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Godfroy O, Zheng M, Yao H, Henschen A, Peters AF, Scornet D, Colin S, Ronchi P, Hipp K, Nagasato C, Motomura T, Cock JM, Coelho SM. The baseless mutant links protein phosphatase 2A with basal cell identity in the brown alga Ectocarpus. Development 2023; 150:dev201283. [PMID: 36786333 PMCID: PMC10112911 DOI: 10.1242/dev.201283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 01/16/2023] [Indexed: 02/15/2023]
Abstract
The first mitotic division of the initial cell is a key event in all multicellular organisms and is associated with the establishment of major developmental axes and cell fates. The brown alga Ectocarpus has a haploid-diploid life cycle that involves the development of two multicellular generations: the sporophyte and the gametophyte. Each generation deploys a distinct developmental programme autonomously from an initial cell, the first cell division of which sets up the future body pattern. Here, we show that mutations in the BASELESS (BAS) gene result in multiple cellular defects during the first cell division and subsequent failure to produce basal structures during both generations. BAS encodes a type B″ regulatory subunit of protein phosphatase 2A (PP2A), and transcriptomic analysis identified potential effector genes that may be involved in determining basal cell fate. The bas mutant phenotype is very similar to that observed in distag (dis) mutants, which lack a functional Tubulin-binding co-factor Cd1 (TBCCd1) protein, indicating that TBCCd1 and PP2A are two essential components of the cellular machinery that regulates the first cell division and mediates basal cell fate determination.
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Affiliation(s)
- Olivier Godfroy
- Laboratory of Integrative Biology of Marine Models, Sorbonne Université, UPMC University of Paris 06, CNRS, UMR 8227, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | - Min Zheng
- Department of Algal Development and Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Haiqin Yao
- Laboratory of Integrative Biology of Marine Models, Sorbonne Université, UPMC University of Paris 06, CNRS, UMR 8227, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | - Agnes Henschen
- Department of Algal Development and Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | | | - Delphine Scornet
- Laboratory of Integrative Biology of Marine Models, Sorbonne Université, UPMC University of Paris 06, CNRS, UMR 8227, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | - Sebastien Colin
- Department of Algal Development and Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Paolo Ronchi
- Electron Microscopy Core Facility, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Katharina Hipp
- Department of Algal Development and Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Chikako Nagasato
- Muroran Marine Station, Field Science Center for Northern Biosphere, Hokkaido University, Muroran, 051-0013, Japan
| | - Taizo Motomura
- Muroran Marine Station, Field Science Center for Northern Biosphere, Hokkaido University, Muroran, 051-0013, Japan
| | - J. Mark Cock
- Laboratory of Integrative Biology of Marine Models, Sorbonne Université, UPMC University of Paris 06, CNRS, UMR 8227, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | - Susana M. Coelho
- Department of Algal Development and Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
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Shum CW, Nong W, So WL, Li Y, Qu Z, Yip HY, Swale T, Ang PO, Chan KM, Chan TF, Chu KH, Chui AP, Lau KF, Ngai SM, Xu F, Hui JH. Genome of the sea anemone Exaiptasia pallida and transcriptome profiles during tentacle regeneration. Front Cell Dev Biol 2022; 10:900321. [PMID: 36072338 PMCID: PMC9444052 DOI: 10.3389/fcell.2022.900321] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Accepted: 07/08/2022] [Indexed: 12/19/2022] Open
Abstract
Cnidarians including sea anemones, corals, hydra, and jellyfishes are a group of animals well known for their regeneration capacity. However, how non-coding RNAs such as microRNAs (also known as miRNAs) contribute to cnidarian tissue regeneration is poorly understood. Here, we sequenced and assembled the genome of the sea anemone Exaiptasia pallida collected in Hong Kong waters. The assembled genome size of E. pallida is 229.21 Mb with a scaffold N50 of 10.58 Mb and BUSCO completeness of 91.1%, representing a significantly improved genome assembly of this species. The organization of ANTP-class homeobox genes in this anthozoan further supported the previous findings in jellyfishes, where most of these genes are mainly located on three scaffolds. Tentacles of E. pallida were excised, and both mRNA and miRNA were sequenced at 9 time points (0 h, 6 h, 12 h, 18 h, 1 day, 2, 3, 6, and 8 days) from regenerating tentacles. In addition to the Wnt signaling pathway and homeobox genes that are shown to be likely involved in tissue regeneration as in other cnidarians, we have shown that GLWamide neuropeptides, and for the first time sesquiterpenoid pathway genes could potentially be involved in the late phase of cnidarian tissue regeneration. The established sea anemone model will be useful for further investigation of biology and evolution in, and the effect of climate change on this important group of animals.
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Affiliation(s)
- Cheryl W.Y. Shum
- School of Life Sciences, Simon F.S. Li Marine Science Laboratory, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Wenyan Nong
- School of Life Sciences, Simon F.S. Li Marine Science Laboratory, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Wai Lok So
- School of Life Sciences, Simon F.S. Li Marine Science Laboratory, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Yiqian Li
- School of Life Sciences, Simon F.S. Li Marine Science Laboratory, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Zhe Qu
- School of Life Sciences, Simon F.S. Li Marine Science Laboratory, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Ho Yin Yip
- School of Life Sciences, Simon F.S. Li Marine Science Laboratory, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Thomas Swale
- Dovetail Genomics, Scotts Valley, CA, United States
| | - Put O. Ang
- Institute of Space and Earth Information Science, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - King Ming Chan
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Ting Fung Chan
- School of Life Sciences, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Ka Hou Chu
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Apple P.Y. Chui
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Kwok Fai Lau
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Sai Ming Ngai
- School of Life Sciences, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Fei Xu
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
| | - Jerome H.L. Hui
- School of Life Sciences, Simon F.S. Li Marine Science Laboratory, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
- *Correspondence: Jerome H.L. Hui,
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Zhou Z, Li K, Liu J, Zhang H, Fan Y, Chen Y, Han H, Yang J, Liu Y. Expression Profile Analysis to Identify Circular RNA Expression Signatures in Muscle Development of Wu'an Goat Longissimus Dorsi Tissues. Front Vet Sci 2022; 9:833946. [PMID: 35518637 PMCID: PMC9062782 DOI: 10.3389/fvets.2022.833946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 03/21/2022] [Indexed: 11/13/2022] Open
Abstract
The growth and development of skeletal muscle is a physiological process regulated by a variety of genes and signaling pathways. As a posttranscriptional regulatory factor, circRNA plays a certain regulatory role in the development of animal skeletal muscle in the form of a miRNA sponge. However, the role of circRNAs in muscle development and growth in goats is still unclear. In our study, apparent differences in muscle fibers in Wu'an goats of different ages was firstly detected by hematoxylin-eosin (HE) staining, the circRNA expression profiles of longissimus dorsi muscles from 1-month-old (mon1) and 9-month-old (mon9) goats were screened by RNA-seq and verified by RT-qPCR. The host genes of differentially expressed (DE) circRNAs were predicted, and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes analyses (KEGG) of host genes with DE circRNAs were performed to explore the functions of circRNAs. The circRNA-miRNA-mRNA networks were then constructed using Cytoscape software. Ten significantly differentially expressed circRNAs were also verified in the mon1 and mon9 groups by RT-qPCR. Luciferase Reporter Assay was used to verify the binding site between circRNA and its targeted miRNA. The results showed that a total of 686 DE circRNAs were identified between the mon9 and mon1 groups, of which 357 were upregulated and 329 were downregulated. Subsequently, the 467 host genes of DE circRNAs were predicted using Find_circ and CIRI software. The circRNA-miRNA-mRNA network contained 201 circRNAs, 85 miRNAs, and 581 mRNAs; the host mRNAs were associated with "muscle fiber development" and "AMPK signaling pathway" and were enriched in the FoxO signaling pathway. Competing endogenous RNA (ceRNA) network analysis showed that novel_circ_0005314, novel_circ_0005319, novel_circ_0009256, novel_circ_0009845, novel_circ_0005934 and novel_circ_0000134 may play important roles in skeletal muscle growth and development between the mon9 and mon1 groups. Luciferase Reporter Assay confirmed the combination between novel_circ_0005319 and chi-miR-199a-5p, novel_circ_0005934 and chi-miR-450-3p and novel_circ_0000134 and chi-miR-655. Our results provide specific information related to goat muscle development and a reference for the goat circRNA profile.
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Affiliation(s)
- Zuyang Zhou
- College of Life Sciences and Food Engineering, Hebei University of Engineering, Handan, China
| | - Kunyu Li
- College of Life Sciences and Food Engineering, Hebei University of Engineering, Handan, China
| | - Jiannan Liu
- School of Landscape and Ecological Engineering, Hebei University of Engineering, Handan, China
| | - Hui Zhang
- College of Life Sciences and Food Engineering, Hebei University of Engineering, Handan, China
| | - Yekai Fan
- College of Life Sciences and Food Engineering, Hebei University of Engineering, Handan, China
| | - Yulin Chen
- College of Life Sciences and Food Engineering, Hebei University of Engineering, Handan, China
| | - Haiyin Han
- College of Life Sciences and Food Engineering, Hebei University of Engineering, Handan, China
| | - Junqi Yang
- College of Life Sciences and Food Engineering, Hebei University of Engineering, Handan, China
| | - Yufang Liu
- College of Life Sciences and Food Engineering, Hebei University of Engineering, Handan, China
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He JJ, Shang L, Yu QW, Jiao N, Qiu S, Zhu WX, Wu DF, Tian YE, Zhang Q. High expression of protein phosphatase 2 regulatory subunit B'' alpha predicts poor outcome in hepatocellular carcinoma patients after liver transplantation. World J Gastrointest Oncol 2021; 13:716-731. [PMID: 34322200 PMCID: PMC8299934 DOI: 10.4251/wjgo.v13.i7.716] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 06/06/2021] [Accepted: 06/23/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Protein phosphatase 2 regulatory subunit B'' alpha (PPP2R3A) gene has been reported in other tumors, but the influence of PPP2R3A gene expression on the occurrence, development, and prognosis of hepatocellular carcinoma (HCC) remains unclear.
AIM To investigate whether the PPP2R3A gene could be used to predict tumor recurrence and survival of HCC patients after liver transplantation (LT).
METHODS Diseased liver tissues of HCC patients after LT were collected as well as their clinical data and follow-up information. The immunohistochemical method was used to detect the expression of PPP2R3A protein in the tissues of 108 patients with primary liver cancer. The χ2 test was used to analyze the relationship between PPP2R3A protein expression levels and the clinicopathological features of tumors. The Kaplan-Meier method was used to analyze overall postoperative survival. The COX proportional hazard model was used to analyze adverse prognostic factors.
RESULTS Immunohistochemistry showed that the PPP2R3A protein was mainly expressed in the cytoplasm of HCC cells. Compared to corresponding peritumoral tissues, expression was higher in HCC tissues (P ≤ 0.001). Correlation analysis showed that high PPP2R3A expression was correlated with preoperative serum alpha-fetoprotein (AFP) levels (P = 0.003), tumor-node-metastasis-t stage (P ≤ 0.001), and envelope invasion (P = 0.001). Univariate analysis showed that overall survival (P ≤ 0.001) and recurrence-free survival (P = 0.025) of patients with high PPP2R3A expression (≥ 4 points) were poor compared to those with low expression (< 4 points). The overall survival rates or recurrence-free survival rates at 1, 2, and 3 years with high PPP2R3A expression were 73%, 38%, and 23% or 31%, 23%, and 23%, respectively. Multivariate analysis showed that high PPP2R3A expression (hazard ratio = 2.900, 95% confidence interval: 1.411–5.960, P = 0.004) was an independent survival risk factor of HCC patients after LT, and it was also an independent predictor of postoperative tumor recurrence. This study also showed in patients with AFP ≥ 400 ng/mL, the overall survival (P ≤ 0.001) and recurrence-free survival (P = 0.023) of those with high PPP2R3A expression were significantly worse compared to those with low PPP2R3A expression. When PPP2R3A expression was low, the overall survival rate (P = 0.461) or recurrence-free survival rate (P = 0.072) after LT in patients with AFP < 400 ng/mL and ≥ 400 ng/mL was not significantly difference. The 1, 2, and 3 year survival rate of patients with low PPP2R3A expression and AFP < 400 ng/mL were 98%, 80%, and 69%, respectively, while patients who met Hangzhou criteria had a post-transplant 1, 2, and 3 years overall survival rate of 89%, 66%, and 55%, respectively.
