ATP2A1 and type 1 diabetes mellitus: Accordingly, the expression levels of the ryanodine receptor (Ryr2), SERCA2a (Atp2a), phospholamban (Pnl) and the Na(+)/Ca(2+) exchanger (NCX) were significantly lower in T1DM mice compared to the type 2 counterpart, as assessed with RT-PCR in freshly isolated CMs from the T1DM, T2DM and CTRL mice (Figure 7C).