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Nadel G, Yao Z, Hacohen-Lev-Ran A, Wainstein E, Maik-Rachline G, Ziv T, Naor Z, Admon A, Seger R. Phosphorylation of PP2Ac by PKC is a key regulatory step in the PP2A-switch-dependent AKT dephosphorylation that leads to apoptosis. Cell Commun Signal 2024; 22:154. [PMID: 38419089 PMCID: PMC10900696 DOI: 10.1186/s12964-024-01536-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 02/17/2024] [Indexed: 03/02/2024] Open
Abstract
BACKGROUND Although GqPCR activation often leads to cell survival by activating the PI3K/AKT pathway, it was previously shown that in several cell types AKT activity is reduced and leads to JNK activation and apoptosis. The mechanism of AKT inactivation in these cells involves an IGBP1-coupled PP2Ac switch that induces the dephosphorylation and inactivation of both PI3K and AKT. However, the machinery involved in the initiation of PP2A switch is not known. METHODS We used phospho-mass spectrometry to identify the phosphorylation site of PP2Ac, and raised specific antibodies to follow the regulation of this phosphorylation. Other phosphorylations were monitored by commercial antibodies. In addition, we used coimmunoprecipitation and proximity ligation assays to follow protein-protein interactions. Apoptosis was detected by a TUNEL assay as well as PARP1 cleavage using SDS-PAGE and Western blotting. RESULTS We identified Ser24 as a phosphorylation site in PP2Ac. The phosphorylation is mediated mainly by classical PKCs (PKCα and PKCβ) but not by novel PKCs (PKCδ and PKCε). By replacing the phosphorylated residue with either unphosphorylatable or phosphomimetic residues (S24A and S24E), we found that this phosphorylation event is necessary and sufficient to mediate the PP2A switch, which ultimately induces AKT inactivation, and a robust JNK-dependent apoptosis. CONCLUSION Our results show that the PP2A switch is induced by PKC-mediated phosphorylation of Ser24-PP2Ac and that this phosphorylation leads to apoptosis upon GqPCR induction of various cells. We propose that this mechanism may provide an unexpected way to treat some cancer types or problems in the endocrine machinery.
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Affiliation(s)
- Guy Nadel
- Department of Immunology and Regenerative Biology, the Weizmann Institute of Science, Rehovot, Israel
| | - Zhong Yao
- Department of Immunology and Regenerative Biology, the Weizmann Institute of Science, Rehovot, Israel
| | - Avital Hacohen-Lev-Ran
- Department of Immunology and Regenerative Biology, the Weizmann Institute of Science, Rehovot, Israel
| | - Ehud Wainstein
- Department of Immunology and Regenerative Biology, the Weizmann Institute of Science, Rehovot, Israel
| | - Galia Maik-Rachline
- Department of Immunology and Regenerative Biology, the Weizmann Institute of Science, Rehovot, Israel
| | - Tamar Ziv
- Smoler Proteomic Center, Technion-Israel Institute of Technology, Haifa, Israel
| | - Zvi Naor
- Department of Biochemistry and Molecular Biology, Tel Aviv University, Tel Aviv, Israel
| | - Arie Admon
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Rony Seger
- Department of Immunology and Regenerative Biology, the Weizmann Institute of Science, Rehovot, Israel.
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2
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Herting JR, König JH, Hadova K, Heinick A, Müller FU, Pauls P, Seidl MD, Soppa C, Kirchhefer U. Hypercontractile cardiac phenotype in mice overexpressing the regulatory subunit PR72 of protein phosphatase 2A. Front Cardiovasc Med 2023; 10:1239555. [PMID: 37868783 PMCID: PMC10590119 DOI: 10.3389/fcvm.2023.1239555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 09/22/2023] [Indexed: 10/24/2023] Open
Abstract
Background The activity, localization, and substrate specificity of the protein phosphatase 2A (PP2A) heterotrimer are controlled by various regulatory B subunits. PR72 belongs to the B'' gene family and has been shown to be upregulated in human heart failure. However, little is known about the functions of PR72 in the myocardium. Methods To address this issue, we generated a transgenic mouse model with heart-specific overexpression of PP2A-PR72. Biochemical and physiological methods were used to determine contractility, Ca2+ cycling parameters, and protein phosphorylation. Results A 2.5-fold increase in PR72 expression resulted in moderate cardiac hypertrophy. Maximal ventricular pressure was increased in catheterized transgenic mice (TG) compared to wild-type (WT) littermates. This was accompanied by an increased shortening of sarcomere length and faster relaxation at the single-cell level in TG. In parallel with these findings, the peak amplitude of Ca2+ transients was increased, and the decay in intracellular Ca2+ levels was shortened in TG compared to WT. The changes in Ca2+ cycling in TG were also evident from an increase in the full duration and width at half maximum of Ca2+ sparks. Consistent with the contractile data, phosphorylation of phospholamban at threonine-17 was higher in TG hearts. The lower expression of the Na+/Ca2+ exchanger may also contribute to the hypercontractile state in transgenic myocardium. Conclusion Our results suggest that PP2A-PR72 plays an important role in regulating cardiac contractile function and Ca2+ cycling, indicating that the upregulation of PR72 in heart failure is an attempt to compensate functionally.
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Affiliation(s)
- Julius R. Herting
- Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, Universität Münster, Münster, Germany
| | - Jule H. König
- Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, Universität Münster, Münster, Germany
| | - Katarina Hadova
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Comenius University in Bratislava, Bratislava, Slovakia
| | - Alexander Heinick
- Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, Universität Münster, Münster, Germany
| | - Frank U. Müller
- Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, Universität Münster, Münster, Germany
| | - Paul Pauls
- Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, Universität Münster, Münster, Germany
| | - Matthias D. Seidl
- Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, Universität Münster, Münster, Germany
| | - Carolina Soppa
- Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, Universität Münster, Münster, Germany
| | - Uwe Kirchhefer
- Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, Universität Münster, Münster, Germany
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3
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Peris I, Romero-Murillo S, Vicente C, Narla G, Odero MD. Regulation and role of the PP2A-B56 holoenzyme family in cancer. Biochim Biophys Acta Rev Cancer 2023; 1878:188953. [PMID: 37437699 DOI: 10.1016/j.bbcan.2023.188953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 07/07/2023] [Accepted: 07/08/2023] [Indexed: 07/14/2023]
Abstract
Protein phosphatase 2A (PP2A) inactivation is common in cancer, leading to sustained activation of pro-survival and growth-promoting pathways. PP2A consists of a scaffolding A-subunit, a catalytic C-subunit, and a regulatory B-subunit. The functional complexity of PP2A holoenzymes arises mainly through the vast repertoire of regulatory B-subunits, which determine both their substrate specificity and their subcellular localization. Therefore, a major challenge for developing more effective therapeutic strategies for cancer is to identify the specific PP2A complexes to be targeted. Of note, the development of small molecules specifically directed at PP2A-B56α has opened new therapeutic avenues in both solid and hematological tumors. Here, we focus on the B56/PR61 family of PP2A regulatory subunits, which have a central role in directing PP2A tumor suppressor activity. We provide an overview of the mechanisms controlling the formation and regulation of these complexes, the pathways they control, and the mechanisms underlying their deregulation in cancer.
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Affiliation(s)
- Irene Peris
- Department of Biochemistry and Genetics, University of Navarra, Pamplona, Spain; Centro de Investigación Médica Aplicada (CIMA), University of Navarra, Pamplona, Spain; Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain.
| | - Silvia Romero-Murillo
- Department of Biochemistry and Genetics, University of Navarra, Pamplona, Spain; Centro de Investigación Médica Aplicada (CIMA), University of Navarra, Pamplona, Spain
| | - Carmen Vicente
- Centro de Investigación Médica Aplicada (CIMA), University of Navarra, Pamplona, Spain; Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
| | - Goutham Narla
- Division of Genetic Medicine, Department of Internal Medicine, The University of Michigan Medical School, Ann Arbor, MI, USA
| | - Maria D Odero
- Department of Biochemistry and Genetics, University of Navarra, Pamplona, Spain; Centro de Investigación Médica Aplicada (CIMA), University of Navarra, Pamplona, Spain; Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain; CIBERONC, Instituto de Salud Carlos III, Madrid, Spain.
