1
|
Guo M, Li Z, Gu M, Gu J, You Q, Wang L. Targeting phosphatases: From molecule design to clinical trials. Eur J Med Chem 2024; 264:116031. [PMID: 38101039 DOI: 10.1016/j.ejmech.2023.116031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 12/03/2023] [Accepted: 12/04/2023] [Indexed: 12/17/2023]
Abstract
Phosphatase is a kind of enzyme that can dephosphorylate target proteins, which can be divided into serine/threonine phosphatase and tyrosine phosphatase according to its mode of action. Current evidence showed multiple phosphatases were highly correlated with diseases including various cancers, demonstrating them as potential targets. However, currently, targeting phosphatases with small molecules faces many challenges, resulting in no drug approved. In this case, phosphatases are even regarded as "undruggable" targets for a long time. Recently, a variety of strategies have been adopted in the design of small molecule inhibitors targeting phosphatases, leading many of them to enter into the clinical trials. In this review, we classified these inhibitors into 4 types, including (1) molecular glues, (2) small molecules targeting catalytic sites, (3) allosteric inhibition, and (4) bifunctional molecules (proteolysis targeting chimeras, PROTACs). These molecules with diverse strategies prove the feasibility of phosphatases as drug targets. In addition, the combination therapy of phosphatase inhibitors with other drugs has also entered clinical trials, which suggests a broad prospect. Thus, targeting phosphatases with small molecules by different strategies is emerging as a promising way in the modulation of pathogenetic phosphorylation.
Collapse
Affiliation(s)
- Mochen Guo
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing, 210009, China; Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
| | - Zekun Li
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing, 210009, China; Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
| | - Mingxiao Gu
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing, 210009, China; Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
| | - Junrui Gu
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
| | - Qidong You
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing, 210009, China; Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China.
| | - Lei Wang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing, 210009, China; Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China.
| |
Collapse
|
2
|
Ramos-Alvarez I, Lee L, Jensen RT. Cofilin activation in pancreatic acinar cells plays a pivotal convergent role for mediating CCK-stimulated enzyme secretion and growth. Front Physiol 2023; 14:1147572. [PMID: 37138671 PMCID: PMC10149936 DOI: 10.3389/fphys.2023.1147572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 04/05/2023] [Indexed: 05/05/2023] Open
Abstract
Introduction: The actin regulatory protein, cofilin plays a key signaling role in many cells for numerous cellular responses including in proliferation, development, motility, migration, secretion and growth. In the pancreas it is important in islet insulin secretion, growth of pancreatic cancer cells and in pancreatitis. However, there are no studies on its role or activation in pancreatic acinar cells. Methods: To address this question, we studied the ability of CCK to activate cofilin in pancreatic acinar cells, AR42J cells and CCK1-R transfected Panc-1 cells, the signaling cascades involved and its effect on enzyme secretion and MAPK activation, a key mediator of pancreatic growth. Results: CCK (0.3 and 100 nM), TPA, carbachol, Bombesin, secretin and VIP decreased phospho-cofilin (i.e., activate cofilin) and both phospho-kinetic and inhibitor studies of cofilin, LIM kinase (LIMK) and Slingshot Protein Phosphatase (SSH1) demonstrated these conventional activators of cofilin were not involved. Serine phosphatases inhibitors (calyculin A and okadaic acid), however inhibited CCK/TPA-cofilin activation. Studies of various CCK-activated signaling cascades showed activation of PKC/PKD, Src, PAK4, JNK, ROCK mediated cofilin activation, but not PI3K, p38, or MEK. Furthermore, using both siRNA and cofilin inhibitors, cofilin activation was shown to be essential for CCK-mediated enzyme secretion and MAPK activation. Conclusion: These results support the conclusion that cofilin activation plays a pivotal convergent role for various cell signaling cascades in CCK mediated growth/enzyme secretion in pancreatic acini.
Collapse
Affiliation(s)
- Irene Ramos-Alvarez
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Lingaku Lee
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
- National Kyushu Cancer Center, Department of Hepato-Biliary-Pancreatology, Fukuoka, Japan
| | - Robert T. Jensen
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
- *Correspondence: Robert T. Jensen,
| |
Collapse
|
3
|
Ferreira AF, Santiago J, Silva JV, Oliveira PF, Fardilha M. PP1, PP2A and PP2B Interplay in the Regulation of Sperm Motility: Lessons from Protein Phosphatase Inhibitors. Int J Mol Sci 2022; 23:ijms232315235. [PMID: 36499559 PMCID: PMC9737803 DOI: 10.3390/ijms232315235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 11/30/2022] [Accepted: 12/01/2022] [Indexed: 12/11/2022] Open
Abstract
Male fertility relies on the ability of spermatozoa to fertilize the egg in the female reproductive tract (FRT). Spermatozoa acquire activated motility during epididymal maturation; however, to be capable of fertilization, they must achieve hyperactivated motility in the FRT. Extensive research found that three protein phosphatases (PPs) are crucial to sperm motility regulation, the sperm-specific protein phosphatase type 1 (PP1) isoform gamma 2 (PP1γ2), protein phosphatase type 2A (PP2A) and protein phosphatase type 2B (PP2B). Studies have reported that PP activity decreases during epididymal maturation, whereas protein kinase activity increases, which appears to be a requirement for motility acquisition. An interplay between these PPs has been extensively investigated; however, many specific interactions and some inconsistencies remain to be elucidated. The study of PPs significantly advanced following the identification of naturally occurring toxins, including calyculin A, okadaic acid, cyclosporin, endothall and deltamethrin, which are powerful and specific PP inhibitors. This review aims to overview the protein phosphorylation-dependent biochemical pathways underlying sperm motility acquisition and hyperactivation, followed by a discussion of the PP inhibitors that allowed advances in the current knowledge of these pathways. Since male infertility cases still attain alarming numbers, additional research on the topic is required, particularly using other PP inhibitors.
Collapse
Affiliation(s)
- Ana F. Ferreira
- Laboratory of Signal Transduction, Institute for Biomedicine-iBiMED, Medical Sciences Department, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Joana Santiago
- Laboratory of Signal Transduction, Institute for Biomedicine-iBiMED, Medical Sciences Department, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Joana V. Silva
- Laboratory of Signal Transduction, Institute for Biomedicine-iBiMED, Medical Sciences Department, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Pedro F. Oliveira
- QOPNA & LAQV, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Margarida Fardilha
- Laboratory of Signal Transduction, Institute for Biomedicine-iBiMED, Medical Sciences Department, University of Aveiro, 3810-193 Aveiro, Portugal
- Correspondence: ; Tel.: +351-918-143-947
| |
Collapse
|
4
|
Kashani E, Vassella E. Pleiotropy of PP2A Phosphatases in Cancer with a Focus on Glioblastoma IDH Wildtype. Cancers (Basel) 2022; 14:5227. [PMID: 36358647 PMCID: PMC9654311 DOI: 10.3390/cancers14215227] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 10/13/2022] [Accepted: 10/20/2022] [Indexed: 07/29/2023] Open
Abstract
Serine/Threonine protein phosphatase 2A (PP2A) is a heterotrimeric (or occasionally, heterodimeric) phosphatase with pleiotropic functions and ubiquitous expression. Despite the fact that they all contribute to protein dephosphorylation, multiple PP2A complexes exist which differ considerably by their subcellular localization and their substrate specificity, suggesting diverse PP2A functions. PP2A complex formation is tightly regulated by means of gene expression regulation by transcription factors, microRNAs, and post-translational modifications. Furthermore, a constant competition between PP2A regulatory subunits is taking place dynamically and depending on the spatiotemporal circumstance; many of the integral subunits can outcompete the rest, subjecting them to proteolysis. PP2A modulation is especially important in the context of brain tumors due to its ability to modulate distinct glioma-promoting signal transduction pathways, such as PI3K/Akt, Wnt, Ras, NF-κb, etc. Furthermore, PP2A is also implicated in DNA repair and survival pathways that are activated upon treatment of glioma cells with chemo-radiation. Depending on the cancer cell type, preclinical studies have shown some promise in utilising PP2A activator or PP2A inhibitors to overcome therapy resistance. This review has a special focus on "glioblastoma, IDH wild-type" (GBM) tumors, for which the therapy options have limited efficacy, and tumor relapse is inevitable.
Collapse
Affiliation(s)
- Elham Kashani
- Institute of Pathology, University of Bern, 3008 Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, 3012 Bern, Switzerland
| | - Erik Vassella
- Institute of Pathology, University of Bern, 3008 Bern, Switzerland
| |
Collapse
|
5
|
Wu CH, Tatavarty V, Jean Beltran PM, Guerrero AA, Keshishian H, Krug K, MacMullan MA, Li L, Carr SA, Cottrell JR, Turrigiano GG. A bidirectional switch in the Shank3 phosphorylation state biases synapses toward up- or downscaling. eLife 2022; 11:74277. [PMID: 35471151 PMCID: PMC9084893 DOI: 10.7554/elife.74277] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 04/25/2022] [Indexed: 11/13/2022] Open
Abstract
Homeostatic synaptic plasticity requires widespread remodeling of synaptic signaling and scaffolding networks, but the role of post-translational modifications in this process has not been systematically studied. Using deep-scale quantitative analysis of the phosphoproteome in mouse neocortical neurons, we found widespread and temporally complex changes during synaptic scaling up and down. We observed 424 bidirectionally modulated phosphosites that were strongly enriched for synapse-associated proteins, including S1539 in the autism spectrum disorder-associated synaptic scaffold protein Shank3. Using a parallel proteomic analysis performed on Shank3 isolated from rat neocortical neurons by immunoaffinity, we identified two sites that were persistently hypophosphorylated during scaling up and transiently hyperphosphorylated during scaling down: one (rat S1615) that corresponded to S1539 in mouse, and a second highly conserved site, rat S1586. The phosphorylation status of these sites modified the synaptic localization of Shank3 during scaling protocols, and dephosphorylation of these sites via PP2A activity was essential for the maintenance of synaptic scaling up. Finally, phosphomimetic mutations at these sites prevented scaling up but not down, while phosphodeficient mutations prevented scaling down but not up. These mutations did not impact baseline synaptic strength, indicating that they gate, rather than drive, the induction of synaptic scaling. Thus, an activity-dependent switch between hypo- and hyperphosphorylation at S1586 and S1615 of Shank3 enables scaling up or down, respectively. Collectively, our data show that activity-dependent phosphoproteome dynamics are important for the functional reconfiguration of synaptic scaffolds and can bias synapses toward upward or downward homeostatic plasticity.
Collapse
Affiliation(s)
- Chi-Hong Wu
- Department of Biology, Brandeis UniversityWalthamUnited States
| | | | | | | | - Hasmik Keshishian
- Proteomics Platform, Broad Institute of MIT and HarvardCambridgeUnited States
| | - Karsten Krug
- Proteomics Platform, Broad Institute of MIT and HarvardCambridgeUnited States
| | - Melanie A MacMullan
- Proteomics Platform, Broad Institute of MIT and HarvardCambridgeUnited States
| | - Li Li
- Stanley Center for Psychiatric Research, Broad Institute of MIT and HarvardCambridgeUnited States
| | - Steven A Carr
- Proteomics Platform, Broad Institute of MIT and HarvardCambridgeUnited States
| | - Jeffrey R Cottrell
- Stanley Center for Psychiatric Research, Broad Institute of MIT and HarvardCambridgeUnited States
| | | |
Collapse
|
6
|
Nathanael J, Suardana P, Vianney YM, Dwi Putra SE. The role of FoxO1 and its modulation with small molecules in the development of diabetes mellitus: A review. Chem Biol Drug Des 2021; 99:344-361. [PMID: 34862852 DOI: 10.1111/cbdd.13989] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 11/11/2021] [Accepted: 11/21/2021] [Indexed: 12/14/2022]
Abstract
Diabetes mellitus type 2 (T2D) is one of the metabolic disorders suffered by a global human being. Certain factors, such as lifestyle and heredity, can increase a person's tendency for T2D. Various genes and proteins play a role in the development of insulin resistance and ultimately diabetes in which one central protein that is discussed in this review is FoxO1. In this review, we regard FoxO1 activation as detrimental, promote high plasma glucose level, and induce insulin resistance. Indeed, many contrasting studies arise since FoxO1 is an important protein to alleviate oxidative stress and promote cell survival, for example, also by preventing hyperglycemic-induced cell death. Inter-relation to PPARG, another important protein in metabolism, is also discussed. Ultimately, we discussed contrasting approaches of targeting FoxO1 to combat diabetes mellitus by small molecules.
