Muscle FBPase binds to cardiomyocyte mitochondria under glycogen synthase kinase-3 inhibition or elevation of cellular Ca2+ level

A growing body of research suggests that fructose 1,6-bisphosphatase (FBPase) might be involved in regulation of cell mortality/survival. However, the precise role of FBPase in the process remains unknown. Here, we show for the first time that in HL-1 cardiomyocytes, inhibition of glycogen synthase kinase-3 results in translocation of FBPase to mitochondria. In vitro experiments demonstrate that FBPase reduces the rate of calcium-induced mitochondrial swelling, affects ATP synthesis and interacts with mitochondrial proteins involved in regulation of volume and energy homeostasis. We suggest that FBPase might be engaged in a regulation of cell survival by influencing mitochondrial function.Structured summary of protein interactionsFBPasephysically interacts with VDAC2, Vdac3, ATP synthase subunit beta, Slc25a5, ATP synthase subunit alpha, Histone cluster 1, H1d, Histone H2A, Histone H4 and Histone H3 by affinity chromatography technology (View interaction)FBPasephysically interacts with ATP synthase subunit β, ATP synthase subunit α, ADP/ATP translocase 1, ADP/ATP translocase 2 and VDAC2 by cross-linking study (View interaction)

► Inhibition of GSK3 results in translocation of FBPase to mitochondria.
► FBPase reduces Ca2+-induced mitochondrial swelling.
► FBPase influences mitochondrial ATP synthesis.