ISSN:
1432-2013
Keywords:
Key words K+ channel gating
;
Redox modulation
;
Inactivation
;
Cloned channel
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract The effects of cysteine-modifying reagents on the gating of rat cloned Kv1.4 channels expressed in HEK-293 cells were examined using the whole-cell patch-clamp technique. Cells transfected with Kv1.4 expressed a rapidly inactivating K+ current with a mid-point of activation of −31 mV and a slope factor of 5 mV measured with tail current protocols in 35 mM Rb+ external solutions. The cysteine-specific oxidizing agents 2,2′-dithiobis-5-nitropyridine (DTBNP, 50 μM) and chloramine-T (CL-T, 500 μM) removed inactivation of Kv1.4. These effects were reversed by the reducing agent dithiothreitol (DTT, 10 mM). In addition, DTBNP and CL-T also slowed Kv1.4 deactivation and increased the voltage sensitivity of deactivation. The action of cysteine-modifying reagents on Kv1.4 suggests that redox state affects channel gating, with oxidation tending to stabilize the open state of the channel, both by removing inactivation and slowing deactivation.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02207283
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