Fig 6. Currents of BK channel are decreased in CRL4^CRBN deficient glioma cells.

(A) The whole cell currents of U87mG cells were detected by voltage clamp. BK currents were presented as the difference between the currents under basal condition and after treatment of paxilline (10 μM, BK channel blocker) for at least 10 mins. The I-V curve of BK currents in WT cells, CRBN KO cells and CRBN KO cells treated with MLN4924 (0.1 μM) for 24 hrs were shown on the bottom right (n = 5 for each group, P < 0.01). (B) The whole cell currents in CRBN KO cell lines stably expressing vehicle, WT CRBN and R419X mutation-bearing CRBN were detected. The I-V curve of BK currents (paxalline-subtracted currents) in these cell lines were shown on the right panel (n = 5 for each group, P < 0.01). (C) BK single-channel currents were recorded with a pipette voltage from 20 mV to 80mV using the excised inside-out configuration and were then identified by its pharmacological sensitivity. Mean single channel current and mean NPo versus voltage relationships were derived from data sets exemplified in the current traces (n = 5 for each group).