Control of K(Ca) channels by calcium nano/microdomains.
Transient elevations in cytoplasmic Ca(2+) trigger a multitude of Ca(2+)-dependent processes in CNS neurons and many other cell types. The specificity, speed, and reliability of these processes is achieved and ensured by tightly restricting Ca(2+) signals to very local spatiotemporal domains, "Ca(2+) nano- and microdomains," that are centered around Ca(2+)-permeable channels. This arrangement requires that the Ca(2+)-dependent effectors reside within these spatial boundaries where the properties of the Ca(2+) domain and the Ca(2+) sensor of the effector determine the channel-effector activity. We use Ca(2+)-activated K(+) channels (K(Ca)) with either micromolar (BK(Ca) channels) or submicromolar (SK(Ca) channels) affinity for Ca(2+) ions to provide distance constraints for Ca(2+)-effector coupling in local Ca(2+) domains and review their significance for the cell physiology of K(Ca) channels in the CNS. The results may serve as a model for other processes operated by local Ca(2+) domains.
Fakler
Bernd
B
Institute of Physiology, Engesser Str. 4, 79108 Freiburg, Germany. bernd.fakler@physiologie.uni-freiburg.de
Adelman
John P
JP
D000818:Animals; D002118:Calcium / Q000502:physiology*; D020013:Calcium Signaling / Q000502:physiology*; D002490:Central Nervous System / Q000166:cytology / Q000502:physiology; D003593:Cytoplasm / Q000378:metabolism; D006801:Humans; D021962:Membrane Microdomains / Q000502:physiology*; D009474:Neurons / Q000378:metabolism; D024681:Potassium Channels, Calcium-Activated / Q000378:metabolism*; D015290:Second Messenger Systems / Q000502:physiology*
D024681:Potassium Channels, Calcium-Activated; D002118:Calcium