| 2002 |
PPM1D (Wip1) dephosphorylates and inactivates p38 MAPK, creating a negative feedback loop on p53 activity. Retrovirus-mediated overexpression of PPM1D reduced p53 phosphorylation at Ser33 and Ser46 (p38 MAPK target sites), abrogated Ras-induced apoptosis, and partially rescued cells from cell-cycle arrest. |
Retroviral overexpression, phosphorylation analysis, apoptosis/cell-cycle assays, MEF transformation assay in nude mice |
Nature genetics |
High |
12021785
|
| 2005 |
PPM1D binds Chk1 and dephosphorylates ATR-targeted phospho-Ser345, reducing Chk1 kinase activity. PPM1D also dephosphorylates p53 at phospho-Ser15. These dephosphorylations correlate with reduced intra-S and G2/M checkpoint activity after UV and ionizing radiation. |
Co-immunoprecipitation, in vitro phosphatase assay, checkpoint activity assays after UV/IR |
Genes & development |
High |
15870257
|
| 2006 |
Wip1 (PPM1D) dephosphorylates ATM at Ser1981, a site critical for ATM monomerization and activation, thereby resetting ATM phosphorylation as cells complete DNA repair. Overexpression of Wip1 reduces ATM-dependent signaling cascade activation after DNA damage; Wip1 deficiency results in constitutive ATM activation. |
In vitro phosphatase assay, overexpression and knockdown experiments, immunoblotting for ATM-S1981 phosphorylation |
Molecular cell |
High |
16949371
|
| 2004 |
PPM1D interacts with the nuclear isoform of uracil DNA glycosylase UNG2 and suppresses base excision repair (BER). PPM1D dephosphorylates UNG2 at phosphothreonine 6, reducing UNG2 activity. Point mutations inactivating PPM1D phosphatase activity abrogate BER suppression. |
Co-immunoprecipitation, in vitro phosphatase assay, active-site mutagenesis, BER activity assay |
Molecular cell |
High |
15327777
|
| 2006 |
Wip1 binds Chk2 and dephosphorylates phospho-Thr68 (the ATM-targeted activation site), thereby antagonizing Chk2 activation after ionizing irradiation. Wip1 overexpression suppresses the G2/M DNA damage checkpoint contribution of Chk2. |
Co-immunoprecipitation, in vitro phosphatase assay, G2/M checkpoint assay |
Oncogene |
High |
16798742 16936775
|
| 2006 |
Nuclear localization of both Chk2 and Wip1 is required for their association. The SQ/TQ domain of Chk2 (containing Thr68) and the N-terminal ~100 amino acids of Wip1 are necessary and sufficient for binding. Intrinsic kinase activity of Chk2 (but not phosphatase activity of Wip1) is required for their association when full-length proteins are used. |
Structure-function analysis with deletion and point mutants, co-immunoprecipitation, nuclear localization experiments |
The Journal of biological chemistry |
High |
16798742
|
| 2007 |
Recombinant Wip1 catalytic domain dephosphorylates phosphoserine and phosphothreonine specifically in the p(S/T)Q motif (ATM/ATR substrate motif). Acidic, hydrophobic, or aromatic residues flanking the p(S/T)Q enhance dephosphorylation; basic residues have negative influence. New putative substrates identified include HDM2, SMC1A, ATR, and Wip1 itself. |
In vitro phosphatase kinetics with peptide variants, site-directed mutagenesis, 3D molecular modeling |
Biochemistry |
High |
17939684
|
| 2008 |
PPM1D (Wip1) dephosphorylates Mdm2 at Ser395 (an ATM target site), stabilizing Mdm2, enhancing Mdm2-p53 binding, and promoting ubiquitination and degradation of p53. Wip1 thus facilitates Mdm2-mediated p53 degradation as part of a negative feedback loop. |
In vitro phosphatase assay, co-immunoprecipitation, ubiquitination assay, p53 stability measurements |
Cell cycle (Georgetown, Tex.) |
Medium |
18333294
|
| 2010 |
Wip1 directly dephosphorylates γ-H2AX (phospho-H2AX) in vitro and in vivo. Ectopic Wip1 expression significantly reduces γ-H2AX levels after ionizing radiation and UV; forced premature dephosphorylation disrupts recruitment of DNA repair factors to damage sites and delays DNA damage repair. |
In vitro phosphatase assay, ectopic expression, immunofluorescence, DNA repair kinetics assay |
Cancer research |
High |
20460517
|
| 2010 |