Collapse
Affiliation(s)
- Joshua Nathanael
- Department of Biotechnology, Faculty of Biotechnology, University of Surabaya, Surabaya, East Java, Indonesia
| | - Putu Suardana
- Department of Biotechnology, Faculty of Biotechnology, University of Surabaya, Surabaya, East Java, Indonesia
| | - Yoanes Maria Vianney
- Department of Biotechnology, Faculty of Biotechnology, University of Surabaya, Surabaya, East Java, Indonesia
| | - Sulistyo Emantoko Dwi Putra
- Department of Biotechnology, Faculty of Biotechnology, University of Surabaya, Surabaya, East Java, Indonesia
| |
Collapse
|
7
|
Ai X, Yan J, Pogwizd SM. Serine-threonine protein phosphatase regulation of Cx43 dephosphorylation in arrhythmogenic disorders. Cell Signal 2021; 86:110070. [PMID: 34217833 PMCID: PMC8963383 DOI: 10.1016/j.cellsig.2021.110070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 06/11/2021] [Accepted: 06/29/2021] [Indexed: 12/11/2022]
Abstract
Regulation of cell-to-cell communication in the heart by the gap junction protein Connexin43 (Cx43) involves modulation of Cx43 phosphorylation state by protein kinases, and dephosphorylation by protein phosphatases. Dephosphorylation of Cx43 has been associated with impaired intercellular coupling and enhanced arrhythmogenesis in various pathologic states. While there has been extensive study of the protein kinases acting on Cx43, there has been limited studies of the protein phosphatases that may underlie Cx43 dephosphorylation. The focus of this review is to introduce serine-threonine protein phosphatase regulation of Cx43 phosphorylation state and cell-to-cell communication, and its impact on arrhythmogenesis in the setting of chronic heart failure and myocardial ischemia, as well as on atrial fibrillation. We also discuss the therapeutic potential of modulating protein phosphatases to treat arrhythmias in these clinical settings.
Collapse
Affiliation(s)
- Xun Ai
- Department of Physiology & Biophysics, Rush University, Chicago, IL, United States of America
| | - Jiajie Yan
- Department of Physiology & Biophysics, Rush University, Chicago, IL, United States of America
| | - Steven M Pogwizd
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States of America.
| |
Collapse
|
8
|
Kortenoeven MLA, Esteva-Font C, Dimke H, Poulsen SB, Murali SK, Fenton RA. High dietary potassium causes ubiquitin-dependent degradation of the kidney sodium-chloride cotransporter. J Biol Chem 2021; 297:100915. [PMID: 34174287 PMCID: PMC8318901 DOI: 10.1016/j.jbc.2021.100915] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 06/10/2021] [Accepted: 06/22/2021] [Indexed: 11/24/2022] Open
Abstract
The thiazide-sensitive sodium-chloride cotransporter (NCC) in the renal distal convoluted tubule (DCT) plays a critical role in regulating blood pressure (BP) and K+ homeostasis. During hyperkalemia, reduced NCC phosphorylation and total NCC abundance facilitate downstream electrogenic K+ secretion and BP reduction. However, the mechanism for the K+-dependent reduction in total NCC levels is unknown. Here, we show that NCC levels were reduced in ex vivo renal tubules incubated in a high-K+ medium for 24–48 h. This reduction was independent of NCC transcription, but was prevented using inhibitors of the proteasome (MG132) or lysosome (chloroquine). Ex vivo, high K+ increased NCC ubiquitylation, but inhibition of the ubiquitin conjugation pathway prevented the high K+-mediated reduction in NCC protein. In tubules incubated in high K+ media ex vivo or in the renal cortex of mice fed a high K+ diet for 4 days, the abundance and phosphorylation of heat shock protein 70 (Hsp70), a key regulator of ubiquitin-dependent protein degradation and protein folding, were decreased. Conversely, in similar samples the expression of PP1α, known to dephosphorylate Hsp70, was also increased. NCC coimmunoprecipitated with Hsp70 and PP1α, and inhibiting their actions prevented the high K+-mediated reduction in total NCC levels. In conclusion, we show that hyperkalemia drives NCC ubiquitylation and degradation via a PP1α-dependent process facilitated by Hsp70. This mechanism facilitates K+-dependent reductions in NCC to protect plasma K+ homeostasis and potentially reduces BP.
Collapse
Affiliation(s)
- Marleen L A Kortenoeven
- Department of Biomedicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark; Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.
| | - Cristina Esteva-Font
- Department of Biomedicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark
| | - Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark; Department of Nephrology, Odense University Hospital, Odense, Denmark
| | - Søren B Poulsen
- Department of Biomedicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark
| | - Sathish K Murali
- Department of Biomedicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark
| | - Robert A Fenton
- Department of Biomedicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark.
| |
Collapse
|
9
|
Zhang Q, Fan Z, Zhang L, You Q, Wang L. Strategies for Targeting Serine/Threonine Protein Phosphatases with Small Molecules in Cancer. J Med Chem 2021; 64:8916-8938. [PMID: 34156850 DOI: 10.1021/acs.jmedchem.1c00631] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Among numerous posttranslational regulation patterns, phosphorylation is reversibly controlled by the balance of kinases and phosphatases. The major form of cellular signaling involves the reversible phosphorylation of proteins on tyrosine, serine, or threonine residues. However, altered phosphorylation levels are found in diverse diseases, including cancer, making kinases and phosphatases ideal drug targets. In contrast to the success of prosperous kinase inhibitors, design of small molecules targeting phosphatase is struggling due to past bias and difficulty. This is especially true for serine/threonine phosphatases, one of the largest phosphatase families. From this perspective, we aim to provide insights into serine/threonine phosphatases and the small molecules targeting these proteins for drug development, especially in cancer. Through highlighting the modulation strategies, we aim to provide basic principles for the design of small molecules and future perspectives for the application of drugs targeting serine/threonine phosphatases.
Collapse
Affiliation(s)
- Qiuyue Zhang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China.,Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Zhongjiao Fan
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China.,Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Lianshan Zhang
- Shanghai Hengrui Pharmaceutical Co., Ltd., Shanghai 200245, China
| | - Qidong You
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China.,Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Lei Wang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China.,Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| |
Collapse
|
10
|
Davuluri G, Welch N, Sekar J, Gangadhariah M, Alchirazi KA, Mohan ML, Kumar A, Kant S, Thapaliya S, Stine M, McMullen MR, McCullough RL, Stark GR, Nagy LE, Prasad SVN, Dasarathy S. Activated Protein Phosphatase 2A Disrupts Nutrient Sensing Balance Between Mechanistic Target of Rapamycin Complex 1 and Adenosine Monophosphate-Activated Protein Kinase, Causing Sarcopenia in Alcohol-Associated Liver Disease. Hepatology 2021; 73:1892-1908. [PMID: 32799332 PMCID: PMC8847884 DOI: 10.1002/hep.31524] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 07/09/2020] [Accepted: 07/29/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND AND AIMS Despite the high clinical significance of sarcopenia in alcohol-associated cirrhosis, there are currently no effective therapies because the underlying mechanisms are poorly understood. We determined the mechanisms of ethanol-induced impaired phosphorylation of mechanistic target of rapamycin complex 1 (mTORC1) and adenosine monophosphate-activated protein kinase (AMPK) with consequent dysregulated skeletal muscle protein homeostasis (balance between protein synthesis and breakdown). APPROACH AND RESULTS Differentiated murine myotubes, gastrocnemius muscle from mice with loss and gain of function of regulatory genes following ethanol treatment, and skeletal muscle from patients with alcohol-associated cirrhosis were used. Ethanol increases skeletal muscle autophagy by dephosphorylating mTORC1, circumventing the classical kinase regulation by protein kinase B (Akt). Concurrently and paradoxically, ethanol exposure results in dephosphorylation and inhibition of AMPK, an activator of autophagy and inhibitor of mTORC1 signaling. However, AMPK remains inactive with ethanol exposure despite lower cellular and tissue adenosine triphosphate, indicating a "pseudofed" state. We identified protein phosphatase (PP) 2A as a key mediator of ethanol-induced signaling and functional perturbations using loss and gain of function studies. Ethanol impairs binding of endogenous inhibitor of PP2A to PP2A, resulting in methylation and targeting of PP2A to cause dephosphorylation of mTORC1 and AMPK. Activity of phosphoinositide 3-kinase-γ (PI3Kγ), a negative regulator of PP2A, was decreased in response to ethanol. Ethanol-induced molecular and phenotypic perturbations in wild-type mice were observed in PI3Kγ-/- mice even at baseline. Importantly, overexpressing kinase-active PI3Kγ but not the kinase-dead mutant reversed ethanol-induced molecular perturbations. CONCLUSIONS Our study describes the mechanistic underpinnings for ethanol-mediated dysregulation of protein homeostasis by PP2A that leads to sarcopenia with a potential for therapeutic approaches by targeting the PI3Kγ-PP2A axis.
Collapse
Affiliation(s)
- Gangarao Davuluri
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, OH
| | - Nicole Welch
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, OH,Department of Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, OH
| | - Jinendiran Sekar
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, OH
| | | | | | - Maradumane L Mohan
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic, Cleveland, OH
| | - Avinash Kumar
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, OH
| | - Sashi Kant
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, OH
| | - Samjhana Thapaliya
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, OH
| | - McKenzie Stine
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, OH
| | - Megan R McMullen
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, OH
| | | | - George R. Stark
- Department of Cancer Biology, Cleveland Clinic, Cleveland, OH
| | - Laura E. Nagy
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, OH
| | - Sathyamangla V Naga Prasad
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic, Cleveland, OH,Address correspondence to: Srinivasan Dasarathy MD, Gastroenterology and Hepatology, NE4 208 Lerner Research Institute, 9500 Euclid Avenue, Cleveland Clinic, Cleveland, OH 44195, , Tel: 2164442980, Fax 2164453889; Sathyamangla V Naga Prasad PhD, Cardiovascular and Metabolic Sciences, NB50, Lerner Research Institute, 9500 Euclid Avenue, Cleveland Clinic, Cleveland, OH 44195, , Tel: 2164443734, Fax: 2164458204
| | - Srinivasan Dasarathy
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, OH,Department of Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, OH,Address correspondence to: Srinivasan Dasarathy MD, Gastroenterology and Hepatology, NE4 208 Lerner Research Institute, 9500 Euclid Avenue, Cleveland Clinic, Cleveland, OH 44195, , Tel: 2164442980, Fax 2164453889; Sathyamangla V Naga Prasad PhD, Cardiovascular and Metabolic Sciences, NB50, Lerner Research Institute, 9500 Euclid Avenue, Cleveland Clinic, Cleveland, OH 44195, , Tel: 2164443734, Fax: 2164458204
| |
Collapse
|
11
|
Papke CM, Smolen KA, Swingle MR, Cressey L, Heng RA, Toporsian M, Deng L, Hagen J, Shen Y, Chung WK, Kettenbach AN, Honkanen RE. A disorder-related variant (E420K) of a PP2A-regulatory subunit (PPP2R5D) causes constitutively active AKT-mTOR signaling and uncoordinated cell growth. J Biol Chem 2021; 296:100313. [PMID: 33482199 PMCID: PMC7952134 DOI: 10.1016/j.jbc.2021.100313] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 01/13/2021] [Accepted: 01/15/2021] [Indexed: 02/08/2023] Open
Abstract
Functional genomic approaches have facilitated the discovery of rare genetic disorders and improved efforts to decipher their underlying etiology. PPP2R5D-related disorder is an early childhood onset condition characterized by intellectual disability, hypotonia, autism-spectrum disorder, macrocephaly, and dysmorphic features. The disorder is caused by de novo single nucleotide changes in PPP2R5D, which generate heterozygous dominant missense variants. PPP2R5D is known to encode a B'-type (B'56δ) regulatory subunit of a PP2A-serine/threonine phosphatase. To help elucidate the molecular mechanisms altered in PPP2R5D-related disorder, we used a CRISPR-single-base editor to generate HEK-293 cells in which a single transition (c.1258G>A) was introduced into one allele, precisely recapitulating a clinically relevant E420K variant. Unbiased quantitative proteomic and phosphoproteomic analyses of endogenously expressed proteins revealed heterozygous-dominant changes in kinase/phosphatase signaling. These data combined with orthogonal validation studies revealed a previously unrecognized interaction of PPP2R5D with AKT in human cells, leading to constitutively active AKT-mTOR signaling, increased cell size, and uncoordinated cellular growth in E420K-variant cells. Rapamycin reduced cell size and dose-dependently reduced RPS6 phosphorylation in E420K-variant cells, suggesting that inhibition of mTOR1 can suppress both the observed RPS6 hyperphosphorylation and increased cell size. Together, our findings provide a deeper understanding of PPP2R5D and insight into how the E420K-variant alters signaling networks influenced by PPP2R5D. Our comprehensive approach, which combines precise genome editing, isobaric tandem mass tag labeling of peptides generated from endogenously expressed proteins, and concurrent liquid chromatography-mass spectrometry (LC-MS3), also provides a roadmap that can be used to rapidly explore the etiologies of additional genetic disorders.
