Catalyzes the hydrolysis of fructose 1,6-bisphosphate to fructose 6-phosphate in the presence of divalent cations and probably participates in glycogen synthesis from carbohydrate precursors, such as lactate. beta-D-fructose 1,6-bisphosphate + H2O = beta-D-fructose 6-phosphate + phosphate Binds 3 Mg(2+) ions per subunit. Subject to complex allosteric regulation. The enzyme can assume an active R-state, or an inactive T-state. Intermediate conformations may exist. AMP acts as allosteric inhibitor. Fructose 2,6-bisphosphate acts as competitive inhibitor. Strongly inhibited by Ca(2+). Carbohydrate biosynthesis; gluconeogenesis. Homotetramer. Interacts with ALDOA; the interaction blocks inhibition by physiological concentrations of AMP and reduces inhibition by Ca(2+). Interacts with alpha-actinin and F-actin. In neonatal cardiomyocytes, distributed throughout the cytosol, accumulating in the intercalated disks which occur at the Z line of cardiomyocytes and connect adjacent cells, and also located in the nucleus; dissociates from the Z line following an increase in cytosolic Ca(2+) concentration (By similarity). In muscle precursor cells, localizes predominantly to the nucleus and to a lesser extent to the cytoplasm at the proliferative phase, while mainly localizing to the cytoplasm at the differentiation phase (By similarity). Colocalizes with ALDOA and alpha-actinin on both sides of the Z line of skeletal muscle; dissociates rapidly from the Z line following an increase in cytosolic Ca(2+) concentration. Belongs to the FBPase class 1 family.