CONCLUSION High expression of PPP2R3A might be a potential marker for predicting poor prognosis of HCC after LT. Combined with serum AFP levels, PPP2R3A might enhance the accuracy of predicting HCC outcome in patients after LT and supplement the efficacy of the Hangzhou criteria.
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Affiliation(s)
- Jia-Jia He
- Clinical College of General Hospital of Chinese People's Armed Police Force, Anhui Medical University, Hefei 230032, Anhui, China
- Department of Organ Transplantation, The Third Medical Center of Chinese PLA General Hospital, Beijing 100039, China
| | - Lei Shang
- Department of Health Statistics, Fourth Military Medical University, Xi'an 710032, Shanxi Province, China
| | - Qun-Wei Yu
- Department of Ophthalmology, The Third Medical Center of Chinese PLA General Hospital, Beijing 100039, China
| | - Ning Jiao
- Department of Organ Transplantation, The Third Medical Center of Chinese PLA General Hospital, Beijing 100039, China
| | - Shuang Qiu
- Department of Organ Transplantation, The Third Medical Center of Chinese PLA General Hospital, Beijing 100039, China
| | - Wei-Xiong Zhu
- Department of Organ Transplantation, The Third Medical Center of Chinese PLA General Hospital, Beijing 100039, China
| | - Dong-Feng Wu
- Department of Organ Transplantation, The Third Medical Center of Chinese PLA General Hospital, Beijing 100039, China
| | - Yun-Er Tian
- Department of Organ Transplantation, The Third Medical Center of Chinese PLA General Hospital, Beijing 100039, China
| | - Qing Zhang
- Clinical College of General Hospital of Chinese People's Armed Police Force, Anhui Medical University, Hefei 230032, Anhui, China
- Department of Organ Transplantation, The Third Medical Center of Chinese PLA General Hospital, Beijing 100039, China
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He JJ, Shang L, Yu QW, Jiao N, Qiu S, Zhu WX, Wu DF, Tian YE, Zhang Q. High expression of protein phosphatase 2 regulatory subunit B'' alpha predicts poor outcome in hepatocellular carcinoma patients after liver transplantation. World J Gastrointest Oncol 2021. [DOI: 10.4251/wjgo.v13.i7.541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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Sandal P, Jong CJ, Merrill RA, Song J, Strack S. Protein phosphatase 2A - structure, function and role in neurodevelopmental disorders. J Cell Sci 2021; 134:270819. [PMID: 34228795 DOI: 10.1242/jcs.248187] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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.
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Affiliation(s)
- Priyanka Sandal
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| | - Chian Ju Jong
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| | - Ronald A Merrill
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| | - Jianing Song
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| | - Stefan Strack
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
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Dzulko M, Pons M, Henke A, Schneider G, Krämer OH. The PP2A subunit PR130 is a key regulator of cell development and oncogenic transformation. Biochim Biophys Acta Rev Cancer 2020; 1874:188453. [PMID: 33068647 DOI: 10.1016/j.bbcan.2020.188453] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 10/10/2020] [Accepted: 10/11/2020] [Indexed: 12/25/2022]
Abstract
Protein phosphatase 2A (PP2A) is a major serine/threonine phosphatase. This enzyme is involved in a plethora of cellular processes, including apoptosis, autophagy, cell proliferation, and DNA repair. Remarkably, PP2A can act as a context-dependent tumor suppressor or promoter. Active PP2A complexes consist of structural (PP2A-A), regulatory (PP2A-B), and catalytic (PP2A-C) subunits. The regulatory subunits define the substrate specificity and the subcellular localization of the holoenzyme. Here we condense the increasing evidence that the PP2A B-type subunit PR130 is a critical regulator of cell identity and oncogenic transformation. We summarize knowledge on the biological functions of PR130 in normal and transformed cells, targets of the PP2A-PR130 complex, and how diverse extra- and intracellular stimuli control the expression and activity of PR130. We additionally review the impact of PP2A-PR130 on cardiac functions, neuronal processes, and anti-viral defense and how this might affect cancer development and therapy.
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Affiliation(s)
- Melanie Dzulko
- Department of Toxicology, University Medical Center, 55131 Mainz, Germany
| | - Miriam Pons
- Department of Toxicology, University Medical Center, 55131 Mainz, Germany
| | - Andreas Henke
- Section of Experimental Virology, Institute of Medical Microbiology, Jena University Hospital, Friedrich Schiller University, 07745 Jena, Germany
| | - Günter Schneider
- Klinik und Poliklinik für Innere Medizin II, Technical University of Munich, 81675 Munich, Germany
| | - Oliver H Krämer
- Department of Toxicology, University Medical Center, 55131 Mainz, Germany.
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Gammons MV, Renko M, Flack JE, Mieszczanek J, Bienz M. Feedback control of Wnt signaling based on ultrastable histidine cluster co-aggregation between Naked/NKD and Axin. eLife 2020; 9:e59879. [PMID: 33025907 PMCID: PMC7581431 DOI: 10.7554/elife.59879] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 10/06/2020] [Indexed: 12/20/2022] Open
Abstract
Feedback control is a universal feature of cell signaling pathways. Naked/NKD is a widely conserved feedback regulator of Wnt signaling which controls animal development and tissue homeostasis. Naked/NKD destabilizes Dishevelled, which assembles Wnt signalosomes to inhibit the β-catenin destruction complex via recruitment of Axin. Here, we discover that the molecular mechanism underlying Naked/NKD function relies on its assembly into ultra-stable decameric core aggregates via its conserved C-terminal histidine cluster (HisC). HisC aggregation is facilitated by Dishevelled and depends on accumulation of Naked/NKD during prolonged Wnt stimulation. Naked/NKD HisC cores co-aggregate with a conserved histidine cluster within Axin, to destabilize it along with Dishevelled, possibly via the autophagy receptor p62, which binds to HisC aggregates. Consistent with this, attenuated Wnt responses are observed in CRISPR-engineered flies and human epithelial cells whose Naked/NKD HisC has been deleted. Thus, HisC aggregation by Naked/NKD provides context-dependent feedback control of prolonged Wnt responses.
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Affiliation(s)
- Melissa V Gammons
- MRC Laboratory of Molecular Biology, Cambridge Biomedical CampusCambridgeUnited Kingdom
| | - Miha Renko
- MRC Laboratory of Molecular Biology, Cambridge Biomedical CampusCambridgeUnited Kingdom
| | - Joshua E Flack
- MRC Laboratory of Molecular Biology, Cambridge Biomedical CampusCambridgeUnited Kingdom
| | - Juliusz Mieszczanek
- MRC Laboratory of Molecular Biology, Cambridge Biomedical CampusCambridgeUnited Kingdom
| | - Mariann Bienz
- MRC Laboratory of Molecular Biology, Cambridge Biomedical CampusCambridgeUnited Kingdom
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Chen H, Xu J, Wang P, Shu Q, Huang L, Guo J, Zhang X, Zhang H, Wang Y, Shen Z, Chen X, Zhang Q. Protein phosphatase 2 regulatory subunit B''Alpha silencing inhibits tumor cell proliferation in liver cancer. Cancer Med 2019; 8:7741-7753. [PMID: 31647192 PMCID: PMC6912040 DOI: 10.1002/cam4.2620] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 09/29/2019] [Accepted: 10/06/2019] [Indexed: 12/24/2022] Open
Abstract
Aim To explore the effects of protein phosphatase 2 regulatory subunit B''Alpha (PPP2R3A) on the proliferation and migration of liver cancer cells. Methods Expression of PPP2R3A in tumor tissues of hepatocellular carcinoma (HCC) patients was detected by immunohistochemistry and western blotting. In two liver cancer cell lines (HepG2 and HuH7), PPP2R3A expression was silenced and then overexpression with PPP2R3A lentiviral vectors, and the effects of PPP2R3A knockdown or overexpression on the proliferation, cell cycle, migration, and invasion of HCC cells were determined in vitro. In a xenograft cancer model in nude mice, the in vivo effects of PPP2R3A knockdown on tumor growth and cancer cell proliferation were evaluated. Results PPP2R3A expression was found in tumor foci in six of eight HCC samples, at a level higher than that in the adjacent para‐tumor tissues. PPP2R3A expression was observed primarily in the cytoplasm of the cancer cells. Knockdown of PPP2R3A resulted in significant inhibition of hepatoma cell proliferation (P < .05), migration (P < .01), and invasion (P < .01) as well as a significant delay in the G1/S transition in both liver cancer lines (P < .05) and increased p53 expression. Conversely, overexpression of PPP2R3A promoted the proliferation (P < .05) and altered cell cycle progression (P < .05) of both liver cancer cell lines. In vivo, PPP2R3A knockdown in liver cancer cells led to significant reductions in the tumor volume (P < .001) and the expression of Ki‐67 in tumor tissues (P < .05). Conclusion PPP2R3A may play a role in liver cancer via the regulation of tumor cell proliferation and invasion.
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Affiliation(s)
- Huijuan Chen
- Department of Liver Transplantation, The Third Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, China.,Graduate School, Anhui Medical University, Hefei, China
| | - Jing Xu
- National Translational Science Center for Molecular Medicine & Department of Cell Biology, State Key Laboratory of Cancer Biology, Fourth Military Medical University, Xi'an, China
| | - Peixiao Wang
- Department of Gastroenterology, Henan Children's Hospital, Zhengzhou, China
| | - Qingming Shu
- Pathology Department, The Third Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, China
| | - Lihong Huang
- Medical Department, The Third Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, China
| | - Jing Guo
- Medical Department, The Third Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, China
| | - Xuyi Zhang
- Medical Department, The Third Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, China
| | - Hongying Zhang
- Medical Department, The Third Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, China
| | - Ying Wang
- Department of Liver Transplantation, The Third Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, China
| | - Zhongyang Shen
- Department of Liver Transplantation, The Third Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, China.,Department of Transplantation Surgery, Tianjin First Central Hospital, Tianjin, China
| | - Xinguo Chen
- Department of Liver Transplantation, The Third Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, China
| | - Qing Zhang
- Department of Liver Transplantation, The Third Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, China
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Chen J, Shu S, Chen Y, Liu Z, Yu L, Yang L, Xu Y, Zhang M. AIM2 deletion promotes neuroplasticity and spatial memory of mice. Brain Res Bull 2019; 152:85-94. [DOI: 10.1016/j.brainresbull.2019.07.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 06/18/2019] [Accepted: 07/08/2019] [Indexed: 11/16/2022]
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Pedone E, Marucci L. Role of β-Catenin Activation Levels and Fluctuations in Controlling Cell Fate. Genes (Basel) 2019; 10:genes10020176. [PMID: 30823613 PMCID: PMC6410200 DOI: 10.3390/genes10020176] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 02/18/2019] [Indexed: 12/12/2022] Open
Abstract
Cells have developed numerous adaptation mechanisms to external cues by controlling signaling-pathway activity, both qualitatively and quantitatively. The Wnt/β-catenin pathway is a highly conserved signaling pathway involved in many biological processes, including cell proliferation, differentiation, somatic cell reprogramming, development, and cancer. The activity of the Wnt/β-catenin pathway and the temporal dynamics of its effector β-catenin are tightly controlled by complex regulations. The latter encompass feedback loops within the pathway (e.g., a negative feedback loop involving Axin2, a β-catenin transcriptional target) and crosstalk interactions with other signaling pathways. Here, we provide a review shedding light on the coupling between Wnt/β-catenin activation levels and fluctuations across processes and cellular systems; in particular, we focus on development, in vitro pluripotency maintenance, and cancer. Possible mechanisms originating Wnt/β-catenin dynamic behaviors and consequently driving different cellular responses are also reviewed, and new avenues for future research are suggested.
