Abstract
Large‐conductance Ca2+‐activated K+ (BK) channel activity is known to be an essential factor for the control of tone and/or motility in various types of tissues containing smooth muscle cells (SMCs) as one of main components. Recently leucine‐rich‐repeat‐containing proteins (LRRC) have been identified as novel auxiliary (γ) subunits of BK channel. However, the distribution and contribution of BKγ subunits in SMCs is unknown. We found that LRRC26 (BKγ1) is highly and specifically expressed in mouse bronchial SMCs (mBSMCs). In the present study, we examined functional roles of BKγ subunits in mouse bronchial SMCs (mBSMCs). Co‐immunoprecipitation and single molecule image analyses showed the direct interaction between BKα and BKγ1 in BSMCs. Whole‐cell patch‐clamp analyses revealed that BK channel sensitivity to intracellular Ca2+ concentration was much higher in mBSMCs than that in mouse aortic SMCs (mASMCs). Mallotoxin, which activates BK channels only in the absence of BKγ1, dose‐dependently activated BK channel currents in mASMCs, but not in mBSMCs. Knock‐down of BKγ1 in mBSMCs significantly reduced BK channel Ca2+ sensitivity and contraction induced by a BK channel blocker. Taken together, BKγ1 in mBSMCs substantially contributes to keep BK channel activity high and the resting membrane potential deep under resting conditions. Thus, BKγ1 in mBSMCs may be responsible to keep the airway resistance stably low under physiological conditions.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Published Version
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