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. 2013 Jul 2;8(7):e67561. doi: 10.1371/journal.pone.0067561

Figure 2. Sec5 regulates release of insulin granules from the readily-releasable and reserve pools.

Figure 2

Changes in cell membrane capacitance (ΔCm) were measured from single INS-1 cells using a train of eight depolarizing pulses (500 ms in duration) from −70 mV to 0 mv. (A) Cofocal imaging shows that Sec5 protein expression in almost all INS-1 831/13 cells are knocked down by Sec5 lenti-shRNA, indicated by the GFP co-expression, and almost complete abrogation of Sec5-TxRd staining. (B) Representative recordings of capacitance from Htrl-1 (Control) lenti-shRNA and Sec5 lenti-shRNA (Sec5 KD) INS-1 832/13 cells. (C) Summary of the change in capacitance (ΔCm) normalized to basal cell membrane capacitance (fF/pF) from control (n  = 10 cells) and Sec5 KD (n  = 9) INS-1 832/13 cells. Values represent the mean ± SEM. *p<0.05. (D) Summary of the size of the RRP of insulin granules (ΔCm1st–2nd pulse) and the rate of granule mobilization (ΔCm3rd-8th pulse) (n  = 9–10 cells). Values represent the mean ± SEM. *p<0.05.