HSPA9 and type 2 diabetes mellitus: In summary, our data validate that the T2D-induced cardiac MAM thickness alteration results in a decreased IP3-stimulated Ca2+ transfer to heart mitochondria due to a reduced formation of the IP3R1/Grp75/VDAC1 Ca2+ channeling complex, leading to the disruption of mitochondrial bioenergetics, yet not to an oxidative stress exacerbation.