Type 1 phosphatidylinositol 4,5-bisphosphate 4-phosphatase (Type 1 PtdIns-4,5-P2 4-Ptase) (EC 3.1.3.78) (PtdIns-4,5-P2 4-Ptase I) (Transmembrane protein 55B)
1_MAADG 6_ ERSPL 11_ LSEPI 16_ DGGAG 21_ GNGLV 26_ GPGGS 31_ GAGPG 36_ GGLTP 41_ SAPPY 46_ GAAFP 51_ PFPEG 56_ HPAVL 61_ PGEDP 66_ PPYSP 71_ LTSPD 76_ SGSAP 81_ MITCR 86_ VCQSL 91_ INVEG 96_ KMHQH 101_ VVKCG 106_ VCNEA 111_ TPIKN 116_ APPGK 121_ KYVRC 126_ PCNCL 131_ LICKV 136_ TSQRI 141_ ACPRP 146_ YCKRI 151_ INLGP 156_ VHPGP 161_ LSPEP 166_ QPMGV 171_ RVICG 176_ HCKNT 181_ FLWTE 186_ FTDRT 191_ LARCP 196_ HCRKV 201_ SSIGR 206_ RYPRK 211_ RCICC 216_ FLLGL 221_ LLAVT 226_ ATGLA 231_ FGTWK 236_ HARRY 241_ GGIYA 246_ AWAFV 251_ ILLAV 256_ LCLGR 261_ ALYWA 266_ CMKVS 271_HPVQN
1: Catalyzes the hydrolysis of phosphatidylinositol-4,5-bisphosphate (PtdIns-4,5-P2) to phosphatidylinositol-4-phosphate (PtdIns-4-P) (PubMed:16365287). Does not hydrolyze phosphatidylinositol 3,4,5-trisphosphate, phosphatidylinositol 3,4-bisphosphate, inositol 3,5-bisphosphate, inositol 3,4-bisphosphate, phosphatidylinositol 5-monophosphate, phosphatidylinositol 4-monophosphate and phosphatidylinositol 3-monophosphate (PubMed:16365287). Regulates lysosomal positioning by recruiting JIP4 to lysosomal membranes, thus inducing retrograde transport of lysosomes along microtubules (PubMed:29146937). Contributes to assembly of the V-ATPase complex in lipid rafts of the lysosomal membrane and to subsequent amino acid-dependent activation of mTORC1 (PubMed:29644770). May play a role in the regulation of cellular cholesterol metabolism (PubMed:25035345)