Purchase this article with an account.
Yuan Pan, Joseph G. Laird, Sheila A. Baker; Characterization of HCN1 Trafficking in Rod Photoreceptors. Invest. Ophthalmol. Vis. Sci. 2012;53(14):1612.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Hyperpolarization-activated cyclic nucleotide-gated channel 1 (HCN1) is a non-selective cation channel that is expressed in retina, brain and heart. It functions by shaping membrane potential and synaptic output. In photoreceptors, HCN1 is exclusively localized in the membrane of inner segments and synaptic termini. Failing to targeting HCN1 to its proper sub-cellular compartments will prevent it from functioning. This might also lead to disease given that defects in sorting and targeting of membrane proteins in photoreceptors are common causes of retinal degeneration. Here in this study, our goal is to study HCN1 trafficking in rods by identifying the targeting signal and testing if ankyrin-B is involved in this process.
To identify a targeting signal, the C-terminus of HCN1 was attached to a membrane reporter and expressed in transgenic Xenopus rods. Localization of the transgenically expressed protein were visualized with confocal microscopy. To test if there is an interaction between HCN1 and ankyrin-B, we used co-immunoprecipitation and a membrane recruitment assay in HEK293 cells.
We found that the carboxyl terminus following the cyclic nucleotide binding domain of HCN1 (601-890) is sufficient for its targeting. In addition, the membrane recruitment assay and co-immunoprecipitation results do not support an interaction between HCN1 and ankyrin-B.
Ankyrin-B is not directly involved in HCN1 targeting. And we identified a novel region within the C-terminus of HCN1 that is sufficient for its targeting in rods.
This PDF is available to Subscribers Only