| 1999 |
PME-1 (protein phosphatase methylesterase-1) was identified as a novel protein that stably associates with catalytically inactive mutants of PP2A C subunit. Bacterially expressed PME-1 demethylated the PP2A C subunit in vitro, and okadaic acid inhibited this reaction. PME-1 contains a lipase-like motif with a catalytic triad-activated serine as its active site nucleophile. |
Co-purification with inactive PP2A mutants, microsequencing, cDNA cloning, in vitro demethylation assay with bacterially expressed protein, inhibitor studies |
The Journal of biological chemistry |
High |
10318862
|
| 2008 |
Targeted disruption of the PME-1 gene in mice causes perinatal lethality and a virtually complete loss of demethylated PP2A in the nervous system and peripheral tissues. PME-1 knockout tissues also showed dramatically reduced PP2A catalytic activity over a peptide substrate and alterations in phosphoproteome content. |
Genetic knockout (targeted disruption), biochemical assay of PP2A activity, phosphoproteome analysis |
PloS one |
High |
18596935
|
| 2009 |
PME-1-mediated inhibition of PP2A promotes basal ERK pathway activity in malignant glioma cells; PME-1 supports ERK pathway signaling upstream of Raf but downstream of growth factor receptors and protein kinase C. |
siRNA knockdown, epistasis analysis with pathway modulators, cell-based signaling assays |
Cancer research |
Medium |
19293187
|
| 2010 |
Expression of PME-1 or the methylation-site mutant PP2A C subunit (L309Δ), which decrease intracellular methylated PP2A-C and Bα levels, block N2a cell differentiation and LCMT1-mediated neurite formation, establishing a mechanistic link between PP2A demethylation by PME-1 and regulation of neuronal process outgrowth. |
Overexpression, knockdown (inducible and non-inducible), methylation-site mutant expression, neurite outgrowth assay |
Journal of neurochemistry |
Medium |
21044074
|
| 2012 |
GSK-3β regulates demethylation of PP2A at leucine-309 by upregulating PME-1 and inhibiting PPMT1; knockdown of PME-1 or PPMT1 eliminated GSK-3β effects on PP2A-C demethylation. |
siRNA knockdown, Western blot for PP2A methylation status, epistasis via double knockdown |
FEBS letters |
Medium |
22732552
|
| 2014 |
PME-1 can bind and regulate protein phosphatase 4 (PP4) catalytic subunit but not the related protein phosphatase 6 (PP6), demonstrating substrate selectivity among type 2A phosphatases. |
Co-immunoprecipitation, overexpression, functional assays in endometrial cancer cells |
Cancer research |
Medium |
24928782
|
| 2014 |
Carnosic acid promotes PME-1-mediated demethylation of the PP2A catalytic subunit, leading to suppressed PP2A activity and alleviation of PP2A-mediated repression of PKB/Akt, thereby stimulating glucose uptake via GLUT4 translocation in skeletal muscle cells. |
siRNA knockdown of PME-1, PP2A activity assay, GLUT4 translocation assay, PKB phosphorylation measurements |
Cellular signalling |
Medium |
25038454
|
| 2015 |
PME-1 methylesterase activity protects the PP2A catalytic subunit from ubiquitin/proteasome degradation; loss of PME-1 enhanced poly-ubiquitination of PP2Ac and shortened its half-life, leading to reduced PP2Ac levels and paradoxically lower PP2A activity. |
PME-1 knockout MEFs, chemical inhibition of PME-1, rescue experiments with wild-type and catalytic mutant PME-1, ubiquitination assays, protein half-life measurement |
PloS one |
High |
26678046
|
| 2015 |
Depletion of PME-1 or pharmacological inhibition of PME-1, or overexpression of LCMT1, leads to short mitotic spindles, while depletion of LCMT1 or overexpression of PME-1 leads to long spindles; perturbation of the LCMT1-PME-1 methylation equilibrium causes mitotic arrest, spindle assembly checkpoint activation, defective cell divisions, and apoptosis. |
siRNA knockdown, overexpression, pharmacological inhibition, immunofluorescence microscopy of spindle size |
Cell cycle (Georgetown, Tex.) |
Medium |
25839665
|
| 2016 |
PME-1-mediated PP2A inhibition drives resistance of glioma cells to multikinase inhibitors; this resistance is dependent on specific PP2A complexes and is mediated by a decrease in cytoplasmic HDAC4 activity, with synthetic lethality requiring coexpression of proapoptotic BAD. |
PME-1 overexpression/knockdown, drug sensitivity assays, genetic epistasis with HDAC4 and BAD |
Cancer research |
Medium |
27671680
|
| 2018 |
PME-1 demethylates PP2Ac in cell extracts even at 0°C unless prevented by a PME-1 methylesterase inhibitor, promoting dissociation of PP2A heterotrimers containing B55 or PR72 subunits but not those with B56 subunits, revealing differential sensitivity of PP2A holoenzyme families to methylation status. |