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Affiliation(s)
- Elisa Pedone
- Department of Engineering Mathematics, University of Bristol, Bristol, BS8 1UB, UK.
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, BS8 1TD, UK.
| | - Lucia Marucci
- Department of Engineering Mathematics, University of Bristol, Bristol, BS8 1UB, UK.
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, BS8 1TD, UK.
- BrisSynBio, Bristol, BS8 1TQ, UK.
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12
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Song G, Han M, Li Z, Gan X, Chen X, Yang J, Dong S, Yan M, Wan J, Wang Y, Huang Z, Yin Z, Zheng F. Deletion of Pr72 causes cardiac developmental defects in Zebrafish. PLoS One 2018; 13:e0206883. [PMID: 30481179 PMCID: PMC6258505 DOI: 10.1371/journal.pone.0206883] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 10/22/2018] [Indexed: 01/20/2023] Open
Abstract
The alpha regulator subunit B'' of protein phosphatase 2 (PPP2R3A), a regulatory subunit of protein phosphatase 2A (PP2A), was reported to present a special subcellular localization in cardiomyocytes and elevate in non-ischemia failing hearts. PPP2R3A has two transcriptions PR72 and PR130. PR72 acts as a negative regulator of the Wnt signaling cascade, while the Wnt signaling cascade plays a pivotal role in cardiac development. And PR130 was found to be involved in cardiac development of zebrafish in our previous study. Thus, to investigate the function of PR72 in heart, two stable pr72 knockout (KO) zebrafish lines were generated using Transcription Activator-Like Effector Nuclease (TALEN) technology. Homozygous pr72 KO fish struggled to survive to adulthood and exhibited cardiac developmental defects, including enlarged ventricular chambers, reduced cardiomyocytes and decreased cardiac function. And the defective sarcomere ultrastructure that affected mitochondria, I bands, Z lines, and intercalated disks was also observed. Furthermore, the abnormal heart looping was detected in mutants which could be rescued by injection with wild type pr72 mRNA. Additionally, it was found that Wnt effectors were elevated in mutants. Those indicated that deletion of pr72 in zebrafish interrupted cardiac development, probably through activation of the Wnt pathway.
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Affiliation(s)
- Guibo Song
- Center for Gene Diagnosis, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Mingjun Han
- Center for Gene Diagnosis, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Zuhua Li
- Center for Gene Diagnosis, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Xuedong Gan
- Department of Cardiology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Xiaowen Chen
- Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Jie Yang
- Center for Gene Diagnosis, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Sufang Dong
- Center for Gene Diagnosis, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Ming Yan
- Center for Gene Diagnosis, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Jun Wan
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yanggan Wang
- Department of Cardiology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Zhuliang Huang
- Center for Gene Diagnosis, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Zhan Yin
- Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- * E-mail: (FZ); (ZY)
| | - Fang Zheng
- Center for Gene Diagnosis, Zhongnan Hospital of Wuhan University, Wuhan, China
- * E-mail: (FZ); (ZY)
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13
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Nam RK, Benatar T, Amemiya Y, Wallis CJ, Romero JM, Tsagaris M, Sherman C, Sugar L, Seth A. MicroRNA-652 induces NED in LNCaP and EMT in PC3 prostate cancer cells. Oncotarget 2018; 9:19159-19176. [PMID: 29721191 PMCID: PMC5922385 DOI: 10.18632/oncotarget.24937] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 03/06/2018] [Indexed: 12/17/2022] Open
Abstract
MicroRNAs (miRNAs) are small noncoding RNA molecules that post-transcriptionally regulate gene expression. Dysregulation of miRNAs is frequently associated with disease and, in particular, is involved in prostate cancer progression. Next generation miRNA sequencing identified a panel of five miRNAs associated with prostate cancer recurrence and metastasis. High expression of one of these five miRNAs, miR-652, correlated significantly with an increased rate of prostate cancer biochemical recurrence. Overexpression of miR-652 in prostate cancer cells, PC3 and LNCaP, resulted in increased growth, migration and invasion. Prostate cancer cell xenografts overexpressing miR-652 showed increased tumorigenicity and metastases. We found that miR-652 directly targets the B" regulatory subunit, PPP2R3A, of the tumor suppressor PP2A, inducing epithelial-mesenchymal transition (EMT) in PC3 cells and neuroendocrine-like differentiation (NED) in LNCaP cells. The mesenchymal marker N-cadherin increased and epithelial marker E-cadherin decreased in PC3 cells overexpressing miR-652. In LNCaP cells and xenografted tumors, overexpression of miR-652 increased markers of NED, including chromogranin A, neuron specific enolase, and synaptophysin. MiR-652 may contribute to prostate tumor progression by promoting NED through decreased PP2A function. MiR-652 expression could serve as a biomarker for aggressive prostate cancer, as well as provide an opportunity for novel therapy in prostate cancer.
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Affiliation(s)
- Robert K. Nam
- 1 Division of Urology, Sunnybrook Health Sciences Centre, Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada
| | - Tania Benatar
- 2 Platform Biological Sciences, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Yutaka Amemiya
- 3 Genomics Facility, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Christopher J.D. Wallis
- 1 Division of Urology, Sunnybrook Health Sciences Centre, Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada
| | - Joan Miguel Romero
- 2 Platform Biological Sciences, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Melina Tsagaris
- 2 Platform Biological Sciences, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Christopher Sherman
- 4 Department of Anatomic Pathology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
- 5 Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Linda Sugar
- 4 Department of Anatomic Pathology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
- 5 Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Arun Seth
- 2 Platform Biological Sciences, Sunnybrook Research Institute, Toronto, ON, Canada
- 3 Genomics Facility, Sunnybrook Research Institute, Toronto, ON, Canada
- 4 Department of Anatomic Pathology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
- 5 Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
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14
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Janssens V, Zwaenepoel K, Rossé C, Petit MMR, Goris J, Parker PJ. PP2A binds to the LIM domains of lipoma-preferred partner through its PR130/B″ subunit to regulate cell adhesion and migration. J Cell Sci 2016; 129:1605-18. [PMID: 26945059 PMCID: PMC5333791 DOI: 10.1242/jcs.175778] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Accepted: 02/18/2016] [Indexed: 01/23/2023] Open
Abstract
Here, we identify the LIM protein lipoma-preferred partner (LPP) as a binding partner of a specific protein phosphatase 2A (PP2A) heterotrimer that is characterised by the regulatory PR130/B″α1 subunit (encoded by PPP2R3A). The PR130 subunit interacts with the LIM domains of LPP through a conserved Zn²⁺-finger-like motif in the differentially spliced N-terminus of PR130. Isolated LPP-associated PP2A complexes are catalytically active. PR130 colocalises with LPP at multiple locations within cells, including focal contacts, but is specifically excluded from mature focal adhesions, where LPP is still present. An LPP-PR130 fusion protein only localises to focal adhesions upon deletion of the domain of PR130 that binds to the PP2A catalytic subunit (PP2A/C), suggesting that PR130-LPP complex formation is dynamic and that permanent recruitment of PP2A activity might be unfavourable for focal adhesion maturation. Accordingly, siRNA-mediated knockdown of PR130 increases adhesion of HT1080 fibrosarcoma cells onto collagen I and decreases their migration in scratch wound and Transwell assays. Complex formation with LPP is mandatory for these PR130-PP2A functions, as neither phenotype can be rescued by re-expression of a PR130 mutant that no longer binds to LPP. Our data highlight the importance of specific, locally recruited PP2A complexes in cell adhesion and migration dynamics.
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Affiliation(s)
- Veerle Janssens
- Francis Crick Institute, Protein Phosphorylation Laboratory, 44 Lincoln's Inn Fields, London WC2A 3PX, UK Laboratory of Protein Phosphorylation and Proteomics, Dept. of Cellular and Molecular Medicine, KU Leuven, Herestraat 49 PO-box 901, Leuven B-3000, Belgium
| | - Karen Zwaenepoel
- Laboratory of Protein Phosphorylation and Proteomics, Dept. of Cellular and Molecular Medicine, KU Leuven, Herestraat 49 PO-box 901, Leuven B-3000, Belgium
| | - Carine Rossé
- Francis Crick Institute, Protein Phosphorylation Laboratory, 44 Lincoln's Inn Fields, London WC2A 3PX, UK Research Centre, Institut Curie, Paris 75005, France
| | - Marleen M R Petit
- Molecular Oncology Laboratory, Dept. of Human Genetics, KU Leuven, Herestraat 49 PO-box 602, Leuven B-3000, Belgium
| | - Jozef Goris
- Laboratory of Protein Phosphorylation and Proteomics, Dept. of Cellular and Molecular Medicine, KU Leuven, Herestraat 49 PO-box 901, Leuven B-3000, Belgium
| | - Peter J Parker
- Francis Crick Institute, Protein Phosphorylation Laboratory, 44 Lincoln's Inn Fields, London WC2A 3PX, UK Division of Cancer Studies King's College London, Guy's Hospital Campus, Thomas Street, London SE1 9RT, UK
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15
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Abstract
Protein phosphatase 2A (PP2A) plays a critical multi-faceted role in the regulation of the cell cycle. It is known to dephosphorylate over 300 substrates involved in the cell cycle, regulating almost all major pathways and cell cycle checkpoints. PP2A is involved in such diverse processes by the formation of structurally distinct families of holoenzymes, which are regulated spatially and temporally by specific regulators. Here, we review the involvement of PP2A in the regulation of three cell signaling pathways: wnt, mTOR and MAP kinase, as well as the G1→S transition, DNA synthesis and mitotic initiation. These processes are all crucial for proper cell survival and proliferation and are often deregulated in cancer and other diseases.
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Affiliation(s)
- Nathan Wlodarchak
- a McArdle Laboratory for Cancer Research, University of Wisconsin-Madison , Madison , WI , USA
| | - Yongna Xing
- a McArdle Laboratory for Cancer Research, University of Wisconsin-Madison , Madison , WI , USA
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16
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Abstract
Wnt signaling plays an important role in development and disease. In this review we focus on the role of the canonical Wnt signaling pathway in somatic stem cell biology and its critical role in tissue homeostasis. We present current knowledge how Wnt/β-catenin signaling affects tissue stem cell behavior in various organ systems, including the gut, mammary gland, the hematopoietic and nervous system. We discuss evidence that canonical Wnt signaling can both maintain potency and an undifferentiated state as well as cause differentiation in somatic stem cells, depending on the cellular and environmental context. Based on studies by our lab and others, we will attempt to explain the dichotomous behavior of this signaling pathway in determining cell fate decisions and put special emphasis on the interaction of β-catenin with two highly homologous co-activator proteins, CBP and p300, to shed light on the their differential role in the outcome of Wnt/β-catenin signaling. Furthermore, we review current knowledge regarding the aberrant regulation of Wnt/β-catenin signaling in cancer biology, particularly its pivotal role in the context of cancer stem cells. Finally, we discuss data demonstrating that small molecule modulators of the β-catenin/co-activator interaction can be used to shift the balance between undifferentiated proliferation and differentiation, which potentially presents a promising therapeutic approach to stem cell based disease mechanisms.