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4
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Vertyshev AY, Akberdin IR, Kolpakov FA. Numerous Trigger-like Interactions of Kinases/Protein Phosphatases in Human Skeletal Muscles Can Underlie Transient Processes in Activation of Signaling Pathways during Exercise. Int J Mol Sci 2023; 24:11223. [PMID: 37446402 DOI: 10.3390/ijms241311223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 07/03/2023] [Accepted: 07/05/2023] [Indexed: 07/15/2023] Open
Abstract
Optimizing physical training regimens to increase muscle aerobic capacity requires an understanding of the internal processes that occur during exercise that initiate subsequent adaptation. During exercise, muscle cells undergo a series of metabolic events that trigger downstream signaling pathways and induce the expression of many genes in working muscle fibers. There are a number of studies that show the dependence of changes in the activity of AMP-activated protein kinase (AMPK), one of the mediators of cellular signaling pathways, on the duration and intensity of single exercises. The activity of various AMPK isoforms can change in different directions, increasing for some isoforms and decreasing for others, depending on the intensity and duration of the load. This review summarizes research data on changes in the activity of AMPK, Ca2+/calmodulin-dependent protein kinase II (CaMKII), and other components of the signaling pathways in skeletal muscles during exercise. Based on these data, we hypothesize that the observed changes in AMPK activity may be largely related to metabolic and signaling transients rather than exercise intensity per se. Probably, the main events associated with these transients occur at the beginning of the exercise in a time window of about 1-10 min. We hypothesize that these transients may be partly due to putative trigger-like kinase/protein phosphatase interactions regulated by feedback loops. In addition, numerous dynamically changing factors, such as [Ca2+], metabolite concentration, and reactive oxygen and nitrogen species (RONS), can shift the switching thresholds and change the states of these triggers, thereby affecting the activity of kinases (in particular, AMPK and CaMKII) and phosphatases. The review considers the putative molecular mechanisms underlying trigger-like interactions. The proposed hypothesis allows for a reinterpretation of the experimental data available in the literature as well as the generation of ideas to optimize future training regimens.
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Affiliation(s)
| | - Ilya R Akberdin
- Department of Computational Biology, Scientific Center for Information Technologies and Artificial Intelligence, Sirius University of Science and Technology, 354340 Sochi, Russia
- Biosoft.Ru, Ltd., 630058 Novosibirsk, Russia
- Department of Natural Sciences, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Fedor A Kolpakov
- Department of Computational Biology, Scientific Center for Information Technologies and Artificial Intelligence, Sirius University of Science and Technology, 354340 Sochi, Russia
- Biosoft.Ru, Ltd., 630058 Novosibirsk, Russia
- Federal Research Center for Information and Computational Technologies, 630090 Novosibirsk, Russia
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Zheng J, Wang Y, Liu Y, Han S, Zhang Y, Luo Y, Yan Y, Li J, Zhao L. cPKCγ Deficiency Exacerbates Autophagy Impairment and Hyperphosphorylated Tau Buildup through the AMPK/mTOR Pathway in Mice with Type 1 Diabetes Mellitus. Neurosci Bull 2022; 38:1153-1169. [PMID: 35596894 PMCID: PMC9554100 DOI: 10.1007/s12264-022-00863-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 02/03/2022] [Indexed: 01/26/2023] Open
Abstract
Type 1 diabetes mellitus (T1DM)-induced cognitive dysfunction is common, but its underlying mechanisms are still poorly understood. In this study, we found that knockout of conventional protein kinase C (cPKC)γ significantly increased the phosphorylation of Tau at Ser214 and neurofibrillary tangles, but did not affect the activities of GSK-3β and PP2A in the hippocampal neurons of T1DM mice. cPKCγ deficiency significantly decreased the level of autophagy in the hippocampal neurons of T1DM mice. Activation of autophagy greatly alleviated the cognitive impairment induced by cPKCγ deficiency in T1DM mice. Moreover, cPKCγ deficiency reduced the AMPK phosphorylation levels and increased the phosphorylation levels of mTOR in vivo and in vitro. The high glucose-induced Tau phosphorylation at Ser214 was further increased by the autophagy inhibitor and was significantly decreased by an mTOR inhibitor. In conclusion, these results indicated that cPKCγ promotes autophagy through the AMPK/mTOR signaling pathway, thus reducing the level of phosphorylated Tau at Ser214 and neurofibrillary tangles.
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Affiliation(s)
- Jiayin Zheng
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China
| | - Yue Wang
- The National Clinical Research Center for Mental Disorders & Beijing Key Laboratory of Mental Disorders, Beijing Anding Hospital, Capital Medical University, Beijing, 100088, China
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, 100088, China
| | - Yue Liu
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China
| | - Song Han
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China
| | - Ying Zhang
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China
| | - Yanlin Luo
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China
| | - Yi Yan
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China
| | - Junfa Li
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China.
| | - Li Zhao
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China.
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6
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Glaser D, Heinick A, Herting JR, Massing F, Müller FU, Pauls P, Rozhdestvensky TS, Schulte JS, Seidl MD, Skryabin BV, Stümpel F, Kirchhefer U. Impaired myocellular Ca 2+ cycling in protein phosphatase PP2A-B56α knockout mice is normalized by β-adrenergic stimulation. J Biol Chem 2022; 298:102362. [PMID: 35963431 PMCID: PMC9478386 DOI: 10.1016/j.jbc.2022.102362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 07/25/2022] [Accepted: 07/26/2022] [Indexed: 11/24/2022] Open
Abstract
The activity of protein phosphatase 2A (PP2A) is determined by the expression and localization of the regulatory B-subunits. PP2A-B56α is the dominant isoform of the B′-family in the heart. Its role in regulating the cardiac response to β-adrenergic stimulation is not yet fully understood. We therefore generated mice deficient in B56α to test the functional cardiac effects in response to catecholamine administration versus corresponding WT mice. We found the decrease in basal PP2A activity in hearts of KO mice was accompanied by a counter-regulatory increase in the expression of B′ subunits (β and γ) and higher phosphorylation of sarcoplasmic reticulum Ca2+ regulatory and myofilament proteins. The higher phosphorylation levels were associated with enhanced intraventricular pressure and relaxation in catheterized KO mice. In contrast, at the cellular level, we detected depressed Ca2+ transient and sarcomere shortening parameters in KO mice at basal conditions. Consistently, the peak amplitude of the L-type Ca2+ current was reduced and the inactivation kinetics of ICaL were prolonged in KO cardiomyocytes. However, we show β-adrenergic stimulation resulted in a comparable peak amplitude of Ca2+ transients and myocellular contraction between KO and WT cardiomyocytes. Therefore, we propose higher isoprenaline-induced Ca2+ spark frequencies might facilitate the normalized Ca2+ signaling in KO cardiomyocytes. In addition, the application of isoprenaline was associated with unchanged L-type Ca2+ current parameters between both groups. Our data suggest an important influence of PP2A-B56α on the regulation of Ca2+ signaling and contractility in response to β-adrenergic stimulation in the myocardium.
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Affiliation(s)
- Dennis Glaser
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Alexander Heinick
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Julius R Herting
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Fabian Massing
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Frank U Müller
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Paul Pauls
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Timofey S Rozhdestvensky
- Department of Medicine, Core Facility Transgenic Animal and Genetic Engineering Models (TRAM), University of Münster, Münster, Germany
| | - Jan S Schulte
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Matthias D Seidl
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Boris V Skryabin
- Department of Medicine, Core Facility Transgenic Animal and Genetic Engineering Models (TRAM), University of Münster, Münster, Germany
| | - Frank Stümpel
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Uwe Kirchhefer
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany.
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7
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York NS, Sanchez-Arias JC, McAdam ACH, Rivera JE, Arbour LT, Swayne LA. Mechanisms underlying the role of ankyrin-B in cardiac and neurological health and disease. Front Cardiovasc Med 2022; 9:964675. [PMID: 35990955 PMCID: PMC9386378 DOI: 10.3389/fcvm.2022.964675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 07/11/2022] [Indexed: 11/13/2022] Open
Abstract
The ANK2 gene encodes for ankyrin-B (ANKB), one of 3 members of the ankyrin family of proteins, whose name is derived from the Greek word for anchor. ANKB was originally identified in the brain (B denotes “brain”) but has become most widely known for its role in cardiomyocytes as a scaffolding protein for ion channels and transporters, as well as an interacting protein for structural and signaling proteins. Certain loss-of-function ANK2 variants are associated with a primarily cardiac-presenting autosomal-dominant condition with incomplete penetrance and variable expressivity characterized by a predisposition to supraventricular and ventricular arrhythmias, arrhythmogenic cardiomyopathy, congenital and adult-onset structural heart disease, and sudden death. Another independent group of ANK2 variants are associated with increased risk for distinct neurological phenotypes, including epilepsy and autism spectrum disorders. The mechanisms underlying ANKB's roles in cells in health and disease are not fully understood; however, several clues from a range of molecular and cell biological studies have emerged. Notably, ANKB exhibits several isoforms that have different cell-type–, tissue–, and developmental stage– expression profiles. Given the conservation within ankyrins across evolution, model organism studies have enabled the discovery of several ankyrin roles that could shed important light on ANKB protein-protein interactions in heart and brain cells related to the regulation of cellular polarity, organization, calcium homeostasis, and glucose and fat metabolism. Along with this accumulation of evidence suggesting a diversity of important ANKB cellular functions, there is an on-going debate on the role of ANKB in disease. We currently have limited understanding of how these cellular functions link to disease risk. To this end, this review will examine evidence for the cellular roles of ANKB and the potential contribution of ANKB functional variants to disease risk and presentation. This contribution will highlight the impact of ANKB dysfunction on cardiac and neuronal cells and the significance of understanding the role of ANKB variants in disease.
