Subcellular localization of liver FBPase is modulated by metabolic conditions.

In primary cultured hepatocytes, fructose-1,6-bisphosphatase (FBPase) localization is modulated by glucose, dihydroxyacetone (DHA) and insulin. In the absence of these substrates, FBPase was present in the cytoplasm, but the addition of glucose or DHA induced its translocation to the nucleus. As expected, we observed the opposite effect of glucose on glucokinase localization. The addition of insulin in the absence of glucose largely increased the amount of nuclear FBPase. Moreover, at high concentrations of glucose or DHA, FBPase shifted from the cytosol to the cell periphery and co-localized with GS. Interestingly, the synthesis of Glu-6-P and glycogen induced by DHA was not inhibited by insulin. These results indicate that FBPase is involved in glycogen synthesis from gluconeogenic precursors. Overall, these findings show that translocation may be a new integrative mechanism for gluconeogenesis and glyconeogenesis.