Modulation of large conductance Ca2+-activated K+ channel by Gαh (transglutaminase II) in the vascular smooth muscle cell

초록

 Among G-proteins, Gh is unique in structural differences in the GTP-binding domain and possessing transglutaminase activity. We have studied the role of G protein in modulation of large conductance Ca2+-activated K+ (Maxi-K+) channel by the inside-out mode of patch clamp in smooth muscle cells from superior mesenteric artery of the rabbit. When the non-hydrolyzable GTP analogue, GTPγS, was applied, the channel activity was increased about 2.5-fold. Addition of GDPβS resulted in reversal of the GTPγS effect. When the Gαh7 antibody was applied, the GTPγS-stimulated channel activity was significantly inhibited to control level, suggesting that Gαh is involved in activation of the Maxi-K+ channel in smooth muscle cells.

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