Collapse
Affiliation(s)
- Cinta M Papke
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA
| | - Kali A Smolen
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA; Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA
| | - Mark R Swingle
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA
| | - Lauren Cressey
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA; Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA
| | - Richard A Heng
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA
| | - Mourad Toporsian
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA
| | - Liyong Deng
- Department of Pediatrics, Columbia University Irving Medical Center, New York, New York, USA
| | - Jacob Hagen
- Department of Pediatrics, Columbia University Irving Medical Center, New York, New York, USA
| | - Yufeng Shen
- Department of Systems Biology, Columbia University Irving Medical Center, New York, New York, USA
| | - Wendy K Chung
- Department of Pediatrics, Columbia University Irving Medical Center, New York, New York, USA; Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, New York, USA; Department of Medicine, Columbia University Medical Center, New York, New York, USA
| | - Arminja N Kettenbach
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA; Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA.
| | - Richard E Honkanen
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA.
| |
Collapse
|
12
|
Abstract
Two formal syntheses and one total synthesis of fostriecin (1) have been achieved, as well as, the synthesis of its related congener dihydro-dephospho-fostriecin. All the routes use the Sharpless dihydroxylation to set the absolute stereochemistry at C-8/9 positions and a Leighton allylation to set the C-5 position of the natural product. In the formal syntheses a Noyori transfer hydrogenation of an ynone was used to set the C-11 position while the total synthesis employed a combination of asymmetric dihydroxylation and Pd-π-allyl reduction to set the C-11 position. Finally in the total synthesis, a trans-hydroboration of the C-12/13 alkyne was used in combination with a Suzuki cross coupling to establish the Z,Z,E-triene of fostriecin (1).
Collapse
Affiliation(s)
- Gao Dong
- Department of Chemistry, West Virginia University, Morgantown, WV 26506, US
| | - Bohui Li
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, US
| | - George O'Doherty
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, US
| |
Collapse
|
13
|
Dynamic Phosphorylation and Dephosphorylation of Cyclase-Associated Protein 1 by Antagonistic Signaling through Cyclin-Dependent Kinase 5 and cAMP Are Critical for the Protein Functions in Actin Filament Disassembly and Cell Adhesion. Mol Cell Biol 2020; 40:MCB.00282-19. [PMID: 31791978 DOI: 10.1128/mcb.00282-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 11/25/2019] [Indexed: 12/15/2022] Open
Abstract
Cyclase-associated protein 1 (CAP1) is a conserved actin-regulating protein that enhances actin filament dynamics and also regulates adhesion in mammalian cells. We previously found that phosphorylation at the Ser307/Ser309 tandem site controls its association with cofilin and actin and is important for CAP1 to regulate the actin cytoskeleton. Here, we report that transient Ser307/Ser309 phosphorylation is required for CAP1 function in both actin filament disassembly and cell adhesion. Both the phosphomimetic and the nonphosphorylatable CAP1 mutant, which resist transition between phosphorylated and dephosphorylated forms, had defects in rescuing the reduced rate of actin filament disassembly in the CAP1 knockdown HeLa cells. The phosphorylation mutants also had defects in alleviating the elevated focal adhesion kinase (FAK) activity and the enhanced focal adhesions in the knockdown cells. In dissecting further phosphoregulatory cell signals for CAP1, we found that cyclin-dependent kinase 5 (CDK5) phosphorylates both Ser307 and Ser309 residues, whereas cAMP signaling induces dephosphorylation at the tandem site, through its effectors protein kinase A (PKA) and exchange proteins directly activated by cAMP (Epac). No evidence supports an involvement of activated protein phosphatase in executing the dephosphorylation downstream from cAMP, whereas preventing CAP1 from accessing its kinase CDK5 appears to underlie CAP1 dephosphorylation induced by cAMP. Therefore, this study provides direct cellular evidence that transient phosphorylation is required for CAP1 functions in both actin filament turnover and adhesion, and the novel mechanistic insights substantially extend our knowledge of the cell signals that function in concert to regulate CAP1 by facilitating its transient phosphorylation.
Collapse
|
14
|
Gao D, Li B, O’Doherty GA. Synthesis of Dehydro-Dephospho-Fostriecin and Formal Total Synthesis of Fostriecin. Org Lett 2019; 21:8334-8338. [PMID: 31584287 DOI: 10.1021/acs.orglett.9b03120] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Dong Gao
- Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Bohui Li
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
| | | |
Collapse
|
15
|
Javadpour P, Dargahi L, Ahmadiani A, Ghasemi R. To be or not to be: PP2A as a dual player in CNS functions, its role in neurodegeneration, and its interaction with brain insulin signaling. Cell Mol Life Sci 2019; 76:2277-2297. [PMID: 30874837 PMCID: PMC11105459 DOI: 10.1007/s00018-019-03063-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Revised: 02/16/2019] [Accepted: 03/07/2019] [Indexed: 12/26/2022]
Abstract
Accumulating evidence has reached the consensus that the balance of phosphorylation state of signaling molecules is a pivotal point in the regulation of cell signaling. Therefore, characterizing elements (kinases-phosphatases) in the phosphorylation balance are at great importance. However, the role of phosphatase enzymes is less investigated than kinase enzymes. PP2A is a member of serine/threonine protein phosphatase that its imbalance has been reported in neurodegenerative diseases. Therefore, we reviewed the superfamily of phosphatases and more specifically PP2A, its regulation, and physiological functions participate in CNS. Thereafter, we discussed the latest findings about PP2A dysregulation in Alzheimer and Parkinson diseases and possible interplay between this phosphatase and insulin signaling pathways. Finally, activating/inhibitory modulators for PP2A activity as well as experimental methods for PP2A study have been reviewed.
Collapse
Affiliation(s)
- Pegah Javadpour
- Department of Physiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Leila Dargahi
- Neurobiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Abolhassan Ahmadiani
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Rasoul Ghasemi
- Department of Physiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
- Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| |
Collapse
|
16
|
Regulation of Neuronal Na +/K +-ATPase by Specific Protein Kinases and Protein Phosphatases. J Neurosci 2019; 39:5440-5451. [PMID: 31085608 DOI: 10.1523/jneurosci.0265-19.2019] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 03/27/2019] [Accepted: 04/16/2019] [Indexed: 01/13/2023] Open
Abstract
The Na+/K+-ATPase (NKA) is a ubiquitous membrane-bound enzyme responsible for generating and maintaining the Na+ and K+ electrochemical gradients across the plasmalemma of living cells. Numerous studies in non-neuronal tissues have shown that this transport mechanism is reversibly regulated by phosphorylation/dephosphorylation of the catalytic α subunit and/or associated proteins. In neurons, Na+/K+ transport by NKA is essential for almost all neuronal operations, consuming up to two-thirds of the neuron's energy expenditure. However, little is known about its cellular regulatory mechanisms. Here we have used an electrophysiological approach to monitor NKA transport activity in male rat hippocampal neurons in situ We report that this activity is regulated by a balance between serine/threonine phosphorylation and dephosphorylation. Phosphorylation by the protein kinases PKG and PKC inhibits NKA activity, whereas dephosphorylation by the protein phosphatases PP-1 and PP-2B (calcineurin) reverses this effect. Given that these kinases and phosphatases serve as downstream effectors in key neuronal signaling pathways, they may mediate the coupling of primary messengers, such as neurotransmitters, hormones, and growth factors, to the NKAs, through which multiple brain functions can be regulated or dysregulated.SIGNIFICANCE STATEMENT The Na+/K+-ATPase (NKA), known as the "Na+ pump," is a ubiquitous membrane-bound enzyme responsible for generating and maintaining the Na+ and K+ electrochemical gradients across the plasma membrane of living cells. In neurons, as in most types of cells, the NKA generates the negative resting membrane potential, which is the basis for almost all aspects of cellular function. Here we used an electrophysiological approach to monitor physiological NKA transport activity in single hippocampal pyramidal cells in situ We have found that neuronal NKA activity is oppositely regulated by phosphorylation and dephosphorylation, and we have identified the main protein kinases and phosphatases mediating this regulation. This fundamental form of NKA regulation likely plays a role in multiple brain functions.
Collapse
|
17
|
Ramos F, Villoria MT, Alonso-Rodríguez E, Clemente-Blanco A. Role of protein phosphatases PP1, PP2A, PP4 and Cdc14 in the DNA damage response. Cell Stress 2019; 3:70-85. [PMID: 31225502 PMCID: PMC6551743 DOI: 10.15698/cst2019.03.178] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Maintenance of genome integrity is fundamental for cellular physiology. Our hereditary information encoded in the DNA is intrinsically susceptible to suffer variations, mostly due to the constant presence of endogenous and environmental genotoxic stresses. Genomic insults must be repaired to avoid loss or inappropriate transmission of the genetic information, a situation that could lead to the appearance of developmental anomalies and tumorigenesis. To safeguard our genome, cells have evolved a series of mechanisms collectively known as the DNA damage response (DDR). This surveillance system regulates multiple features of the cellular response, including the detection of the lesion, a transient cell cycle arrest and the restoration of the broken DNA molecule. While the role of multiple kinases in the DDR has been well documented over the last years, the intricate roles of protein dephosphorylation have only recently begun to be addressed. In this review, we have compiled recent information about the function of protein phosphatases PP1, PP2A, PP4 and Cdc14 in the DDR, focusing mainly on their capacity to regulate the DNA damage checkpoint and the repair mechanism encompassed in the restoration of a DNA lesion.
