Phosphatidylinositol (PtdIns) phosphatase that specifically hydrolyzes the 5-phosphate of phosphatidylinositol-3,4,5-trisphosphate (PtdIns(3,4,5)P3), phosphatidylinositol 4,5-bisphosphate PtdIns (4,5)P2 and phosphatidylinositol 3,5-bisphosphate (PtdIns(3,5)P2). Specific for lipid substrates, inactive towards water soluble inositol phosphates (By similarity) (PubMed:10405344). Plays an essential role in the primary cilium by controlling ciliary growth and phosphoinositide 3-kinase (PI3K) signaling and stability (By similarity). a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol-4,5-bisphosphate) + H2O = a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol 4-phosphate) + phosphate a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol-3,4,5-trisphosphate) + H2O = a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol-3,4-bisphosphate) + phosphate a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol-3,5-bisphosphate) + H2O = a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol-3-phosphate) + phosphate Interacts (when prenylated) with PDE6D; this is important for normal location in cilia. Peripheral membrane protein associated with Golgi stacks. Belongs to the inositol 1,4,5-trisphosphate 5-phosphatase type IV family. Truncated N-terminus.