Acts as a 2,3-bisphosphoglycerate 3-phosphatase, by mediating the dephosphorylation of 2,3-bisphosphoglycerate (2,3-BPG) to produce phospho-D-glycerate without formation of 3-phosphoglycerate (By similarity). Acts as a phosphoinositide 5- and phosphoinositide 6-phosphatase and regulates cellular levels of inositol pentakisphosphate (InsP5) and inositol hexakisphosphate (InsP6). May play a role in bone development (endochondral ossification). May play a role in the transition of chondrocytes from proliferation to hypertrophy (By similarity). Through the regulation of intracellular inositol polyphosphates, may control intracellular cation homeostasis, including that of calcium and iron, hence affecting free cation availability required for neural cell signaling (PubMed:33257696). myo-inositol hexakisphosphate + H2O = myo-inositol pentakisphosphate (mixed isomers) + phosphate. (2R)-2,3-bisphosphoglycerate + H2O = (2R)-2-phosphoglycerate + phosphate Also attached to the plasma membrane in erythrocytes. Widely expressed with highest levels in kidney, intestine, thymus and liver. Expressed in different stages of embryogenesis, from 7.5 dpc through 14.5 dpc. The highest levels of expression is found in the visceral endoderm at 7.5 dpc and 8.5 dpc and in the fetal liver at 12.5 dpc and 14.5 dpc. Knockout mice are born at Mendelian ratio and are fertile. Although brain histology does not identify major differences in cerebellar or cerebral cortex architecture, a mild, but significant 10% decrease in the brain weight was identified associated with a reduced cortical thickness in homozygous mutant mice at postnatal day 21 (PubMed:33257696). At 14.5 dpc, neural progenitors show a decrease of about one third in intracellular free Ca(2+) levels compared to wild-type progenitors (PubMed:33257696). Belongs to the histidine acid phosphatase family. MINPP1 subfamily.