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Published October 2, 1997 | public
Journal Article

Prolonged photoresponses in transgenic mouse rods lacking arrestin

Abstract

Arrestins are soluble cytoplasmic proteins that bind to G-protein-coupled receptors, thus switching off activation of the G protein and terminating the signalling pathway that triggers the cellular response. Although visual arrestin has been shown to quench the catalytic activity of photoexcited, phosphorylated rhodopsin in a reconstituted system, its role in the intact rod cell remains unclear because phosphorylation alone reduces the catalytic activity of rhodopsin. Here we have recorded photocurrents of rods from transgenic mice in which one or both copies of the arrestin gene were disrupted. Photoresponses were unaffected when arrestin expression was halved, indicating that arrestin binding is not rate limiting for recovery of the rod photoresponse, as it is in Drosophila . With arrestin absent, the flash response displayed a rapid partial recovery followed by a prolonged final phase. This behaviour indicates that an arrestin-independent mechanism initiates the quench of rhodopsin's catalytic activity and that arrestin completes the quench. The intensity dependence of the photoresponse in rods lacking arrestin further suggests that, although arrestin is required for normal signal termination, it does not participate directly in light adaptation.

Additional Information

© 1997 Macmillan Publishers Ltd. Received 3 April; accepted 2 July 1997. This work was supported by grants from the National Eye Institute (D.A.B.), the National Institute on Aging (M.I.S.), the National Institute of General Medical Sciences (R.L.D.), the Ruth and Milton Steinbach Fund (D.A.B., J.C.), The McKnight Endowment Fund for Neuroscience (D.A.B.), Research to Prevent Blindness (J.C., C.L.M.) and Lions' of Massachusetts (C.L.M.).

Additional details

Created:
August 19, 2023
Modified:
October 23, 2023