In vitro demethylation assay, pharmacological PME-1 inhibition, immunoprecipitation of PP2A subcomplexes |
FEBS open bio |
Medium |
30186749
|
| 2018 |
USP36 deubiquitinase stabilizes PME-1 through its deubiquitinating enzyme activity; depletion of USP36 decreases PME-1 expression level, and USP36 promotes ERK and Akt signaling pathways through PME-1. |
Co-immunoprecipitation, siRNA knockdown, ubiquitination assay, Western blot for PME-1 stability |
FEBS letters |
Medium |
29577269
|
| 2020 |
Systematic phosphoproteomics revealed that PME-1 depletion (to reactivate PP2A) modulates phosphorylation of targets in kinase signaling, cytoskeleton, RNA splicing, DNA repair, and nuclear lamina pathways, and that PME-1, CIP2A, and SET are non-redundant in phosphotarget regulation. |
siRNA depletion, mass spectrometry-based phosphoproteomics in HeLa cells |
The Journal of biological chemistry |
Medium |
32071079
|
| 2022 |
Cryo-EM structure of a PP2A-B56 holoenzyme–PME-1 complex revealed that PME-1 disordered regions, including a substrate-mimicking motif, tether to the B56 regulatory subunit at remote sites, occupy the holoenzyme substrate-binding groove, and allow large structural shifts in both holoenzyme and PME-1 to activate the methylesterase. B56 interface mutations selectively block PME-1 activity toward PP2A-B56 holoenzymes and affect cellular PP2A methylation and p53 signaling. |
High-resolution cryo-EM structure, in vitro demethylation assay, B56 interface mutagenesis, cellular p53 signaling assay |
eLife |
High |
35924897
|
| 2023 |
PME-1 sensitizes glioblastoma cells to oxidative stress-induced cell death via nuclear PP2A-B55α activity; oxidative stress increases nuclear localization of PP2A-B55α, binding of PP2A-B55α to PME-1, and B55α-bound PP2A-C demethylation. PME-1 overexpression increases stress-induced phosphorylation and activity of MAPKAPK2 and RIPK1, causing sensitization. The methylesterase function, PP2A binding capacity, and nuclear localization of PME-1 are all required for this effect. |
Pharmacological PME-1 inhibition (AMZ30), PME-1 mutants (methylesterase-dead, PP2A binding-dead, nuclear localization mutants), subcellular fractionation, co-immunoprecipitation, kinase activity assays |
Cell death discovery |
High |
37500619
|
| 2023 |
Transcriptome analysis of PME-1 knockout mouse embryonic fibroblasts showed that PME-1 suppresses inflammatory signaling, activates PI3K/Akt signaling, and promotes epithelial-mesenchymal transition at the transcriptional level. |
PME-1 knockout MEFs, RNA-seq transcriptome analysis |
Biochemical and biophysical research communications |
Low |
38043157
|
| 2024 |
CHK1 directly phosphorylates the PP2A catalytic subunit (including Thr219) to promote PME-1 association with PP2Ac; CHK1 inhibitors block PME-1/PP2Ac association without affecting PP2Ac methylation levels. Reciprocally, PME-1 binding to PP2Ac hinders PP2A-mediated dephosphorylation of CHK1. |
NanoBiT bioluminescence protein-protein interaction assay, compound screening, in vitro kinase/phosphatase assays, phospho-mass spectrometry, anti-phospho-Thr219 antibody generation and validation |
The Journal of biological chemistry |
High |
38588804
|
| 2025 |
Two distinct mechanisms of PME-1 are both essential for mouse development: (1) methylesterase activity (abolished by S156A knock-in) is required to prevent systemic apoptosis, brain atrophy with cerebellar layer collapse, increased inflammation, and elevated reactive oxygen species in mitochondria; (2) PP2A inhibitory binding activity (abolished by M335D knock-in) is required for olfactory epithelium integrity and survival for ~2 days postnatally. Both phenotypes differ from the perinatal lethality of PME-1 null mice, demonstrating non-redundancy of the two mechanisms in vivo. |
Knock-in mouse models (S156A and M335D point mutants), histological and gene expression analysis, primary embryonic fibroblast assays (mitochondrial number, oxygen consumption rate, ROS levels) |
FASEB journal |
High |
40326231
|
| 2023 |
PME-1 overexpression suppresses anoikis in PTEN-deficient prostate cancer cells; PME-1 inhibition increased apoptosis in in ovo PCa tumor xenografts and attenuated PCa cell survival in zebrafish circulation. PME-1-deficient PC3 cells display increased trimethylation at H3K9 and H3K27, correlating with increased apoptosis sensitivity. |
PME-1 overexpression, siRNA knockdown, in ovo xenograft, zebrafish circulation assay, histone modification analysis (ChIP/Western) |
Molecular oncology |
Medium |
36461911
|