scholarly journals Protein phosphatase 2A – structure, function and role in neurodevelopmental disorders

2021 ◽  
Vol 134 (13) ◽  
Author(s):  
Priyanka Sandal ◽  
Chian Ju Jong ◽  
Ronald A. Merrill ◽  
Jianing Song ◽  
Stefan Strack
Keyword(s):  
Neurodevelopmental Disorders ◽  
Protein Phosphatase ◽  
Mammalian Cells ◽  
Large Scale ◽  
De Novo ◽  
Protein Phosphatase 2A ◽  
Cell Types ◽  
De Novo Mutations ◽  
Sequencing Studies ◽  
Phosphatase 2A

ABSTRACT Neurodevelopmental disorders (NDDs), including intellectual disability (ID), autism and schizophrenia, have high socioeconomic impact, yet poorly understood etiologies. A recent surge of large-scale genome or exome sequencing studies has identified a multitude of mostly de novo mutations in subunits of the protein phosphatase 2A (PP2A) holoenzyme that are strongly associated with NDDs. PP2A is responsible for at least 50% of total Ser/Thr dephosphorylation in most cell types and is predominantly found as trimeric holoenzymes composed of catalytic (C), scaffolding (A) and variable regulatory (B) subunits. PP2A can exist in nearly 100 different subunit combinations in mammalian cells, dictating distinct localizations, substrates and regulatory mechanisms. PP2A is well established as a regulator of cell division, growth, and differentiation, and the roles of PP2A in cancer and various neurodegenerative disorders, such as Alzheimer's disease, have been reviewed in detail. This Review summarizes and discusses recent reports on NDDs associated with mutations of PP2A subunits and PP2A-associated proteins. We also discuss the potential impact of these mutations on the structure and function of the PP2A holoenzymes and the etiology of NDDs.

scholarly journals Large-scale targeted sequencing identifies risk genes for neurodevelopmental disorders

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Tianyun Wang ◽  
◽  
Kendra Hoekzema ◽  
Davide Vecchio ◽  
Huidan Wu ◽  
...  
Keyword(s):  
Neurodevelopmental Disorders ◽  
Large Scale ◽  
De Novo ◽  
Targeted Sequencing ◽  
Published Data ◽  
De Novo Mutations ◽  
Risk Genes ◽  
Mutation Burden ◽  
Number Of Patients ◽  
Significant Burden

Abstract Most genes associated with neurodevelopmental disorders (NDDs) were identified with an excess of de novo mutations (DNMs) but the significance in case–control mutation burden analysis is unestablished. Here, we sequence 63 genes in 16,294 NDD cases and an additional 62 genes in 6,211 NDD cases. By combining these with published data, we assess a total of 125 genes in over 16,000 NDD cases and compare the mutation burden to nonpsychiatric controls from ExAC. We identify 48 genes (25 newly reported) showing significant burden of ultra-rare (MAF < 0.01%) gene-disruptive mutations (FDR 5%), six of which reach family-wise error rate (FWER) significance (p < 1.25E−06). Among these 125 targeted genes, we also reevaluate DNM excess in 17,426 NDD trios with 6,499 new autism trios. We identify 90 genes enriched for DNMs (FDR 5%; e.g., GABRG2 and UIMC1); of which, 61 reach FWER significance (p < 3.64E−07; e.g., CASZ1). In addition to doubling the number of patients for many NDD risk genes, we present phenotype–genotype correlations for seven risk genes (CTCF, HNRNPU, KCNQ3, ZBTB18, TCF12, SPEN, and LEO1) based on this large-scale targeted sequencing effort.

scholarly journals Loss of a Protein Phosphatase 2A Regulatory Subunit (Cdc55p) Elicits Improper Regulation of Swe1p Degradation

2000 ◽  
Vol 20 (21) ◽  
pp. 8143-8156 ◽  
Author(s):  
Haifeng Yang ◽  
Wei Jiang ◽  
Matthew Gentry ◽  
Richard L. Hallberg
Keyword(s):  
Phosphatase Activity ◽  
Protein Phosphatase ◽  
Protein Phosphatase 2A ◽  
Cell Types ◽  
Regulatory Subunit ◽  
Cyclin Dependent Kinase ◽  
Wild Type ◽  
Phosphatase 2A