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Affiliation(s)
- Nicole S. York
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | | | - Alexa C. H. McAdam
- Department of Medical Genetics, University of British Columbia, Victoria, BC, Canada
| | - Joel E. Rivera
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Laura T. Arbour
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Department of Medical Genetics, University of British Columbia, Victoria, BC, Canada
- *Correspondence: Laura T. Arbour
| | - Leigh Anne Swayne
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Department of Cellular and Physiological Sciences and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
- Leigh Anne Swayne
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8
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Cristóbal I, Santos A, Rojo F, García-Foncillas J. The PP2A pathway plays a crucial role in controlling cardiac physiology. Am J Physiol Heart Circ Physiol 2022; 323:H65-H66. [PMID: 35648099 DOI: 10.1152/ajpheart.00203.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Ion Cristóbal
- Cancer Unit for Research on Novel Therapeutic Targets, Oncohealth Institute, IIS-Fundación Jiménez Díaz-UAM, Madrid, Spain.,Translational Oncology Division, Oncohealth Institute, IIS-Fundación Jiménez Díaz-UAM, Madrid, Spain
| | - Andrea Santos
- Cancer Unit for Research on Novel Therapeutic Targets, Oncohealth Institute, IIS-Fundación Jiménez Díaz-UAM, Madrid, Spain.,Translational Oncology Division, Oncohealth Institute, IIS-Fundación Jiménez Díaz-UAM, Madrid, Spain
| | - Federico Rojo
- Pathology Department, IIS-Fundación Jiménez Díaz-UAM, Madrid, Spain
| | - Jesús García-Foncillas
- Translational Oncology Division, Oncohealth Institute, IIS-Fundación Jiménez Díaz-UAM, Madrid, Spain
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9
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Pluteanu F, Kirchhefer U. Reply to Cristóbal et al. Am J Physiol Heart Circ Physiol 2022; 323:H67-H68. [PMID: 35648098 DOI: 10.1152/ajpheart.00236.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 05/16/2022] [Indexed: 11/22/2022]
Affiliation(s)
- Florentina Pluteanu
- Department of Anatomy, Animal Physiology and Biophysics, University of Bucharest, Bucharest, Romania
| | - Uwe Kirchhefer
- Institute of Pharmacology and Toxicology, University of Muenster, Muenster, Germany
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10
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Cullati SN, Chaikuad A, Chen JS, Gebel J, Tesmer L, Zhubi R, Navarrete-Perea J, Guillen RX, Gygi SP, Hummer G, Dötsch V, Knapp S, Gould KL. Kinase domain autophosphorylation rewires the activity and substrate specificity of CK1 enzymes. Mol Cell 2022; 82:2006-2020.e8. [DOI: 10.1016/j.molcel.2022.03.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 01/27/2022] [Accepted: 03/01/2022] [Indexed: 12/01/2022]
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11
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Pluteanu F, Boknik P, Heinick A, König C, Müller FU, Weidlich A, Kirchhefer U. Activation of PKC results in improved contractile effects and Ca cycling by inhibition of PP2A-B56α. Am J Physiol Heart Circ Physiol 2022; 322:H427-H441. [PMID: 35119335 DOI: 10.1152/ajpheart.00539.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Protein phosphatase 2A (PP2A) represents a heterotrimer that is responsible for the dephosphorylation of important regulatory myocardial proteins. The present study was aimed to test whether the phosphorylation of PP2A-B56α at Ser41 by PKC is involved in the regulation of myocyte Ca2+ cycling and contraction. For this purpose, heart preparations of wild-type (WT) and transgenic mice overexpressing the non-phosphorylatable S41A mutant form (TG) were stimulated by administration of the direct PKC activator phorbol 12-myristate 13-acetate (PMA), and functional effects were studied. PKC activation was accompanied by the inhibition of PP2A activity in WT cardiomyocytes, whereas this effect was absent in TG. Consistently, the increase in the sarcomere length shortening and the peak amplitude of Ca2+ transients after PMA administration in WT cardiomyocytes was attenuated in TG. However, the co-stimulation with 1 µM isoprenaline was able to offset these functional deficits. Moreover, TG hearts did not show an increase in the phosphorylation of the myosin-binding protein C after administration of PMA but was detected in corresponding WT. PMA modulated voltage-dependent activation of the L-type Ca2+ channel (LTCC) differently in the two genotypes, shifting V1/2a by +1.5 mV in TG and by 2.4 mV in WT. In the presence of PMA, ICaL inactivation remained unchanged in TG, whereas it was slower in corresponding WT. Our data suggest that PKC-activated enhancement of myocyte contraction and intracellular Ca2+ signaling is mediated by phosphorylation of B56α at Ser41, leading to a decrease in PP2A activity.
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Affiliation(s)
- Florentina Pluteanu
- Department of Anatomy, Animal Physiology and Biophysics, University of Bucharest, Bucharest, Romania
| | - Peter Boknik
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Alexander Heinick
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Christiane König
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Frank U Müller
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Adam Weidlich
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Uwe Kirchhefer
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
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12
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Dörner MF, Boknik P, Köpp F, Buchwalow IB, Neumann J, Gergs U. Mechanisms of Systolic Cardiac Dysfunction in PP2A, PP5 and PP2AxPP5 Double Transgenic Mice. Int J Mol Sci 2021; 22:ijms22179448. [PMID: 34502355 PMCID: PMC8431312 DOI: 10.3390/ijms22179448] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 08/26/2021] [Accepted: 08/26/2021] [Indexed: 12/15/2022] Open
Abstract
As part of our ongoing studies on the potential pathophysiological role of serine/threonine phosphatases (PP) in the mammalian heart, we have generated transgenic mice with cardiac muscle cell-specific overexpression of PP2Acα (PP2A) and PP5 (PP5). For further studies we crossbred PP2A and PP5 mice to obtain PP2AxPP5 double transgenic mice (PP2AxPP5, DT) and compared them with littermate wild-type mice (WT) serving as a control. The mortality of DT mice was greatly enhanced vs. other genotypes. Cardiac fibrosis was noted histologically and mRNA levels of collagen 1α, collagen 3α and fibronectin 1 were augmented in DT. DT and PP2A mice exhibited an increase in relative heart weight. The ejection fraction (EF) was reduced in PP2A and DT but while the EF of PP2A was nearly normalized after β-adrenergic stimulation by isoproterenol, it was almost unchanged in DT. Moreover, left atrial preparations from DT were less sensitive to isoproterenol treatment both under normoxic conditions and after hypoxia. In addition, levels of the hypertrophy markers atrial natriuretic peptide and B-type natriuretic peptide as well as the inflammation markers interleukin 6 and nuclear factor kappa B were increased in DT. PP2A enzyme activity was enhanced in PP2A vs. WT but similar to DT. This was accompanied by a reduced phosphorylation state of phospholamban at serine-16. Fittingly, the relaxation times in left atria from DT were prolonged. In summary, cardiac co-overexpression of PP2A and PP5 were detrimental to animal survival and cardiac function, and the mechanism may involve dephosphorylation of important regulatory proteins but also fibrosis and inflammation.
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Affiliation(s)
- Mara-Francine Dörner
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, D-06097 Halle, Germany; (M.-F.D.); (F.K.); (J.N.)
- Mibe GmbH Arzneimittel, D-06796 Brehna, Germany
| | - Peter Boknik
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Westfälische Wilhelms-Universität, D-48149 Münster, Germany;
| | - Friedrich Köpp
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, D-06097 Halle, Germany; (M.-F.D.); (F.K.); (J.N.)
| | - Igor B. Buchwalow
- Institute for Hematopathology, Fangdieckstr. 75a, D-22547 Hamburg, Germany;
| | - Joachim Neumann
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, D-06097 Halle, Germany; (M.-F.D.); (F.K.); (J.N.)
| | - Ulrich Gergs
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, D-06097 Halle, Germany; (M.-F.D.); (F.K.); (J.N.)