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17
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Maubant S, Tesson B, Maire V, Ye M, Rigaill G, Gentien D, Cruzalegui F, Tucker GC, Roman-Roman S, Dubois T. Transcriptome analysis of Wnt3a-treated triple-negative breast cancer cells. PLoS One 2015; 10:e0122333. [PMID: 25848952 PMCID: PMC4388387 DOI: 10.1371/journal.pone.0122333] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 02/10/2015] [Indexed: 12/31/2022] Open
Abstract
The canonical Wnt/β-catenin pathway is activated in triple-negative breast cancer (TNBC). The activation of this pathway leads to the expression of specific target genes depending on the cell/tissue context. Here, we analyzed the transcriptome of two different TNBC cell lines to define a comprehensive list of Wnt target genes. The treatment of cells with Wnt3a for 6h up-regulated the expression (fold change > 1.3) of 59 genes in MDA-MB-468 cells and 241 genes in HCC38 cells. Thirty genes were common to both cell lines. Beta-catenin may also be a transcriptional repressor and we found that 18 and 166 genes were down-regulated in response to Wnt3a treatment for 6h in MDA-MB-468 and HCC38 cells, respectively, of which six were common to both cell lines. Only half of the activated and the repressed transcripts have been previously described as Wnt target genes. Therefore, our study reveals 137 novel genes that may be positively regulated by Wnt3a and 104 novel genes that may be negatively regulated by Wnt3a. These genes are involved in the Wnt pathway itself, and also in TGFβ, p53 and Hedgehog pathways. Thorough characterization of these novel potential Wnt target genes may reveal new regulators of the canonical Wnt pathway. The comparison of our list of Wnt target genes with those published in other cellular contexts confirms the notion that Wnt target genes are tissue-, cell line- and treatment-specific. Genes up-regulated in Wnt3a-stimulated cell lines were more strongly expressed in TNBC than in luminal A breast cancer samples. These genes were also overexpressed, but to a much lesser extent, in HER2+ and luminal B tumors. We identified 72 Wnt target genes higher expressed in TNBCs (17 with a fold change >1.3) which may reflect the chronic activation of the canonical Wnt pathway that occurs in TNBC tumors.
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Affiliation(s)
- Sylvie Maubant
- Breast Cancer Biology Group, Translational Research Department, Institut Curie, Centre de Recherche, Paris, France
| | - Bruno Tesson
- Breast Cancer Biology Group, Translational Research Department, Institut Curie, Centre de Recherche, Paris, France
- INSERM U900, Bioinformatics, Biostatistics, Epidemiology and Computational Systems Biology of Cancer, Institut Curie, Centre de Recherche, Paris, France
- Mines ParisTech, Fontainebleau, France
| | - Virginie Maire
- Breast Cancer Biology Group, Translational Research Department, Institut Curie, Centre de Recherche, Paris, France
| | - Mengliang Ye
- Breast Cancer Biology Group, Translational Research Department, Institut Curie, Centre de Recherche, Paris, France
| | - Guillem Rigaill
- Unité de Recherche en Génomique Végétale, INRA-CNRS-Université d'Evry Val d'Essonne, Evry, France
| | - David Gentien
- Platform of Molecular Biology Facilities, Translational Research Department, Institut Curie, Centre de Recherche, Paris, France
| | - Francisco Cruzalegui
- Institut de Recherches SERVIER, Pôle Innovation Thérapeutique Oncologie, Croissy-sur-Seine, France
| | - Gordon C. Tucker
- Institut de Recherches SERVIER, Pôle Innovation Thérapeutique Oncologie, Croissy-sur-Seine, France
| | - Sergio Roman-Roman
- Translational Research Department, Institut Curie, Centre de Recherche, Paris, France
| | - Thierry Dubois
- Breast Cancer Biology Group, Translational Research Department, Institut Curie, Centre de Recherche, Paris, France
- * E-mail:
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18
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El-Hage P, Petitalot A, Monsoro-Burq AH, Maczkowiak F, Driouch K, Formstecher E, Camonis J, Sabbah M, Bièche I, Lidereau R, Lallemand F. The Tumor-Suppressor WWOX and HDAC3 Inhibit the Transcriptional Activity of the β-Catenin Coactivator BCL9-2 in Breast Cancer Cells. Mol Cancer Res 2015; 13:902-12. [PMID: 25678599 DOI: 10.1158/1541-7786.mcr-14-0180] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 01/19/2015] [Indexed: 11/16/2022]
Abstract
UNLABELLED The WW domain containing oxidoreductase (WWOX) has recently been shown to inhibit of the Wnt/β-catenin pathway by preventing the nuclear import of disheveled 2 (DVL2) in human breast cancer cells. Here, it is revealed that WWOX also interacts with the BCL9-2, a cofactor of the Wnt/β-catenin pathway, to enhance the activity of the β-catenin-TCF/LEF (T-cell factor/lymphoid enhancer factors family) transcription factor complexes. By using both a luciferase assay in MCF-7 cells and a Xenopus secondary axis induction assay, it was demonstrated that WWOX inhibits the BCL9-2 function in Wnt/β-catenin signaling. WWOX does not affect the BCL9-2-β-catenin association and colocalizes with BCL9-2 and β-catenin in the nucleus of the MCF-7 cells. Moreover, WWOX inhibits the β-catenin-TCF1 interaction. Further examination found that HDAC3 associates with BCL9-2, enhances the inhibitory effect of WWOX on BCL9-2 transcriptional activity, and promotes the WWOX-BCL9-2 interaction, independent of its deacetylase activity. However, WWOX does not influence the HDAC3-BCL9-2 interaction. Altogether, these results strongly indicate that nuclear WWOX interacts with BCL9-2 associated with β-catenin only when BCL9-2 is in complex with HDAC3 and inhibits its transcriptional activity, in part, by inhibiting the β-catenin-TCF1 interaction. The promotion of the WWOX-BCL9-2 interaction by HDAC3, independent of its deacetylase activity, represents a new mechanism by which this HDAC inhibits transcription. IMPLICATIONS The inhibition of the transcriptional activity of BCL9-2 by WWOX and HDAC3 constitutes a new molecular mechanism and provides new insight for a broad range of cancers.
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Affiliation(s)
- Perla El-Hage
- Institut Curie, Service de Génétique, Unité de pharmacogénomique, Paris, France
| | - Ambre Petitalot
- Institut Curie, Service de Génétique, Unité de pharmacogénomique, Paris, France
| | - Anne-Hélène Monsoro-Burq
- Institut Curie, CNRS UMR3347, INSERM U1021, Centre Universitaire, Paris, France. Université Paris Sud, Centre Universitaire, Paris, France
| | - Frédérique Maczkowiak
- Institut Curie, CNRS UMR3347, INSERM U1021, Centre Universitaire, Paris, France. Université Paris Sud, Centre Universitaire, Paris, France
| | - Keltouma Driouch
- Institut Curie, Service de Génétique, Unité de pharmacogénomique, Paris, France
| | | | | | - Michèle Sabbah
- INSERM U938, hôpital Saint-Antoine, Université Pierre et Marie Curie, Paris, France
| | - Ivan Bièche
- Institut Curie, Service de Génétique, Unité de pharmacogénomique, Paris, France
| | - Rosette Lidereau
- Institut Curie, Service de Génétique, Unité de pharmacogénomique, Paris, France
| | - François Lallemand
- Institut Curie, Service de Génétique, Unité de pharmacogénomique, Paris, France.
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Carmen Figueroa-Aldariz M, Castañeda-Patlán MC, Santoyo-Ramos P, Zentella A, Robles-Flores M. Protein phosphatase 2A is essential to maintain active Wnt signaling and its Aβ tumor suppressor subunit is not expressed in colon cancer cells. Mol Carcinog 2014; 54:1430-41. [DOI: 10.1002/mc.22217] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 08/01/2014] [Indexed: 12/21/2022]
Affiliation(s)
- M. Carmen Figueroa-Aldariz
- Departamento de Bioquímica; Facultad de Medicina; Universidad Nacional Autónoma de México (UNAM); Mexico D.F. Mexico
| | - M. Cristina Castañeda-Patlán
- Departamento de Bioquímica; Facultad de Medicina; Universidad Nacional Autónoma de México (UNAM); Mexico D.F. Mexico
| | - Paula Santoyo-Ramos
- Departamento de Bioquímica; Facultad de Medicina; Universidad Nacional Autónoma de México (UNAM); Mexico D.F. Mexico
| | - Alejandro Zentella
- Departamento de Bioquímica; Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán; Mexico D.F. Mexico
| | - Martha Robles-Flores
- Departamento de Bioquímica; Facultad de Medicina; Universidad Nacional Autónoma de México (UNAM); Mexico D.F. Mexico
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20
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De P, Carlson J, Leyland-Jones B, Dey N. Oncogenic nexus of cancerous inhibitor of protein phosphatase 2A (CIP2A): an oncoprotein with many hands. Oncotarget 2014; 5:4581-602. [PMID: 25015035 PMCID: PMC4148086 DOI: 10.18632/oncotarget.2127] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 06/20/2014] [Indexed: 12/23/2022] Open
Abstract
Oncoprotein CIP2A a Cancerous Inhibitor of PP2A forms an "oncogenic nexus" by virtue of its control on PP2A and MYC stabilization in cancer cells. The expression and prognostic function of CIP2A in different solid tumors including colorectal carcinoma, head and neck cancers, gastric cancers, lung carcinoma, cholangiocarcinoma, esophageal cancers, pancreatic carcinoma, brain cancers, breast carcinoma, bladder cancers, ovarian carcinoma, renal cell carcinomas, tongue cancers, cervical carcinoma, prostate cancers, and oral carcinoma as well as a number of hematological malignancies are just beginning to emerge. Herein, we reviewed the recent progress in our understanding of (1) how an "oncogenic nexus" of CIP2A participates in the tumorigenic transformation of cells and (2) how we can prospect/view the clinical relevance of CIP2A in the context of cancer therapy. The review will try to understand the role of CIP2A (a) as a biomarker in cancers and evaluate the prognostic value of CIP2A in different cancers (b) as a therapeutic target in cancers and (c) in drug response and developing chemo-resistance in cancers.
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Affiliation(s)
- Pradip De
- Department of Molecular & Experimental Medicine, Avera Research Institute, Sioux Falls, SD
- Department of Internal Medicine, SSOM, University of South Dakota, Sioux Falls, SD
| | - Jennifer Carlson
- Department of Molecular & Experimental Medicine, Avera Research Institute, Sioux Falls, SD
| | - Brian Leyland-Jones
- Department of Molecular & Experimental Medicine, Avera Research Institute, Sioux Falls, SD
- Department of Internal Medicine, SSOM, University of South Dakota, Sioux Falls, SD
| | - Nandini Dey
- Department of Molecular & Experimental Medicine, Avera Research Institute, Sioux Falls, SD
- Department of Internal Medicine, SSOM, University of South Dakota, Sioux Falls, SD
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21
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Dovega R, Tsutakawa S, Quistgaard EM, Anandapadamanaban M, Löw C, Nordlund P. Structural and biochemical characterization of human PR70 in isolation and in complex with the scaffolding subunit of protein phosphatase 2A. PLoS One 2014; 9:e101846. [PMID: 25007185 PMCID: PMC4090178 DOI: 10.1371/journal.pone.0101846] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 06/10/2014] [Indexed: 11/30/2022] Open
Abstract
Protein Phosphatase 2A (PP2A) is a major Ser/Thr phosphatase involved in the regulation of various cellular processes. PP2A assembles into diverse trimeric holoenzymes, which consist of a scaffolding (A) subunit, a catalytic (C) subunit and various regulatory (B) subunits. Here we report a 2.0 Å crystal structure of the free B’’/PR70 subunit and a SAXS model of an A/PR70 complex. The crystal structure of B’’/PR70 reveals a two domain elongated structure with two Ca2+ binding EF-hands. Furthermore, we have characterized the interaction of both binding partner and their calcium dependency using biophysical techniques. Ca2+ biophysical studies with Circular Dichroism showed that the two EF-hands display different affinities to Ca2+. In the absence of the catalytic C-subunit, the scaffolding A-subunit remains highly mobile and flexible even in the presence of the B’’/PR70 subunit as judged by SAXS. Isothermal Titration Calorimetry studies and SAXS data support that PR70 and the A-subunit have high affinity to each other. This study provides additional knowledge about the structural basis for the function of B’’ containing holoenzymes.
