Rapid transducin deactivation in intact stacks of bovine rod outer segment disks as studied by light scattering techniques Arrestin requires additional soluble proteins for rapid quenching of rhodopsin catalytic activity

FEBS Letters

Wagner, Rafael¹  Uhl, Rainer¹  Ryba, Nicholas¹ 

[1] Max-Planck-Institut für Biophysikalische Chemie, Am Faßberg, D-3400 Göttingen, FRG

关键词: Photoreception;    Transducin deactivation;    Rhodopsin phosphorylation;    48 kDa protein;    Arrestin;    Light scattering;   

DOI  :  10.1016/0014-5793(88)81242-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

In photoreceptors of the living retina both activation and deactivation of transducin must occur in less than 1 s. In ROS preparations used for in vitro studies, however, deactivation takes minutes. This is due to the fact that activated transducin is released into the free aqueous space, whereby GTPase activity and consequent deactivation of the protein are slowed down, and due to the dilution of soluble ROS proteins involved in the quenching of rhodopsin activity. In this paper, using a convenient, non-invasive light scattering assay, we demonstrate that in an intact stack of disks, where active transducin stays membrane associated and is rapidly deactivated, the activity of rhodopsin can also be quenched in the time range of seconds when soluble ROS proteins are supplemented. Arrestin, the 48 kDa protein of the photoreceptor, is one of the proteins required for rapid recovery, however, it requires the synergistic action of other soluble proteins (besides rhodopsin kinase) in order to exert its effect: When arrestin is included in the reaction mixture without the ‘helper protein(s)’, it cannot speed recovery, and when a mixture of soluble proteins is added which lacks arrestin, there is also no effect. The nature and identity of this (these) helper protein(s) are still unclear.

【 授权许可】

Unknown