Abstract
The Ca2+-binding protein recoverin may regulate visual transduction in retinal rods and cones, but its functional role and mechanism of action remain controversial. We compared the photoresponses of rods from control mice and from mice in which the recoverin gene was knocked out. Our analysis indicates that Ca2+-recoverin prolongs the dark-adapted flash response and increases the rod's sensitivity to dim steady light. Knockout rods had faster Ca2+ dynamics, indicating that recoverin is a significant Ca2+ buffer in the outer segment, but incorporation of exogenous buffer did not restore wild-type behavior. We infer that Ca 2+-recoverin potentiates light-triggered phosphodiesterase activity, probably by effectively prolonging the catalytic activity of photoexcited rhodopsin.
Original language | English (US) |
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Pages (from-to) | 729-741 |
Number of pages | 13 |
Journal | Journal of General Physiology |
Volume | 123 |
Issue number | 6 |
DOIs | |
State | Published - Jun 2004 |
Keywords
- Calcium-binding proteins
- Knockout mice
- Light adaptation
- Photoreceptors
- Phototransduction
ASJC Scopus subject areas
- Physiology