WIP1 overexpression inhibits nucleotide excision repair (NER) kinetics in a phosphatase-activity-dependent manner; phosphatase-dead WIP1 mutants fail to inhibit NER. XPA and XPC are identified as potential WIP1 dephosphorylation targets in the NER pathway. |
Overexpression and depletion experiments, CPD repair kinetics assay, in vitro phosphatase assay with XPA/XPC, phosphatase-dead mutant analysis |
DNA repair |
High |
20451471
|
| 2012 |
Truncating gain-of-function mutations in exon 6 of PPM1D (carboxy-terminal to the phosphatase domain) result in enhanced suppression of p53 in response to ionizing radiation, without simple loss of function. These mosaic mutations encode hyperactive PPM1D isoforms. |
Next-generation sequencing, functional p53 suppression assay after IR in cells with exon 6 truncating variants |
Nature |
Medium |
23242139
|
| 2013 |
Exon 6 truncating mutations in PPM1D result in C-terminally truncated Wip1 with gain-of-function activity that impairs the p53-dependent G1 checkpoint and affects the DNA damage response pathway. |
Identification and functional characterization of exon 6 mutations, cell cycle checkpoint assay, DDR pathway analysis |
The Journal of cell biology |
Medium |
23649806
|
| 2013 |
Wip1 is required for epigenetic remodeling of heterochromatin through regulation of BRCA1 interaction with HP1, recruitment of DNA methyltransferases, and subsequent DNA methylation. ATM attenuation reverses heterochromatin methylation, placing Wip1 upstream of ATM in heterochromatin silencing. |
Chromatin immunoprecipitation, DNA methylation assays, co-immunoprecipitation (BRCA1-HP1), genetic epistasis with ATM |
Cancer cell |
Medium |
24135283
|
| 2014 |
PPM1D exon 6 truncating mutations in brainstem gliomas enhance PPM1D's ability to suppress CHK2 activation and attenuate p53 activation in vitro, establishing these as gain-of-function somatic driver mutations. |
Exome sequencing, functional in vitro assays for CHK2 suppression and p53 activation |
Nature genetics |
Medium |
24880341
|
| 2014 |
Allosteric small-molecule inhibitors of Wip1 bind a 'flap' subdomain near the catalytic site that is structurally divergent from other PP2C family members, conferring selectivity. GSK2830371 binding to this site increases phosphorylation of Wip1 substrates and inhibits growth of hematopoietic tumor cell lines and Wip1-amplified breast tumor cells harboring wild-type TP53. |
Structure-activity relationship, biochemical binding assay, pharmacodynamic studies, xenograft tumor model |
Nature chemical biology |
High |
24390428
|
| 2014 |
Phosphoglycerate mutase 1 (PGAM1) binds WIP1 in the cytoplasm, preventing its nuclear translocation and subsequent dephosphorylation of the ATM signaling pathway, thereby regulating DNA damage response efficiency. |
Co-immunoprecipitation (cytoplasmic fractionation), PGAM1 knockdown, γ-H2AX foci assay, kinase-dead mutant rescue |
Cell reports |
Medium |
32294440
|
| 2015 |
PPM1D interacts with and dephosphorylates Ulk1 at Ser637 in a p53-dependent manner after genotoxic stress, triggering Ulk1 puncta formation and inducing autophagy. Genetic ablation of PPM1D reduces Ulk1 Ser637 dephosphorylation, inhibits autophagy, and accelerates apoptosis induced by X-ray irradiation by preventing autophagic degradation of proapoptotic Noxa. |
Co-immunoprecipitation, in vitro phosphatase assay, Ulk1 puncta imaging, genetic KO, autophagy flux assay, apoptosis assay |
EMBO reports |
High |
27670885
|
| 2015 |
PPM1D dephosphorylates RBM38 at serine 195, modulating p53 mRNA translation. RBM38 directly binds PPM1D 3'-UTR and promotes PPM1D expression; PPM1D dephosphorylation of RBM38 reduces p53 mRNA translation and p53-dependent growth suppression. |
Co-immunoprecipitation, in vitro dephosphorylation assay, luciferase reporter (3'-UTR), RNA-binding assay |
Oncogene |
Medium |
25823026
|
| 2015 |
Wip1 deficiency in HSCs leads to sustained p53 activation, impaired repopulating activity, and aging-like phenotypes. Deletion of p53 (but not p21) completely rescues the multilineage repopulation defect of Wip1-deficient HSCs, defining a Wip1-p53 axis in HSC differentiation. Separately, HSC pool expansion in Wip1-/- mice is mediated by mTORC1-dependent proliferation, distinct from the p53-dependent differentiation defect. |
