Western Blot Analysis of Protein Samples

Isolated islets were sonicated and extracted in a Nonidet-P40 lysis buffer (Sigma-Aldrich; St Louis, MO, USA). Proteins were separated via electrophoresis on either a 5%, 7.5%, or 10% sodium dodecyl sulfate-polyacrylamide gel and transferred onto a nitrocellulose membrane (Bio-Rad Laboratories, Hercules, CA, USA). Primary antibodies used for detection are listed in Supplementary Table 2. Proteins were detected using ECL™-Plus Western Blot detecting reagents (Perkin-Elmer, Wellesley, MA, USA) and imaged using the Versadoc Imaging System (Bio-Rad Laboratories). Image Lab software (Bio-Rad Laboratories) was used to quantify band intensities using densitometry, and data were normalized to total or appropriate loading controls [17 (link), 30 (link), 31 (link)].