The discovery around how supportive tissue cells of light-sensing photoreceptor cells convert vitamin A for vision could inform potential treatments for vision disorders associated with mutations in the RPE65 gene.

A study, led by the National Eye Institute’s (NEI) Laboratory of Retinal Cell and Molecular Biology, uncovered the mystery behind how a previously uncharacterized region of protein RPE65 binds with retinal pigment epithelium (RPE) cells’ membrane by becoming a spiral shape in order to enter the membrane and complete the vitamin A conversion process that restores the photoreceptors sensitivity to light in the eye.

Dr Sheetal Uppal, research fellow at NEI and the study’s first author, said: ‘Our findings solve a long-standing puzzle in RPE65’s structure, clarifying its function, while expanding our knowledge of membrane-binding in a way that we hope will inform disease models in more accurate ways.

‘Methods such as crystallography, which we use to visualize the atoms of a protein in crystal form, failed to give us a complete picture of RPE’s structure with this crucial region missing. We had to think of a new strategy to characterize this aspect of RPE65’s structure, so we turned to biochemistry.’