Click here to close Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly. We suggest using a current version of Chrome, FireFox, or Safari.
XB-ART-20399
Neuron 1995 Jan 01;141:177-83. doi: 10.1016/0896-6273(95)90252-x.
Show Gene links Show Anatomy links

A histidine residue associated with the gate of the cyclic nucleotide-activated channels in rod photoreceptors.

Gordon SE , Zagotta WN .


???displayArticle.abstract???
Ion channels directly activated by the binding of cGMP mediate the electrical response to light in rod photoreceptors. Here, we identify a region of the channel associated with the activation gate using potentiation by intracellular Ni2+. Low concentrations of Ni2+ caused a dramatic increase in the response of rod channels expressed in Xenopus oocytes to both cGMP and cAMP. Whereas saturating cAMP normally activated less than 1% of the channels, Ni2+ increased the cAMP potency nearly 50-fold. Ni2+ did not produce potentiation in the related channel from the olfactory epithelium. We localized the Ni(2+)-binding site to a histidine residue in the putative intracellular mouth of the rod channel (H420). We propose a mechanism for potentiation in which Ni2+ binds to H420 primarily when the channel is open, stabilizing the open conformation. These experiments suggest that H420 is associated with the activation gate.

???displayArticle.pubmedLink??? 7530019
???displayArticle.link??? Neuron
???displayArticle.grants??? [+]

Genes referenced: camp