FIG. 3.

Munc18b depletion in INS-1 cells disrupts SM-activated SNARE complex formation. INS-1 cells were transduced with Munc18b siRNA or control scrambled RNA and then kept at basal condition (0.8 mmol/L glucose) or simulated with 16.7 mmol/L glucose plus 10 nmol/L GLP-1 with IBMX (150 μmol/L) and then subjected to coimmunoprecipitation (left panel) with antibodies against Syn-1A (A), Syn-2 (B), or Syn-3 (C). Corresponding right panel showing “input” controls (25 μg protein, total INS-1 lysates) confirmed the reduction in Munc18b levels and similar levels of indicated SNARE proteins. Results shown are representative of three independent experiments, with densitometry analyses in Supplementary Fig. 3. IP, immunoprecipitation.