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Affiliation(s)
- Rebecca Dovega
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Susan Tsutakawa
- Life Science Division, Lawrence Berkeley National Lab (LBNL), Berkeley, California, United States of America
| | - Esben M. Quistgaard
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Madhanagopal Anandapadamanaban
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden
| | - Christian Löw
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Pär Nordlund
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- * E-mail:
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22
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Yu UY, Yoo BC, Ahn JH. Regulatory B Subunits of Protein Phosphatase 2A Are Involved in Site-specific Regulation of Tau Protein Phosphorylation. Korean J Physiol Pharmacol 2014; 18:155-61. [PMID: 24757378 PMCID: PMC3994303 DOI: 10.4196/kjpp.2014.18.2.155] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 02/12/2014] [Accepted: 02/28/2014] [Indexed: 11/15/2022]
Abstract
Overexpression of amyloid precursor protein with the Swedish mutation causes abnormal hyperphosphorylation of the microtubule-associated protein tau. Hyperphosphorylated isoforms of tau are major components of neurofibrillary tangles, which are histopathological hallmarks of Alzheimer's disease. Protein phosphatase 2A (PP2A), a major tau protein phosphatase, consists of a structural A subunit, catalytic C subunit, and a variety of regulatory B subunits. The B subunits have been reported to modulate function of the PP2A holoenzyme by regulating substrate binding, enzyme activity, and subcellular localization. In the current study, we characterized regulatory B subunit-specific regulation of tau protein phosphorylation. We showed that the PP2A B subunit PPP2R2A mediated dephosphorylation of tau protein at Ser-199, Ser-202/Thr-205, Thr-231, Ser-262, and Ser-422. Down-regulation of PPP2R5D expression decreased tau phosphorylation at Ser-202/Thr-205, Thr-231, and Ser-422, which indicates activation of the tau kinase glycogen synthase kinase 3 beta (GSK3β) by PP2A with PPP2R5D subunit. The level of activating phosphorylation of the GSK3β kinase Akt at Thr-308 and Ser-473 were both increased by PPP2R5D knockdown. We also characterized B subunit-specific phosphorylation sites in tau using mass spectrometric analysis. Liquid chromatography-mass spectrometry revealed that the phosphorylation status of the tau protein may be affected by PP2A, depending on the specific B subunits. These studies further our understanding of the function of various B subunits in mediating site-specific regulation of tau protein phosphorylation.
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Affiliation(s)
- Un Young Yu
- Department of Biochemistry, Ewha Womans University College of Medicine, Seoul 158-710, Korea
| | - Byong Chul Yoo
- Colorectal Cancer Branch, Research Institute, National Cancer Center, Goyang 410-768, Korea
| | - Jung-Hyuck Ahn
- Department of Biochemistry, Ewha Womans University College of Medicine, Seoul 158-710, Korea
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Wlodarchak N, Guo F, Satyshur KA, Jiang L, Jeffrey PD, Sun T, Stanevich V, Mumby MC, Xing Y. Structure of the Ca2+-dependent PP2A heterotrimer and insights into Cdc6 dephosphorylation. Cell Res 2013; 23:931-46. [PMID: 23752926 DOI: 10.1038/cr.2013.77] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Revised: 04/17/2013] [Accepted: 04/25/2013] [Indexed: 01/07/2023] Open
Abstract
The B″/PR72 family of protein phosphatase 2A (PP2A) is an important PP2A family involved in diverse cellular processes, and uniquely regulated by calcium binding to the regulatory subunit. The PR70 subunit in this family interacts with cell division control 6 (Cdc6), a cell cycle regulator important for control of DNA replication. Here, we report crystal structures of the isolated PR72 and the trimeric PR70 holoenzyme at a resolution of 2.1 and 2.4 Å, respectively, and in vitro characterization of Cdc6 dephosphorylation. The holoenzyme structure reveals that one of the PR70 calcium-binding motifs directly contacts the scaffold subunit, resulting in the most compact scaffold subunit conformation among all PP2A holoenzymes. PR70 also binds distinctively to the catalytic subunit near the active site, which is required for PR70 to enhance phosphatase activity toward Cdc6. Our studies provide a structural basis for unique regulation of B″/PR72 holoenzymes by calcium ions, and suggest the mechanisms for precise control of substrate specificity among PP2A holoenzymes.
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Park S, Scheffler TL, Rossie SS, Gerrard DE. AMPK activity is regulated by calcium-mediated protein phosphatase 2A activity. Cell Calcium 2013; 53:217-23. [PMID: 23298795 DOI: 10.1016/j.ceca.2012.12.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Revised: 11/06/2012] [Accepted: 12/08/2012] [Indexed: 12/17/2022]
Abstract
AMP-activated protein kinase (AMPK) is activated by upstream kinases and negatively regulated by protein phosphatases. Intracellular calcium mediates protein phosphatase 2A (PP2A), which is in a heterotrimeric complex with the PR72 subunit. The PR72 subunit contains two calcium-binding sites formed by EF hands. Our previous study has shown that chronic calcium exposure decreases AMPK activity. To define the specific molecular mechanism whereby calcium can deactivate AMPK, activities of AMPK and PP2A were analyzed in C2C12 muscle cell cultures and skeletal muscle tissues from mutant pigs possessing the AMPKγ3-mutation or the ryanodine receptor (RyR1) calcium gating mutation, or both. C2C12 myotubes treated with calcium releasing agent (caffeine) for 10h decreased (P<0.05) AICAR-induced AMPK activity to control levels and this negative effect was eliminated by ryanodine receptor stabilizer, dantrolene. Interestingly, muscle from pigs with the RyR1 mutation and C2C12 cells administered with 10h caffeine showed higher (P<0.05) PP2A activity compared to controls. More importantly, the inhibitory effect of caffeine on AMPK activity was attenuated by the PP2A inhibitor, calyculin A or siRNA induced knockdown of PP2A. These data show the inhibitory effect of chronic calcium on AMPK activity is exerted through the activation of PP2A.
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Affiliation(s)
- S Park
- National Institute of Animal Science, R.D.A., Suwon 441-706, Republic of Korea
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25
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Kurimchak A, Graña X. PP2A holoenzymes negatively and positively regulate cell cycle progression by dephosphorylating pocket proteins and multiple CDK substrates. Gene 2012; 499:1-7. [PMID: 22387205 DOI: 10.1016/j.gene.2012.02.015] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 02/04/2012] [Accepted: 02/13/2012] [Indexed: 12/11/2022]
Abstract
Cell cycle progression is negatively regulated by the retinoblastoma family of pocket proteins and CDK inhibitors (CKIs). In contrast, CDKs promote progression through multiple phases of the cell cycle. One prominent way by which CDKs promote cell cycle progression is by inactivation of pocket proteins via hyperphosphorylation. Reactivation of pocket proteins to halt cell cycle progression requires dephosphorylation of multiple CDK-phosphorylated sites and is accomplished by PP2A and PP1 serine/threonine protein phosphatases. The same phosphatases are also implicated in dephosphorylation of multiple CDK substrates as cells exit mitosis and reenter the G1 phase of the cell cycle. This review is primarily focused on the role of PP2A and PP1 in the activation of pocket proteins during the cell cycle and in response to signaling cues that trigger cell cycle exit. Other functions of PP2A during the cell cycle will be discussed in brief, as comprehensive reviews on this topic have been published recently (De Wulf et al., 2009; Wurzenberger and Gerlich, 2011).
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Affiliation(s)
- Alison Kurimchak
- Fels Institute for Cancer Research and Molecular Biology, Philadelphia, PA 19140, USA
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26
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Abstract
The decision for a stem cell to undergo a symmetric versus an asymmetric differentiation is probably the most critical cellular decision process in adults, as it probably underlies a large array of diseases, is associated with a decrease in tissue maintenance/homeostasis and the ability to repair properly, may mediate pathological processes such as cancer, fibrosis and neurodegeneration, and may be the underlying problem associated in general with aging. Interestingly and importantly, the decision to divide asymmetrically or symmetrically may be the major fundamental intrinsic difference between normal somatic stem and cancer stem cells. Based upon work done primarily in our laboratory over the past 10 years (both published and unpublished data), the article provides perspective on the critical importance of symmetric versus asymmetric divisions and the role of differential usage of the highly homologous coactivators Creb-binding protein (CBP) or p300 in the Wnt/catenin signaling cascade in stem cells and how they can be pharmacologically manipulated.
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Abstract
Wnt signaling is crucial for cell proliferation and differentiation. It represents a complex network with mechanisms of self-regulation through positive and negative feedback. Recent increasing interest in this signaling pathway has led to the discovery of many new proteins that down-regulate Wnt activity. Here, we provide a short description of the most important and best-studied inhibitors, group them according to the target molecule within the Wnt cascade, and discuss their clinical potential. Although most of the inhibitors discussed here may also interact with proteins from other signaling pathways, we focus only on their ability to modulate Wnt signaling.
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Abstract
Wnt signaling is a major player during development and its misregulation often leads to disease, especially cancer. The negative feedback Wnt regulator homologs, Nkd1 and Nkd2, have been shown to inhibit Wnt signaling during development, and current evidence suggests that Nkds degrade Dvl proteins to antagonize Wnt signaling. Here, we demonstrate that during early zebrafish development Nkd1 does not alter either endogenous or exogenous levels of Dvl2. Furthermore, Dvl2 does not affect the levels of Nkd1. Cumulatively, these results demonstrate that Dvl2 is a ubiquitous and stable protein and that Nkds may not always function to degrade Dvl proteins as a method of inhibiting Wnt signaling.
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Affiliation(s)
- Whitney M Lum
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
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Abstract
The simian virus 40 small t (SV40ST) oncoprotein interacts with protein phosphatase 2A (PP2A), an abundantly expressed family of serine-threonine phosphatases. This interaction is essential for the transformation of human cells by SV40, and several PP2A subunits have been implicated as tumor suppressor genes. However, the pathways controlled by specific PP2A complexes involved in cell transformation remain incompletely understood. Using a comprehensive loss-of-function approach, we identified 4 PP2A regulatory subunits [B56α, B56γ, PR72/PR130, and PTPA (protein phosphatase 2A activator)], which when suppressed replaced the expression of SV40ST in human cell transformation. We found that manipulation of complexes containing PP2A B56α, B56γ, and PR72/PR130 activates the pathways regulated by c-Myc, Wnt, and PI3K (phosphoinositide 3-kinase)/Akt in a manner that depends on their specific phosphatase activity. In contrast, suppression of PTPA disrupts the assembly of PP2A heterotrimeric complexes, which leads to the activation of these same oncogenic pathways. These observations delineate the PP2A family members and pathways perturbed by SV40ST during human cell transformation.
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Affiliation(s)
- Anna A Sablina
- Department of Medical Oncology, Dana-Farber Cancer Institute, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA.
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Schneider I, Schneider PN, Derry SW, Lin S, Barton LJ, Westfall T, Slusarski DC. Zebrafish Nkd1 promotes Dvl degradation and is required for left-right patterning. Dev Biol 2010; 348:22-33. [PMID: 20858476 DOI: 10.1016/j.ydbio.2010.08.040] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 08/22/2010] [Accepted: 08/27/2010] [Indexed: 12/20/2022]
Abstract
The establishment of the left-right (LR) axis in zebrafish embryos relies on signals from the dorsal forerunner cells (DFC) and the Kupffer's vesicle (KV). While the Wnt signaling network influences many aspects of embryonic development, its precise role in LR patterning is still unclear. One branch of the Wnt network leads to stabilization of β-catenin and activation of downstream target genes. Other Wnt ligands appear to act independently of β-catenin to modulate calcium release and influence cell polarity. Central to regulation of β-catenin and coordination of convergent extension (CE) movements is Dishevelled (Dvl). Naked Cuticle (Nkd) binds Dvl and modulates β-catenin-dependent and independent Wnt signaling. Here, we analyze the expression patterns of three zebrafish Nkd homologs and find enriched expression of nkd1 in DFCs and KV. Dvl is degraded upon Nkd1 overexpression in zebrafish. Knockdown of Nkd1 specifically in the DFC results in β-catenin nuclear localization and transcriptional activation as well as alterations to DFC migration, KV formation, ciliogenesis and LR patterning. Furthermore, we identify asymmetric expression of the Nodal antagonist charon around the KV and show that Nkd1 knockdown impacts asymmetric charon expression. Our findings show that Nkd1 acts as a β-catenin antagonist in the DFCs necessary for LR patterning.