- Correspondence: ; Tel.: +49-345-557-4093
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13
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Lemos Duarte M, Trimbake NA, Gupta A, Tumanut C, Fan X, Woods C, Ram A, Gomes I, Bobeck EN, Schechtman D, Devi LA. High-throughput screening and validation of antibodies against synaptic proteins to explore opioid signaling dynamics. Commun Biol 2021; 4:238. [PMID: 33619305 PMCID: PMC7900253 DOI: 10.1038/s42003-021-01744-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Accepted: 11/13/2020] [Indexed: 12/12/2022] Open
Abstract
Antibodies represent powerful tools to examine signal transduction pathways. Here, we present a strategy integrating multiple state-of-the-art methods to produce, validate, and utilize antibodies. Focusing on understudied synaptic proteins, we generated 137 recombinant antibodies. We used yeast display antibody libraries from the B cells of immunized rabbits, followed by FACS sorting under stringent conditions to identify high affinity antibodies. The antibodies were validated by high-throughput functional screening, and genome editing. Next, we explored the temporal dynamics of signaling in single cells. A subset of antibodies targeting opioid receptors were used to examine the effect of treatment with opiates that have played central roles in the worsening of the 'opioid epidemic.' We show that morphine and fentanyl exhibit differential temporal dynamics of receptor phosphorylation. In summary, high-throughput approaches can lead to the identification of antibody-based tools required for an in-depth understanding of the temporal dynamics of opioid signaling.
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Affiliation(s)
- Mariana Lemos Duarte
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1603, New York City, NY, 10029, USA
| | - Nikita A Trimbake
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1603, New York City, NY, 10029, USA
- Regeneron Pharmaceutical, 777 Old Saw Mill River Rd, Tarrytown, NY, 10591, USA
| | - Achla Gupta
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1603, New York City, NY, 10029, USA
| | | | - Xiaomin Fan
- AvantGen Inc., 6162 Nancy Ridge Dr #150, San Diego, CA, 92121, USA
| | - Catherine Woods
- AvantGen Inc., 6162 Nancy Ridge Dr #150, San Diego, CA, 92121, USA
| | - Akila Ram
- Department of Biology, Utah State University, Logan, UT, 84322, USA
| | - Ivone Gomes
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1603, New York City, NY, 10029, USA
| | - Erin N Bobeck
- Department of Biology, Utah State University, Logan, UT, 84322, USA
| | - Deborah Schechtman
- Department of Biochemistry, University of São Paulo, 748 Av Prof Lineu Prestes, room 1208 Cidade Universitaria, São Paulo, SP, 05508000, Brazil
| | - Lakshmi A Devi
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1603, New York City, NY, 10029, USA.
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14
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Bollmann P, Werner F, Jaron M, Bruns TA, Wache H, Runte J, Boknik P, Kirchhefer U, Müller FU, Buchwalow IB, Rothemund S, Neumann J, Gergs U. Initial Characterization of Stressed Transgenic Mice With Cardiomyocyte-Specific Overexpression of Protein Phosphatase 2C. Front Pharmacol 2021; 11:591773. [PMID: 33597873 PMCID: PMC7883593 DOI: 10.3389/fphar.2020.591773] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 12/07/2020] [Indexed: 12/17/2022] Open
Abstract
As part of our ongoing studies on the potential pathophysiological role of serine/threonine phosphatases (PP) in the mammalian heart, we have generated mice with cardiac-specific overexpression of PP2Cβ (PP2C-TG) and compared them with littermate wild type mice (WT) serving as a control. Cardiac fibrosis was noted histologically in PP2C-TG. Collagen 1a, interleukin-6 and the natriuretic peptides ANP and BNP were augmented in PP2C-TG vs. WT (p < 0.05). Left atrial preparations from PP2C-TG were less resistant to hypoxia than atria from WT. PP2C-TG maintained cardiac function after the injection of lipopolysaccharide (LPS, a model of sepsis) and chronic isoproterenol treatment (a model of heart failure) better than WT. Crossbreeding of PP2C-TG mice with PP2A-TG mice (a genetic model of heart failure) resulted in double transgenic (DT) mice that exhibited a pronounced increase of heart weight in contrast to the mild hypertrophy noted in the mono-transgenic mice. The ejection fraction was reduced in PP2C-TG and in PP2A-TG mice compared with WT, but the reduction was the highest in DT compared with WT. PP2A enzyme activity was enhanced in PP2A-TG and DT mice compared with WT and PP2C-TG mice. In summary, cardiac overexpression of PP2Cβ and co-overexpression of both the catalytic subunit of PP2A and PP2Cβ were detrimental to cardiac function. PP2Cβ overexpression made cardiac preparations less resistant to hypoxia than WT, leading to fibrosis, but PP2Cβ overexpression led to better adaptation to some stressors, such as LPS or chronic β-adrenergic stimulation. Hence, the effect of PP2Cβ is context sensitive.
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Affiliation(s)
- Paula Bollmann
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - Franziska Werner
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - Marko Jaron
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - Tom A Bruns
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - Hartmut Wache
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - Jochen Runte
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - Peter Boknik
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Westfälische Wilhelms-Universität, Münster, Germany
| | - Uwe Kirchhefer
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Westfälische Wilhelms-Universität, Münster, Germany
| | - Frank U Müller
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Westfälische Wilhelms-Universität, Münster, Germany
| | | | | | - Joachim Neumann
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - Ulrich Gergs
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
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15
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Cairns J, Ly RC, Niu N, Kalari KR, Carlson EE, Wang L. CDC25B partners with PP2A to induce AMPK activation and tumor suppression in triple negative breast cancer. NAR Cancer 2020; 2:zcaa039. [PMID: 33385163 PMCID: PMC7751685 DOI: 10.1093/narcan/zcaa039] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 11/25/2020] [Accepted: 11/30/2020] [Indexed: 12/28/2022] Open
Abstract
Cell division cycle 25 (CDC25) dual specificity phosphatases positively regulate the cell cycle by activating cyclin-dependent kinase/cyclin complexes. Here, we demonstrate that in addition to its role in cell cycle regulation, CDC25B functions as a regulator of protein phosphatase 2A (PP2A), a major cellular Ser/Thr phosphatase, through its direct interaction with PP2A catalytic subunit. Importantly, CDC25B alters the regulation of AMP-activated protein kinase signaling (AMPK) by PP2A, increasing AMPK activity by inhibiting PP2A to dephosphorylate AMPK. CDC25B depletion leads to metformin resistance by inhibiting metformin-induced AMPK activation. Furthermore, dual inhibition of CDC25B and PP2A further inhibits growth of 3D organoids isolated from patient derived xenograft model of breast cancer compared to CDC25B inhibition alone. Our study identifies CDC25B as a regulator of PP2A, and uncovers a mechanism of controlling the activity of a key energy metabolism marker, AMPK.
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Affiliation(s)
- Junmei Cairns
- Division of Clinical Pharmacology, Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA
| | - Reynold C Ly
- Division of Clinical Pharmacology, Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA
- Division of Clinical Pharmacology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Nifang Niu
- Division of Clinical Pharmacology, Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA
| | - Krishna R Kalari
- Division of Biostatistics and Informatics, Department of Health Sciences Research, Mayo Clinic, Rochester, MN 55905, USA
| | - Erin E Carlson
- Division of Biostatistics and Informatics, Department of Health Sciences Research, Mayo Clinic, Rochester, MN 55905, USA
| | - Liewei Wang
- To whom correspondence should be addressed. Tel: +1 507 284 5264; Fax: +1 507 284 4455;
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16
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Protein kinase CK2 phosphorylation of SAPS3 subunit increases PP6 phosphatase activity with Aurora A kinase. Biochem J 2020; 477:431-444. [PMID: 31904830 DOI: 10.1042/bcj20190740] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 12/04/2019] [Accepted: 01/06/2020] [Indexed: 12/11/2022]
Abstract
Protein Ser/Thr phosphatase-6 (PP6) regulates pathways for activation of NF-kB, YAP1 and Aurora A kinase (AURKA). PP6 is a heterotrimer comprised of a catalytic subunit, one of three different SAPS subunits and one of three different ankyrin-repeat ANKRD subunits. Here, we show FLAG-PP6C expressed in cells preferentially binds endogenous SAPS3, and the complex is active with the chemical substrate DiFMUP. SAPS3 has multiple acidic sequence motifs recognized by protein kinase CK2 (CK2) and SAPS3 is phosphorylated by purified CK2, without affecting its associated PP6 phosphatase activity. However, HA3-SAPS3-PP6 phosphatase activity using pT288 AURKA as substrate is significantly increased by phosphorylation with CK2. The substitution of Ala in nine putative phosphorylation sites in SAPS3 was required to prevent CK2 activation of the phosphatase. Different CK2 chemical inhibitors equally increased phosphorylation of endogenous AURKA in living cells, consistent with reduction in PP6 activity. CRISPR/Cas9 deletion or siRNA knockdown of SAPS3 resulted in highly activated endogenous AURKA, and a high proportion of cells with abnormal nuclei. Activation of PP6 by CK2 can form a feedback loop with bistable changes in substrates.