Collapse
Affiliation(s)
- Facundo Ramos
- Cell Cycle and Genome Stability Group. Institute of Functional Biology and Genomics (IBFG). Spanish National Research Council (CSIC), University of Salamanca (USAL), C/Zacarías González 2, Salamanca 37007, SPAIN
| | - María Teresa Villoria
- Cell Cycle and Genome Stability Group. Institute of Functional Biology and Genomics (IBFG). Spanish National Research Council (CSIC), University of Salamanca (USAL), C/Zacarías González 2, Salamanca 37007, SPAIN
| | - Esmeralda Alonso-Rodríguez
- Cell Cycle and Genome Stability Group. Institute of Functional Biology and Genomics (IBFG). Spanish National Research Council (CSIC), University of Salamanca (USAL), C/Zacarías González 2, Salamanca 37007, SPAIN
| | - Andrés Clemente-Blanco
- Cell Cycle and Genome Stability Group. Institute of Functional Biology and Genomics (IBFG). Spanish National Research Council (CSIC), University of Salamanca (USAL), C/Zacarías González 2, Salamanca 37007, SPAIN
| |
Collapse
|
18
|
Swingle MR, Honkanen RE. Inhibitors of Serine/Threonine Protein Phosphatases: Biochemical and Structural Studies Provide Insight for Further Development. Curr Med Chem 2019; 26:2634-2660. [PMID: 29737249 PMCID: PMC10013172 DOI: 10.2174/0929867325666180508095242] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 02/05/2018] [Accepted: 03/29/2018] [Indexed: 11/22/2022]
Abstract
BACKGROUND The reversible phosphorylation of proteins regulates many key functions in eukaryotic cells. Phosphorylation is catalyzed by protein kinases, with the majority of phosphorylation occurring on side chains of serine and threonine residues. The phosphomonoesters generated by protein kinases are hydrolyzed by protein phosphatases. In the absence of a phosphatase, the half-time for the hydrolysis of alkyl phosphate dianions at 25º C is over 1 trillion years; knon ~2 x 10-20 sec-1. Therefore, ser/thr phosphatases are critical for processes controlled by reversible phosphorylation. METHODS This review is based on the literature searched in available databases. We compare the catalytic mechanism of PPP-family phosphatases (PPPases) and the interactions of inhibitors that target these enzymes. RESULTS PPPases are metal-dependent hydrolases that enhance the rate of hydrolysis ([kcat/kM]/knon ) by a factor of ~1021, placing them among the most powerful known catalysts on earth. Biochemical and structural studies indicate that the remarkable catalytic proficiencies of PPPases are achieved by 10 conserved amino acids, DXH(X)~26DXXDR(X)~20- 26NH(X)~50H(X)~25-45R(X)~30-40H. Six act as metal-coordinating residues. Four position and orient the substrate phosphate. Together, two metal ions and the 10 catalytic residues position the phosphoryl group and an activated bridging water/hydroxide nucleophile for an inline attack upon the substrate phosphorous atom. The PPPases are conserved among species, and many structurally diverse natural toxins co-evolved to target these enzymes. CONCLUSION Although the catalytic site is conserved, opportunities for the development of selective inhibitors of this important group of metalloenzymes exist.
Collapse
Affiliation(s)
- Mark R Swingle
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile AL 36688, United States
| | - Richard E Honkanen
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile AL 36688, United States
| |
Collapse
|
19
|
Coover RA, Healy TE, Guo L, Chaney KE, Hennigan RF, Thomson CS, Aschbacher-Smith LE, Jankowski MP, Ratner N. Tonic ATP-mediated growth suppression in peripheral nerve glia requires arrestin-PP2 and is evaded in NF1. Acta Neuropathol Commun 2018; 6:127. [PMID: 30470263 PMCID: PMC6251093 DOI: 10.1186/s40478-018-0635-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 11/14/2018] [Indexed: 12/15/2022] Open
Abstract
Normal Schwann cells (SCs) are quiescent in adult nerves, when ATP is released from the nerve in an activity dependent manner. We find that suppressing nerve activity in adult nerves causes SC to enter the cell cycle. In vitro, ATP activates the SC G-protein coupled receptor (GPCR) P2Y2. Downstream of P2Y2, β-arrestin-mediated signaling results in PP2-mediated de-phosphorylation of AKT, and PP2 activity is required for SC growth suppression. NF1 deficient SC show reduced growth suppression by ATP, and are resistant to the effects of β-arrestin-mediated signaling, including PP2-mediated de-phosphorylation of AKT. In patients with the disorder Neurofibromatosis type 1, NF1 mutant SCs proliferate and form SC tumors called neurofibromas. Elevating ATP levels in vivo reduced neurofibroma cell proliferation. Thus, the low proliferation characteristic of differentiated adult peripheral nerve may require ongoing, nerve activity-dependent, ATP. Additionally, we identify a mechanism through which NF1 SCs may evade growth suppression in nerve tumors.
Collapse
|
20
|
Autophosphorylated CaMKII Facilitates Spike Propagation in Rat Optic Nerve. J Neurosci 2018; 38:8087-8105. [PMID: 30076212 DOI: 10.1523/jneurosci.0078-18.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 07/14/2018] [Accepted: 08/01/2018] [Indexed: 11/21/2022] Open
Abstract
Repeated spike firing can transmit information at synapses and modulate spike timing, shape, and conduction velocity. These latter effects have been found to result from voltage-induced changes in ion currents and could alter the signals carried by axons. Here, we test whether Ca2+/calmodulin-dependent protein kinase II (CaMKII) regulates spike propagation in adult rat optic nerve. We find that small-, medium-, and large-diameter axons bind anti-Thr286-phosphorylated CaMKII (pT286) antibodies and that, in isolated optic nerves, electrical stimulation reduces pT286 levels, spike propagation is hastened by CaMKII autophosphorylation and slowed by CaMKII dephosphorylation, single and multiple spikes slow propagation of subsequently activated spikes, and more frequent stimulation produces greater slowing. Likewise, exposing freely moving animals to flickering illumination reduces pT286 levels in optic nerves and electrically eliciting spikes in vivo in either the optic nerve or optic chiasm slows subsequent spike propagation in the optic nerve. By increasing the time that elapses between successive spikes as they propagate, pT286 dephosphorylation and activity-induced spike slowing reduce the frequency of propagated spikes below the frequency at which they were elicited and would thus limit the frequency at which axons synaptically drive target neurons. Consistent with this, the ability of retinal ganglion cells to drive at least some lateral geniculate neurons has been found to increase when presented with light flashes at low and moderate temporal frequencies but less so at high frequencies. Activity-induced decreases in spike frequency may also reduce the energy required to maintain normal intracellular Na+ and Ca2+ levels.SIGNIFICANCE STATEMENT By propagating along axons at constant velocities, spikes could drive synapses as frequently as they are initiated. However, the onset of spiking has been found to alter the conduction velocity of subsequent ("follower") spikes in various preparations. Here, we find that spikes reduce spike frequency in rat optic nerve by slowing follower spike propagation and that electrically stimulated spiking ex vivo and spike-generating flickering illumination in vivo produce net decreases in axonal Ca2+/calmodulin-dependent protein kinase II (CaMKII) autophosphorylation. Consistent with these effects, propagation speed increases and decreases, respectively, with CaMKII autophosphorylation and dephosphorylation. Lowering spike frequency by CaMKII dephosphorylation is a novel consequence of axonal spiking and light adaptation that could decrease synaptic gain as stimulus frequency increases and may also reduce energy use.
Collapse
|
21
|
Antiphospholipid antibodies induce thrombosis by PP2A activation via apoER2-Dab2-SHC1 complex formation in endothelium. Blood 2018; 131:2097-2110. [PMID: 29500169 DOI: 10.1182/blood-2017-11-814681] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 02/23/2018] [Indexed: 01/10/2023] Open
Abstract
In the antiphospholipid syndrome (APS), antiphospholipid antibody (aPL) recognition of β2 glycoprotein I promotes thrombosis, and preclinical studies indicate that this is due to endothelial nitric oxide synthase (eNOS) antagonism via apolipoprotein E receptor 2 (apoER2)-dependent processes. How apoER2 molecularly links these events is unknown. Here, we show that, in endothelial cells, the apoER2 cytoplasmic tail serves as a scaffold for aPL-induced assembly and activation of the heterotrimeric protein phosphatase 2A (PP2A). Disabled-2 (Dab2) recruitment to the apoER2 NPXY motif promotes the activating L309 methylation of the PP2A catalytic subunit by leucine methyl transferase-1. Concurrently, Src homology domain-containing transforming protein 1 (SHC1) recruits the PP2A scaffolding subunit to the proline-rich apoER2 C terminus along with 2 distinct regulatory PP2A subunits that mediate inhibitory dephosphorylation of Akt and eNOS. In mice, the coupling of these processes in endothelium is demonstrated to underlie aPL-invoked thrombosis. By elucidating these intricacies in the pathogenesis of APS-related thrombosis, numerous potential new therapeutic targets have been identified.
Collapse
|
22
|
Nayak AA, Mumbrekar KD, Rao BSS. Pharmacological approach to increasing the retention of radiation-induced γ-H2AX foci using phosphatase inhibitors: significance in radiation biodosimetry. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2018; 38:318-328. [PMID: 29447119 DOI: 10.1088/1361-6498/aaa97a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In a scenario of accidental mass radiation exposure transportation and analysis of samples may take some time, resulting in loss of biomarker information over this period. The present study aims to use phosphatase inhibitors for longer retention of focal signals to adopt γ-H2AX as a biodosimetric biomarker for the management of early triage. Peripheral blood lymphocytes isolated from healthy individuals were irradiated in vitro with x-rays and γ-H2AX foci were analysed using fluorescent microscopy and flow cytometric methods. Further, the effect of protein phosphatase 2A inhibitors such as calyculin A, fostriecin and okadiac acid on the retention of foci was studied. Fluorescent microscopy was found to be a more sensitive method than flow cytometry. Calyculin A showed significant retention of focal signals at 6 h with 1.5-fold increased retention compared to radiation alone; this may prove beneficial in early triage management because of a better dose approximation.
Collapse
Affiliation(s)
- Akshaykumar A Nayak
- Department of Radiation Biology and Toxicology, School of Life Sciences, Manipal Academy of Higher Education, Manipal 576 104, Karnataka, India
| | | | | |
Collapse
|
23
|
de la Torre C, Domínguez-Berrocal L, Murguía JR, Marcos MD, Martínez-Máñez R, Bravo J, Sancenón F. ϵ
-Polylysine-Capped Mesoporous Silica Nanoparticles as Carrier of the C
9h
Peptide to Induce Apoptosis in Cancer Cells. Chemistry 2018; 24:1890-1897. [DOI: 10.1002/chem.201704161] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Indexed: 01/22/2023]
Affiliation(s)
- Cristina de la Torre
- Instituto Interuniversitario de Investigación de Reconocimiento, Molecular y Desarrollo Tecnológico (IDM); Universitat Politècnica de, Valencia, Universitat de València; Valencia Camino de Vera s/n 46022 Valencia Spain
- CIBER de Bioingeniería, Biomateriales y Nanomedicina; Madrid Spain
- Departamento de Química; Universidad Politécnica de Valencia; Camino de Vera s/n 46022 Valencia Spain
| | - Leticia Domínguez-Berrocal
- Departamento de Genómica y Proteómica; Instituto de, Biomedicina de Valencia; c/ Jaime Roig 11 46010 Valencia Spain
| | - José R. Murguía
- Instituto Interuniversitario de Investigación de Reconocimiento, Molecular y Desarrollo Tecnológico (IDM); Universitat Politècnica de, Valencia, Universitat de València; Valencia Camino de Vera s/n 46022 Valencia Spain
- CIBER de Bioingeniería, Biomateriales y Nanomedicina; Madrid Spain
| | - M. Dolores Marcos
- Instituto Interuniversitario de Investigación de Reconocimiento, Molecular y Desarrollo Tecnológico (IDM); Universitat Politècnica de, Valencia, Universitat de València; Valencia Camino de Vera s/n 46022 Valencia Spain
- CIBER de Bioingeniería, Biomateriales y Nanomedicina; Madrid Spain
- Departamento de Química; Universidad Politécnica de Valencia; Camino de Vera s/n 46022 Valencia Spain
| | - Ramón Martínez-Máñez
- Instituto Interuniversitario de Investigación de Reconocimiento, Molecular y Desarrollo Tecnológico (IDM); Universitat Politècnica de, Valencia, Universitat de València; Valencia Camino de Vera s/n 46022 Valencia Spain
- CIBER de Bioingeniería, Biomateriales y Nanomedicina; Madrid Spain
- Departamento de Química; Universidad Politécnica de Valencia; Camino de Vera s/n 46022 Valencia Spain
| | - Jerónimo Bravo
- Departamento de Genómica y Proteómica; Instituto de, Biomedicina de Valencia; c/ Jaime Roig 11 46010 Valencia Spain
| | - Félix Sancenón
- Instituto Interuniversitario de Investigación de Reconocimiento, Molecular y Desarrollo Tecnológico (IDM); Universitat Politècnica de, Valencia, Universitat de València; Valencia Camino de Vera s/n 46022 Valencia Spain
- CIBER de Bioingeniería, Biomateriales y Nanomedicina; Madrid Spain
- Departamento de Química; Universidad Politécnica de Valencia; Camino de Vera s/n 46022 Valencia Spain
| |
Collapse
|
24
|
Fiore M. The synthesis of mono-alkyl phosphates and their derivatives: an overview of their nature, preparation and use, including synthesis under plausible prebiotic conditions. Org Biomol Chem 2018; 16:3068-3086. [DOI: 10.1039/c8ob00469b] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Nucleic acids, phospholipids and other organic phosphates play central roles in biological pathways.
