First Author | Gross OP | Year | 2010 |
Journal | J Neurosci | Volume | 30 |
Issue | 9 | Pages | 3450-7 |
PubMed ID | 20203204 | Mgi Jnum | J:159020 |
Mgi Id | MGI:4441079 | Doi | 10.1523/JNEUROSCI.5391-09.2010 |
Citation | Gross OP, et al. (2010) Control of rhodopsin's active lifetime by arrestin-1 expression in mammalian rods. J Neurosci 30(9):3450-7 |
abstractText | 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 approximately 40 ms in wild-type mouse rods, much faster than previous estimates. |