title: Kinetics of rhodopsin's chromophore monitored in a single photoreceptor.
abstract: Absorption of light isomerizes the retinyl chromophore of the photoreceptor pigment rhodopsin from 11-cis to all-trans, generating the photoactivated rhodopsin form. The photoisomerization of the chromophore however destroys rhodopsin, and its regeneration requires the removal of the all-trans and the supply of fresh 11-cis chromophore. The all-trans chromophore is removed through a series of steps beginning with its release from photoactivated rhodopsin in the form of all-trans-retinal, leaving behind the apoprotein opsin. All-trans-retinal is then reduced to all-trans-retinol, which is transported out of the photoreceptor. Rhodopsin is regenerated from opsin and fresh 11-cis-retinal arriving to the photoreceptor from the retinal pigment epithelium. Both all-trans and 11-cis-retinal can form precursors of lipofuscin, a pigment that accumulates with age in the lysosomal compartment of the retinal pigment epithelium. All-trans-retinal, all-trans-retinol, and lipofuscin precursors all emit significant and distinct fluorescence signals, allowing their monitoring in single photoreceptor cells with fluorescence imaging. Here we describe the procedures for measuring these fluorophores in single mouse rod photoreceptors.
authors.affiliation: Departments of Ophthalmology and Neurosciences, Medical University of South Carolina, 167 Ashley Ave., Charleston, SC, 29425, USA.
authors.forename: Leopold
authors.initials: L
authors.lastname: Adler
authors.forename: Nicholas P
authors.initials: NP
authors.lastname: Boyer
authors.forename: Chunhe
authors.initials: C
authors.lastname: Chen
authors.forename: Yiannis
authors.initials: Y
authors.lastname: Koutalos
mesh_terms: D000818:Animals; D008062:Lipofuscin / Q000378:metabolism; D051379:Mice; D010786:Photoreceptor Cells / Q000378:metabolism*; D012243:Rhodopsin / Q000378:metabolism*; D014212:Tretinoin / Q000378:metabolism; D014801:Vitamin A / Q000378:metabolism
chemical_list: D008062:Lipofuscin; D014801:Vitamin A; D014212:Tretinoin; D012243:Rhodopsin