Functional analyses of αCTF in MIN6-m9 cells.

MIN6-m9 cells were untreated (−), or transfected with the empty pCX4bsr vector, or the vector expressing either αCTF or αCTFmut. After 2 days of transfection, CADM1 levels were assessed in a western blot using a CADM1 antibody (a). Arrowheads indicate full-length CADM, αCTF, and αCTFmut. The blot was reprobed with an anti-β-actin antibody to show the protein loading. (b) Glucose-induced insulin secretion assay. The mean ratio (fold increase) relative to the baseline (t = 0) and normalized to the cell volume is plotted with a bar indicating SE. There was no difference between any pair at each timepoint; the smallest P-values by t-test are shown. (c) TUNEL assay. TUNEL and DAPI fluorescent stains are colored green and blue, respectively. TUNEL-positive cells are recognized by bluish white nuclei where the two stains merge (indicated by arrows). Mean ± SE of the percentage of TUNEL-positive cells and P-values by t-test are shown below the photomicrographs. Data in b and c are representative of three independent assays, respectively. Bar  = 50 µm.