Binding of GTP to transducin is not inhibited by arrestin and phosphorylated rhodopsin

FEBS Letters

Akino, Toyoaki¹  Ohguro, Hiroshi¹  Yoshizawa, Tôru²  Saito, Tetsuya¹  Fukada, Yoshitaka² 

[1] Department of Biochemistry, Sapporo Medical College, Sapporo 060, Japan;Department of Biophysics, Faculty of Science, Kyoto University, Kyoto 606 Japan

关键词: Rod outer segment;    Guanosine triphosphate-binding protein;    Transducin;    Arrestin;    Rhodopsin;    Phosphorylation;    (Bovine retina);    ROS;    rod outer segments;    Rh;    rhodopsin;    Rh∗;    photobleaching intermediate of rhodopsin;    DTT;    dithiothreitol;    GppNHp;    guanosine-5'-(β;    γ-imido)triphosphate;   

DOI  :  10.1016/0014-5793(90)80606-J

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

In the presence of a photobleaching intermediate of unphosphorylated or phosphorylated rhodopsin (Rh^∗), the binding of GppNHp to transducin was measured with or without arrestin for elucidation of the shut-off mechanism of the visual transduction process in bovine rod outer segments. The ability of Rh^∗ to catalyze the formation of the transducin-GppNHp complex in the absence of arrestin was independent of the degree of phosphorylation of Rh^∗. Furthermore, the catalyzing ability of the phosphorylated Rh^∗ was not reduced by the addition of arrestin. These observations indicate that the interaction between phosphorylated Rh^∗ and transducin was not inhibited by arrestin. Thus, the hypothesis was not supported that the PDE shut-off process is a simple competition between transducin and arrestin for binding to phosphorylated Rh^∗.

【 授权许可】

Unknown