14-3-3 gamma binds regulator of G protein signaling 14 (RGS14) at distinct sites to inhibit the RGS14:G alpha(i)-AIF(4)(-) signaling complex and RGS14 nuclear localization

• Type of Material: Article
• Authors: Kyle J. Gerber, Emory University; Katherine E. Squires, Emory University; John R Hepler, Emory University
• Language: English
• Date: 2018-09-21
• Publisher: American Society for Biochemistry and Molecular Biology
• Publication Version: Final Published Version
• Copyright Statement: © 2018 Gerber et al.
• Final Published Version (URL): http://dx.doi.org/10.1074/jbc.RA118.002816
• Title of Journal or Parent Work: Journal of Biological Chemistry
• ISSN: 0021-9258
• Volume: 293
• Issue: 38
• Start Page: 14616
• End Page: 14631
• Grant/Funding Information: The Emory University Integrated Cellular Imaging Microscopy Core of the Emory Neuroscience was supported by NINDS, National Institutes of Health Core Facilities Grant 5P30NS055077.; This work was supported by National Institutes of Health Grants 5R01NS037112 and 1R21NS087488 (to J. R. H.); Grant F31NS098648 (to K. J. G.); and Training Grant T32 GM008602 (to K. J. G. and K. E. S.).
• Keywords: GoLoco motif; ACTIVATION; EXOENZYME-S; PHOSPHORYLATION; protein-protein interaction; Science & Technology; COUPLED RECEPTORS; Biochemistry & Molecular Biology; RGS14; 14-3-3 protein; H-Ras; regulator of G protein signaling (RGS); Ras protein; RAF-1 KINASE; KINASE-ACTIVITY; G protein; PSEUDOMONAS-AERUGINOSA; G protein regulatory (GPR) motif; heterotrimeric G protein; Gi; nucleus; STRUCTURAL BASIS; Life Sciences & Biomedicine; LONG-TERM POTENTIATION; LIVE CELLS
• Research Categories: Health Sciences, Pharmacology; Chemistry, Biochemistry

Abstract

Regulator of G protein signaling 14 (RGS14) is a multifunctional brain scaffolding protein that integrates G protein and Ras/ERK signaling pathways. It is also a nucleocytoplasmic shuttling protein. RGS14 binds active Gα i/o via its RGS domain, Raf and active H-Ras–GTP via its R1 Ras-binding domain (RBD), and inactive Gα i1/3 via its G protein regulatory (GPR) domain. RGS14 suppresses long-term potentiation (LTP) in the CA2 region of the hippocampus, thereby regulating hippocampally based learning and memory. The 14-3-3 family of proteins is necessary for hippocampal LTP and associative learning and memory. Here, we show direct interaction between RGS14 and 14-3-3ɣ at two distinct sties, one phosphorylation-independent and the other phosphorylation-dependent at Ser-218 that is markedly potentiated by signaling downstream of active H-Ras. Using bioluminescence resonance energy transfer (BRET), we show that the pSer-218 – dependent RGS14/14-3-3ɣ interaction inhibits active Gα i1 –AlF 4- binding to the RGS domain of RGS14 but has no effect on active H-Ras and inactive Gα i1 –GDP binding to RGS14. By contrast, the phosphorylation-independent binding of 14-3-3 has no effect on RGS14/Gα i interactions but, instead, inhibits (directly or indirectly) RGS14 nuclear import and nucleocytoplasmic shuttling. Together, our findings describe a novel mechanism of negative regulation of RGS14 functions, specifically interactions with active Gα i and nuclear import, while leaving the function of other RGS14 domains intact. Ongoing studies will further elucidate the physiological function of this interaction between RGS14 and 14-3-3ɣ, providing insight into the functions of both RGS14 and 14-3-3 in their roles in modulating synaptic plasticity in the hippocampus.