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This content will become publicly available on February 21, 2019

Title: GPCR6A Is a Molecular Target for the Natural Products Gallate and EGCG in Green Tea

1 Scope: The molecular mechanisms whereby gallates in green tea exert metabolic effects are poorly understood.2 Methods and results: We found that GPRC6A, a multi-ligand-sensing G-protein-coupled receptor that regulates energy metabolism, sex hormone production, and prostate cancer progression, is a target for gallates. Sodium gallate (SG), gallic acid (GA) > ethyl gallate (EG) > octyl gallate (OG) dose dependently activated ERK in HEK-293 cells transfected with GPRC6A but not in non-transfected controls. SG also stimulated insulin secretion in β-cells isolated from wild-type mice similar to the endogenous GPRC6A ligands, osteocalcin (Ocn) and testosterone (T). Side-chain additions to create OG resulted in loss of GPRC6A agonist activity. Another component of green tea, epigallocatechin 3-gallate (EGCG), dose-dependently inhibited Ocn activation of GPRC6A in HEK-293 cells transfected with GPRC6A and blocked the effect of Ocn in stimulating glucose production in CH10T1/2 cells. Using structural models of the venus fly trap (VFT) and 7-transmembrane (7-TM) domains of GPRC6A, calculations suggest that l-amino acids and GA bind to the VFT, whereas EGCG is calculated to bind to sites in both the VFT and 7-TM.3 In conclusion, GA and EGCG have offsetting agonist and antagonist effects on GPRC6A that may account for the variable metabolic effectmore » of green tea consumption.« less
 [1] ;  [2] ;  [1] ;  [3] ;  [3] ;  [1]
  1. Univ. of Tennessee Health Science Center, Memphis, TN (United States). Dept. of Medicine
  2. Univ. of Tennessee, Knoxville, TN (United States). UT/ORNL Center for Molecular Biophysics
  3. Univ. of Tennessee, Knoxville, TN (United States). UT/ORNL Center for Molecular Biophysics and Dept. of Biochemistry and Cellular and Molecular Biology
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Molecular Nutrition & Food Research
Additional Journal Information:
Journal Volume: 62; Journal Issue: 8; Journal ID: ISSN 1613-4125
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
Country of Publication:
United States
59 BASIC BIOLOGICAL SCIENCES; computational modeling; EGCG; gallic acid; GPCR; GPRC6A
OSTI Identifier: