RT Journal Article
SR Electronic
T1 Control of Rhodopsin's Active Lifetime by Arrestin-1 Expression in Mammalian Rods
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 3450
OP 3457
DO 10.1523/JNEUROSCI.5391-09.2010
VO 30
IS 9
A1 Owen P. Gross
A1 Marie E. Burns
YR 2010
UL http://www.jneurosci.org/content/30/9/3450.abstract
AB In rod photoreceptors, deactivation of the light-activated G-protein-coupled receptor rhodopsin (R*) is initiated by phosphorylation and completed through subsequent binding of visual arrestin (Arr1). The in vivo kinetics of these individual interactions have proven difficult to determine with precision since R* lifetime is much shorter than the lifetimes of downstream G-protein and effector molecules. Here, we have used a transgenic mouse line with accelerated downstream deactivation kinetics to reveal the contribution of Arr1 binding to the overall time course of rhodopsin deactivation. Photoresponses revealed that the lifetime of R* is significantly increased in rods that express half of the normal amount of Arr1, in a manner consistent with a twofold decrease in the rate of Arr1 binding across a wide range of flash strengths. A basic model of photoresponse deactivation consistent with established photoreceptor biochemistry shows that R* phosphorylation and Arr1 binding occur with a time constant of ∼40 ms in wild-type mouse rods, much faster than previous estimates.