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31
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Lukaszewicz AI, McMillan MK, Kahn M. Small molecules and stem cells. Potency and lineage commitment: the new quest for the fountain of youth. J Med Chem 2010; 53:3439-53. [PMID: 20047330 DOI: 10.1021/jm901361d] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Agnès I Lukaszewicz
- Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research at USC, Los Angeles, CA 90033, USA
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Jung H, Kim HJ, Lee SK, Kim R, Kopachik W, Han JK, Jho EH. Negative feedback regulation of Wnt signaling by Gbetagamma-mediated reduction of Dishevelled. Exp Mol Med 2010; 41:695-706. [PMID: 19561403 DOI: 10.3858/emm.2009.41.10.076] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Wnt signaling is known to be important for diverse embryonic and post-natal cellular events and be regulated by the proteins Dishevelled and Axin. Although Dishevelled is activated by Wnt and involved in signal transduction, it is not clear how Dishevelled-mediated signaling is turned off. We report that guanine nucleotide binding protein beta 2 (Gnb2; Gbeta2) bound to Axin and Gbeta2 inhibited Wnt mediated reporter activity. The inhibition involved reduction of the level of Dishevelled, and the Gbeta2gamma2 mediated reduction of Dishevelled was countered by increased expression of Axin. Consistent with these effects in HEK293T cells, injection of Gbeta2gamma2 into Xenopus embryos inhibited the formation of secondary axes induced either by XWnt8 or Dishevelled, but not by beta-catenin. The DEP domain of Dishevelled is necessary for both interaction with Gbeta2gamma2 and subsequent degradation of Dishevelled via the lysosomal pathway. Signaling induced by Gbeta2gamma2 is required because a mutant of Gbeta2, Gbeta2 (W332A) with lower signaling activity, had reduced ability to downregulate the level of Dishevelled. Activation of Wnt signaling by either of two methods, increased Frizzled signaling or transient transfection of Wnt, also led to increased degradation of Dishevelled and the induced Dishevelled loss is dependent on Gbeta1 and Gbeta2. Other studies with agents that interfere with PLC action and calcium signaling suggested that loss of Dishevelled is mediated through the following pathway: Wnt/Frizzled-->Gbetagamma-->PLC-->Ca(+2)/PKC signaling. Together the evidence suggests a novel negative feedback mechanism in which Gbeta2gamma2 inhibits Wnt signaling by degradation of Dishevelled.
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Affiliation(s)
- Hwajin Jung
- Department of Life Science, The University of Seoul, Seoul 130-743, Korea
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Abstract
The Wnt signaling pathways have been conserved throughout evolution and regulate cell proliferation, morphology, motility, and fate during embryonic development. These pathways also play important roles throughout adult life to maintain homeostasis of tissues including skin, blood, intestine, and brain by regulating somatic stem cells and their niches. Aberrant regulation of the Wnt pathway leads to neoplastic proliferation in these same tissues. It has been suggested that Wnt signaling is also involved in the regulation of cancer stem cells (CSC), because there are many similarities in the signaling pathways that regulate normal adult stem cells and CSC. In this Perspective, we have focused on the Wnt/beta-catenin signaling pathway, which is the most intensively studied and best characterized Wnt signaling pathway. We provide an overview on the function of the Wnt/beta-catenin signaling pathway in CSC, and the possibility of the development of novel therapeutics to target this pathway.
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Affiliation(s)
- Fumi Takahashi-Yanaga
- Department of Clinical Pharmacology, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan
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Holloway KR, Calhoun TN, Saxena M, Metoyer CF, Kandler EF, Rivera CA, Pruitt K. SIRT1 regulates Dishevelled proteins and promotes transient and constitutive Wnt signaling. Proc Natl Acad Sci U S A. 2010;107:9216-9221. [PMID: 20439735 DOI: 10.1073/pnas.0911325107] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Sirtuin 1 (SIRT1) is a class III histone deacetylase that deacetylates histone and nonhistone proteins to regulate gene transcription and protein function. Because SIRT1 regulates very diverse responses such as apoptosis, insulin sensitivity, autophagy, differentiation, and stem cell pluripotency, it has been a challenge to reconcile how it orchestrates such pleiotropic effects. Here we show that SIRT1 serves as an important regulator of Wnt signaling. We demonstrate that SIRT1 loss of function leads to a significant decrease in the levels of all three Dishevelled (Dvl) proteins. Furthermore, we demonstrate that SIRT1 and Dvl proteins complex in vivo and that inhibition of SIRT1 leads to changes in gene expression of Wnt target genes. Finally, we demonstrate that Wnt-stimulated cell migration is inhibited by a SIRT1 inhibitor. Because the three mammalian Dvl proteins serve as key messengers for as many as 19 Wnt ligands, SIRT1-mediated regulation of Dvl proteins may explain the diverse physiological responses observed in different cellular contexts. Previously, SIRT1 had only been shown to mediate the epigenetic silencing of Wnt antagonists. In contrast, here we report that SIRT1 regulates Dvl protein levels and Wnt signaling in several cellular contexts. These findings demonstrate that SIRT1 is a regulator of transient and constitutive Wnt signaling.
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Hu T, Li C, Cao Z, Van Raay TJ, Smith JG, Willert K, Solnica-Krezel L, Coffey RJ. Myristoylated Naked2 antagonizes Wnt-beta-catenin activity by degrading Dishevelled-1 at the plasma membrane. J Biol Chem 2010; 285:13561-8. [PMID: 20177058 PMCID: PMC2859517 DOI: 10.1074/jbc.m109.075945] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Revised: 02/19/2010] [Indexed: 12/23/2022] Open
Abstract
In Drosophila, naked cuticle is an inducible antagonist of the Wnt-beta-catenin pathway, likely acting at the level of Dishevelled (Dsh/Dvl), an essential component of this pathway. The mechanism by which naked cuticle and its two vertebrate orthologs, Naked1 (NKD1) and Naked2 (NKD2), inhibit Dvl function is unknown. NKD2 is myristoylated, a co-translational modification that leads to its plasma membrane localization. In contrast, myristoylation-deficient G2A NKD2 is cytoplasmic. Herein we show that the ability of Nkd2/NKD2 to antagonize Wnt-beta-catenin activity during zebrafish embryonic development and in mammalian HEK293 cells is myristoylation-dependent. NKD2 and Dvl-1 interact and co-localize at the lateral membrane of polarized epithelial cells. In reciprocal overexpression and siRNA knockdown experiments, NKD2 and Dvl-1 destabilize each other via enhanced polyubiquitylation; this effect is also dependent upon Naked2 myristoylation. Cell fractionation and ubiquitylation assays indicate that endogenous NKD2 interacts with a slower migrating, ubiquitylated form of Dvl-1 in plasma membrane fractions. These results provide a mechanism by which NKD2 antagonizes Wnt signaling: myristoylated NKD2 interacts with Dvl-1 at the plasma membrane, and this interaction leads to their mutual ubiquitin-mediated proteasomal degradation.
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Affiliation(s)
- Tianhui Hu
- From the Cancer Research Center, Xiamen University Medical College, and
- Key Laboratory of the Ministry of Education for Cell Biology and Tumor Cell Engineering, Xiamen University, Xiamen, 361005 Fujian, China
- the Departments of Medicine and Cell and Developmental Biology and
| | - Cunxi Li
- the Departments of Medicine and Cell and Developmental Biology and
| | - Zheng Cao
- the Departments of Medicine and Cell and Developmental Biology and
| | - Terence J. Van Raay
- the Departments of Medicine and Cell and Developmental Biology and
- Biological Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Jason G. Smith
- the Departments of Medicine and Cell and Developmental Biology and
| | - Karl Willert
- the Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California 92093, and
| | - Lila Solnica-Krezel
- Biological Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Robert J. Coffey
- the Departments of Medicine and Cell and Developmental Biology and
- the Department of Veterans Affairs Medical Center, Nashville, Tennessee 37232
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36
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Flegg CP, Sharma M, Medina-Palazon C, Jamieson C, Galea M, Brocardo MG, Mills K, Henderson BR. Nuclear export and centrosome targeting of the protein phosphatase 2A subunit B56alpha: role of B56alpha in nuclear export of the catalytic subunit. J Biol Chem 2010; 285:18144-54. [PMID: 20378546 DOI: 10.1074/jbc.m109.093294] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Protein phosphatase (PP) 2A is a heterotrimeric enzyme regulated by specific subunits. The B56 (or B'/PR61/PPP2R5) class of B-subunits direct PP2A or its substrates to different cellular locations, and the B56alpha, -beta, and -epsilon isoforms are known to localize primarily in the cytoplasm. Here we studied the pathways that regulate B56alpha subcellular localization. We detected B56alpha in the cytoplasm and nucleus, and at the nuclear envelope and centrosomes, and show that cytoplasmic localization is dependent on CRM1-mediated nuclear export. The inactivation of CRM1 by leptomycin B or by siRNA knockdown caused nuclear accumulation of ectopic and endogenous B56alpha. Conversely, CRM1 overexpression shifted B56alpha to the cytoplasm. We identified a functional nuclear export signal at the C terminus (NES; amino acids 451-469), and site-directed mutagenesis of the NES (L461A) caused nuclear retention of full-length B56alpha. Active NESs were identified at similar positions in the cytoplasmic B56-beta and epsilon isoforms, but not in the nuclear-localized B56-delta or gamma isoforms. The transient expression of B56alpha induced nuclear export of the PP2A catalytic (C) subunit, and this was blocked by the L461A NES mutation. In addition, B56alpha co-located with the PP2A active (A) subunit at centrosomes, and its centrosome targeting involved sequences that bind to the A-subunit. Fluorescence Recovery after Photobleaching (FRAP) assays revealed dynamic and immobile pools of B56alpha-GFP, which was rapidly exported from the nucleus and subject to retention at centrosomes. We propose that B56alpha can act as a PP2A C-subunit chaperone and regulates PP2A activity at diverse subcellular locations.
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Affiliation(s)
- Cameron P Flegg
- From the Westmead Institute for Cancer Research, Westmead Millennium Institute at Westmead Hospital, University of Sydney, Westmead New South Wales 2145, Australia
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Abstract
Wnt signaling controls a variety of developmental and homeostatic events. As a key component of Wnt signaling, Dishevelled (Dvl/Dsh) protein relays Wnt signals from receptors to downstream effectors. In the canonical Wnt pathway that depends on the nuclear translocation of beta-catenin, Dvl is recruited by the receptor Frizzled and prevents the constitutive destruction of cytosolic beta-catenin. In the non-canonical Wnt pathways such as Wnt-Frizzled/PCP (planar cell polarity) signaling, Dvl signals via the Daam1-RhoA axis and the Rac1 axis. In addition, Dvl plays important roles in Wnt-GSK3beta-microtubule signaling, Wnt-calcium signaling, Wnt-RYK signaling, Wnt-atypical PKC signaling, etc. Dvl also functions to mediate receptor endocytosis. To fulfill its multifaceted functions, it is not surprising that Dvl associates with various kinds of proteins. Its activity is also modulated dynamically by phosphorylation, ubiquitination and degradation. In this review, we summarize the current understanding of Dvl functions in Wnt signal transduction and its biological functions in mouse development, and also discuss the molecular mechanisms of its actions.