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17
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Wu YL, Lin YY, Sun D. Novel regulation of PKC-induced inflammation by Akt and protein phosphatase 2A in ovarian granulosa cells. CHINESE J PHYSIOL 2020; 63:179-186. [DOI: 10.4103/cjp.cjp_44_20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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18
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Polycystin-1 Inhibits Cell Proliferation through Phosphatase PP2A/B56 α. BIOMED RESEARCH INTERNATIONAL 2019; 2019:2582401. [PMID: 31641668 PMCID: PMC6770331 DOI: 10.1155/2019/2582401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 07/21/2019] [Accepted: 08/21/2019] [Indexed: 01/15/2023]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is associated with a number of cellular defects such as hyperproliferation, apoptosis, and dedifferentiation. Mutations in polycystin-1 (PC1) account for ∼85% of ADPKD. Here, we showed that wild-type (WT) or mutant PC1 composed of the last five transmembrane (TM) domains and the C-terminus (termed PC1-5TMC) inhibits cell proliferation and protein translation, as well as the downstream effectors of mTOR, consistent with previous reports. Knockdown of B56α, a subunit of the protein phosphatase 2A (PP2A) complex, or application of PP2A inhibitor okadaic acid or calyculin A, abolished the inhibitory effect of PC1 and PC1-5TMC on proliferation, indicating that PP2A/B56α mediates the regulation of cell proliferation by PC1. In addition to the phosphorylated S6 and 4EBP1, B56α was also downregulated by PC1 and PC1-5TMC. Furthermore, the downregulation of B56α, which may be mediated by mTOR but not AKT, can account for the dependence of PC1-inhibited proliferation on PP2A.
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19
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Zhao JL, Zhang LQ, Liu N, Xu SL, Yue ZL, Zhang LL, Deng ZP, Burlingame AL, Sun DY, Wang ZY, Sun Y, Zhang SW. Mutual Regulation of Receptor-Like Kinase SIT1 and B'κ-PP2A Shapes the Early Response of Rice to Salt Stress. THE PLANT CELL 2019; 31:2131-2151. [PMID: 31221736 PMCID: PMC6751134 DOI: 10.1105/tpc.18.00706] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 05/22/2019] [Accepted: 06/14/2019] [Indexed: 05/03/2023]
Abstract
The receptor-like kinase SIT1 acts as a sensor in rice (Oryza sativa) roots, relaying salt stress signals via elevated kinase activity to enhance salt sensitivity. Here, we demonstrate that Protein Phosphatase 2A (PP2A) regulatory subunit B'κ constrains SIT1 activity under salt stress. B'κ-PP2A deactivates SIT1 directly by dephosphorylating the kinase at Thr515/516, a salt-induced phosphorylation site in the activation loop that is essential for SIT1 activity. B'κ overexpression suppresses the salt sensitivity of rice plants expressing high levels of SIT1, thereby contributing to salt tolerance. B'κ functions in a SIT1 kinase-dependent manner. During early salt stress, activated SIT1 phosphorylates B'κ; this not only enhances its binding with SIT1, it also promotes B'κ protein accumulation via Ser502 phosphorylation. Consequently, by blocking SIT1 phosphorylation, B'κ inhibits and fine-tunes SIT1 activity to balance plant growth and stress adaptation.
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Affiliation(s)
- Ji-Long Zhao
- College of Life Science, Hebei Normal University, Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, Shijiazhuang, Hebei 050024, China
| | - Li-Qing Zhang
- College of Life Science, Hebei Normal University, Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, Shijiazhuang, Hebei 050024, China
| | - Ning Liu
- College of Life Science, Hebei Normal University, Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, Shijiazhuang, Hebei 050024, China
| | - Shou-Ling Xu
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California 94143
| | - Zhi-Liang Yue
- College of Life Science, Hebei Normal University, Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, Shijiazhuang, Hebei 050024, China
| | - Lu-Lu Zhang
- College of Life Science, Hebei Normal University, Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, Shijiazhuang, Hebei 050024, China
| | - Zhi-Ping Deng
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Alma L Burlingame
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California 94143
| | - Da-Ye Sun
- College of Life Science, Hebei Normal University, Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, Shijiazhuang, Hebei 050024, China
| | - Zhi-Yong Wang
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305
| | - Ying Sun
- College of Life Science, Hebei Normal University, Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, Shijiazhuang, Hebei 050024, China
| | - Sheng-Wei Zhang
- College of Life Science, Hebei Normal University, Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, Shijiazhuang, Hebei 050024, China
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20
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Yang T, Liu T, Gan J, Yu K, Chen K, Xue W, Lan L, Yang S, Yang CG. Structural Insight into the Mechanism of Staphylococcus aureus Stp1 Phosphatase. ACS Infect Dis 2019; 5:841-850. [PMID: 30868877 DOI: 10.1021/acsinfecdis.8b00316] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Staphylococcus aureus Stp1, which belongs to the bacterial metal-dependent protein phosphatase (PPM) family, is a promising candidate for antivirulence targeting. How Stp1 recognizes the phosphorylated peptide remains unclear, however. In order to investigate the recognition mechanism of Stp1 in depth, we have determined a series of crystal structures of S. aureus Stp1 in different states and the structural complex of Stp1 bound with a phosphorylated peptide His12. Different phosphorylated peptides, including MgrA- and GraR-derived phosphopeptides, are substrates of Stp1, which supports the function of Stp1 as a selective Ser/Thr phosphatase. In addition, interestingly, the crystal structures of R161-Stp1 variants combined with the biochemical activity validations have uncovered that R161 residue plays a key role to control the conformation switches of the flap domain in order to facilitate substrate binding and the dephosphorylation process. Our findings provide crucial structural insight into the molecular mechanism of S. aureus Stp1 phosphatase and reveal the phosphorylated peptides for biochemistry study and inhibitor screening of Stp1.
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Affiliation(s)
- Teng Yang
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals, Guizhou University, 2708 South Huaxi Road, Guiyang, Guizhou 550025, P. R. China
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, P. R. China
| | - Tingting Liu
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, P. R. China
- University of the Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, P. R. China
| | - Jianhua Gan
- School of Life Sciences, Fudan University, 2005 Songhu Road, Shanghai 200433, P. R. China
| | - Kunqian Yu
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, P. R. China
- University of the Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, P. R. China
| | - Kaixian Chen
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, P. R. China
- University of the Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, P. R. China
| | - Wei Xue
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals, Guizhou University, 2708 South Huaxi Road, Guiyang, Guizhou 550025, P. R. China
| | - Lefu Lan
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, P. R. China
- University of the Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, P. R. China
| | - Song Yang
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals, Guizhou University, 2708 South Huaxi Road, Guiyang, Guizhou 550025, P. R. China
| | - Cai-Guang Yang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, P. R. China
- University of the Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, P. R. China
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21
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Brautigan DL, Shenolikar S. Protein Serine/Threonine Phosphatases: Keys to Unlocking Regulators and Substrates. Annu Rev Biochem 2019; 87:921-964. [PMID: 29925267 DOI: 10.1146/annurev-biochem-062917-012332] [Citation(s) in RCA: 112] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Protein serine/threonine phosphatases (PPPs) are ancient enzymes, with distinct types conserved across eukaryotic evolution. PPPs are segregated into types primarily on the basis of the unique interactions of PPP catalytic subunits with regulatory proteins. The resulting holoenzymes dock substrates distal to the active site to enhance specificity. This review focuses on the subunit and substrate interactions for PPP that depend on short linear motifs. Insights about these motifs from structures of holoenzymes open new opportunities for computational biology approaches to elucidate PPP networks. There is an expanding knowledge base of posttranslational modifications of PPP catalytic and regulatory subunits, as well as of their substrates, including phosphorylation, acetylation, and ubiquitination. Cross talk between these posttranslational modifications creates PPP-based signaling. Knowledge of PPP complexes, signaling clusters, as well as how PPPs communicate with each other in response to cellular signals should unlock the doors to PPP networks and signaling "clouds" that orchestrate and coordinate different aspects of cell physiology.
