| Type: | Domain | Name: | Phosducin N-terminal domain |
| Description: | The outer and inner segments of vertebrate rod photoreceptor cells contain phosducin, a soluble phosphoprotein that complexes with the beta/gamma-subunits of the GTP-bindingprotein, transducin. Light-induced changes in cyclic nucleotide levels modulate the phosphorylation of phosducin by protein kinase A []. The protein is thought to participate in the regulation ofvisual phototransduction or in the integration of photo-receptor metabolism. Similar proteins have been isolated from the pineal gland and it is believed that the functionalrole of the protein is the same in both retina and pineal gland [].This entry represents the N-terminal domain of phosducin. Together with the C-terminal domain, it covers one side and the top of the seven-bladed beta propeller of Gt beta gamma. The binding of phosducin induces a distinct structural change in the beta propeller of Gt beta gamma, such that a small cavity opens up between blades 6 and 7 []. Binding of phosducin results in sequestration of beta gamma from the membrane to the cytosol and turns off the signal-transduction cascade. Regulation of this membrane association/dissociation switch of Gt beta gamma by phosducin may be a general mechanism for attenuation of G protein coupled signal transduction cascades. | Short Name: | Phosducin_N_dom |
