Referenced in: none

Automatically associated channels: Kv2.1

Title: NFATc3 regulates BK channel function in murine urinary bladder smooth muscle.

Authors: J J Layne, M E Werner, D C Hill-Eubanks, M T Nelson

Journal, date & volume: Am. J. Physiol., Cell Physiol., 2008 Sep , 295, C611-23

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/18579799

Abstract
The nuclear factor of activated T-cells (NFAT) is a Ca(2+)-dependent transcription factor that has been reported to regulate the expression of smooth muscle contractile proteins and ion channels. Here we report that large conductance Ca(2+)-sensitive potassium (BK) channels and voltage-gated K(+) (K(V)) channels may be regulatory targets of NFATc3 in urinary bladder smooth muscle (UBSM). UBSM myocytes from NFATc3-null mice displayed a reduction in iberiotoxin (IBTX)-sensitive BK currents, a decrease in mRNA for the pore-forming alpha-subunit of the BK channel, and a reduction in BK channel density compared with myocytes from wild-type mice. Tetraethylammonium chloride-sensitive K(V) currents were elevated in UBSM myocytes from NFATc3-null mice, as was mRNA for the Shab family member K(V)2.1. Despite K(V) current upregulation, bladder strips from NFATc3-null mice displayed an elevated contractile response to electrical field stimulation relative to strips from wild-type mice, but this difference was abrogated in the presence of the BK channel blocker IBTX. These results support a role for the transcription factor NFATc3 in regulating UBSM contractility, primarily through an NFATc3-dependent increase in BK channel activity.