Cyclic Nucleotide-gated Ion Channel - Inhibition of CNG Channels

Inhibition of CNG Channels

Studies have shown the differential inhibition of CNG channels by diacylglycerol (DAG) in Xenopus oocytes. DAG can be used as a closed state inhibitor. Using DAG to inhibit homomultimeric rod channels, or those that contain two or more identical peptide chains, was similar to the inhibition of native rod channels. Using DAG to inhibit the homomultimeric olfactory channels was not as effective, even with a high concentration of DAG. More than one molecule of DAG is needed to inhibit a channel effectively. DAG molecules position themselves to stabilize the close state of a CNG channel, by binding to the channel or by changing the interaction between the lipid bilayerof the cell membrane and the channel. Studies with chimeras rod and olfactory channels suggest that differences in DAG inhibition are due to differences in the attached loop of the transmembrane segment.