Bisretinoid phospholipid and vitamin a aldehyde: Shining a light

25Citations
Citations of this article
25Readers
Mendeley users who have this article in their library.

This article is free to access.

Abstract

Vitamin A aldehyde covalently bound to opsin protein is embedded in a phospholipid-rich membrane that supports photon absorption and phototransduction in photoreceptor cell outer segments. Following absorption of a photon, the 11-cis-retinal chromophore of visual pigment in photoreceptor cells isomerizes to all-trans-retinal. To maintain photosensitivity 11-cis-retinal must be replaced. At the same time, however, all-transretinal has to be handled so as to prevent nonspecific aldehyde activity. Some molecules of retinaldehyde upon release from opsin are efficiently reduced to retinol. Other molecules are released into the lipid phase of the disc membrane where they form a conjugate [N-retinylidene-PE (NRPE)] through a Schiff base linkage with PE. The reversible formation of NRPE serves as a transient sink for retinaldehyde that is intended to return retinaldehyde to the visual cycle. However, if instead of hydrolyzing to PE and retinaldehyde, NRPE reacts with a second molecule of retinaldehyde, a synthetic pathway is initiated that leads to the formation of multiple species of unwanted bisretinoid fluorophores. We report on recently identified members of the bisretinoid family, some of which differ with respect to the acyl chains associated with the glycerol backbone. We discussprocessing of the lipidmoieties of these fluorophores in lysosomes of retinal pigment epithelial cells, their fluorescence characters, and new findings related to light- and ironassociated oxidation of bisretinoids.

Cite

CITATION STYLE

APA

Kim, H. J., & Sparrow, J. R. (2021). Bisretinoid phospholipid and vitamin a aldehyde: Shining a light. Journal of Lipid Research, 62. https://doi.org/10.1194/JLR.TR120000742

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free