A1 Refereed original research article in a scientific journal

Single Molecule Analysis of Functionally Asymmetric G Protein-coupled Receptor (GPCR) Oligomers Reveals Diverse Spatial and Structural Assemblies




AuthorsJonas KC, Fanelli F, Huhtaniemi IT, Hanyaloglu AC

PublisherAMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC

Publication year2015

Journal:Journal of Biological Chemistry

Journal name in sourceJOURNAL OF BIOLOGICAL CHEMISTRY

Journal acronymJ BIOL CHEM

Volume290

Issue7

First page 3875

Last page3892

Number of pages18

ISSN0021-9258

eISSN1083-351X

DOIhttps://doi.org/10.1074/jbc.M114.622498


Abstract

Formation of G protein-coupled receptors (GPCRs) into dimers and higher order oligomers represents a key mechanism in pleiotropic signaling, yet how individual protomers function within oligomers remains poorly understood. We present a super-resolution imaging approach, resolving single GPCR molecules to similar to 8 nm resolution in functional asymmetric dimers and oligomers using dual-color photoactivatable dyes and localization microscopy (PD-PALM). PD-PALM of two functionally defined mutant luteinizing hormone receptors (LHRs), a ligand-binding deficient receptor (LHRB-) and a signaling-deficient (LHRS-) receptor, which only function via intermolecular cooperation, favored oligomeric over dimeric formation. PD-PALM imaging of trimers and tetramers revealed specific spatial organizations of individual protomers in complexes where the ratiometric composition of LHRB- to LHRS- modulated ligand-induced signal sensitivity. Structural modeling of asymmetric LHR oligomers strongly aligned with PD-PALM-imaged spatial arrangements, identifying multiple possible helix interfaces mediating inter-protomer associations. Our findings reveal that diverse spatial and structural assemblies mediating GPCR oligomerization may acutely fine-tune the cellular signaling profile.




Last updated on 2024-26-11 at 23:22