Extracellular calcium alters calcium-sensing receptor network integrating intracellular calcium-signaling and related key pathway

• Type of Material: Article
• Authors: Rakshya Gorkhali, Georgia State University; Li Tian, Georgia State University; Bin Dong, Georgia State University; Pritha Bagchi, Emory University; Xiaonan Deng, Georgia State University; Shrikant Pawar, Georgia State University; Duc Duong, Emory University; Ning Fang, Georgia State University; Nicholas Seyfried, Emory University; Jenny Yang, Georgia State University
• Language: English
• Date: 2021-10-18
• Publisher: NATURE PORTFOLIO
• Publication Version: Final Published Version
• Copyright Statement: © The Author(s) 2021
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1038/s41598-021-00067-2
• Title of Journal or Parent Work: SCIENTIFIC REPORTS
• Volume: 11
• Issue: 1
• Start Page: 20576
• End Page: 20576
• Grant/Funding Information: This work was supported in part by American Heart Association to J.J.Y., the Center of Diagnostics and Therapeutics Fellowship, Georgia State University fellowships to R.G. and S.D. and Brains and Behavior Fellowship, Georgia State University fellowship to L.T.
• Keywords: BINDING PROTEIN; CA2+-SENSING RECEPTOR; Multidisciplinary Sciences; DEPENDENT REGULATION; BETA; PROTEIN-KINASE-C; INHIBITION; CELL-SURFACE EXPRESSION; ENDOPLASMIC-RETICULUM; Science & Technology - Other Topics; TRAFFICKING; CA2+; Science & Technology
• Research Categories: Health Sciences, Medicine and Surgery; Chemistry, Biochemistry

Abstract

G-protein-coupled receptors (GPCRs) are a target for over 34% of current drugs. The calcium-sensing receptor (CaSR), a family C GPCR, regulates systemic calcium (Ca2+) homeostasis that is critical for many physiological, calciotropical, and noncalciotropical outcomes in multiple organs. However, the mechanisms by which extracellular Ca2+ (Ca2+ex) and the CaSR mediate networks of intracellular Ca2+-signaling and players involved throughout the life cycle of CaSR are largely unknown. Here we report the first CaSR protein–protein interactome with 94 novel putative and 8 previously published interactors using proteomics. Ca2+ex promotes enrichment of 66% of the identified CaSR interactors, pertaining to Ca2+ dynamics, endocytosis, degradation, trafficking, and primarily to protein processing in the endoplasmic reticulum (ER). These enhanced ER-related processes are governed by Ca2+ex-activated CaSR which directly modulates ER-Ca2+ (Ca2+ER), as monitored by a novel ER targeted Ca2+-sensor. Moreover, we validated the Ca2+ex dependent colocalizations and interactions of CaSR with ER-protein processing chaperone, 78-kDa glucose regulated protein (GRP78), and with trafficking-related protein. Live cell imaging results indicated that CaSR and vesicle-associated membrane protein-associated A (VAPA) are inter-dependent during Ca2+ex induced enhancement of near-cell membrane expression. This study significantly extends the repertoire of the CaSR interactome and reveals likely novel players and pathways of CaSR participating in Ca2+ER dynamics, agonist mediated ER-protein processing and surface expression.