Higher-order architecture of rhodopsin in intact photoreceptors and its implication for phototransduction kinetics
| Autor: | M. Gunkel, Johannes Schöneberg, Ulrich Benjamin Kaupp, Ashraf Al-Amoudi, W. Alkhaldi, Frank Noé, S. Irsen |
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| Rok vydání: | 2014 |
| Předmět: |
Cell signaling
Rhodopsin ultrastructure [Photoreceptor Cells] genetic structures G protein Kinetics Plasma protein binding Biology Mice Structural Biology metabolism [Photoreceptor Cells] Animals Photoreceptor Cells Transducin metabolism [Rhodopsin] Molecular Biology Vision Ocular metabolism [Transducin] chemistry [Rhodopsin] Mice Inbred C57BL Rod Photoreceptors Crystallography ddc:540 Biophysics biology.protein sense organs Protein Multimerization Visual phototransduction Protein Binding |
| Zdroj: | Structure 23(4), 628-638 (2015). doi:10.1016/j.str.2015.01.015 Structure |
| ISSN: | 1878-4186 |
| DOI: | 10.1016/j.str.2015.01.015 |
| Popis: | SummaryThe visual pigment rhodopsin belongs to the family of G protein-coupled receptors that can form higher oligomers. It is controversial whether rhodopsin forms oligomers and whether oligomers are functionally relevant. Here, we study rhodopsin organization in cryosections of dark-adapted mouse rod photoreceptors by cryoelectron tomography. We identify four hierarchical levels of organization. Rhodopsin forms dimers; at least ten dimers form a row. Rows form pairs (tracks) that are aligned parallel to the disk incisures. Particle-based simulation shows that the combination of tracks with fast precomplex formation, i.e. rapid association and dissociation between inactive rhodopsin and the G protein transducin, leads to kinetic trapping: rhodopsin first activates transducin from its own track, whereas recruitment of transducin from other tracks proceeds more slowly. The trap mechanism could produce uniform single-photon responses independent of rhodopsin lifetime. In general, tracks might provide a platform that coordinates the spatiotemporal interaction of signaling molecules. |
| Databáze: | OpenAIRE |
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