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Affiliation(s)
- David L Brautigan
- Center for Cell Signaling and Department of Microbiology, Immunology and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA;
| | - Shirish Shenolikar
- Signature Research Programs in Cardiovascular and Metabolic Disorders and Neuroscience and Behavioral Disorders, Duke-NUS Medical School, Singapore 169857
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22
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Biphasic Functional Interaction between the Adenovirus E4orf4 Protein and DNA-PK. J Virol 2019; 93:JVI.01365-18. [PMID: 30842317 DOI: 10.1128/jvi.01365-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 02/22/2019] [Indexed: 02/06/2023] Open
Abstract
The adenovirus (Ad) E4orf4 protein contributes to virus-induced inhibition of the DNA damage response (DDR) by reducing ATM and ATR signaling. Consequently, E4orf4 inhibits DNA repair and sensitizes transformed cells to killing by DNA-damaging drugs. Inhibition of ATM and ATR signaling contributes to the efficiency of virus replication and may provide one explanation for the cancer selectivity of cell death induced by the expression of E4orf4 alone. In this report, we investigate a direct interaction of E4orf4 with the DDR. We show that E4orf4 physically associates with the DNA-dependent protein kinase (DNA-PK), and we demonstrate a biphasic functional interaction between these proteins, wherein DNA-PK is required for ATM and ATR inhibition by E4orf4 earlier during infection but is inhibited by E4orf4 as infection progresses. This biphasic process is accompanied by initial augmentation and a later inhibition of DNA-PK autophosphorylation as well as by colocalization of DNA-PK with early Ad replication centers and distancing of DNA-PK from late replication centers. Moreover, inhibition of DNA-PK improves Ad replication more effectively when a DNA-PK inhibitor is added later rather than earlier during infection. When expressed alone, E4orf4 is recruited to DNA damage sites in a DNA-PK-dependent manner. DNA-PK inhibition reduces the ability of E4orf4 to induce cancer cell death, likely because E4orf4 is prevented from arriving at the damage sites and from inhibiting the DDR. Our results support an important role for the E4orf4-DNA-PK interaction in Ad replication and in facilitation of E4orf4-induced cancer-selective cell death.IMPORTANCE Several DNA viruses evolved mechanisms to inhibit the cellular DNA damage response (DDR), which acts as an antiviral defense system. We present a novel mechanism by which the adenovirus (Ad) E4orf4 protein inhibits the DDR. E4orf4 interacts with the DNA damage sensor DNA-PK in a biphasic manner. Early during infection, E4orf4 requires DNA-PK activity to inhibit various branches of the DDR, whereas it later inhibits DNA-PK itself. Furthermore, although both E4orf4 and DNA-PK are recruited to virus replication centers (RCs), DNA-PK is later distanced from late-phase RCs. Delayed DNA-PK inhibition greatly contributes to Ad replication efficiency. When E4orf4 is expressed alone, it is recruited to DNA damage sites. Inhibition of DNA-PK prevents both recruitment and the previously reported ability of E4orf4 to kill cancer cells. Our results support an important role for the E4orf4-DNA-PK interaction in Ad replication and in facilitation of E4orf4-induced cancer-selective cell death.
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Bhat SA, Sood A, Shukla R, Hanif K. AT2R Activation Prevents Microglia Pro-inflammatory Activation in a NOX-Dependent Manner: Inhibition of PKC Activation and p47phox Phosphorylation by PP2A. Mol Neurobiol 2018; 56:3005-3023. [DOI: 10.1007/s12035-018-1272-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 07/19/2018] [Indexed: 12/22/2022]
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Nakatsumi H, Oka T, Higa T, Shirane M, Nakayama KI. Nuclear-cytoplasmic shuttling protein PP2A B56 contributes to mTORC1-dependent dephosphorylation of FOXK1. Genes Cells 2018; 23:599-605. [PMID: 29845697 DOI: 10.1111/gtc.12597] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 04/24/2018] [Indexed: 12/17/2022]
Abstract
Mammalian target of rapamycin complex 1 (mTORC1) kinase is a master regulator of the cellular response to nutrition-related signals such as insulin and amino acids. mTORC1 is activated on the lysosomal membrane and induces phosphorylation of a variety of downstream molecules. We previously showed that activated mTORC1 induces protein phosphatase 2A (PP2A)-mediated dephosphorylation of the transcription factor forkhead box K1 (FOXK1). The mechanism underlying the signal transduction from the cytoplasmic mTORC1 to the nuclear FOXK1 has remained unclear, however, we now show that a nuclear-cytoplasmic transport system is necessary for the mTORC1-FOXK1 signal transduction. This reaction is mediated by a shuttling protein B56, which is a regulatory subunit of PP2A and plays an essential role in the mTORC1-dependent dephosphorylation of FOXK1. These results suggest that PP2AB56 phosphatase contributes to the signaling for mTORC1-dependent transcriptional regulation.
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Affiliation(s)
- Hirokazu Nakatsumi
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.,Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Takeru Oka
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Tsunaki Higa
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Michiko Shirane
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.,Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Keiichi I Nakayama
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
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25
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Mao Z, Liu C, Lin X, Sun B, Su C. PPP2R5A: A multirole protein phosphatase subunit in regulating cancer development. Cancer Lett 2018; 414:222-229. [DOI: 10.1016/j.canlet.2017.11.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 11/20/2017] [Accepted: 11/21/2017] [Indexed: 12/21/2022]
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26
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Kim LW. Dual TORCs driven and B56 orchestrated signaling network guides eukaryotic cell migration. BMB Rep 2017; 50:437-444. [PMID: 28571594 PMCID: PMC5625690 DOI: 10.5483/bmbrep.2017.50.9.091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Indexed: 11/20/2022] Open
Abstract
Different types of eukaryotic cells may adopt seemingly distinct modes of directional cell migration. However, several core aspects are regarded common whether the movement is either ameoboidal or mesenchymal. The region of cells facing the attractive signal is often termed leading edge where lamellipodial structures dominates and the other end of the cell called rear end is often mediating cytoskeletal F-actin contraction involving Myosin-II. Dynamic remodeling of cell-to-matrix adhesion involving integrin is also evident in many types of migrating cells. All these three aspects of cell migration are significantly affected by signaling networks of TorC2, TorC1, and PP2A/B56. Here we review the current views of the mechanistic understanding of these regulatory signaling networks and how these networks affect eukaryotic cell migration.
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Affiliation(s)
- Lou W Kim
- Department of Biological Sciences, Florida International University, Miami, FL 33199, USA
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27
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Huang P, Wang B, Wang X, Xing M, Guo Z, Xu L. HEK293 cells exposed to microcystin-LR show reduced protein phosphatase 2A activity and more stable cytoskeletal structure when overexpressing α4 protein. ENVIRONMENTAL TOXICOLOGY 2017; 32:255-264. [PMID: 26784437 DOI: 10.1002/tox.22230] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Revised: 12/04/2015] [Accepted: 12/06/2015] [Indexed: 06/05/2023]
Abstract
Microcystin-LR (MC-LR) is one of the most toxic members of microcystins released by freshwater cyanobacterial. The major mechanism of MC-LR toxicity has been attributed to its inhibition of protein phosphatases 1 (PP1) and 2A (PP2A). In our prior research, α4 protein, a regulator of PP2A, was found not only crucial for PP2A regulation but also for the overall response of HEK 293 cells encountering MC-LR. To explore the role of α4 in MC-LR toxicity via PP2A regulation, here, HEK 293 cells overexpressing α4 protein were exposed to MC-LR and PP2A, cytoskeletal organization, and cytoskeleton-related proteins were investigated. The results showed that PP2A activity decreased and PP2A/C subunit expression and phosphorylation at Tyr307 increased significantly in the group exposed to high MC-LR. Vimentin IF became concentrated and formed perinuclear bundles. However, the assembly of actin filament and microtubules remained unchanged and the expression and phosphorylation of the cytoskeleton-related proteins HSP27 and VASP did not increase significantly. Some of these results differ from those of our previous study in which normal HEK293 cells were exposed to MC-LR. Our results indicate that elevated α4 expression confers some resistance to MC-LR-induced cytoskeletal change These new findings provide helpful insights into the mechanism of MC-LR toxicity and the role of α4 in regulating PP2A function. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 255-264, 2017.
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Affiliation(s)
- Pu Huang
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Beilei Wang
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Xiaofeng Wang
- Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, 310051, China
| | - Mingluan Xing
- Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, 310051, China
| | - Zonglou Guo
- Department of Biosystem Engineering, College of Biosystem Engineering and Food Science, Zhejiang University, Hangzhou, 310058, China
| | - Lihong Xu
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, 310058, China
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28
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Juraszek B, Nałęcz KA. Protein phosphatase PP2A - a novel interacting partner of carnitine transporter OCTN2 (SLC22A5) in rat astrocytes. J Neurochem 2016; 139:537-551. [DOI: 10.1111/jnc.13777] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 07/15/2016] [Accepted: 08/08/2016] [Indexed: 11/29/2022]
Affiliation(s)
- Barbara Juraszek
- Laboratory of Transport through Biomembranes; Department of Molecular and Cellular Neurobiology; Nencki Institute of Experimental Biology of Polish Academy of Sciences; Warsaw Poland
| | - Katarzyna A. Nałęcz
- Laboratory of Transport through Biomembranes; Department of Molecular and Cellular Neurobiology; Nencki Institute of Experimental Biology of Polish Academy of Sciences; Warsaw Poland
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29
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The broken "Off" switch in cancer signaling: PP2A as a regulator of tumorigenesis, drug resistance, and immune surveillance. BBA CLINICAL 2016; 6:87-99. [PMID: 27556014 PMCID: PMC4986044 DOI: 10.1016/j.bbacli.2016.08.002] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Revised: 08/01/2016] [Accepted: 08/02/2016] [Indexed: 12/31/2022]
Abstract
Aberrant activation of signal transduction pathways can transform a normal cell to a malignant one and can impart survival properties that render cancer cells resistant to therapy. A diverse set of cascades have been implicated in various cancers including those mediated by serine/threonine kinases such RAS, PI3K/AKT, and PKC. Signal transduction is a dynamic process involving both "On" and "Off" switches. Activating mutations of RAS or PI3K can be viewed as the switch being stuck in the "On" position resulting in continued signaling by a survival and/or proliferation pathway. On the other hand, inactivation of protein phosphatases such as the PP2A family can be seen as the defective "Off" switch that similarly can activate these pathways. A problem for therapeutic targeting of PP2A is that the enzyme is a hetero-trimer and thus drug targeting involves complex structures. More importantly, since PP2A isoforms generally act as tumor suppressors one would want to activate these enzymes rather than suppress them. The elucidation of the role of cellular inhibitors like SET and CIP2A in cancer suggests that targeting these proteins can have therapeutic efficacy by mechanisms involving PP2A activation. Furthermore, drugs such as FTY-720 can activate PP2A isoforms directly. This review will cover the current state of knowledge of PP2A role as a tumor suppressor in cancer cells and as a mediator of processes that can impact drug resistance and immune surveillance.
