Article Abstract:
The hydrophobic pore near the C1 regions of inward rectifier K+ channel (IRK) are responsible for the regulatory properties of these channels. The guanine nucleotide-binding (G) protein subunit, G(sub beta-gamma), controls IRKs in Xenopus oocytes. The G(sub beta-gamma) subunits interact with the intracellular regions near the hydrophobic channel pores. Studies on the chimeric channels containing the hydrophobic pore region of RB-IRK2, attached to the carboxy terminal region of GIRK, show voltage- and receptor-dependent activity.
User Contributions:
Comment about this article or add new information about this topic:
Article Abstract:
Two-hybrid yeast screen was used in the identification of the GTP-binding protein RhoA which suppresses the activity of the delayed rectifier potassium channel Kv1.2. Immunoprecipitation studies reveal that RhoA associates with the potassium channel while overexpression of the protein in the Xenopus heterologous expression system reduced the current generated by the channel. RhoA plays an important role in the receptor-mediated downregulation of delayed rectifier potassium channels.
User Contributions:
Comment about this article or add new information about this topic:
Article Abstract:
Experimental studies of inward rectifier K+ channels reveal that intracellular polyamine spermine (SPM) causes the voltage-dependent inward rectification of the K+ channels. Physiological levels of SPM mediate the voltage-dependent rectification even without free Mg2+ and in inward rectifier K+ mutant channels that lack endogenous rectification. Physiological concentrations of SPM also cause the voltage dependency of rectification.
User Contributions:
Comment about this article or add new information about this topic: