Fig. 2.

Modulation of KCNQ current induced by CF-Inp and iRap in tsA cells. (A) Translocation of CF-Inp (blue) and RFP-PH(PLC-δ) (red) upon addition of Oxo-M (10 µM) or iRap (5 µM) to cells cotransfected with M₁R. Scale bar, 10 µm. Asterisks indicate times of the four images shown. (B) Channel modulation by iRap (5 µM) or Oxo-M (10 µM) in cells expressing CF constructs with LDR or CF-Inp alone. Insets show the current waveforms at indicated times a to d; the dotted line indicates zero current. V_m, membrane voltage protocol; I_{−20 mV}, KCNQ current recorded at −20 mV. (C) Current inhibition by iRap and Oxo-M in cells expressing combinations of LDR and CF constructs. (D) Rate constants of current inhibition with various iRap concentrations. Inset shows the rate constants (s⁻¹) for inhibition by iRap (5 µM) or Oxo-M (10 µM) in CF-Inp–expressing cells (n = 3 to 10 cells). (E) Effect of Oxo-M and iRap on KCNQ channel in a cell treated with the PLC inhibitor U73122 (3 µM). (F) Current inhibition by Oxo-M and iRap in cells treated with U73122 or overexpressing IP₃ 5-phosphatase (n = 3 to 7 cells). Error bars in (C), (D), and (F) indicate SEM.