Kinetics of cone specific G-protein signaling in avian photoreceptor cells.

Autor: Yee C; Division of Biochemistry, Department of Neuroscience, University of Oldenburg, Oldenburg, Germany., Görtemaker K; Division of Biochemistry, Department of Neuroscience, University of Oldenburg, Oldenburg, Germany., Wellpott R; Division of Biochemistry, Department of Neuroscience, University of Oldenburg, Oldenburg, Germany., Koch KW; Division of Biochemistry, Department of Neuroscience, University of Oldenburg, Oldenburg, Germany.; Research Center Neurosensory Sciences, University of Oldenburg, Oldenburg, Germany.
Jazyk: angličtina
Zdroj: Frontiers in molecular neuroscience [Front Mol Neurosci] 2023 Jan 17; Vol. 16, pp. 1107025. Date of Electronic Publication: 2023 Jan 17 (Print Publication: 2023).
DOI: 10.3389/fnmol.2023.1107025
Abstrakt: Cone photoreceptor cells of night-migratory songbirds seem to process the primary steps of two different senses, vision and magnetoreception. The molecular basis of phototransduction is a prototypical G protein-coupled receptor pathway starting with the photoexcitation of rhodopsin or cone opsin thereby activating a heterotrimeric G protein named transducin. This interaction is well understood in vertebrate rod cells, but parameter describing protein-protein interactions of cone specific proteins are rare and not available for migratory birds. European robin is a model organism for studying the orientation of birds in the earth magnetic field. Recent findings showed a link between the putative magnetoreceptor cryptochrome 4a and the cone specific G-protein of European robin. In the present work, we investigated the interaction of European robin cone specific G protein and cytoplasmic regions of long wavelength opsin. We identified the second loop in opsin connecting transmembrane regions three and four as a critical binding interface. Surface plasmon resonance studies using a synthetic peptide representing the second cytoplasmic loop and purified G protein α -subunit showed a high affinity interaction with a K D value of 21 nM. Truncation of the G protein α -subunit at the C-terminus by six amino acids slightly decreased the affinity. Our results suggest that binding of the G protein to cryptochrome can compete with the interaction of G protein and non-photoexcited long wavelength opsin. Thus, the parallel presence of two different sensory pathways in bird cone photoreceptors is reasonable under dark-adapted conditions or during illumination with short wavelengths.
Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
(Copyright © 2023 Yee, Görtemaker, Wellpott and Koch.)
Databáze: MEDLINE
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