Converts phosphatidylinositol 3,4,5-trisphosphate (PtdIns 3,4,5-P3) to PtdIns-P2, and phosphatidylinositol 4,5-bisphosphate (PtdIns 4,5-P2) to phosphatidylinositol 4-phosphate (PI-4-P). By controlling the phosphoinositide composition of the cilia membrane of auditory receptor neurons, regulates the cilia localization of ktub and consequently the transient receptor potential channels iav and nompC. 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 Localized to the transition zone, which marks the boundary between the plasma membrane and the ciliary membrane. Viable and fertile, however flies display a decrease in extracellular sound-evoked potentials. This hearing defect is likely due to the increased levels of phosphatidylinositol 4,5-bisphosphate (PtdIns 4,5-P2) in the ciliary base that results in the abnormal localization of membrane proteins such as ktub, iav and nompC. Expression of ktub in the cilia is decreased and displays abnormal accumulation inside chordotonal cilia, iav is enriched in the ciliary base, and nompC which is typically found in the distal cilia, is slightly mislocalized towards the proximal cilia and its expression is decreased. However there is no effect on the localization of eys. Belongs to the inositol 1,4,5-trisphosphate 5-phosphatase type IV family.