title: A G Protein-Coupled Receptor Dimerization Interface in Human Cone Opsins.
abstract: G protein-coupled receptors (GPCRs) detect a wide variety of physical and chemical signals and transmit that information across the cellular plasma membrane. Dimerization is a proposed modulator of GPCR signaling, but the structure and stability of class A GPCR dimerization have been difficult to establish. Here we investigated the dimerization affinity and binding interface of human cone opsins, which initiate and sustain daytime color vision. Using a time-resolved fluorescence approach, we found that human red cone opsin exhibits a strong propensity for dimerization, whereas the green and blue cone opsins do not. Through mutagenesis experiments, we identified a dimerization interface in the fifth transmembrane helix of human red cone opsin involving amino acids I230, A233, and M236. Insights into this dimerization interface of red cone opsin should aid ongoing investigations of the structure and function of GPCR quaternary interactions in cell signaling. Finally, we demonstrated that the same residues needed for dimerization are also partially responsible for the spectral tuning of red cone opsin. This last observation has the potential to open up new lines of inquiry regarding the functional role of dimerization for red cone opsin.
authors.affiliation: Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University , 2109 Adelbert Road, Cleveland, Ohio 44106, United States.
authors.forename: Beata
authors.initials: B
authors.lastname: Jastrzebska
authors.affiliation: Department of Chemistry, University of Akron , 190 Buchtel Common, Akron, Ohio 44325, United States.
authors.forename: William D
authors.initials: WD
authors.lastname: Comar
authors.affiliation: Department of Chemistry, University of Akron , 190 Buchtel Common, Akron, Ohio 44325, United States.
authors.forename: Megan J
authors.initials: MJ
authors.lastname: Kaliszewski
authors.affiliation: Department of Chemistry, University of Akron , 190 Buchtel Common, Akron, Ohio 44325, United States.
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Skinner
authors.affiliation: Department of Chemistry, University of Akron , 190 Buchtel Common, Akron, Ohio 44325, United States.
authors.forename: Morgan H
authors.initials: MH
authors.lastname: Torcasio
authors.affiliation: Department of Chemistry, University of Akron , 190 Buchtel Common, Akron, Ohio 44325, United States.
authors.forename: Anthony S
authors.initials: AS
authors.lastname: Esway
authors.affiliation: Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University , 2109 Adelbert Road, Cleveland, Ohio 44106, United States.
authors.forename: Hui
authors.initials: H
authors.lastname: Jin
authors.affiliation: Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University , 2109 Adelbert Road, Cleveland, Ohio 44106, United States.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Palczewski
authors.affiliation: Department of Chemistry, University of Akron , 190 Buchtel Common, Akron, Ohio 44325, United States.
authors.forename: Adam W
authors.identifier: http://orcid.org/0000-0001-5216-9017
authors.initials: AW
authors.lastname: Smith
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002462:Cell Membrane / Q000378:metabolism; D002522:Chlorocebus aethiops; D055358:Cone Opsins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D015151:Immunoblotting; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D009154:Mutation; D055503:Protein Multimerization; D043562:Receptors, G-Protein-Coupled / Q000737:chemistry* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013050:Spectrometry, Fluorescence; D000097573:Red Fluorescent Protein
chemical_list: D055358:Cone Opsins; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D043562:Receptors, G-Protein-Coupled; D000097573:Red Fluorescent Protein