Dephosphorylates phosphatidylinositol phosphates, such as phosphatidylinositol 3,4,5-trisphosphate (PIP3) and phosphatidylinositol 3,5-diphosphates, with preference for PIP3 (PubMed:23897475). Phosphate can be hydrolyzed from the D3 and D5 positions in the inositol ring (PubMed:23897475). Has low tyrosine- protein phosphatase activity in vitro; however, the relevance of such activity in vivo is unclear (By similarity). Plays an important role in adipogenesis of mesenchymal stem cells (MSCs). Regulates the phosphorylation state of AKT1 by regulating the levels of PIP3 in MSCs and preadipocyte cells (PubMed:19351528). Required for hair bundle maturation, a process that enables hair cells to detect and transmit sound and balance signals effectively, therefore affecting auditory function (PubMed:20472657, PubMed:29309402). May act by regulating the level of phosphatidylinositol 4,5-bisphosphate (PIP2) level in the basal region of hair bundles (By similarity). {ECO:0000250|UniProtKB:O88488, ECO:0000250|UniProtKB:P0C5E4, ECO:0000269|PubMed:19351528, ECO:0000269|PubMed:20472657, ECO:0000269|PubMed:23897475, ECO:0000269|PubMed:29309402}. This is the function of PTPRQ (protein tyrosine phosphatase receptor type Q, Ensembl gene identifier ENSG00000139304).