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38
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Guo J, Cagatay T, Zhou G, Chan CC, Blythe S, Suyama K, Zheng L, Pan K, Qian C, Hamelin R, Thibodeau SN, Klein PS, Wharton KA, Liu W. Mutations in the human naked cuticle homolog NKD1 found in colorectal cancer alter Wnt/Dvl/beta-catenin signaling. PLoS One 2009; 4:e7982. [PMID: 19956716 DOI: 10.1371/journal.pone.0007982] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Accepted: 10/19/2009] [Indexed: 12/27/2022] Open
Abstract
Background Mutation of Wnt signal antagonists Apc or Axin activates β-catenin signaling in many cancers including the majority of human colorectal adenocarcinomas. The phenotype of apc or axin mutation in the fruit fly Drosophila melanogaster is strikingly similar to that caused by mutation in the segment-polarity gene, naked cuticle (nkd). Nkd inhibits Wnt signaling by binding to the Dishevelled (Dsh/Dvl) family of scaffold proteins that link Wnt receptor activation to β-catenin accumulation and TCF-dependent transcription, but human NKD genes have yet to be directly implicated in cancer. Methodology/Principal Findings We identify for the first time mutations in NKD1 - one of two human nkd homologs - in a subset of DNA mismatch repair-deficient colorectal tumors that are not known to harbor mutations in other Wnt-pathway genes. The mutant Nkd1 proteins are defective at inhibiting Wnt signaling; in addition, the mutant Nkd1 proteins stabilize β-catenin and promote cell proliferation, in part due to a reduced ability of each mutant Nkd1 protein to bind and destabilize Dvl proteins. Conclusions/Significance Our data raise the hypothesis that specific NKD1 mutations promote Wnt-dependent tumorigenesis in a subset of DNA mismatch-repair-deficient colorectal adenocarcinomas and possibly other Wnt-signal driven human cancers.
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Ganner A, Lienkamp S, Schäfer T, Romaker D, Wegierski T, Park TJ, Spreitzer S, Simons M, Gloy J, Kim E, Wallingford JB, Walz G. Regulation of ciliary polarity by the APC/C. Proc Natl Acad Sci U S A 2009; 106:17799-804. [PMID: 19805045 DOI: 10.1073/pnas.0909465106] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Planar cell polarity signaling controls a variety of polarized cell behaviors. In multiciliated Xenopus epidermal cells, recruitment of Dishevelled (Dvl) to the basal body and its localization to the center of the ciliary rootlet are required to correctly position the motile cilia. We now report that the anaphase-promoting complex (APC/C) recognizes a D-box motif of Dvl and ubiquitylates Dvl on a highly conserved lysine residue. Inhibition of APC/C function by knockdown of the ANAPC2 subunit disrupts the polarity of motile cilia and alters the directionality of the fluid movement along the epidermis of the Xenopus embryo. Our results suggest that the APC/C activity enables cilia to correctly polarize in Xenopus epidermal cells.
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Zhang W, Yang J, Liu Y, Chen X, Yu T, Jia J, Liu C. PR55 alpha, a regulatory subunit of PP2A, specifically regulates PP2A-mediated beta-catenin dephosphorylation. J Biol Chem 2009; 284:22649-56. [PMID: 19556239 DOI: 10.1074/jbc.m109.013698] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
A central question in Wnt signaling is the regulation of beta-catenin phosphorylation and degradation. Multiple kinases, including CKI alpha and GSK3, are involved in beta-catenin phosphorylation. Protein phosphatases such as PP2A and PP1 have been implicated in the regulation of beta-catenin. However, which phosphatase dephosphorylates beta-catenin in vivo and how the specificity of beta-catenin dephosphorylation is regulated are not clear. In this study, we show that PP2A regulates beta-catenin phosphorylation and degradation in vivo. We demonstrate that PP2A is required for Wnt/beta-catenin signaling in Drosophila. Moreover, we have identified PR55 alpha as the regulatory subunit of PP2A that controls beta-catenin phosphorylation and degradation. PR55 alpha, but not the catalytic subunit, PP2Ac, directly interacts with beta-catenin. RNA interference knockdown of PR55 alpha elevates beta-catenin phosphorylation and decreases Wnt signaling, whereas overexpressing PR55 alpha enhances Wnt signaling. Taken together, our results suggest that PR55 alpha specifically regulates PP2A-mediated beta-catenin dephosphorylation and plays an essential role in Wnt signaling.
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Affiliation(s)
- Wen Zhang
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas 77555, USA
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Vares G, Wang B, Shang Y, Ohyama H, Tanaka K, Nakajima T, Nenoi M, Hayata I. Adaptive response in embryogenesis: vi. Comparative microarray analysis of gene expressions in mouse fetuses. Int J Radiat Biol 2009; 85:70-86. [PMID: 19205986 DOI: 10.1080/09553000802635039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
PURPOSE Exposure of sublethal doses of ionizing radiation can induce protective mechanisms against a subsequent higher dose irradiation. This phenomenon, called radiation-induced adaptive response (AR), has been described in a wide range of biological models. We previously demonstrated the existence of AR in mice during late organogenesis. In this study, we investigated molecular mechanisms underlying AR in this model. MATERIALS AND METHODS Using DNA microarrays, we performed a global analysis of transcriptome regulations in adapted and non-adapted cells collected from whole mouse fetuses, after in utero exposure to priming irradiation. RESULTS We identified AR-specific gene modulations. Our results suggested the involvement of signal transduction and Tumor protein (p53)-related pathways in the induction of AR. CONCLUSIONS Our results are in agreement with previous investigations showing that AR could be dependant on p53 activity. The observed gene modulations may also have possible consequences for subsequent developmental process of the fetus. This is the first report of AR-specific modulations at the molecular level in utero, which could serve as a basis for subsequent studies aimed at understanding AR in this model and possible long-term effects.
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Affiliation(s)
- G Vares
- National Institute of Radiological Sciences, Anagawa, Inage-ku, Chiba, Japan
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42
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Wang L, Heidt DG, Lee CJ, Yang H, Logsdon CD, Zhang L, Fearon ER, Ljungman M, Simeone DM. Oncogenic function of ATDC in pancreatic cancer through Wnt pathway activation and beta-catenin stabilization. Cancer Cell 2009; 15:207-19. [PMID: 19249679 PMCID: PMC2673547 DOI: 10.1016/j.ccr.2009.01.018] [Citation(s) in RCA: 183] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Revised: 10/24/2008] [Accepted: 01/16/2009] [Indexed: 12/13/2022]
Abstract
Pancreatic cancer is a deadly disease characterized by late diagnosis and resistance to therapy. Much progress has been made in defining gene defects in pancreatic cancer, but a full accounting of its molecular pathogenesis remains to be provided. Here, we show that expression of the ataxia-telangiectasia group D complementing gene (ATDC), also called TRIM29, is elevated in most invasive pancreatic cancers and pancreatic cancer precursor lesions. ATDC promoted cancer cell proliferation in vitro and enhanced tumor growth and metastasis in vivo. ATDC expression correlated with elevated beta-catenin levels in pancreatic cancer, and beta-catenin function was required for ATDC's oncogenic effects. ATDC was found to stabilize beta-catenin via ATDC-induced effects on the Disheveled-2 protein, a negative regulator of glycogen synthase kinase 3beta in the Wnt/beta-catenin signaling pathway.
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Affiliation(s)
- Lidong Wang
- Department of Surgery, University of Michigan Medical Center, Ann Arbor, MI. 48109
| | - David G. Heidt
- Department of Surgery, University of Michigan Medical Center, Ann Arbor, MI. 48109
| | - Cheong J. Lee
- Department of Surgery, University of Michigan Medical Center, Ann Arbor, MI. 48109
| | - Huibin Yang
- Department of Surgery, University of Michigan Medical Center, Ann Arbor, MI. 48109
| | - Craig D. Logsdon
- Department of Cancer Biology, MD Anderson Cancer Center, Houston, Tx. 77030
| | - Lizhi Zhang
- Department of Pathology, Mayo Clinic, Rochester, Minn. 55905
| | - Eric R. Fearon
- Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, MI. 48109
- Department of Pathology, University of Michigan Medical Center, Ann Arbor, MI. 48109
- Human Genetics, University of Michigan, Ann Arbor, MI., 48109
| | - Mats Ljungman
- Radiation Oncology, University of Michigan Medical Center, Ann Arbor, MI. 48109
| | - Diane M. Simeone
- Department of Surgery, University of Michigan Medical Center, Ann Arbor, MI. 48109
- Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI. 48109
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Zwaenepoel K, Louis JV, Goris J, Janssens V. Diversity in genomic organisation, developmental regulation and distribution of the murine PR72/B" subunits of protein phosphatase 2A. BMC Genomics 2008; 9:393. [PMID: 18715506 PMCID: PMC2529318 DOI: 10.1186/1471-2164-9-393] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2008] [Accepted: 08/20/2008] [Indexed: 01/03/2023] Open
Abstract
Background Protein phosphatase 2A (PP2A) is a serine/threonine-specific phosphatase displaying vital functions in growth and development through its role in various signalling pathways. PP2A holoenzymes comprise a core dimer composed of a catalytic C and a structural A subunit, which can associate with a variable B-type subunit. The importance of the B-type subunits for PP2A regulation cannot be overestimated as they determine holoenzyme localisation, activity and substrate specificity. Three B-type subunit families have been identified: PR55/B, PR61/B' and PR72/B", of which the latter is currently the least characterised. Results We deduced the sequences and genomic organisation of the different murine PR72/B" isoforms: three genes encode nine isoforms, five of which are abundantly expressed and give rise to genuine PP2A subunits. Thereby, one novel subunit was identified. Using Northern blotting, we examined the tissue-specific and developmental expression of these subunits. All subunits are highly expressed in heart, suggesting an important cardiac function. Immunohistochemical analysis revealed a striated expression pattern of PR72 and PR130 in heart and skeletal muscle, but not in bladder smooth muscle. The subcellular localisation and cell cycle regulatory ability of several PR72/B" isoforms were determined, demonstrating differences as well as similarities. Conclusion In contrast to PR55/B and PR61/B', the PR72/B" family seems evolutionary more divergent, as only two of the murine genes have a human orthologue. We have integrated these results in a more consistent nomenclature of both human and murine PR72/B" genes and their transcripts/proteins. Our results provide a platform for the future generation of PR72/B" knockout mice.
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Affiliation(s)
- Karen Zwaenepoel
- Protein Phosphorylation and Proteomics Group, Dept, Molecular Cell Biology, Faculty of Medicine, K,U, Leuven, Gasthuisberg O&N1, Herestraat 49 box 901, B-3000 Leuven, Belgium.
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Abstract
The Wnt signaling pathway is conserved across species, and is essential for early development. We previously identified nucleoredoxin (NRX) as a protein that interacts with dishevelled (Dvl) in vivo to negatively regulate the Wnt/beta-catenin pathway. However, whether NRX affects another branch of the Wnt pathway, the Wnt/planar cell polarity (PCP) pathway, remains unclear. Here we show that NRX regulates the Wnt/PCP pathway. In Xenopus laevis, over-expression or depletion of NRX by injection of NRX mRNA or antisense morpholino oligonucleotide, respectively, yields the bent-axis phenotype that is typically observed in embryos with abnormal PCP pathway activity. In co-injection experiments of Dvl and NRX mRNA, NRX suppresses the Dvl-induced bent-axis phenotype. Over-expression or depletion of NRX also suppresses the convergent extension movements that are believed to underlie normal gastrulation. We also found that NRX can inhibit Dvl-induced up-regulation of c-Jun phosphorylation. These results indicate that NRX plays crucial roles in the Wnt/PCP pathway through Dvl and regulates Xenopus gastrulation movements.
