PPIB and myocardial ischemia: Concurrently, in vivo, myocardial ischemia led to a significant increase in the calcium regulatory proteins cyclophilin D (CypD) and mitochondrial Ca2+ uniporter (MCU) on MAMs, while sigma-1 receptor (Sig-1R) and neurite outgrowth inhibitor B (NOGO-B) were significantly reduced.