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Salminen A, Kaarniranta K, Kauppinen A. Age-related changes in AMPK activation: Role for AMPK phosphatases and inhibitory phosphorylation by upstream signaling pathways. Ageing Res Rev 2016; 28:15-26. [PMID: 27060201 DOI: 10.1016/j.arr.2016.04.003] [Citation(s) in RCA: 131] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 03/18/2016] [Accepted: 04/05/2016] [Indexed: 02/07/2023]
Abstract
AMP-activated protein kinase (AMPK) is a fundamental regulator of energy metabolism, stress resistance, and cellular proteostasis. AMPK signaling controls an integrated signaling network which is involved in the regulation of healthspan and lifespan e.g. via FoxO, mTOR/ULK1, CRCT-1/CREB, and SIRT1 signaling pathways. Several studies have demonstrated that the activation capacity of AMPK signaling declines with aging, which impairs the maintenance of efficient cellular homeostasis and enhances the aging process. However, it seems that the aging process affects AMPK activation in a context-dependent manner since occasionally, it can also augment AMPK activation, possibly attributable to the type of insult and tissue homeostasis. Three protein phosphatases, PP1, PP2A, and PP2C, inhibit AMPK activation by dephosphorylating the Thr172 residue of AMPKα, required for AMPK activation. In addition, several upstream signaling pathways can phosphorylate Ser/Thr residues in the β/γ interaction domain of the AMPKα subunit that subsequently blocks the activation of AMPK. These inhibitory pathways include the insulin/AKT, cyclic AMP/PKA, and RAS/MEK/ERK pathways. We will examine the evidence whether the efficiency of AMPK responsiveness declines during the aging process. Next, we will review the mechanisms involved in curtailing the activation of AMPK. Finally, we will elucidate the potential age-related changes in the inhibitory regulation of AMPK signaling that might be a part of the aging process.
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Affiliation(s)
- Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland.
| | - Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Finland
| | - Anu Kauppinen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland
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31
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Lange S, Gehmlich K, Lun AS, Blondelle J, Hooper C, Dalton ND, Alvarez EA, Zhang X, Bang ML, Abassi YA, Dos Remedios CG, Peterson KL, Chen J, Ehler E. MLP and CARP are linked to chronic PKCα signalling in dilated cardiomyopathy. Nat Commun 2016; 7:12120. [PMID: 27353086 PMCID: PMC4931343 DOI: 10.1038/ncomms12120] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 05/31/2016] [Indexed: 11/28/2022] Open
Abstract
MLP (muscle LIM protein)-deficient mice count among the first mouse models for dilated cardiomyopathy (DCM), yet the exact role of MLP in cardiac signalling processes is still enigmatic. Elevated PKCα signalling activity is known to be an important contributor to heart failure. Here we show that MLP directly inhibits the activity of PKCα. In end-stage DCM, PKCα is concentrated at the intercalated disc of cardiomyocytes, where it is sequestered by the adaptor protein CARP in a multiprotein complex together with PLCβ1. In mice deficient for both MLP and CARP the chronic PKCα signalling chain at the intercalated disc is broken and they remain healthy. Our results suggest that the main role of MLP in heart lies in the direct inhibition of PKCα and that chronic uninhibited PKCα activity at the intercalated disc in the absence of functional MLP leads to heart failure. Altered function of the muscle LIM protein (MLP) causes dilated cardiomyopathy in mice and humans. Lange et al. explain the molecular role of MLP in the heart by showing that it affects the signalling complex at the intercalated discs of failing hearts that consists of PKCα, PLCβ1 and CARP by inhibiting PKCα auto-phosphorylation and function.
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Affiliation(s)
- Stephan Lange
- School of Medicine, University of California, San Diego, La Jolla CA-92093, USA
| | - Katja Gehmlich
- BHF Centre of Research Excellence Oxford, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, UK
| | - Alexander S Lun
- School of Medicine, University of California, San Diego, La Jolla CA-92093, USA
| | - Jordan Blondelle
- School of Medicine, University of California, San Diego, La Jolla CA-92093, USA
| | - Charlotte Hooper
- BHF Centre of Research Excellence Oxford, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, UK
| | - Nancy D Dalton
- School of Medicine, University of California, San Diego, La Jolla CA-92093, USA
| | - Erika A Alvarez
- School of Medicine, University of California, San Diego, La Jolla CA-92093, USA
| | - Xiaoyu Zhang
- ACEA Biosciences, 6779 Mesa Ridge Rd #100, San Diego, CA-92121, USA
| | - Marie-Louise Bang
- Institute of Genetic and Biomedical Research, UOS Milan, National Research Council, Rozzano (Milan) 20089, Italy.,Humanitas Clinical and Research Center, Rozzano (Milan) 20089, Italy
| | - Yama A Abassi
- ACEA Biosciences, 6779 Mesa Ridge Rd #100, San Diego, CA-92121, USA
| | | | - Kirk L Peterson
- School of Medicine, University of California, San Diego, La Jolla CA-92093, USA
| | - Ju Chen
- School of Medicine, University of California, San Diego, La Jolla CA-92093, USA
| | - Elisabeth Ehler
- BHF Centre of Research Excellence at King's College London, Cardiovascular Division and Randall Division of Cell and Molecular Biophysics, London SE1 1UL, UK
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32
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Athanasopoulos PS, Jacob W, Neumann S, Kutsch M, Wolters D, Tan EK, Bichler Z, Herrmann C, Heumann R. Identification of protein phosphatase 2A as an interacting protein of leucine-rich repeat kinase 2. Biol Chem 2016; 397:541-54. [DOI: 10.1515/hsz-2015-0189] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 02/17/2016] [Indexed: 11/15/2022]
Abstract
Abstract
Mutations in the gene coding for the multi-domain protein leucine-rich repeat kinase 2 (LRRK2) are the leading cause of genetically inherited Parkinson’s disease (PD). Two of the common found mutations are the R1441C and G2019S. In this study we identified protein phosphatase 2A (PP2A) as an interacting partner of LRRK2. We were able to demonstrate that the Ras of complex protein (ROC) domain is sufficient to interact with the three subunits of PP2A in human neuroblastoma SH-SY5Y cells and in HeLa cells. The alpha subunit of PP2A is interacting with LRRK2 in the perinuclear region of HeLa cells. Silencing the catalytic subunit of PP2A by shRNA aggravated cellular degeneration induced by the pathogenic R1441C-LRRK2 mutant expressed in neuroblastoma SH-SY5Y cells. A similar enhancement of apoptotic nuclei was observed by downregulation of the catalytic subunit of PP2A in cultured cortical cells derived from neurons overexpressing the pathogenic mutant G2019S-LRRK2. Conversely, pharmacological activation of PP2A by sodium selenate showed a partial neuroprotection from R1441C-LRRK2-induced cellular degeneration. All these data suggest that PP2A is a new interacting partner of LRRK2 and reveal the importance of PP2A as a potential therapeutic target in PD.
