Phototransduction Biophysics
نویسندگان
چکیده
Phototransduction biophysics comprises intracellular molecular reactions and ion fluxes through ion channels on the photoreceptor membrane that converts light into an electrical signal. Phototransduction biophysics serves the purpose of counting photons and integrating these counts to an estimate – a macroscopic voltage response – of light changes from a small area of visual space. To do this task well in vastly varying light conditions, photoreceptors rely upon stochastic adaptive sampling of light information.
منابع مشابه
Evolution of opsins and phototransduction.
Opsins are the universal photoreceptor molecules of all visual systems in the animal kingdom. They can change their conformation from a resting state to a signalling state upon light absorption, which activates the G protein, thereby resulting in a signalling cascade that produces physiological responses. This process of capturing a photon and transforming it into a physiological response is kn...
متن کاملModeling the role of incisures in vertebrate phototransduction.
Phototransduction is mediated by a G-protein-coupled receptor-mediated cascade, activated by light and localized to rod outer segment (ROS) disk membranes, which, in turn, drives a diffusion process of the second messengers cGMP and Ca2+ in the ROS cytosol. This process is hindered by disks-which, however, bear physical cracks, known as incisures, believed to favor the longitudinal diffusion of...
متن کاملIs vertebrate phototransduction solved? New insights into the molecular mechanism of phototransduction.
Rods and cones use phototransduction to convert the energy of an absorbed photon to an electrophysiological signal. Recent application of multidisciplinary techniques to the study of phototransduction has clarified several fundamental steps between the photon capture and physiological responses (Fig. 1). Important discoveries during the last two years have paved the way for further research on ...
متن کاملJellyfish vision starts with cAMP signaling mediated by opsin-G(s) cascade.
Light sensing starts with phototransduction in photoreceptor cells. The phototransduction cascade has diverged in different species, such as those mediated by transducin in vertebrate rods and cones, by G(q)-type G protein in insect and molluscan rhabdomeric-type visual cells and vertebrate photosensitive retinal ganglion cells, and by G(o)-type G protein in scallop ciliary-type visual cells. H...
متن کاملLoss of Gq/11 Genes Does Not Abolish Melanopsin Phototransduction
In mammals, a subset of retinal ganglion cells (RGCs) expresses the photopigment melanopsin, which renders them intrinsically photosensitive (ipRGCs). These ipRGCs mediate various non-image-forming visual functions such as circadian photoentrainment and the pupillary light reflex (PLR). Melanopsin phototransduction begins with activation of a heterotrimeric G protein of unknown identity. Severa...
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