title: Peripherin-2 couples rhodopsin to the CNG channel in outer segments of rod photoreceptors.
abstract: Outer segments (OSs) of rod photoreceptors are cellular compartments specialized in the conversion of light into electrical signals. This process relies on the light-triggered change in the intracellular levels of cyclic guanosine monophosphate, which in turn controls the activity of cyclic nucleotide-gated (CNG) channels in the rod OS plasma membrane. The rod CNG channel is a macromolecular complex that in its core harbors the ion-conducting CNGA1 and CNGB1a subunits. To identify additional proteins of the complex that interact with the CNGB1a core subunit, we applied affinity purification of mouse retinal proteins followed by mass spectrometry. In combination with in vitro and in vivo co-immunoprecipitation and fluorescence resonance energy transfer (FRET), we found that the tetraspanin peripherin-2 links CNGB1a to the light-detector rhodopsin. Using immunoelectron microscopy, we found that this peripherin-2/rhodopsin/CNG channel complex localizes to the contact region between the disk rims and the plasma membrane. FRET measurements revealed that the fourth transmembrane domain (TM4) of peripherin-2 is required for the interaction with rhodopsin. Quantitatively, the binding affinity of the peripherin-2/rhodopsin interaction was in a similar range as that observed for rhodopsin dimers. Finally, we demonstrate that the p.G266D retinitis pigmentosa mutation found within TM4 selectively abolishes the binding of peripherin-2 to rhodopsin. This finding suggests that the specific disruption of the rhodopsin/peripherin-2 interaction in the p.G266D mutant might contribute to the pathophysiology in affected persons.
authors: Munich Center for Integrated Protein Science CIPSM and Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, München, Germany.
authors: Elvir
authors: E
authors: Becirovic
authors: Munich Center for Integrated Protein Science CIPSM and Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, München, Germany.
authors: O N Phuong
authors: ON
authors: Nguyen
authors: Munich Center for Integrated Protein Science CIPSM and Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, München, Germany.
authors: Christos
authors: C
authors: Paparizos
authors: Munich Center for Integrated Protein Science CIPSM and Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, München, Germany.
authors: Elisabeth S
authors: ES
authors: Butz
authors: Cell and Matrix Biology, Institute of Zoology, Johannes-Gutenberg Universität Mainz, Mainz, Germany.
authors: Gabi
authors: G
authors: Stern-Schneider
authors: Cell and Matrix Biology, Institute of Zoology, Johannes-Gutenberg Universität Mainz, Mainz, Germany.
authors: Uwe
authors: U
authors: Wolfrum
authors: Research Unit Protein Science, Helmholtz Center Munich, German Research Center for Environmental Health GmbH, München, Germany and.
authors: Stefanie M
authors: SM
authors: Hauck
authors: Research Unit Protein Science, Helmholtz Center Munich, German Research Center for Environmental Health GmbH, München, Germany and Center for Ophthalmology, Institute for Ophthalmic Research, Tübingen, Germany.
authors: Marius
authors: M
authors: Ueffing
authors: Munich Center for Integrated Protein Science CIPSM and Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, München, Germany.
authors: Christian
authors: C
authors: Wahl-Schott
authors: Munich Center for Integrated Protein Science CIPSM and Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, München, Germany.
authors: Stylianos
authors: S
authors: Michalakis
authors: Munich Center for Integrated Protein Science CIPSM and Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, München, Germany, mbiel@cup.uni-muenchen.de.
authors: Martin
authors: M
authors: Biel
mesh_terms: D000818:Animals; D054815:Cyclic Nucleotide-Gated Cation Channels / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D051379:Mice; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D064531:Peripherins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012160:Retina / Q000378:metabolism; D055214:Retinal Photoreceptor Cell Outer Segment / Q000378:metabolism*; D017948:Retinal Rod Photoreceptor Cells / Q000378:metabolism*; D012174:Retinitis Pigmentosa / Q000235:genetics / Q000378:metabolism*; D012243:Rhodopsin / Q000235:genetics / Q000378:metabolism*
chemical_list: C518242:Cnga1 protein, mouse; C529481:Cngb1 protein, mouse; D054815:Cyclic Nucleotide-Gated Cation Channels; D009419:Nerve Tissue Proteins; D064531:Peripherins; C578996:Prph2 protein, mouse; D012243:Rhodopsin