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Affiliation(s)
- Yosuke Funato
- Laboratory of Intracellular Signaling, Institute for Protein Research, Osaka University, Suita, Osaka, Japan
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45
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Davis AJ, Yan Z, Martinez B, Mumby MC. Protein phosphatase 2A is targeted to cell division control protein 6 by a calcium-binding regulatory subunit. J Biol Chem 2008; 283:16104-14. [PMID: 18397887 PMCID: PMC2414307 DOI: 10.1074/jbc.m710313200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Revised: 02/29/2008] [Indexed: 12/19/2022] Open
Abstract
The cell division control protein 6 (Cdc6) is essential for formation of pre-replication complexes at origins of DNA replication. Phosphorylation of Cdc6 by cyclin-dependent kinases inhibits ubiquitination of Cdc6 by APC/C(cdh1) and degradation by the proteasome. Experiments described here show that the PR70 member of the PPP2R3 family of regulatory subunits targets protein phosphatase 2A (PP2A) to Cdc6. Interaction with Cdc6 is mediated by residues within the C terminus of PR70, whereas interaction with PP2A requires N-terminal sequences conserved within the PPP2R3 family. Two functional EF-hand calcium-binding motifs mediate a calcium-enhanced interaction of PR70 with PP2A. Calcium has no effect on the interaction of PR70 with Cdc6 but enhances the association of PP2A with Cdc6 through its effects on PR70. Knockdown of PR70 by RNA interference results in an accumulation of endogenous and expressed Cdc6 protein that is dependent on the cyclin-dependent protein kinase phosphorylation sites on Cdc6. Knockdown of PR70 also causes G(1) arrest, suggesting that PR70 function is critical for progression into S phase. These observations indicate that PP2A can be targeted in a calcium-regulated manner to Cdc6 via the PR70 subunit, where it plays a role in regulating protein phosphorylation and stability.
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Affiliation(s)
- Anthony J. Davis
- Department of Pharmacology,
University of Texas Southwestern Medical Center at Dallas, Dallas, Texas
75390-9041 and the Division of
Cardiology, Department of Medicine, Duke University, Medical Center, Durham,
North Carolina 27710
| | - Zhen Yan
- Department of Pharmacology,
University of Texas Southwestern Medical Center at Dallas, Dallas, Texas
75390-9041 and the Division of
Cardiology, Department of Medicine, Duke University, Medical Center, Durham,
North Carolina 27710
| | - Bobbie Martinez
- Department of Pharmacology,
University of Texas Southwestern Medical Center at Dallas, Dallas, Texas
75390-9041 and the Division of
Cardiology, Department of Medicine, Duke University, Medical Center, Durham,
North Carolina 27710
| | - Marc C. Mumby
- Department of Pharmacology,
University of Texas Southwestern Medical Center at Dallas, Dallas, Texas
75390-9041 and the Division of
Cardiology, Department of Medicine, Duke University, Medical Center, Durham,
North Carolina 27710
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Eichhorn PJA, Creyghton MP, Bernards R. Protein phosphatase 2A regulatory subunits and cancer. Biochim Biophys Acta Rev Cancer 2008; 1795:1-15. [PMID: 18588945 DOI: 10.1016/j.bbcan.2008.05.005] [Citation(s) in RCA: 273] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Revised: 05/20/2008] [Accepted: 05/21/2008] [Indexed: 01/06/2023]
Abstract
The serine/threonine protein phosphatase (PP2A) is a trimeric holoenzyme that plays an integral role in the regulation of a number of major signaling pathways whose deregulation can contribute to cancer. The specificity and activity of PP2A are highly regulated through the interaction of a family of regulatory B subunits with the substrates. Accumulating evidence indicates that PP2A acts as a tumor suppressor. In this review we summarize the known effects of specific PP2A holoenzymes and their roles in cancer relevant pathways. In particular we highlight PP2A function in the regulation of MAPK and Wnt signaling.
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Affiliation(s)
- Pieter J A Eichhorn
- Division of Molecular Carcinogenesis, Center for Cancer Genomics and Center for Biomedical Genetics, The Netherlands Cancer Institute, Amsterdam, The Netherlands
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47
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Westermarck J, Hahn WC. Multiple pathways regulated by the tumor suppressor PP2A in transformation. Trends Mol Med 2008; 14:152-60. [PMID: 18329957 DOI: 10.1016/j.molmed.2008.02.001] [Citation(s) in RCA: 268] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2007] [Revised: 02/01/2008] [Accepted: 02/04/2008] [Indexed: 12/21/2022]
Abstract
Reversible protein phosphorylation plays a central role in regulating intracellular signaling. Dysregulation of the mechanisms that regulate phosphorylation plays a direct role in cancer initiation and maintenance. Although abundant evidence supports the role of kinase oncogenes in cancer development, recent work has illuminated the role of specific protein phosphatases in malignant transformation. Protein phosphatase 2A (PP2A) is the major serine-threonine phosphatase in mammalian cells. Inactivation of PP2A by viral oncoproteins, mutation of specific subunits or overexpression of endogenous inhibitors contributes to cell transformation by regulating specific phosphorylation events. Here, we review recent progress in our understanding of how PP2A regulates mitogenic signaling pathways in cancer pathogenesis and how PP2A activity is modulated in human cancers.
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48
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Baek S, Seeling JM. Identification of a novel conserved mixed-isoform B56 regulatory subunit and spatiotemporal regulation of protein phosphatase 2A during Xenopus laevis development. BMC Dev Biol 2007; 7:139. [PMID: 18093315 PMCID: PMC2257934 DOI: 10.1186/1471-213x-7-139] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2007] [Accepted: 12/19/2007] [Indexed: 01/26/2023]
Abstract
Background Wnt signaling is a key regulator of development and tumorigenesis. Protein phosphatase 2A (PP2A), which consists of a catalytic C, a structural A, and a regulatory B subunit, plays diverse roles in Wnt signaling through its B56 subunits. B56 is a multigene family encoding for proteins with a conserved core domain and divergent amino- and carboxy-termini. Ectopic B56α and B56γ reduce β-catenin abundance and B56α reduces Wnt-dependent transcription, suggesting that B56α and B56γ inhibit Wnt signaling. In contrast, B56ε is required for Wnt signaling. Knowledge of where and when B56 subunits are expressed during Xenopus development will aid in our understanding of their roles in Wnt signaling. Results We have undertaken expression analyses of B56α and B56γ in Xenopus laevis. We cloned Xenopus B56α; it is 88% identical to human B56α. Xenopus B56γ is 94% identical with human B56γ, however, a novel evolutionarily conserved mixed-isoform transcript was identified that contains a B56δ-like amino-terminal domain and a B56γ core domain. The B56δ-like variable domain exon is located upstream of the B56γ variable domain exon at the human B56γ locus, suggesting that the mixed-isoform transcript is due to alternative splicing. B56γ transcripts with different 3' ends were identified that lack or possess a 35 base pair sequence, resulting in either a transcript similar to human B56γ1, or an uncharacterized evolutionarily conserved sequence. Real time RT-PCR analyses revealed that B56α is expressed at moderate levels before the midblastula transition (MBT), at reduced levels during gastrulation and neurulation, and at high levels during organogenesis, while B56γ is expressed at low levels until organogenesis. B56α is enriched in the ventral hemisphere pre-MBT, while B56γ is ventrally enriched post-MBT. Aα, Aβ, Cα and Cβ are expressed in early Xenopus development, suggesting the presence of a functional heterotrimer. Conclusion Our data suggest that B56 functional diversity is achieved in part through the synthesis of a novel mixed-isoform B56δ/γ transcript. Our data also suggest that B56α functions pre-MBT, inhibiting Wnt signaling on the ventral side of the embryo, and again during organogenesis, while B56γ functions primarily post-MBT.
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Affiliation(s)
- Sungmin Baek
- Department of Biology, City University of New York, Queens College, 65-30 Kissena Blvd,, Flushing, NY 11367, USA.
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Chan CC, Zhang S, Cagatay T, Wharton KA. Cell-autonomous, myristyl-independent activity of the Drosophila Wnt/Wingless antagonist Naked cuticle (Nkd). Dev Biol 2007; 311:538-53. [PMID: 17942091 DOI: 10.1016/j.ydbio.2007.09.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2007] [Revised: 07/29/2007] [Accepted: 09/04/2007] [Indexed: 12/31/2022]
Abstract
Robust animal development, tissue homeostasis, and stem cell renewal requires precise control of the Wnt/beta-catenin signaling axis. In the embryo of the fruit fly Drosophila melanogaster, the naked cuticle (nkd) gene attenuates signaling by the Wnt ligand Wingless (Wg) during segmentation. nkd mutants have been reported to exhibit abnormalities in wg transcription, Wg protein distribution and/or transport, and the intracellular response to Wg, but the relationship between each alteration and the molecular mechanism of Nkd action remains unclear. In addition, whether Nkd acts in a cell-autonomous or nonautonomous fashion in the embryo is not known. Mammalian Nkd homologs have N-terminal consensus sequences that direct the post-translational addition of a lipophilic myristoyl moiety, but fly and mosquito Nkd, while sharing N-terminal sequence homology, lack a myristoylation consensus sequence. Here we provide evidence that fly Nkd acts cell-autonomously in the embryo, with its N-terminus able to confer unique functional properties and membrane association that cannot be mimicked in vivo by heterologous myristoylation consensus sequences. In conjunction with our recent observation that Nkd requires nuclear localization for function, our data suggest that Nkd acts at more than one subcellular location within signal-receiving cells to attenuate Wg signaling.
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Affiliation(s)
- Chih-Chiang Chan
- Laboratory of Molecular Pathology, Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9072, USA
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50
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Ahn JH, Sung JY, McAvoy T, Nishi A, Janssens V, Goris J, Greengard P, Nairn AC. The B''/PR72 subunit mediates Ca2+-dependent dephosphorylation of DARPP-32 by protein phosphatase 2A. Proc Natl Acad Sci U S A 2007; 104:9876-81. [PMID: 17535922 PMCID: PMC1887582 DOI: 10.1073/pnas.0703589104] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2007] [Indexed: 12/18/2022] Open
Abstract
In dopaminoceptive neurons, dopamine- and cAMP-regulated phosphoprotein of 32 kDa (DARPP-32) plays a central role in integrating the effects of dopamine and other neurotransmitters. Phosphorylation of DARPP-32 at Thr-34 by protein kinase A results in inhibition of protein phosphatase 1 (PP1), and phosphorylation at Thr-75 by Cdk5 (cyclin-dependent kinase 5) results in inhibition of protein kinase A. Dephosphorylation at Thr-34 involves primarily the Ca(2+)-dependent protein phosphatase, PP2B (calcineurin), whereas dephosphorylation of Thr-75 involves primarily PP2A, the latter being subject to control by both cAMP- and Ca(2+)-dependent regulatory mechanisms. In the present study, we have investigated the mechanism of Ca(2+)-dependent regulation of Thr-75 by PP2A. We show that the PR72 (or B'' or PPP2R3A) regulatory subunit of PP2A is highly expressed in striatum. Through the use of overexpression and down-regulation by using RNAi, we show that PP2A, in a heterotrimeric complex with the PR72 subunit, mediates Ca(2+)-dependent dephosphorylation at Thr-75 of DARPP-32. The PR72 subunit contains two Ca(2+) binding sites formed by E and F helices (EF-hands 1 and 2), and we show that the former is necessary for the ability of PP2A activity to be regulated by Ca(2+), both in vitro and in vivo. Our studies also indicate that the PR72-containing form of PP2A is necessary for the ability of glutamate acting at alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid and NMDA receptors to regulate Thr-75 dephosphorylation. These studies further our understanding of the complex signal transduction pathways that regulate DARPP-32. In addition, our studies reveal an alternative intracellular mechanism whereby Ca(2+) can activate serine/threonine phosphatase activity.
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Affiliation(s)
- Jung-Hyuck Ahn
- *Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY 10021
| | - Jee Young Sung
- *Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY 10021
| | - Thomas McAvoy
- *Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY 10021
| | - Akinori Nishi
- Department of Pharmacology, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka 830-0011, Japan
| | - Veerle Janssens
- Division of Biochemistry, Katholieke Universitet Leuven, Herestraat 49, B-3000 Leuven, Belgium; and
| | - Jozef Goris
- Division of Biochemistry, Katholieke Universitet Leuven, Herestraat 49, B-3000 Leuven, Belgium; and
| | - Paul Greengard
- *Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY 10021
| | - Angus C. Nairn
- *Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY 10021
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06508
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