Collapse
Affiliation(s)
- Michele Fiore
- Institut de Chimie et Biochimie Moléculaires et Supramoléculaires
- Université de Lyon
- F-69622 Villeurbanne Cedex
- France
| |
Collapse
|
25
|
Protein phosphatases 1 and 2A and their naturally occurring inhibitors: current topics in smooth muscle physiology and chemical biology. J Physiol Sci 2017; 68:1-17. [PMID: 28681362 PMCID: PMC5754374 DOI: 10.1007/s12576-017-0556-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 06/27/2017] [Indexed: 12/26/2022]
Abstract
Protein phosphatases 1 and 2A (PP1 and PP2A) are the most ubiquitous and abundant serine/threonine phosphatases in eukaryotic cells. They play fundamental roles in the regulation of various cellular functions. This review focuses on recent advances in the functional studies of these enzymes in the field of smooth muscle physiology. Many naturally occurring protein phosphatase inhibitors with different relative PP1/PP2A affinities have been discovered and are widely used as powerful research tools. Current topics in the chemical biology of PP1/PP2A inhibitors are introduced and discussed, highlighting the identification of the gene cluster responsible for the biosynthesis of calyculin A in a symbiont microorganism of a marine sponge.
Collapse
|
26
|
Koszelewski D, Paprocki D, Brodzka A, Ostaszewski R. Enzyme mediated kinetic resolution of δ-hydroxy-α,β-unsaturated esters as a route to optically active δ-lactones. ACTA ACUST UNITED AC 2017. [DOI: 10.1016/j.tetasy.2017.05.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
27
|
Hood AR, Ai X, Pogwizd SM. Regulation of cardiac gap junctions by protein phosphatases. J Mol Cell Cardiol 2017; 107:52-57. [PMID: 28478048 DOI: 10.1016/j.yjmcc.2017.05.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 04/13/2017] [Accepted: 05/02/2017] [Indexed: 01/16/2023]
Abstract
Sufficient connexin-mediated intercellular coupling is critical to maintain gap junctional communication for proper cardiac function. Alterations in connexin phosphorylation state, particularly dephosphorylation of connexin 43 (Cx43), may impact cell coupling and conduction in disease states. Cx43 dephosphorylation may be carried out by protein phosphatase activity. Here, we present an overview of the key phosphatases known to interact with Cx43 or modulators of Cx43, as well as some possible therapeutic targets to regulate phosphatase activity in the heart.
Collapse
Affiliation(s)
- Ashleigh R Hood
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Xun Ai
- Department of Biophysics and Physiology, Rush University, Chicago, IL, United States
| | - Steven M Pogwizd
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL, United States; Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States.
| |
Collapse
|
28
|
Swingle M, Volmar CH, Saldanha SA, Chase P, Eberhart C, Salter EA, D'Arcy B, Schroeder CE, Golden JE, Wierzbicki A, Hodder P, Honkanen RE. An Ultra-High-Throughput Screen for Catalytic Inhibitors of Serine/Threonine Protein Phosphatases Types 1 and 5 (PP1C and PP5C). SLAS DISCOVERY : ADVANCING LIFE SCIENCES R & D 2017; 22:21-31. [PMID: 27628691 PMCID: PMC8041090 DOI: 10.1177/1087057116668852] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Although there has been substantial success in the development of specific inhibitors for protein kinases, little progress has been made in the identification of specific inhibitors for their protein phosphatase counterparts. Inhibitors of PP1 and PP5 are desired as probes for research and to test their potential for drug development. We developed and miniaturized (1536-well plate format) nearly identical homogeneous, fluorescence intensity (FLINT) enzymatic assays to detect inhibitors of PP1 or PP5. The assays were used in an ultra-high-throughput screening (uHTS) campaign, testing >315,000 small-molecule compounds. Both assays demonstrated robust performance, with a Z' of 0.92 ± 0.03 and 0.95 ± 0.01 for the PP1 and PP5 assays, respectively. Screening the same library with both assays aided the identification of class inhibitors and assay artifacts. Confirmation screening and hit prioritization assays used [32P/33P]-radiolabel protein substrates, revealing excellent agreement between the FLINT and radiolabel assays. This screening campaign led to the discovery of four novel unrelated small-molecule inhibitors of PP1 and ~30 related small-molecule inhibitors of PP5. The results suggest that this uHTS approach is suitable for identifying selective chemical probes that inhibit PP1 or PP5 activity, and it is likely that similar assays can be developed for other PPP-family phosphatases.
Collapse
Affiliation(s)
| | - Claude-Henry Volmar
- 2 Scripps Research Institute Molecular Screening Center, Scripps Florida, Jupiter, FL, USA
- 3 Center for Therapeutic Innovation and Department of Psychiatry, University of Miami Miller School of Medicine, Miami, FL, USA
| | - S Adrian Saldanha
- 2 Scripps Research Institute Molecular Screening Center, Scripps Florida, Jupiter, FL, USA
- 4 Forma Therapeutics, Watertown, MA, USA
| | - Peter Chase
- 2 Scripps Research Institute Molecular Screening Center, Scripps Florida, Jupiter, FL, USA
- 5 BMS, Lawrenceville, NJ, USA
| | - Christina Eberhart
- 2 Scripps Research Institute Molecular Screening Center, Scripps Florida, Jupiter, FL, USA
| | | | | | - Chad E Schroeder
- 6 University of Kansas Specialized Chemistry Center, Lawrence, KS, USA
| | - Jennifer E Golden
- 6 University of Kansas Specialized Chemistry Center, Lawrence, KS, USA
| | | | - Peter Hodder
- 2 Scripps Research Institute Molecular Screening Center, Scripps Florida, Jupiter, FL, USA
- 7 Amgen, Thousand Oaks, CA, USA
| | | |
Collapse
|
29
|
Trost BM, Knopf JD, Brindle CS. Synthetic Strategies Employed for the Construction of Fostriecin and Related Natural Products. Chem Rev 2016; 116:15035-15088. [PMID: 28027648 PMCID: PMC5720176 DOI: 10.1021/acs.chemrev.6b00488] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Fostriecin and related natural products present a significant challenge for synthetic chemists due to their structural complexity and chemical sensitivity. This review will chronicle the successful efforts of synthetic chemists in the construction of these biologically active molecules. Key carbon-carbon bond forming reactions will be highlighted, as well as the methods used to install the numerous stereocenters present in this class of compounds.
Collapse
Affiliation(s)
- Barry M. Trost
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, United States
| | - Joshua D. Knopf
- Department of Chemistry, Trinity College, 300 Summit Street, Hartford, Connecticut 06106, United States
| | - Cheyenne S. Brindle
- Department of Chemistry, Trinity College, 300 Summit Street, Hartford, Connecticut 06106, United States
| |
Collapse
|
30
|
Ikehara T, Nakashima S, Nakashima J, Kinoshita T, Yasumoto T. Efficient production of recombinant PP2A at a low temperature using a baculovirus expression system. ACTA ACUST UNITED AC 2016; 11:86-89. [PMID: 28352544 PMCID: PMC5042294 DOI: 10.1016/j.btre.2016.07.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 07/21/2016] [Accepted: 07/30/2016] [Indexed: 11/29/2022]
Abstract
The recombinant human PP2A catalytic subunit (rhPP2Ac) was produced in the baculovirus expression system with High Five insect cells. The expression at 19 °C can produce the rhPP2Ac with a higher activity and in a larger quantity than in the incubation conducted at 27 °C. To examine the effects of the low temperature expression on other phosphatases, we expressed human PP2B and PP2C in High Five insect cells. Optimizing the expression temperature in a baculovirus system is effective for producing a recombinant protein.
Protein phosphatase 2A (PP2A) is an enzyme useful for detecting several natural toxins represented by okadaic acid and microcystins. We found that the production of the recombinant human PP2A catalytic subunit (rhPP2Ac) in High Five insect cells could markedly increase when the cells were cultured at 19 °C instead of 27 °C used under conventional conditions. The yield and purity of the enzyme increased four- and three-folds, respectively. The benefit of the altered culturing temperature was observed with the recombinant human protein phosphatase 2B but not 2Cα. The different responses among the enzymes suggest the involvement of an enzyme-specific mechanism that leads to the catalytic subunit overexpression. This is the first report to produce rhPP2Ac at a temperature lower than that used under conventional culture conditions (27 °C) used in the baculovirus expression system with High Five insect cells.
Collapse
Affiliation(s)
- Tsuyoshi Ikehara
- Department of Food Science and Technology, National Fisheries University, 2-7-1 Nagata-honmachi, Shimonoseki, Yamaguchi, 759-6595, Japan
| | - Shihoko Nakashima
- Faculty of Sports and Health Science, Fukuoka University, Fukuoka, 814-0180, Japan
| | - Junichi Nakashima
- Fukuoka Institute of Health and Environmental Sciences, Mukaizano 39, Dazaifu, Fukuoka, 818-0135, Japan
| | - Tsubasa Kinoshita
- Department of Food Science and Technology, National Fisheries University, 2-7-1 Nagata-honmachi, Shimonoseki, Yamaguchi, 759-6595, Japan
| | - Takeshi Yasumoto
- Japan Food Research Laboratories, 6-11-10 Nagayama, Tama, Tokyo, 206-0025, Japan
| |
Collapse
|
31
|
Rzechorzek NM, Connick P, Livesey MR, Borooah S, Patani R, Burr K, Story D, Wyllie DJA, Hardingham GE, Chandran S. Hypothermic Preconditioning Reverses Tau Ontogenesis in Human Cortical Neurons and is Mimicked by Protein Phosphatase 2A Inhibition. EBioMedicine 2016; 3:141-154. [PMID: 26870825 PMCID: PMC4739435 DOI: 10.1016/j.ebiom.2015.12.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 12/10/2015] [Accepted: 12/11/2015] [Indexed: 11/18/2022] Open
Abstract
Hypothermia is potently neuroprotective, but the molecular basis of this effect remains obscure. Changes in neuronal tau protein are of interest, since tau becomes hyperphosphorylated in injury-resistant, hypothermic brains. Noting inter-species differences in tau isoforms, we have used functional cortical neurons differentiated from human pluripotent stem cells (hCNs) to interrogate tau modulation during hypothermic preconditioning at clinically-relevant temperatures. Key tau developmental transitions (phosphorylation status and splicing shift) are recapitulated during hCN differentiation and subsequently reversed by mild (32 °C) to moderate (28 °C) cooling--conditions which reduce oxidative and excitotoxic stress-mediated injury in hCNs. Blocking a major tau kinase decreases hCN tau phosphorylation and abrogates hypothermic neuroprotection, whilst inhibition of protein phosphatase 2A mimics cooling-induced tau hyperphosphorylation and protects normothermic hCNs from oxidative stress. These findings indicate a possible role for phospho-tau in hypothermic preconditioning, and suggest that cooling drives human tau towards an earlier ontogenic phenotype whilst increasing neuronal resilience to common neurotoxic insults. This work provides a critical step forward in understanding how we might exploit the neuroprotective benefits of cooling without cooling patients.