ABSTRACT CDC55 encodes a Saccharomyces cerevisiaeprotein phosphatase 2A (PP2A) regulatory subunit.cdc55-null cells growing at low temperature exhibit a failure of cytokinesis and produce abnormally elongated buds, butcdc55-null cells producing the cyclin-dependent kinase Cdc28-Y19F, which is unable to be inhibited by Y19 phosphorylation, show a loss of the abnormal morphology. Furthermore,cdc55-null cells exhibit a hyperphosphorylation of Y19. For these reasons, we have examined in wild-type and cdc55-null cells the levels and activities of the kinase (Swe1p) and phosphatase (Mih1p) that normally regulate the extent of Cdc28 Y19 phosphorylation. We find that Mih1p levels are comparable in the two strains, and an estimate of the in vivo and in vitro phosphatase activity of this enzyme in the two cell types indicates no marked differences. By contrast, while Swe1p levels are similar in unsynchronized and S-phase-arrested wild-type and cdc55-null cells, Swe1 kinase is found at elevated levels in mitosis-arrestedcdc55-null cells. This excess Swe1p incdc55-null cells is the result of ectopic stabilization of this protein during G2 and M, thereby accounting for the accumulation of Swe1p in mitosis-arrested cells. We also present evidence indicating that, in cdc55-null cells, misregulated PP2A phosphatase activity is the cause of both the ectopic stabilization of Swe1p and the production of the morphologically abnormal phenotype.

scholarly journals PR48, a Novel Regulatory Subunit of Protein Phosphatase 2A, Interacts with Cdc6 and Modulates DNA Replication in Human Cells

2000 ◽  
Vol 20 (3) ◽  
pp. 1021-1029 ◽  
Author(s):  
Zhen Yan ◽  
Sergei A. Fedorov ◽  
Marc C. Mumby ◽  
R. Sanders Williams
Keyword(s):  
Dna Replication ◽  
Protein Phosphatase ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Protein Phosphatase 2A ◽  
Specific Interaction ◽  
Regulatory Subunit ◽  
Amino Terminal ◽  
Phosphatase 2A ◽  
Initiation Of Dna Replication

ABSTRACT Initiation of DNA replication in eukaryotes is dependent on the activity of protein phosphatase 2A (PP2A), but specific phosphoprotein substrates pertinent to this requirement have not been identified. A novel regulatory subunit of PP2A, termed PR48, was identified by a yeast two-hybrid screen of a human placental cDNA library, using human Cdc6, an essential component of prereplicative complexes, as bait. PR48 binds specifically to an amino-terminal segment of Cdc6 and forms functional holoenzyme complexes with A and C subunits of PP2A. PR48 localizes to the nucleus of mammalian cells, and its forced overexpression perturbs cell cycle progression, causing a G1 arrest. These results suggest that dephosphorylation of Cdc6 by PP2A, mediated by a specific interaction with PR48, is a regulatory event controlling initiation of DNA replication in mammalian cells.

Antitumor antibiotic fostriecin covalently binds to cysteine-269 residue of protein phosphatase 2A catalytic subunit in mammalian cells

2009 ◽  
Vol 17 (23) ◽  
pp. 8113-8122 ◽  
Author(s):  
Toshifumi Takeuchi ◽  
Noriyuki Takahashi ◽  
Kazutomo Ishi ◽  
Tomoe Kusayanagi ◽  
Kouji Kuramochi ◽  
...  
Keyword(s):  
Protein Phosphatase ◽  
Mammalian Cells ◽  
Protein Phosphatase 2A ◽  
Catalytic Subunit ◽  
Antitumor Antibiotic ◽  
Phosphatase 2A

scholarly journals Protein Phosphatase 2A Mediates Oxidative Stress Induced Apoptosis in Osteoblasts

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Chong-xin Huang ◽  
Bo Lv ◽  
Yue Wang
Keyword(s):  
Oxidative Stress ◽  
Lipid Peroxidation ◽  
Protein Phosphatase ◽  
Mammalian Cells ◽  
Protein Phosphatase 2A ◽  
Bone Diseases ◽  
Dna Lesions ◽  
Major Protein ◽  
Phosphatase 2A ◽  
Induced Apoptosis

Osteoporosis is one of the most common bone diseases, which is characterized by a systemic impairment of bone mass and fragility fractures. Age-related oxidative stress is highly associated with impaired osteoblastic dysfunctions and subsequent osteoporosis. In osteoblasts (bone formation cells), reactive oxygen species (ROS) are continuously generated and further cause lipid peroxidation, protein damage, and DNA lesions, leading to osteoblastic dysfunctions, dysdifferentiations, and apoptosis. Although much progress has been made, the mechanism responsible for oxidative stress induced cellular alternations and osteoblastic toxicity is still not fully elucidated. Here, we demonstrate that protein phosphatase 2A (PP2A), a major protein phosphatase in mammalian cells, mediates oxidative stress induced apoptosis in osteoblasts. Our results showed that lipid peroxidation products (4-HNE) may induce dramatic oxidative stress, inflammatory reactions, and apoptosis in osteoblasts. These oxidative stress responses may ectopically activate PP2A phosphatase activity, which may be mediated by inactivation of AKT/mTOR pathway. Moreover, inhibition of PP2A activity by okadaic acid might partly prevent osteoblastic apoptosis under oxidative conditions. These findings may reveal a novel mechanism to clarify the role of oxidative stress for osteoblastic apoptosis and provide new possibilities for the treatment of related bone diseases, such as osteoporosis.

