Fig. 8: Tspan-8 over expression inhibits insulin secretion.

a Western blot of the total amount of Tspan-8 (~25 KDa) in INS-1 cells. OE means over expression and Ctl refers to WT INS-1 cells. One image of four independent experiments is shown. Results are similar in all replicates. Not shown replicates are provided in the source data file. b Western blot of the total amount of human Tspan-8·mScarlet (~51 KDa) in INS-1 cells. Membranes were immunoblotted with anti calnexin and anti RFP antibodies, respectively and developed by ECL. OE means over expression and Ctl refers to WT INS-1 cells. One image of four independent experiments is shown. Results are similar in all replicates. Not shown replicates are provided in the source data file. c Optical plane from a confocal image of live INS-1 cells over expressing human Tspan-8·mScarlet. Arrows point to the plasma membrane. Arrowheads point to intracellular human Tspan-8·mScarlet. Scale bar is 5 µm. One of six independent images is shown. Images were taken from two independent cell cultures. All images showed similar results. d Lysates of WT or hTspan-8·mScarlet-over expressing INS-1 cells were processed for immunoprecipitation of RFP and western blot analysis. OE means over expression and Ctl refers to WT INS-1 cells. One image of two independent experiments is shown. Results are similar in all replicates. e Quantification of glucose-stimulated insulin secretion in WT and hTspan-8·mScarlet-over expressing INS-1 cells. Insulin in the culture media was measured by ELISA. Values are expressed as relative to the control condition. Grouped in different colors are secretion assays that were processed in parallel. Red dots represent the mean +/− the standard deviation. Total number of replicates are 15. The p value (<0.001) of a one-way ANOVA analysis is shown in the plot. Source data for a, b, d and e are provided as a Source Data file.