Collapse
Affiliation(s)
- Nina M Rzechorzek
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, Midlothian EH16 4SB, United Kingdom; MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, Midlothian EH16 4UU, United Kingdom; Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, Midlothian EH16 4SB, United Kingdom.
| | - Peter Connick
- The Anne Rowling Regenerative Neurology Clinic, University of Edinburgh, Edinburgh, Midlothian EH16 4SB, United Kingdom
| | - Matthew R Livesey
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, Midlothian EH16 4SB, United Kingdom; Centre for Integrative Physiology, University of Edinburgh, Edinburgh, Midlothian EH8 9XD, United Kingdom
| | - Shyamanga Borooah
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, Midlothian EH16 4UU, United Kingdom; Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, Midlothian EH16 4SB, United Kingdom; The Anne Rowling Regenerative Neurology Clinic, University of Edinburgh, Edinburgh, Midlothian EH16 4SB, United Kingdom
| | - Rickie Patani
- The Anne Rowling Regenerative Neurology Clinic, University of Edinburgh, Edinburgh, Midlothian EH16 4SB, United Kingdom; Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom
| | - Karen Burr
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, Midlothian EH16 4UU, United Kingdom; Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, Midlothian EH16 4SB, United Kingdom
| | - David Story
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, Midlothian EH16 4UU, United Kingdom; Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, Midlothian EH16 4SB, United Kingdom
| | - David J A Wyllie
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, Midlothian EH16 4SB, United Kingdom; Centre for Integrative Physiology, University of Edinburgh, Edinburgh, Midlothian EH8 9XD, United Kingdom
| | - Giles E Hardingham
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, Midlothian EH8 9XD, United Kingdom
| | - Siddharthan Chandran
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, Midlothian EH16 4SB, United Kingdom; MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, Midlothian EH16 4UU, United Kingdom; Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, Midlothian EH16 4SB, United Kingdom; The Anne Rowling Regenerative Neurology Clinic, University of Edinburgh, Edinburgh, Midlothian EH16 4SB, United Kingdom.
| |
Collapse
|
32
|
Ishida M, Takeya K, Miyazu M, Yoshida A, Takai A. Force-inhibiting effect of Ser/Thr protein phosphatase 2A inhibitors on bovine ciliary muscle. J Smooth Muscle Res 2015; 51:10-21. [PMID: 26004377 PMCID: PMC5137268 DOI: 10.1540/jsmr.51.10] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Ciliary muscle is a smooth muscle characterized by a rapid response to muscarinic receptor stimulation and sustained contraction. Although it is evident that these contractions are Ca(2+)-dependent, detailed molecular mechanisms are still unknown. In order to elucidate the role of Ser/Thr protein phosphatase 2A (PP2A) in ciliary muscle contraction, we examined the effects of okadaic acid and other PP2A inhibitors on contractions induced by carbachol (CCh) and ionomycin in bovine ciliary muscle strips (BCM). Okadaic acid inhibited ionomycin-induced contraction, while it did not cause significant changes in CCh-induced contraction. Fostriecin showed similar inhibitory effects on the contraction of BCM. On the other hand, rubratoxin A inhibited both ionomycin- and CCh-induced contractions. These results indicated that PP2A was involved at least in ionomycin-induced Ca(2+)-dependent contraction, and that BCM had a unique regulatory mechanism in CCh-induced contraction.
Collapse
Affiliation(s)
- Minori Ishida
- Department of Physiology, Asahikawa Medical University, Hokkaido, Japan
| | | | | | | | | |
Collapse
|
33
|
Stockwell J, Chen Z, Niazi M, Nosib S, Cayabyab FS. Protein phosphatase role in adenosine A1 receptor-induced AMPA receptor trafficking and rat hippocampal neuronal damage in hypoxia/reperfusion injury. Neuropharmacology 2015; 102:254-65. [PMID: 26626486 DOI: 10.1016/j.neuropharm.2015.11.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 11/19/2015] [Accepted: 11/21/2015] [Indexed: 12/19/2022]
Abstract
Adenosine signaling via A1 receptor (A1R) and A2A receptor (A2AR) has shown promise in revealing potential targets for neuroprotection in cerebral ischemia. We recently showed a novel mechanism by which A1R activation with N(6)-cyclopentyl adenosine (CPA) induced GluA1 and GluA2 AMPA receptor (AMPAR) endocytosis and adenosine-induced persistent synaptic depression (APSD) in rat hippocampus. This study further investigates the mechanism of A1R-mediated AMPAR internalization and hippocampal slice neuronal damage through activation of protein phosphatase 1 (PP1), 2A (PP2A), and 2B (PP2B) using electrophysiological, biochemical and imaging techniques. Following prolonged A1R activation, GluA2 internalization was selectively blocked by PP2A inhibitors (okadaic acid and fostriecin), whereas inhibitors of PP2A, PP1 (tautomycetin), and PP2B (FK506) all prevented GluA1 internalization. Additionally, GluA1 phosphorylation at Ser831 and Ser845 was reduced after prolonged A1R activation in hippocampal slices. PP2A inhibitors nullified A1R-mediated downregulation of pSer845-GluA1, while PP1 and PP2B inhibitors prevented pSer831-GluA1 downregulation. Each protein phosphatase inhibitor also blunted CPA-induced synaptic depression and APSD. We then tested whether A1R-mediated changes in AMPAR trafficking and APSD contribute to hypoxia-induced neuronal injury. Hypoxia (20 min) induced A1R-mediated internalization of both AMPAR subunits, and subsequent normoxic reperfusion (45 min) increased GluA1 but persistently reduced GluA2 surface expression. Neuronal damage after hypoxia-reperfusion injury was significantly blunted by pre-incubation with the above protein phosphatase inhibitors. Together, these data suggest that A1R-mediated protein phosphatase activation causes persistent synaptic depression by downregulating GluA2-containing AMPARs; this previously undefined role of A1R stimulation in hippocampal neuronal damage represents a novel therapeutic target in cerebral ischemic damage.
Collapse
Affiliation(s)
- Jocelyn Stockwell
- Department of Surgery, Neuroscience Research Group, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
| | - Zhicheng Chen
- Department of Surgery, Neuroscience Research Group, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
| | - Mina Niazi
- Department of Surgery, Neuroscience Research Group, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
| | - Siddarth Nosib
- Department of Surgery, Neuroscience Research Group, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
| | - Francisco S Cayabyab
- Department of Surgery, Neuroscience Research Group, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
| |
Collapse
|
34
|
Garnett JP, Hickman E, Tunkamnerdthai O, Cuthbert AW, Gray MA. Protein phosphatase 1 coordinates CFTR-dependent airway epithelial HCO3- secretion by reciprocal regulation of apical and basolateral membrane Cl(-)-HCO3- exchangers. Br J Pharmacol 2015; 168:1946-60. [PMID: 23215877 DOI: 10.1111/bph.12085] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 11/14/2012] [Accepted: 12/01/2012] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND AND PURPOSE Our recent studies on human airway serous-like Calu-3 cells showed that cAMP agonists stimulated a HCO3(-) rich secretion containing up to 80 mM HCO3(-). This alkaline secretion relied on a coordinated switch in the activity of distinct Cl(-)-HCO3(-) anion exchangers (AE) located at different regions of the cell. At the apical membrane, cAMP agonists activated the electroneutral AE pendrin (SLC26A4), together with cystic fibrosis transmembrane conductance regulator (CFTR), while at the basolateral membrane the agonists inhibited AE2 (SLC4A2). However, the underlying mechanism(s) that orchestrates this cAMP-dependent switch in AE activity has not been elucidated. EXPERIMENTAL APPROACH Apical and basolateral Cl(-)-HCO3(-) exchange was assessed by measuring Cl(-)-dependent changes in intracellular pH (pH(i)). KEY RESULTS We show that protein phosphatase 1 (PP1), together with CFTR, play central roles in this reciprocal regulation of AE activity. Activation of pendrin by cAMP agonists, but not inhibition of the basolateral exchanger, was protein kinase A-dependent. Knocking down CFTR expression, or blocking its activity with GlyH-101, led to incomplete inhibition of the basolateral AE by cAMP, supporting a role for CFTR in this process. Addition of the PP1/2A inhibitor, okadaic acid, but not the PP2A specific inhibitor fostreicin, mimicked the effect of cAMP stimulation. Furthermore, okadaic acid-treated Calu-3 monolayers produced a more alkaline fluid than untreated cells, which was comparable with that produced by cAMP stimulation. CONCLUSIONS AND IMPLICATIONS These results identify PP1 as a novel regulator of AE activity which, in concert with CFTR, coordinates events at both apical and basolateral membranes, crucial for efficient HCO3(-) secretion from Calu-3 cells.
Collapse
Affiliation(s)
- James P Garnett
- Institute for Cell & Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
| | | | | | | | | |
Collapse
|
35
|
Yamauchi S, Isozaki Y, Nishiwaki H, Akiyama K. Syntheses of natural 1,3-polyol/α-pyrone and its all stereoisomers to estimate antifungal activities against plant pathogenic fungi. Bioorg Med Chem Lett 2015; 25:2189-92. [PMID: 25872981 DOI: 10.1016/j.bmcl.2015.03.055] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 03/19/2015] [Accepted: 03/20/2015] [Indexed: 11/24/2022]
Abstract
All stereoisomers of 1,3-polyol/α-pyrone 1-8 with more than 99% ee were synthesized to estimate the effect of stereochemistry on the antifungal activity. The absolute configuration of natural compound was determined as (6R,2'S,4'R)-2. The eight stereoisomers showed the antifungal activity against plant pathogenic Alternaria alternata Japanese pear pathotype and Colletotrichum lagenarium. The large difference of activity level was not observed between stereoisomers, showing 43-72% of growth ratio against control at 0.5mM. The most potent stereoisomer was (6S,2'S,4'S)-8 and the activity of (6R,2'S,4'S)-1 was weakest against both fungi.
