The Light-Regulated cGMP Phosphodiesterase of Vertebrate Photoreceptors: Structure and Mechanism of Activation by Gtα
The cGMP-specific phosphodiesterase (PDE) of vertebrate photoreceptor cells plays a central role in visual signal transduction. Activation of PDE by the G-protein transducin (Gt) is essential for the rapid reduction in cytoplasmic free cGMP concentration that is thought to be responsible for light-induced decreases in membrane current that lead to hyperpolarization and synaptic signaling. Mice with a mutation in a PDE subunit gene suffer from a hereditary retinal degeneration (rd; Bowes et al. 1990; Pittler and Baehr 1991).
KeywordsTitration Cysteine Adenosine Retina Arginine
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