Amino Acids 855 to 876 of the Rodent Metabotropic Glutamate Receptor, mGluR5, C Terminal Domain Are Responsible for Its Inner Nuclear Membrane Localization

Abstract

ABSTRACT OF THE DISSERTATIONTraditionally G-protein coupled receptors (GPCR) are thought to be located onthe cell surface and to transmit extracellular signals into the cytoplasm. A growingnumber of GPCRs, however, have been localized to several subcellular compartmentsincluding the inner nuclear membrane (INM). One such receptor is the metabotropicglutamate receptor 5 (mGluR5) which is not only expressed on the plasma membrane(PM) but is also expressed on the INM mediating Ca2+ changes in the nucleoplasm bycoupling with Gq/11. In the present study, we identified a region in the proximal part ofthe mGluR5 C terminus (amino acids 855-876) which is required for INM localization ofthe receptor. Specifically, replacement of intracellular C terminus of another PM GPCR,GABAB2, with the mGluR5 C terminus led to the nuclear membrane (NM) localization ofthe chimeric receptor. Further, immunocytochemistry, fractionation and Ca2+ imagingtechniques revealed that mGluR5 amino acids 855-876 are required for INM localization.Although these amino acids contain a small basic amino acid stretch akin to bona fidenuclear localization sequences, their mutation did not prevent INM localization. Thesedata suggest that mGluR5 either uses a non-canonical mechanism to localize to the INMand/or that it diffuses there and is subsequently anchored via other interactions. Aretention model is supported by immunoprecipitation and chromatin immunoprecipitationexperiments showing that mGluR5 interacts with nuclear resident biomolecules likeLamin B1 and chromatin. Taken together, this study defines a region in mGluR5 Cterminus required for its INM localization and suggests that nuclear retention is animportant mechanism in this localization process.

Committee Chair

Karen L O'Malley

Committee Members

Thomas J Baranski, Narasimhan Gautam, Robert W Gereau, Phyllis I Hanson, Didier Hodzic

Comments

Permanent URL: https://doi.org/10.7936/K7M906K1

Degree

Doctor of Philosophy (PhD)

Author's Department

Biology & Biomedical Sciences (Molecular Cell Biology)

Author's School

Graduate School of Arts and Sciences

Document Type

Dissertation

Date of Award

Spring 5-15-2012

Language

English (en)

This document is currently not available here.

Share

COinS