Collapse
Affiliation(s)
- Satoshi Yamauchi
- Faculty of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime 790-8566, Japan; South Ehime Fisheries Research Center, 1289-1 Funakoshi, Ainan, Ehime 798-4292, Japan.
| | - Yasuyoshi Isozaki
- Faculty of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime 790-8566, Japan
| | - Hisashi Nishiwaki
- Faculty of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime 790-8566, Japan
| | - Koichi Akiyama
- Integrated Center for Sciences, Tarumi Station, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime 790-8566, Japan
| |
Collapse
|
36
|
Kang Q, Srividhya J, Ipe J, Pomerening JR. Evidence toward a dual phosphatase mechanism that restricts Aurora A (Thr-295) phosphorylation during the early embryonic cell cycle. J Biol Chem 2014; 289:17480-96. [PMID: 24825897 DOI: 10.1074/jbc.m113.527622] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The mitotic kinase Aurora A (AurA) is regulated by a complex network of factors that includes co-activator binding, autophosphorylation, and dephosphorylation. Dephosphorylation of AurA by PP2A (human, Ser-51; Xenopus, Ser-53) destabilizes the protein, whereas mitotic dephosphorylation of its T-loop (human, Thr-288; Xenopus, Thr-295) by PP6 represses AurA activity. However, AurA(Thr-295) phosphorylation is restricted throughout the early embryonic cell cycle, not just during M-phase, and how Thr-295 is kept dephosphorylated during interphase and whether or not this mechanism impacts the cell cycle oscillator were unknown. Titration of okadaic acid (OA) or fostriecin into Xenopus early embryonic extract revealed that phosphatase activity other than PP1 continuously suppresses AurA(Thr-295) phosphorylation during the early embryonic cell cycle. Unexpectedly, we observed that inhibiting a phosphatase activity highly sensitive to OA caused an abnormal increase in AurA(Thr-295) phosphorylation late during interphase that corresponded with delayed cyclin-dependent kinase 1 (CDK1) activation. AurA(Thr-295) phosphorylation indeed influenced this timing, because AurA isoforms retaining an intact Thr-295 residue further delayed M-phase entry. Using mathematical modeling, we determined that one phosphatase would be insufficient to restrict AurA phosphorylation and regulate CDK1 activation, whereas a dual phosphatase topology best recapitulated our experimental observations. We propose that two phosphatases target Thr-295 of AurA to prevent premature AurA activation during interphase and that phosphorylated AurA(Thr-295) acts as a competitor substrate with a CDK1-activating phosphatase in late interphase. These results suggest a novel relationship between AurA and protein phosphatases during progression throughout the early embryonic cell cycle and shed new light on potential defects caused by AurA overexpression.
Collapse
Affiliation(s)
- Qing Kang
- From the Department of Biology, Indiana University, Bloomington, Indiana 47405-7003
| | - Jeyaraman Srividhya
- From the Department of Biology, Indiana University, Bloomington, Indiana 47405-7003
| | - Joseph Ipe
- From the Department of Biology, Indiana University, Bloomington, Indiana 47405-7003
| | - Joseph R Pomerening
- From the Department of Biology, Indiana University, Bloomington, Indiana 47405-7003
| |
Collapse
|
37
|
Synthesis and evaluation of (−)-Massoialactone and analogues as potential anticancer and anti-inflammatory agents. Eur J Med Chem 2014; 76:291-300. [DOI: 10.1016/j.ejmech.2014.02.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 01/06/2014] [Accepted: 02/08/2014] [Indexed: 12/31/2022]
|
38
|
Williams BC, Filter JJ, Blake-Hodek KA, Wadzinski BE, Fuda NJ, Shalloway D, Goldberg ML. Greatwall-phosphorylated Endosulfine is both an inhibitor and a substrate of PP2A-B55 heterotrimers. eLife 2014; 3:e01695. [PMID: 24618897 PMCID: PMC3949306 DOI: 10.7554/elife.01695] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 01/30/2014] [Indexed: 11/13/2022] Open
Abstract
During M phase, Endosulfine (Endos) family proteins are phosphorylated by Greatwall kinase (Gwl), and the resultant pEndos inhibits the phosphatase PP2A-B55, which would otherwise prematurely reverse many CDK-driven phosphorylations. We show here that PP2A-B55 is the enzyme responsible for dephosphorylating pEndos during M phase exit. The kinetic parameters for PP2A-B55's action on pEndos are orders of magnitude lower than those for CDK-phosphorylated substrates, suggesting a simple model for PP2A-B55 regulation that we call inhibition by unfair competition. As the name suggests, during M phase PP2A-B55's attention is diverted to pEndos, which binds much more avidly and is dephosphorylated more slowly than other substrates. When Gwl is inactivated during the M phase-to-interphase transition, the dynamic balance changes: pEndos dephosphorylated by PP2A-B55 cannot be replaced, so the phosphatase can refocus its attention on CDK-phosphorylated substrates. This mechanism explains simultaneously how PP2A-B55 and Gwl together regulate pEndos, and how pEndos controls PP2A-B55. DOI: http://dx.doi.org/10.7554/eLife.01695.001.
Collapse
Affiliation(s)
- Byron C Williams
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, United States
| | - Joshua J Filter
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, United States
| | | | - Brian E Wadzinski
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, United States
| | - Nicholas J Fuda
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, United States
| | - David Shalloway
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, United States
| | - Michael L Goldberg
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, United States
| |
Collapse
|
39
|
Amsailale R, Beyaert M, Smal C, Janssens V, Van Den Neste E, Bontemps F. Protein phosphatase 2A regulates deoxycytidine kinase activityviaSer-74 dephosphorylation. FEBS Lett 2014; 588:727-32. [DOI: 10.1016/j.febslet.2014.01.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 12/10/2013] [Accepted: 01/08/2014] [Indexed: 10/25/2022]
|
40
|
Bernsmeier C, Calabrese D, Heim MH, Duong HTF. Hepatitis C virus dysregulates glucose homeostasis by a dual mechanism involving induction of PGC1α and dephosphorylation of FoxO1. J Viral Hepat 2014; 21:9-18. [PMID: 24329853 DOI: 10.1111/jvh.12208] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 10/15/2013] [Indexed: 12/11/2022]
Abstract
The maintenance of glucose homeostasis is a complex process in which the insulin signalling pathway plays a major role. Disruption of insulin-regulated glucose homeostasis is frequently observed in chronic hepatitis C (CHC) infection and might potentially contribute to type 2 diabetes mellitus (T2DM) development. Presently, the mechanism that links HCV infection to insulin resistance remains unclear. Previously, we have reported that HCV protein expression in HCV transgenic mice (B6HCV) leads to an overexpression of protein phosphatase 2A (PP2A) through an ER stress response. In the present work, we describe an association of FoxO1 hypophosphorylation and upregulation of both PGC-1α and G6Pase to phenotypic hyperglycaemia and insulin resistance in B6HCV mice. In vitro, we observed that PGC1α is concomitantly induced with PP2A. Moreover, we show that the enhanced PP2A expression is sufficient to inhibit insulin-induced FoxO1 phosphorylation via blockade of insulin-mediated Akt activation or/and through direct association and dephosphorylation of pS-FoxO1. Consequently, we found that the gluconeogenic gene glucose-6-phosphatase is upregulated. These observations were confirmed in liver biopsies obtained from CHC patients. In summary, our results show that HCV-mediated upregulation of PP2A catalytic subunit alters signalling pathways that control hepatic glucose homeostasis by inhibiting Akt and dephosphorylation of FoxO1.
Collapse
Affiliation(s)
- C Bernsmeier
- Department of Biomedicine, University and University Hospital Basel, Basel, Switzerland; Division of Gastroenterology and Hepatology, University of Basel, Basel, Switzerland
| | | | | | | |
Collapse
|
41
|
TNF-α downregulates inhibitory neurotransmission through protein phosphatase 1-dependent trafficking of GABA(A) receptors. J Neurosci 2013; 33:15879-93. [PMID: 24089494 DOI: 10.1523/jneurosci.0530-13.2013] [Citation(s) in RCA: 166] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Inflammation has been implicated in the progression of neurological disease, yet precisely how inflammation affects neuronal function remains unclear. Tumor necrosis factor-α (TNFα) is a proinflammatory cytokine that regulates synapse function by controlling neurotransmitter receptor trafficking and homeostatic synaptic plasticity. Here we characterize the mechanisms through which TNFα regulates inhibitory synapse function in mature rat and mouse hippocampal neurons. Acute application of TNFα induces a rapid and persistent decrease of inhibitory synaptic strength and downregulation of cell-surface levels of GABA(A)Rs containing α1, α2, β2/3, and γ2 subunits. We show that trafficking of GABA(A)Rs in response to TNFα is mediated by neuronally expressed TNF receptor 1 and requires activation of p38 MAPK, phosphatidylinositol 3-kinase, protein phosphatase 1 (PP1), and dynamin GTPase. Furthermore, TNFα enhances the association of PP1 with GABA(A)R β3 subunits and dephosphorylates a site on β3 known to regulate phospho-dependent interactions with the endocytic machinery. Conversely, we find that calcineurin and PP2A are not essential components of the signaling pathway and that clustering of the scaffolding protein gephyrin is only reduced after the initial receptor endocytosis. Together, these findings demonstrate a distinct mechanism of regulated GABA(A)R endocytosis that may contribute to the disruption of circuit homeostasis under neuroinflammatory conditions.
Collapse
|
42
|
Zhang M, Yogesha SD, Mayfield JE, Gill GN, Zhang Y. Viewing serine/threonine protein phosphatases through the eyes of drug designers. FEBS J 2013; 280:4739-60. [PMID: 23937612 DOI: 10.1111/febs.12481] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 07/03/2013] [Accepted: 08/02/2013] [Indexed: 01/04/2023]
Abstract
Protein phosphatases, as the counterpart to protein kinases, are essential for homeostatic balance of cell signaling. Small chemical compounds that modulate the specific activity of phosphatases can be powerful tools to elucidate the biological functions of these enzymes. More importantly, many phosphatases are central players in the development of pathological pathways where inactivation can reverse or delay the onset of human diseases. Therefore, potent inhibitors for such phosphatases can be of great therapeutic benefit. In contrast to the seemingly identical enzymatic mechanism and structural characterization of eukaryotic protein kinases, protein phosphatases evolved from diverse ancestors, resulting in different domain architectures, reaction mechanisms and active site properties. In this review, we discuss for each family of serine/threonine protein phosphatases their involvement in biological processes and corresponding strategies for small chemical intervention. Recent advances in modern drug discovery technologies have markedly facilitated the identification of selective inhibitors for some members of the phosphatase family. Furthermore, the rapid growth in knowledge about structure-activity relationships related to possible new drug targets has aided the discovery of natural product inhibitors for the phosphatase family. This review summarizes the current state of investigation of the small molecules that regulate the function of serine/threonine phosphatases, the challenges presented and also strategies to overcome these obstacles.
Collapse
Affiliation(s)
- Mengmeng Zhang
- Department of Chemistry and Biochemistry, University of Texas at Austin, TX, USA
| | | | | | | | | |
Collapse
|
43
|
Rossi R, Bellina F, Lessi M, Manzini C. Development and applications of highly selective palladium-catalyzed monocoupling reactions of (cyclo)alkenes and 1,3-alkadienes bearing two or three electrophilic sites and bis(enol triflates) with terminal alkynes. Tetrahedron 2013. [DOI: 10.1016/j.tet.2013.06.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
|
44
|
Shanker V, Trincucci G, Heim HM, Duong HTF. Protein phosphatase 2A impairs IFNα-induced antiviral activity against the hepatitis C virus through the inhibition of STAT1 tyrosine phosphorylation. J Viral Hepat 2013; 20:612-21. [PMID: 23910645 DOI: 10.1111/jvh.12083] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 01/01/2013] [Indexed: 02/03/2023]
Abstract
Mammalian cells have developed several mechanisms to sense viruses and initiate adequate responses such as production of interferons. Interferons activate the antiviral response through the Jak-STAT signalling pathway. To establish a chronic infection, viruses need to counteract this barrier of defence. The hepatitis C and hepatitis B viruses are known to up-regulate the expression of protein phosphatase 2A (PP2A). In this study, we show that PP2Ac associates with Jak1/Tyk2/STAT1 and reduces Jak1/Tyk2/STAT1 phosphorylation resulting in an impairment of the IFNα-induced HCV antiviral response. Using the fully infectious HCV cell culture system (HCVcc), we demonstrate that the PP2A catalytic activity is not required to block the antiviral effect of IFNα, although it is needed to support HCVcc replication. Our data suggest an important contribution of virus-induced PP2Ac up-regulation in the establishment of a chronic infection.
