Calcium-calmodulin modulation of the olfactory cyclic nucleotide-gated cation channel.
Although several ion channels have been reported to be directly modulated by calcium-calmodulin, they have not been conclusively shown to bind calmodulin, nor are the modulatory mechanisms understood. Study of the olfactory cyclic nucleotide-activated cation channel, which is modulated by calcium-calmodulin, indicates that calcium-calmodulin directly binds to a specific domain on the amino terminus of the channel. This binding reduces the effective affinity of the channel for cyclic nucleotides, apparently by acting on channel gating, which is tightly coupled to ligand binding. The data reveal a control mechanism that resembles those underlying the regulation of enzymes by calmodulin. The results also point to the amino-terminal part of the olfactory channel as an element for gating, which may have general significance in the operation of ion channels with similar overall structures.
Liu
M
M
Howard Hughes Medical Institute, Baltimore, MD.
Chen
T Y
TY
Ahamed
B
B
Li
J
J
Yau
K W
KW
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism*; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism*; D006152:Cyclic GMP / Q000378:metabolism*; D006801:Humans; D015640:Ion Channel Gating; D007473:Ion Channels / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D018034:Olfactory Receptor Neurons / Q000378:metabolism; D010455:Peptides / Q000378:metabolism; D017433:Protein Structure, Secondary; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000378:metabolism
D002147:Calmodulin; D007473:Ion Channels; D010455:Peptides; D011993:Recombinant Fusion Proteins; D000242:Cyclic AMP; D006152:Cyclic GMP; D002118:Calcium