241 human active and 13 inactive phosphatases in total;
194 phosphatases have substrate data;
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336 protein substrates;
83 non-protein substrates;
1215 dephosphorylation interactions;
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299 KEGG pathways;
876 Reactome pathways;
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last scientific update: 11 Mar, 2019
last maintenance update: 01 Sep, 2023
Catalyzes the hydrolysis of the 4-position phosphate ofphosphatidylinositol 4,5-bisphosphate Does not hydrolyzephosphatidylinositol 3,4,5-trisphosphate, phosphatidylinositol3,4-bisphosphate, inositol 3,5-bisphosphate, inositol 3,4-bisphosphate, phosphatidylinositol 5-monophosphate,phosphatidylinositol 4-monophosphate and phosphatidylinositol 3-monophosphate
Under conditions of cellular stress, nuclear levels of phosphatidylinositol-5-phosphate (PI5P) increase and, through interaction with ING2, result in nuclear retention/accumulation of ING2. ING2 binds TP53 (p53) and recruits histone acetyltransferase EP300 (p300) to TP53, leading to TP53 acetylation. Increased nuclear PI5P levels positively regulate TP53 acetylation (Ciruela et al. 2000, Gozani et al. 2003, Jones et al. 2006, Zou et al. 2007, Bultsma et al. 2010)
Under conditions of cellular stress, nuclear levels of phosphatidylinositol-5-phosphate (PI5P) increase. Type I phosphatidylinositol 4,5-bisphosphate 4-phosphatase TMEM55B translocates to the nucleus under stress via an unknown mechanism (Zou et al. 2007) and generates PI5P from the PI(4,5)P2 substrate. The level of PI5P in the nucleus is kept low because of the phosphatidylinositol-5-phosphate 4-kinase activity of nuclear PIP4K2 dimers, mainly dimers containing PIP4K2B (Ciruela et al. 2000). Under conditions of cellular stress, nuclear PIP4K2B is phosphorylated and inactivated by p38 MAP family kinases (Jones et al. 2006)