Collapse
Affiliation(s)
- V Shanker
- Department of Biomedicine, University and University Hospital Basel, Basel, Switzerland
| | | | | | | |
Collapse
|
45
|
Kása A, Czikora I, Verin AD, Gergely P, Csortos C. Protein phosphatase 2A activity is required for functional adherent junctions in endothelial cells. Microvasc Res 2013; 89:86-94. [PMID: 23721711 DOI: 10.1016/j.mvr.2013.05.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 05/13/2013] [Accepted: 05/18/2013] [Indexed: 11/30/2022]
Abstract
Reversible Ser/Thr phosphorylation of cytoskeletal and adherent junction (AJ) proteins has a critical role in the regulation of endothelial cell (EC) barrier function. We have demonstrated earlier that protein phosphatase 2A (PP2A) activity is important in EC barrier integrity. In the present work, macro- and microvascular EC were examined and we provided further evidence on the significance of PP2A in the maintenance of EC cytoskeleton and barrier function with special focus on the Bα (regulatory) subunit of PP2A. Immunofluorescent staining revealed that the inhibition of PP2A results in changes in the organization of EC cytoskeleton as microtubule dissolution and actin re-arrangement were detected. Depletion of Bα regulatory subunit of PP2A had similar effect on the cytoskeleton structure of the cells. Furthermore, transendothelial electric resistance measurements demonstrated significantly slower barrier recovery of Bα depleted EC after thrombin treatment. AJ proteins, VE-cadherin and β-catenin, were detected along with Bα in pull-down assay. Also, the inhibition of PP2A (by okadaic acid or fostriecin) or depletion of Bα caused β-catenin translocation from the membrane to the cytoplasm in parallel with its phosphorylation on Ser552. In conclusion, our data suggest that the A/Bα/C holoenzyme form of PP2A is essential in EC barrier integrity both in micro- and macrovascular EC.
Collapse
Affiliation(s)
- Anita Kása
- Department of Medical Chemistry, University of Debrecen Medical and Health Science Center, Debrecen H-4032, Egyetem tér 1., Hungary
| | | | | | | | | |
Collapse
|
46
|
Theobald B, Bonness K, Musiyenko A, Andrews JF, Urban G, Huang X, Dean NM, Honkanen RE. Suppression of Ser/Thr phosphatase 4 (PP4C/PPP4C) mimics a novel post-mitotic action of fostriecin, producing mitotic slippage followed by tetraploid cell death. Mol Cancer Res 2013; 11:845-55. [PMID: 23671329 DOI: 10.1158/1541-7786.mcr-13-0032] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
UNLABELLED Fostriecin is a natural product purified from Sterptomyces extracts with antitumor activity sufficient to warrant human clinical trials. Unfortunately, difficulties associated with supply and stable drug formulation stalled further development. At a molecular level, fostriecin is known to act as a catalytic inhibitor of four PPP-family phosphatases, and reports describing the design of molecules in this class suggest derivatives targeting enzymes within the fostriecin-sensitive subfamily can be successful. However, it is not clear if the tumor-selective cytotoxicity of fostriecin results from the inhibition of a specific phosphatase, multiple phosphatases, or a limited subset of fostriecin sensitive phosphatases. How the inhibition of sensitive phosphatases contributes to tumor-selective cytotoxicity is also not clear. Here, high-content time-lapse imaging of live cells revealed novel insight into the cellular actions of fostriecin, showing that fostriecin-induced apoptosis is not simply induced following a sustained mitotic arrest. Rather, apoptosis occurred in an apparent second interphase produced when tetraploid cells undergo mitotic slippage. Comparison of the actions of fostriecin and antisense-oligonucleotides specifically targeting human fostriecin-sensitive phosphatases revealed that the suppression PP4C alone is sufficient to mimic many actions of fostriecin. Importantly, targeted suppression of PP4C induced apoptosis, with death occurring in tetraploid cells following mitotic slippage. This effect was not observed following the suppression of PP1C, PP2AC, or PP5C. These data clarify PP4C as a fostriecin-sensitive phosphatase and demonstrate that the suppression of PP4C triggers mitotic slippage/apoptosis. IMPLICATIONS Future development of fostriecin class inhibitors should consider PP4C as a potentially important target. Mol Cancer Res; 11(8); 845-55. ©2013 AACR.
Collapse
Affiliation(s)
- Benjamin Theobald
- Department of Biochemistry and Molecular Biology, MSB 2362, University of South Alabama, Mobile, AL 36688, USA
| | | | | | | | | | | | | | | |
Collapse
|
47
|
Liu XJ, Kong RX, Niu MS, Qiu RG, Tang L. Identification of the post-polyketide synthase modification enzymes for fostriecin biosynthesis in Streptomyces pulveraceus. JOURNAL OF NATURAL PRODUCTS 2013; 76:524-529. [PMID: 23586868 DOI: 10.1021/np300667r] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Fostriecin (FST, 1) is a natural product with promising antitumor activity produced by Streptomyces pulveraceus. Its antitumor activity is associated with the selective inhibition of protein phosphatase activities. The biosynthetic gene cluster for FST has recently been cloned and sequenced. To better understand the post-polyketide synthase (PKS) modification steps in the biosynthetic pathway of FST, we constructed and characterized three post-PKS modification gene mutants of fosG, fosK, and fosM by knockout inactivation in S. pulveraceus. As a result, we determined that a fosK-encoded cytochrome P450 monooxygenase is responsible for C-18 hydroxylation, formation of an unsaturated lactone is dependent upon FosM, and the fosG gene product is involved in hydroxylation at C-4 after the action of FosM to yield PD 113,271 from FST. The accumulated analogues from the ΔfosK and ΔfosM mutant strains possessed a malonyl ester moiety that suggested that all the post-PKS modification steps in FST biosynthesis occur with the polyketide chain bearing a malonyl ester at the C-3 position, with formation of the unsaturated six-membered lactone as the last step in FST biosynthesis.
Collapse
Affiliation(s)
- Xue-Jiao Liu
- Research Center for Molecular Medicine, Faculty of Chemical, Environmental and Biological Science and Technology, Dalian University of Technology, Dalian 116024, People's Republic of China
| | | | | | | | | |
Collapse
|
48
|
Arrouss I, Nemati F, Roncal F, Wislez M, Dorgham K, Vallerand D, Rabbe N, Karboul N, Carlotti F, Bravo J, Mazier D, Decaudin D, Rebollo A. Specific targeting of caspase-9/PP2A interaction as potential new anti-cancer therapy. PLoS One 2013; 8:e60816. [PMID: 23637769 PMCID: PMC3634037 DOI: 10.1371/journal.pone.0060816] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 03/03/2013] [Indexed: 01/02/2023] Open
Abstract
PURPOSE PP2A is a serine/threonine phosphatase critical to physiological processes, including apoptosis. Cell penetrating peptides are molecules that can translocate into cells without causing membrane damage. Our goal was to develop cell-penetrating fusion peptides specifically designed to disrupt the caspase-9/PP2A interaction and evaluate their therapeutic potential in vitro and in vivo. EXPERIMENTAL DESIGN We generated a peptide containing a penetrating sequence associated to the interaction motif between human caspase-9 and PP2A (DPT-C9h), in order to target their association. Using tumour cell lines, primary human cells and primary human breast cancer (BC) xenografts, we investigated the capacity of DPT-C9h to provoke apoptosis in vitro and inhibition of tumour growth (TGI) in vivo. DPT-C9h was intraperitoneally administered at doses from 1 to 25 mg/kg/day for 5 weeks. Relative Tumour Volume (RTV) was calculated. RESULTS We demonstrated that DPT-C9h specifically target caspase-9/PP2A interaction in vitro and in vivo and induced caspase-9-dependent apoptosis in cancer cell lines. DPT-C9h also induced significant TGI in BC xenografts models. The mouse-specific peptide DPT-C9 also induced TGI in lung (K-Ras model) and breast cancer (PyMT) models. DPT-C9h has a specific effect on transformed B cells isolated from chronic lymphocytic leukemia patients without any effect on primary healthy cells. Finally, neither toxicity nor immunogenic responses were observed. CONCLUSION Using the cell-penetrating peptides blocking caspase-9/PP2A interactions, we have demonstrated that DPT-C9h had a strong therapeutic effect in vitro and in vivo in mouse models of tumour progression.
Collapse
Affiliation(s)
- Issam Arrouss
- Inserm UMRS 945, Hôpital Pitié Salpêtrière, Université Pierre et Marie Curie, Paris, France
| | - Fariba Nemati
- Laboratory of Preclinical Investigation, Translational Research Department, Institut Curie, Paris, France
| | - Fernando Roncal
- Centro Nacional de Biotecnologia, Campus de Cantoblanco, Universidad Autónoma de Madrid, Madrid, Spain
| | - Marie Wislez
- URF Pierre et Marie Curie, Hôpital Tenon, Paris, France
| | - Karim Dorgham
- Inserm UMRS 945, Hôpital Pitié Salpêtrière, Université Pierre et Marie Curie, Paris, France
| | - David Vallerand
- Laboratory of Preclinical Investigation, Translational Research Department, Institut Curie, Paris, France
| | | | - Narjesse Karboul
- Laboratory of Preclinical Investigation, Translational Research Department, Institut Curie, Paris, France
| | - Françoise Carlotti
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Jeronimo Bravo
- Instituto de Biomedicina de Valencia, Consejo Superior de Investigaciones Cientificas, Valencia, Spain
| | - Dominique Mazier
- Inserm UMRS 945, Hôpital Pitié Salpêtrière, Université Pierre et Marie Curie, Paris, France
| | - Didier Decaudin
- Laboratory of Preclinical Investigation, Translational Research Department, Institut Curie, Paris, France
- Department of Medical Oncology, Institut Curie, Paris, France
| | - Angelita Rebollo
- Inserm UMRS 945, Hôpital Pitié Salpêtrière, Université Pierre et Marie Curie, Paris, France
| |
Collapse
|
49
|
Suh YH, Park JY, Park S, Jou I, Roche PA, Roche KW. Regulation of metabotropic glutamate receptor 7 (mGluR7) internalization and surface expression by Ser/Thr protein phosphatase 1. J Biol Chem 2013; 288:17544-51. [PMID: 23612982 DOI: 10.1074/jbc.m112.439513] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The metabotropic glutamate receptor type 7 (mGluR7) is the predominant group III mGluR in the presynaptic active zone, where it serves as an autoreceptor to inhibit neurotransmitter release. Our previous studies show that PKC phosphorylation of mGluR7 on Ser-862 is a key mechanism controlling constitutive and activity-dependent surface expression of mGluR7 by regulating a competitive interaction of calmodulin and protein interacting with C kinase (PICK1). As receptor phosphorylation and dephosphorylation are tightly coordinated through the precise action of protein kinases and phosphatases, dephosphorylation by phosphatases is likely to play an active role in governing the activity-dependent or agonist-induced changes in mGluR7 receptor surface expression. In the present study, we find that the serine/threonine protein phosphatase 1 (PP1) has a crucial role in the constitutive and agonist-induced dephosphorylation of Ser-862 on mGluR7. Treatment of neurons with PP1 inhibitors leads to a robust increase in Ser-862 phosphorylation and increased surface expression of mGluR7. In addition, Ser-862 phosphorylation of both mGluR7a and mGluR7b is a target of PP1. Interestingly, agonist-induced dephosphorylation of mGluR7 is regulated by PP1, whereas NMDA-mediated activity-induced dephosphorylation is not, illustrating there are multiple signaling pathways that affect receptor phosphorylation and trafficking. Importantly, PP1γ1 regulates agonist-dependent Ser-862 dephosphorylation and surface expression of mGluR7.
Collapse
Affiliation(s)
- Young Ho Suh
- Department of Pharmacology and Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon 443-721, South Korea.
| | | | | | | | | | | |
Collapse
|
50
|
Kong R, Liu X, Su C, Ma C, Qiu R, Tang L. Elucidation of the Biosynthetic Gene Cluster and the Post-PKS Modification Mechanism for Fostriecin in Streptomyces pulveraceus. ACTA ACUST UNITED AC 2013; 20:45-54. [DOI: 10.1016/j.chembiol.2012.10.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 09/05/2012] [Accepted: 10/25/2012] [Indexed: 11/26/2022]
|