Conditional knockout, bone marrow transplantation competition assay, genetic epistasis (p53 deletion rescue), flow cytometry, mTORC1 pathway analysis |
Nature communications |
High |
25879755
|
| 2018 |
PPM1D truncating mutations (exon 6) encode a protein with elevated expression and activity due to loss of a C-terminal degradation domain. Global phosphoproteomic profiling in PPM1D-mutant cells reveals altered phosphorylation of DNA damage response targets. PPM1D-mutant cells show abrogated DDR, altered cell cycle progression, decreased apoptosis, and reduced mitochondrial priming in the presence of chemotherapy. |
Phosphoproteomics (mass spectrometry), CRISPR mutational profiling, cell cycle and apoptosis assays, mitochondrial priming assay |
Blood |
High |
29954749
|
| 2019 |
WIP1 promotes homologous recombination (HR) DNA repair. WIP1 interacts with BRCA1 and dephosphorylates it; WIP1 activity is needed for correct dynamics of BRCA1 recruitment to chromatin flanking DNA lesions. WIP1 also dephosphorylates 53BP1 at Threonine 543, previously implicated in mediating interaction with RIF1. Loss/inhibition of WIP1 delayed disappearance of IR-induced 53BP1 foci in S/G2 cells and increased sensitivity to PARP inhibitor olaparib. |
Co-immunoprecipitation, in vitro dephosphorylation assay, immunofluorescence (53BP1/BRCA1 foci), WIP1 inhibitor treatment, olaparib sensitivity assay |
Cells |
Medium |
31619012
|
| 2019 |
Mutant PPM1D drives CpG island hypermethylation genome-wide and promotes epigenetic silencing of NAPRT (a NAD biosynthesis gene), creating a synthetic lethal interaction with NAMPT inhibitors. |
Isogenic cell lines, genome-wide methylation profiling, NAMPT inhibitor sensitivity assay in vitro and in vivo |
Nature communications |
Medium |
31439867
|
| 2020 |
Wip1 selectively binds and dephosphorylates Smad4 at Thr277 (a key MAPK phosphorylation site in the linker region), regulating Smad4 nuclear accumulation and half-life. This inhibits TGF-β/BMP signaling; in Xenopus embryos, Wip1 limits mesoderm formation by inhibiting TGF-β/BMP signals. |
Co-immunoprecipitation, in vitro phosphatase assay, nuclear fractionation, Xenopus embryo gain/loss-of-function, cell migration/invasion assay |
EMBO reports |
High |
32103600
|
| 2016 |
PPM1D regulates nucleolar formation by controlling phosphorylation of nucleophosmin (NPM). PPM1D overexpression induces increased nucleolar number independently of p53 status. PPM1D acts as an upstream regulator in a PPM1D-CDC25C-CDK1-PLK1 signaling pathway that controls sequential NPM phosphorylation required for nucleolar formation. |
Overexpression, knockdown, immunofluorescence (nucleolar counting), phospho-NPM analysis, pathway epistasis |
Scientific reports |
Medium |
27619510
|
| 2022 |
GSK2830371 binds an allosteric site of PPM1D (the flap domain). Hydrogen-deuterium exchange mass spectrometry and analytical ultracentrifugation reveal PPM1D exists in equilibrium between two conformations defined by flap domain movement; GSK2830371 shifts the equilibrium to the inactive (flap-closed) form. C-terminal truncating mutations proximal to residue 400 destabilize the protein via loss of a stabilizing N- and C-terminal interaction. |
HDX-MS, sedimentation velocity analytical ultracentrifugation, computational modeling, biochemical binding assays, functional genetic studies |
Nature communications |
High |
35773251
|
| 2022 |
PPM1D inhibition induces phosphorylation of eIF2α and ATF4 accumulation, linking PPM1D to the integrated stress response (ISR). PPM1D inhibition depletes heme and induces HRI-dependent eIF2α phosphorylation. Dual inhibition of PPM1D and MDM2 synergistically induces apoptosis via amplification of p53 transcriptional program through the eIF2α-ATF4 pathway. |
PPM1D inhibitor treatment, eIF2α phosphorylation assay, ATF4 reporter, HRI pathway analysis, RNA-seq, in vivo tumor growth assay |
