Transducin is a protein found in

Transducin (Gt) is a protein naturally expressed in veebrate retina rods and cones and it is very impoant in veebrate phototransduction. It is a type of heterotrimeric G-protein with different a subunits in rod and cone photoreceptors. Light leads to conformational changes in rhodopsin, which in turn leads to the activation of transducin. Transducin activates phosphodiesterase, which results in the breakdown of cGMP. The intensity of the flash response is directly propoional to the number of transducin activated. Ref: guyton and hall textbook of medical physiology 12 edition page number: 742,743,744