Search results for "Rhodopsin"
showing 10 items of 63 documents
Effect of opsin on the shape of the potential energy surfaces at the conical intersection of the Rhodopsin chromophore
2008
Abstract In order to disentangle the role of the protein in the control of the photoisomerization of the chromophore of the visual pigment Rhodopsin, we compare the structure of the ground and excited potential energy surfaces of gas-phase and opsin-embedded 11- cis retinal chromophore at the corresponding (lowest energy) conical intersections. It is shown that, along the branching plane, the asymmetric opsin environment destabilizes one of the ground state relaxation channels emerging from the conical intersection. This suggests that opsin promotes the formation of the product (bathorhodopsin) via enhanced decay probability along the all- trans exit channel. In contrast, in the gas-phase n…
Enrichment of Retinal Ganglion Cells in Rat Retinal Lysate by Excimer Laser Ablation of the Outer Retina
2013
PURPOSE. Retinal ganglion cells (RGC) are a relatively small cell population in the retina. This leads to an unfavorable signal-tonoise ratio when analyzing RGC proteins in whole retina lysate. We present a novel technique to obtain RGC-enriched rat retinal lysate by removing the outer retinal layers with an excimer laser before lysation. METHODS. Outer retinal layers were ablated with an excimer laser on flat mounted retinas from adult albino rats. 4 0 6Diamidino-2-phenylindole dihydrochloride hydrate (DAPI) nuclear staining was used to assess the ablation efficacy (n ! 6). Western blot for layer specific markers (rhodopsin, parvalbumin, b-III-tubulin) was performed to quantify changes in …
Molecular genetics of autosomal dominant retinitis pigmentosa (ADRP): a comprehensive study of 43 Italian families
2005
Retinitis pigmentosa is the most common form of retinal degeneration and is heterogeneous both clinically and genetically. The autosomal dominant forms ( ADRP) can be caused by mutations in 12 different genes. This report describes the first simultaneous mutation analysis of all the known ADRP genes in the same population, represented by 43 Italian families. This analysis allowed the identification of causative mutations in 12 of the families (28% of the total). Seven different mutations were identified, two of which are novel (458delC and 6901C --> T (P2301S), in the CRX and PRPF8 genes, respectively). Several novel polymorphisms leading to amino acid changes in the FSCN2, NRL, IMPDH1, and…
Efficient gene delivery to photoreceptors using AAV2/rh10 and rescue of the Rho–/– mouse
2015
As gene therapies for various forms of retinal degeneration progress toward human clinical trial, it will be essential to have a repertoire of safe and efficient vectors for gene delivery to the target cells. Recombinant adeno-associated virus (AAV) serotype 2/2 has been shown to be well tolerated in the human retina and has provided efficacy in human patients for some inherited retinal degenerations. In this study, the AAV2/8 and AAV2/rh10 serotypes have been compared as a means of gene delivery to mammalian photoreceptor cells using a photoreceptor specific promoter for transgene expression. Both AAV2/8 and AAV2/rh10 provided rescue of the retinal degeneration present in the rhodopsin kno…
A Roadmap to Applying Optogenetics in Neuroscience
2014
Optogenetics allows for the specific manipulation of the activity of genetically defined cell populations in the CNS. Yet, it requires effective gene delivery, light stimulation, and readout strategies. Here, we provide a roadmap aimed at guiding the experimenter in the process of establishing an optogenetic approach tailored to a given research hypothesis in the field of neuroscience.
The GTP- and Phospholipid-Binding Protein TTD14 Regulates Trafficking of the TRPL Ion Channel in Drosophila Photoreceptor Cells
2015
Recycling of signaling proteins is a common phenomenon in diverse signaling pathways. In photoreceptors of Drosophila, light absorption by rhodopsin triggers a phospholipase Cβ-mediated opening of the ion channels transient receptor potential (TRP) and TRP-like (TRPL) and generates the visual response. The signaling proteins are located in a plasma membrane compartment called rhabdomere. The major rhodopsin (Rh1) and TRP are predominantly localized in the rhabdomere in light and darkness. In contrast, TRPL translocates between the rhabdomeral plasma membrane in the dark and a storage compartment in the cell body in the light, from where it can be recycled to the plasma membrane upon subsequ…
Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy
2014
Monitoring the dynamics of protonation and protein backbone conformation changes during the function of a protein is an essential step towards understanding its mechanism. Protonation and conformational changes affect the vibration pattern of amino acid side chains and of the peptide bond, respectively, both of which can be probed by infrared (IR) difference spectroscopy. For proteins whose function can be repetitively and reproducibly triggered by light, it is possible to obtain infrared difference spectra with (sub)microsecond resolution over a broad spectral range using the step-scan Fourier transform infrared technique. With -10(2)-10(3) repetitions of the photoreaction, the minimum num…
Rhodopsin transport in the membrane of the connecting cilium of mammalian photoreceptor cells
2000
The transport of the photopigment rhodopsin from the inner segment to the photosensitive outer segment of vertebrate photoreceptor cells has been one of the main remaining mysteries in photoreceptor cell biology. Because of the lack of any direct evidence for the pathway through the photoreceptor cilium, alternative extracellular pathways have been proposed. Our primary aim in the present study was to resolve rhodopsin trafficking from the inner to the outer segment. We demonstrate, predominantly by high-sensitive immunoelectron microscopy, that rhodopsin is also densely packed in the membrane of the photoreceptor connecting cilium. Present prominent labeling of rhodopsin in the ciliary mem…
Climatic oscillations triggered post-Messinian speciation of Western Palearctic brown frogs (Amphibia, Anura, Ranidae)
2003
Abstract Oscillating glacial cycles over the past 2.4 million years are proposed to have had a major impact on the diversity of contemporary species communities. We used mitochondrial and nuclear DNA sequence data to infer phylogenetic relationships within Western Palearctic brown frogs and to test the influence of Pliocene and Pleistocene climatic changes on their evolution. We sequenced 1976 bp of the mitochondrial genes 16S rRNA and cytochrome b and of the nuclear rhodopsin gene for all current species and subspecies. Based on an established allozyme clock for Western Palearctic water frogs and substitution rate constancy among water frogs and brown frogs, we calibrated a molecular clock…
Peripherin-2 couples rhodopsin to the CNG channel in outer segments of rod photoreceptors.
2014
Outer segments (OS) 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 (cGMP), 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 viv…