Cited-By(3)Protein-protein interactions define specificity in signal transduction and these interactions are central to transmembrane signaling by G-protein-coupled receptors (GPCRs). It is not quite clear, however, whether GPCRs and the regulatory trimeric G-proteins behave as freely and independently diffusible molecules in the plasma membrane or whether they form some preassociated complexes. Here we used clear-native polyacrylamide gel electrophoresis (CN-PAGE) to investigate the presumed coupling between thyrotropin-releasing hormone (TRH) receptor and its cognate Gq/11 protein in HEK293 cells expressing high levels of these proteins. Under different solubilization conditions, the TRH receptor (TRH-R) was identified to form a putative pentameric complex composed of TRH-R homodimer and Gq/11 protein. The presumed association of TRH-R with Gq/11α or Gβ proteins in plasma membranes was verified by RNAi experiments. After 10- or 30-min hormone treatment, TRH-R signaling complexes gradually dissociated with a concomitant release of receptor homodimers. These observations support the model in which GPCRs can be coupled to trimeric G-proteins in preassembled signaling complexes, which might be dynamically regulated upon receptor activation. The precoupling of receptors with their cognate G-proteins can contribute to faster G-protein activation and subsequent signal transfer into the cell interior.

【 授权许可】

Unknown