%0 Journal Article
%A Gunkel, Monika
%A Schöneberg, Johannes
%A Alkhaldi, Weaam
%A Irsen, Stephan
%A Noé, Frank
%A Kaupp, U Benjamin
%A Alamoudi, Ashraf
%T Higher-order architecture of rhodopsin in intact photoreceptors and its implication for phototransduction kinetics.
%J Structure
%V 23
%N 4
%@ 0969-2126
%C Cambridge, Mass.
%I Cell Press
%M DZNE-2020-04197
%P 628-638
%D 2015
%X The 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.
%K Animals
%K Kinetics
%K Mice
%K Mice, Inbred C57BL
%K Photoreceptor Cells: metabolism
%K Photoreceptor Cells: ultrastructure
%K Protein Binding
%K Protein Multimerization
%K Rhodopsin: chemistry
%K Rhodopsin: metabolism
%K Transducin: metabolism
%K Vision, Ocular
%K Rhodopsin (NLM Chemicals)
%K Transducin (NLM Chemicals)
%F PUB:(DE-HGF)16
%9 Journal Article
%$ pmid:25728926
%R 10.1016/j.str.2015.01.015
%U https://pub.dzne.de/record/137875