FIG. 5.

Syntaxin 1A and Munc18-1 are regulated by TCF7L2. Mouse pancreatic islets were treated with TCF7L2 siRNA as described in research design and methods, and protein content was assessed by immunoblot analysis. A: Typical blots are shown. B: Quantification of immunoblots from three separate sets of samples using ImageJ is shown (□, control siRNA; ■, TCF7L2 siRNA). TIRF microscopy of MIN6 cells treated with TCF7L2 shRNA and quantification of granule number at the cell surface was as described in research design and methods. Images shown are averages of 1-s movies acquired at 50 Hz and 20-ms exposure at 100 nm/pixel. Data are means ± SEM, n = 3 (30–35 cells per condition) (C). Scale bar = 2 μm. Example graphs (D) of granule movement analysis from a representative control cell at different times and representative tracks (E) of the different categories of granule movement observed after the addition of 30 mmol/l glucose. All tracks are 30 s or longer (1 = beginning of track, 2 = end), and comparison (F) of the proportion of moving granules in TCF7L2 silenced and control β-cells before and during application of high glucose (n = 5; 15–25 separate cells per condition; □, scrambled; ■, TCF7L2 shRNA). (A high-quality digital representation of this figure is available in the online issue.)