GAD1 and pancreatic insulinoma: Confocal analyses of INS-1 and MIN6 cells, singly transfected with mGAD67-GFP revealed that, in contrast to neurons and several non-neuronal cell lines [23] (S1 Fig.), GAD67-GFP does not concentrate in the Golgi compartment or in cytosolic vesicles in the absence of GAD65, and is instead detected in a diffuse uniform pattern in the cytosol of insulinoma cells (Fig. 1A and B).