ISSN:
1573-6881
Keywords:
maxi-K channels
;
charybdotoxin
;
iberiotoxin
;
smooth muscle
;
ion channel purification
;
slo channels
;
Β-subunit
;
K channel agonists
;
K channel blockers
;
ion channel pharmacology
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Physics
Notes:
Abstract High-conductance calcium-activated potassium (maxi-K) channels comprise a specialized family of K+ channels. They are unique in their dual requirement for depolarization and Ca2+ binding for transition to the open, or conducting, state. Ion conduction through maxi-K channels is blocked by a family of venom-derived peptides, such as charybdotoxin and iberiotoxin. These peptides have been used to study function and structure of maxi-K channels, to identify novel channel modulators, and to follow the purification of functional maxi-K channels from smooth muscle. The channel consists of two dissimilar subunits, α and Β. The α subunit is a member of theslo Ca2+-activated K+ channel gene family and forms the ion conduction pore. The Β subunit is a structurally unique, membrane-spanning protein that contributes to channel gating and pharmacology. Potent, selective maxi-K channel effectors (both agonists and blockers) of low molecular weight have been identified from natural product sources. These agents, together with peptidyl inhibitors and site-directed antibodies raised against α and Β subunit sequences, can be used to anatomically map maxi-K channel expression, and to study the physiologic role of maxi-K channels in various tissues. One goal of such investigations is to determine whether maxi-K channels represent novel therapeutic targets.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02110699
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