Phosphatase that hydrolyzes phosphate groups from the inositol ring of phosphoinositides and inositol phosphates, in a domain-specific manner (PubMed:11084340, PubMed:12699622, PubMed:40969890). The 5-PPase domain catalyzes removal of the 5- phosphate from substrates such as phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P2), phosphatidylinositol-3,4,5-trisphosphate (PtdIns(3,4,5)P3), inositol-1,4,5-trisphosphate (Ins(1,4,5)P3) and inositol-1,3,4,5-tetrakisphosphate (Ins(1,3,4,5)P4) (PubMed:11084340, PubMed:12699622, PubMed:40969890). The SAC domain hydrolyzes phosphates at the 3- and 4-positions of the inositol ring, targeting phosphatidylinositol-3-phosphate (PI(3)P), phosphatidylinositol-4- phosphate (PI(4)P), and phosphatidylinositol-3,5-bisphosphate (PI(3,5)P2) (By similarity). Plays a role in the phosphatidylinositol metabolic process during the early stage of clathrin-coated-pit formation (PubMed:12699622). During EGF activation, plays a role in receptor-mediated endocytosis (RME) by converting PtdIns(4,5)P2 to PtdIns(4)P through the H2O2-dependent oxidation of the 4-phosphatase domain (By similarity). May play a role in tumor cell invadopodia formation (PubMed:23076136). {ECO:0000250|UniProtKB:O55207, ECO:0000269|PubMed:11084340, ECO:0000269|PubMed:12699622, ECO:0000269|PubMed:23076136, ECO:0000269|PubMed:40969890}. This is the function of SYNJ2 (synaptojanin 2, Ensembl gene identifier ENSG00000078269).