ATP2C1 and type 1 diabetes mellitus: On the one hand, SPCA1 expression is reduced in patients suffering from T1DM and T2DM and on the other hand SPCA1 knock-out β-cells show increased rates of apoptosis, augmented cytosolic Ca2+ levels and significantly reduced GSIS (bone), highlighting the importance of the Ca2+ homeostatic function of the golgi apparatus.