High-conductance Ca2+-activated K+ channels: Pharmacology and molecular characterization
1993; Academic Press; Volume: 5; Issue: 2 Linguagem: Inglês
10.1016/s1044-5765(05)80005-3
ISSN1098-1284
AutoresMaría L. García, Margarita García‐Calvo, Hans‐Günther Knaus, Gregory J. Kaczorowski,
Tópico(s)Receptor Mechanisms and Signaling
ResumoHigh-conductance Ca2+-activated K+ channels (maxi-K channels) represent a family of proteins that display high selectivity and conductance for K+. With the discovery and purification of selective, high affinity, peptidyl probes for these channels, it has been possible to develop the molecular pharmacology of the maxi-K channel, and address the physiological role which these channels play in target tissues. Although molecular biology approaches have been successful in cloning other types of K+ channels, the molecular constituents of maxi-K channels are unknown. To gain insight into the structural composition of maxi-K channels, the ChTX receptor from bovine aortic and tracheal sarcolemmal membrane vesicles has been solubilized in functional form with digitonin, characterized, and purified to apparent homogeneity. Reconstitution experiments with these preparations demonstrate the presence of maxi-K channel activity with properties that are indistinguishable from those of the native channel. Studies are underway to determine sequence information for the identified ChTX receptor subunits in order to clone and express the maxi-K channel.
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