scholarly journals Visualization of Subunit Interactions and Ternary Complexes of Protein Phosphatase 2A in Mammalian Cells

PLoS ONE ◽  
2014 ◽  
Vol 9 (12) ◽  
pp. e116074 ◽  
Author(s):  
Shu-Ting Mo ◽  
Shang-Ju Chiang ◽  
Tai-Yu Lai ◽  
Yu-Ling Cheng ◽  
Cheng-En Chung ◽  
...  
Keyword(s):  
Protein Phosphatase ◽  
Mammalian Cells ◽  
Protein Phosphatase 2A ◽  
Ternary Complexes ◽  
Subunit Interactions ◽  
Phosphatase 2A

Na-K-ATPase regulates tight junction permeability through occludin phosphorylation in pancreatic epithelial cells

2007 ◽  
Vol 292 (1) ◽  
pp. G124-G133 ◽  
Author(s):  
Sigrid A. Rajasekaran ◽  
Sonali P. Barwe ◽  
Jegan Gopal ◽  
Sergey Ryazantsev ◽  
Eveline E. Schneeberger ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Tight Junction ◽  
Tight Junctions ◽  
Protein Phosphatase ◽  
Mammalian Cells ◽  
Protein Phosphatase 2A ◽  
Epithelial Cell Line ◽  
Phosphatase 2A ◽  
Apical Junctions ◽  
Well Differentiated

Tight junctions are crucial for maintaining the polarity and vectorial transport functions of epithelial cells. We and others have shown that Na-K-ATPase plays a key role in the organization and permeability of tight junctions in mammalian cells and analogous septate junctions in Drosophila. However, the mechanism by which Na-K-ATPase modulates tight junctions is not known. In this study, using a well-differentiated human pancreatic epithelial cell line HPAF-II, we demonstrate that Na-K-ATPase is present at the apical junctions and forms a complex with protein phosphatase-2A, a protein known to be present at tight junctions. Inhibition of Na-K-ATPase ion transport function reduced protein phosphatase-2A activity, hyperphosphorylated occludin, induced rearrangement of tight junction strands, and increased permeability of tight junctions to ionic and nonionic solutes. These data suggest that Na-K-ATPase is required for controlling the tight junction gate function.

scholarly journals AKT Regulates Mitotic Progression of Mammalian Cells by Phosphorylating MASTL, Leading to Protein Phosphatase 2A Inactivation

2020 ◽  
Vol 40 (10) ◽  
Author(s):  
Irfana Reshi ◽  
Misbah Un Nisa ◽  
Umer Farooq ◽  
Syed Qaaifah Gillani ◽  
Sameer Ahmed Bhat ◽  
...  
Keyword(s):  
Protein Phosphatase ◽  
Mammalian Cells ◽  
Protein Phosphatase 2A ◽  
Critical Role ◽  
Mitotic Progression ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Mitotic Kinases ◽  
Colorectal Cell ◽  
Phosphatase 2A

ABSTRACT Microtubule-associated serine/threonine kinase like (MASTL), also known as Greatwall (Gwl) kinase, has an important role in the regulation of mitosis. By inhibiting protein phosphatase 2A (PP2A), it plays a crucial role in activating one of the most important mitotic kinases, known as cyclin-dependent kinase 1 (CDK1). MASTL has been seen to be upregulated in various types of cancers and is also involved in tumor recurrence. It is activated by CDK1 through phosphorylations in the activation/T-loop, but the complete mechanism of its activation is still unclear. Here, we report that AKT phosphorylates MASTL at residue T299, which plays a critical role in its activation. Our results suggest that AKT increases CDK1-mediated phosphorylation and hence the activity of MASTL, which, in turn, promotes mitotic progression through PP2A inhibition. We also show that the oncogenic potential of AKT is augmented by MASTL activation, since AKT-mediated proliferation in colorectal cell lines can be attenuated by inhibiting and/or silencing MASTL. In brief, we report that AKT plays an important role in the progression of mitosis in mammalian cells and that it does so through the phosphorylation and activation of MASTL.

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