TY  - JOUR
AU  - Gunkel, Monika
AU  - Schöneberg, Johannes
AU  - Alkhaldi, Weaam
AU  - Irsen, Stephan
AU  - Noé, Frank
AU  - Kaupp, U Benjamin
AU  - Alamoudi, Ashraf
TI  - Higher-order architecture of rhodopsin in intact photoreceptors and its implication for phototransduction kinetics.
JO  - Structure
VL  - 23
IS  - 4
SN  - 0969-2126
CY  - Cambridge, Mass.
PB  - Cell Press
M1  - DZNE-2020-04197
SP  - 628-638
PY  - 2015
AB  - 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.
KW  - Animals
KW  - Kinetics
KW  - Mice
KW  - Mice, Inbred C57BL
KW  - Photoreceptor Cells: metabolism
KW  - Photoreceptor Cells: ultrastructure
KW  - Protein Binding
KW  - Protein Multimerization
KW  - Rhodopsin: chemistry
KW  - Rhodopsin: metabolism
KW  - Transducin: metabolism
KW  - Vision, Ocular
KW  - Rhodopsin (NLM Chemicals)
KW  - Transducin (NLM Chemicals)
LB  - PUB:(DE-HGF)16
C6  - pmid:25728926
DO  - DOI:10.1016/j.str.2015.01.015
UR  - https://pub.dzne.de/record/137875
ER  -