In mice muscle fibers, Thoudam et al. [71] reported that obesity-induced upregulation of pyruvate dehydrogenase kinase 4 (PDK4) stabilizes the IP3R1–GRP75–VDAC1 complex at MAMs, thereby increasing the calcium flux into mitochondria. Here, PDK4 is linked to obesity due to melanocortin 4 receptor deficiency.