Nature communications |
Medium |
36456590
|
| 2008 |
A conserved p53 response element in the 5' UTR of the PPM1D gene is required for p53-dependent transcriptional induction after genotoxic stress. CREB binding to a CRE element in the promoter regulates basal PPM1D expression. After UV/IR exposure, increased PPM1D protein levels can occur without increased mRNA, indicating post-transcriptional regulation. |
Transient transfection, chromatin immunoprecipitation, promoter reporter assay, mRNA/protein comparison after DNA damage |
Nucleic acids research |
Medium |
19015127
|
| 2012 |
Wip1 deficiency prevents fat accumulation and atherosclerosis in mice. During atherosclerosis, Wip1 deletion suppresses macrophage conversion to foam cells by acting via a non-canonical ATM-mTOR signaling pathway and selective autophagy to regulate cholesterol efflux, in a p53-independent manner. |
Wip1 knockout mouse model, atherosclerosis model, macrophage foam cell assay, autophagy and cholesterol efflux assays, genetic epistasis with ATM/mTOR |
Cell metabolism |
Medium |
22768840
|
| 2014 |
WIP1 promotes medulloblastoma cell growth and invasion through regulation of CXCR4 cell surface localization via suppression of GRK5 expression. GRK5 promotes Ser339 phosphorylation of CXCR4 and inhibits cell surface CXCR4; WIP1 knockdown reduces GRK5-dependent CXCR4 phosphorylation, decreasing surface CXCR4 and invasion. |
Stable knockdown/overexpression, xenograft mouse model, cell surface CXCR4 assay, GRK5 manipulation, invasion assay |
Oncogene |
Medium |
24632620
|
| 2014 |
WIP1 regulates adult neurogenesis by controlling DKK3-dependent inhibition of WNT signaling. WIP1 is expressed in neural stem/progenitor cells (NPCs) of the mouse SVZ; WIP1 suppresses expression of the WNT pathway inhibitor DKK3. DKK3 inhibits neuroblast formation by suppressing WNT signaling, and Wip1-dependent control of DKK3 promotes neuronal differentiation. |
Transgenic mice with enhanced WIP1 expression, Dkk3 deletion, pharmacological WNT activation, SVZ reporter strain, olfactory behavioral testing |
The Journal of clinical investigation |
Medium |
24911145
|
| 2009 |
Loss of Wip1 sensitizes mouse embryonic fibroblasts to stress-induced apoptosis via activation of both p38-ATF2 and JNK-c-Jun signaling. Wip1 negatively regulates MKK4-JNK-c-Jun signaling during stress-induced apoptosis, representing a dual role in regulating both p38/p53-dependent and JNK-dependent apoptotic pathways. |
Wip1 knockout MEFs, stress-induced apoptosis assays, kinase activity measurements (p38, JNK), phospho-ATF2/c-Jun analysis |
The Journal of biological chemistry |
Medium |
19395378
|
| 2021 |
p21WAF1/CIP1 promotes the interaction between p53 and Wip1 by forming a trimeric complex (p53-p21-Wip1), facilitating Wip1-mediated dephosphorylation of p53-S15 and subsequent Mdm2-mediated p53 degradation. A p21 deletion mutant unable to bind p53 cannot facilitate p53-Wip1 interaction. |
Co-immunoprecipitation, deletion mutant analysis, p53 stability assay, phospho-S15 immunoblotting |
Biochemical and biophysical research communications |
Medium |
33503543
|
| 2017 |
Wip1-deficient macrophages show enhanced migration mediated by Rac1-GTPase and PI3K/AKT signaling pathways. Enhanced phagocytic ability of Wip1-/- macrophages is linked to CD36 plasma membrane recruitment regulated by AMPK activity. |
Wip1 knockout macrophage migration and phagocytosis assays, Rac1-GTPase activity measurement, PI3K/AKT pathway analysis, AMPK activity, CD36 membrane recruitment assay |
Redox biology |
Medium |
28822916
|
| 2014 |
Akt stabilizes PPM1D protein by inhibiting CDDP-induced proteasomal degradation. In chemoresistant gynecological cancer cells, CDDP induces PPM1D nuclear localization while sensitive cells show nuclear exclusion. Active Akt overexpression in sensitive cells stabilizes PPM1D and prevents degradation. |
Nuclear/cytoplasmic fractionation, proteasome inhibitor assay, Akt overexpression/inhibition, PPM1D stability measurements |
Molecular carcinogenesis |
Medium |
25154814
|