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33
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Guerra E, Trerotola M, Tripaldi R, Aloisi AL, Simeone P, Sacchetti A, Relli V, D'Amore A, La Sorda R, Lattanzio R, Piantelli M, Alberti S. Trop-2 Induces Tumor Growth Through AKT and Determines Sensitivity to AKT Inhibitors. Clin Cancer Res 2016; 22:4197-205. [PMID: 27022065 DOI: 10.1158/1078-0432.ccr-15-1701] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 02/29/2016] [Indexed: 11/16/2022]
Abstract
PURPOSE Inhibition of AKT is a key target area for personalized cancer medicine. However, predictive markers of response to AKT inhibitors are lacking. Correspondingly, the AKT-dependent chain of command for tumor growth, which will mediate AKT-dependent therapeutic responses, remains unclear. EXPERIMENTAL DESIGN Proteomic profiling was utilized to identify nodal hubs of the Trop-2 cancer growth-driving network. Kinase-specific inhibitors were used to dissect Trop-2-dependent from Trop-2-independent pathways. In vitro assays, in vivo preclinical models, and case series of primary human breast cancers were utilized to define the mechanisms of Trop-2-driven growth and the mode of action of Trop-2-predicted AKT inhibitors. RESULTS Trop-2 and AKT expression was shown to be tightly coordinated in human breast cancers, with virtual overlap with AKT activation profiles at T308 and S473, consistent with functional interaction in vivo AKT allosteric inhibitors were shown to only block the growth of Trop-2-expressing tumor cells, both in vitro and in preclinical models, being ineffective on Trop-2-null cells. Consistently, AKT-targeted siRNA only impacted on Trop-2-expressing cells. Lentiviral downregulation of endogenous Trop-2 abolished tumor response to AKT blockade, indicating Trop-2 as a mandatory activator of AKT. CONCLUSIONS Our findings indicate that the expression of Trop-2 is a stringent predictor of tumor response to AKT inhibitors. They also support the identification of target-activatory pathways, as efficient predictors of response in precision cancer therapy. Clin Cancer Res; 22(16); 4197-205. ©2016 AACR.
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Affiliation(s)
- Emanuela Guerra
- Unit of Cancer Pathology, CeSI-MeT, University 'G. d'Annunzio,' Chieti, Italy
| | - Marco Trerotola
- Unit of Cancer Pathology, CeSI-MeT, University 'G. d'Annunzio,' Chieti, Italy
| | - Romina Tripaldi
- Unit of Cancer Pathology, CeSI-MeT, University 'G. d'Annunzio,' Chieti, Italy
| | - Anna Laura Aloisi
- Unit of Cancer Pathology, CeSI-MeT, University 'G. d'Annunzio,' Chieti, Italy
| | - Pasquale Simeone
- Unit of Cancer Pathology, CeSI-MeT, University 'G. d'Annunzio,' Chieti, Italy
| | - Andrea Sacchetti
- Unit of Cancer Pathology, CeSI-MeT, University 'G. d'Annunzio,' Chieti, Italy
| | - Valeria Relli
- Unit of Cancer Pathology, CeSI-MeT, University 'G. d'Annunzio,' Chieti, Italy
| | - Antonella D'Amore
- Unit of Cancer Pathology, CeSI-MeT, University 'G. d'Annunzio,' Chieti, Italy
| | - Rossana La Sorda
- Unit of Cancer Pathology, CeSI-MeT, University 'G. d'Annunzio,' Chieti, Italy
| | - Rossano Lattanzio
- Unit of Cancer Pathology, CeSI-MeT, University 'G. d'Annunzio,' Chieti, Italy. Department of Medical, Oral and Biotechnological Sciences, University 'G. d'Annunzio,' Chieti, Italy
| | - Mauro Piantelli
- Unit of Cancer Pathology, CeSI-MeT, University 'G. d'Annunzio,' Chieti, Italy. Department of Medical, Oral and Biotechnological Sciences, University 'G. d'Annunzio,' Chieti, Italy
| | - Saverio Alberti
- Unit of Cancer Pathology, CeSI-MeT, University 'G. d'Annunzio,' Chieti, Italy. Department of Neuroscience, Imaging and Clinical Sciences, Unit of Physiology and Physiopathology, University 'G. d'Annunzio,' Chieti, Italy.
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34
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Lei M, Wang X, Ke Y, Solaro RJ. Regulation of Ca(2+) transient by PP2A in normal and failing heart. Front Physiol 2015; 6:13. [PMID: 25688213 PMCID: PMC4310266 DOI: 10.3389/fphys.2015.00013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 01/09/2015] [Indexed: 11/13/2022] Open
Abstract
Calcium transient in cardiomyocytes is regulated by multiple protein kinases and phosphatases. PP2A is a major protein phosphatase in the heart modulating Ca2+ handling through an array of ion channels, antiporters and pumps, etc. The assembly, localization/translocation, and substrate specificity of PP2A are controlled by different post-translational mechanisms, which in turn are linked to the activities of upstream signaling molecules. Abnormal PP2A expression and activities are associated with defective response to β-adrenergic stimulation and are indication and causal factors in arrhythmia and heart failure.
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Affiliation(s)
- Ming Lei
- Department of Pharmacology, University of Oxford Oxford, UK
| | - Xin Wang
- Faculty of Life Science, University of Manchester Manchester, UK
| | - Yunbo Ke
- Department of Physiology and Biophysics, Center for Cardiovascular Research, University of Illinois at Chicago Chicago, IL, USA
| | - R John Solaro
- Department of Physiology and Biophysics, Center for Cardiovascular Research, University of Illinois at Chicago Chicago, IL, USA
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35
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Ábrahám E, Yu P, Farkas I, Darula Z, Varga E, Lukács N, Ayaydin F, Medzihradszky KF, Dombrádi V, Dudits D, Horváth GV. The B″ regulatory subunit of protein phosphatase 2A mediates the dephosphorylation of rice retinoblastoma-related protein-1. PLANT MOLECULAR BIOLOGY 2015; 87:125-141. [PMID: 25398395 DOI: 10.1007/s11103-014-0265-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 11/04/2014] [Indexed: 06/04/2023]
Abstract
The phosphorylation of plant retinoblastoma-related (RBR) proteins by cyclin-dependent kinases (CDKs) is well documented, but the counteracting phosphatases have not been identified yet. We report here that rice retinoblastoma-related protein-1 (OsRBR1) interacted with the B″ subunit of rice protein phosphatase 2A (OsPP2A B″) and underwent reversible phosphorylation during the cell division cycle. The OsRBR1-OsPP2A B" association required B domain in OsRBR1 and the C-terminal region of OsPP2A B″. We found by immunoprecipitation that OsPP2A B″, OsPP2A catalytic subunit subtype II, PSTAIRE-type CDK and OsRBR1 were in the same protein complex, indicating a physical association between the phosphatase, the kinase and their common substrate. OsPP2A B″ contains three predicted CDK phosphorylation sites: Ser95, Ser102 and Ser119. The in vitro phosphorylation of Ser95 and Ser119 with PSTAIRE-kinases was verified by mass spectrometry. We generated a series of phosphorylation site mutants to mimic the dephosphorylated or phosphorylated states of OsPP2A B″, and confirmed that all of the three predicted sites can be phosphorylated. Yeast two-hybrid experiments suggested that the phosphorylation of OsPP2A B″ promoted the formation of the OsPP2A holoenzyme. A triple phosphorylation mimicking OsPP2A B″ mutant containing holoenzyme showed higher activity in phosphatase assays. Our data collectively show that the phosphatase activity of OsPP2A against OsRBR1 is regulated by the phosphorylation of its B″ regulatory subunit. However, the analysis of the effect of okadaic acid, a phosphatase inhibitor, in rice cell suspension cultures revealed that the dephosphorylation of OsRBR1 was completely inhibited only by high dose (300 nM) of the okadaic acid during the cell cycle progression. Therefore the role of the protein phosphatase 1 should be considered as an additional post translational regulatory component of RBR protein function in higher plants.
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Affiliation(s)
- Edit Ábrahám
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, Szeged, Hungary
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36
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Kirchhefer U, Brekle C, Eskandar J, Isensee G, Kučerová D, Müller FU, Pinet F, Schulte JS, Seidl MD, Boknik P. Cardiac function is regulated by B56α-mediated targeting of protein phosphatase 2A (PP2A) to contractile relevant substrates. J Biol Chem 2014; 289:33862-73. [PMID: 25320082 DOI: 10.1074/jbc.m114.598938] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dephosphorylation of important myocardial proteins is regulated by protein phosphatase 2A (PP2A), representing a heterotrimer that is comprised of catalytic, scaffolding, and regulatory (B) subunits. There is a multitude of B subunit family members directing the PP2A holoenzyme to different myocellular compartments. To gain a better understanding of how these B subunits contribute to the regulation of cardiac performance, we generated transgenic (TG) mice with cardiomyocyte-directed overexpression of B56α, a phosphoprotein of the PP2A-B56 family. The 2-fold overexpression of B56α was associated with an enhanced PP2A activity that was localized mainly in the cytoplasm and myofilament fraction. Contractility was enhanced both at the whole heart level and in isolated cardiomyocytes of TG compared with WT mice. However, peak amplitude of [Ca]i did not differ between TG and WT cardiomyocytes. The basal phosphorylation of cardiac troponin inhibitor (cTnI) and the myosin-binding protein C was reduced by 26 and 35%, respectively, in TG compared with WT hearts. The stimulation of β-adrenergic receptors by isoproterenol (ISO) resulted in an impaired contractile response of TG hearts. At a depolarizing potential of -5 mV, the ICa,L current density was decreased by 28% after administration of ISO in TG cardiomyocytes. In addition, the ISO-stimulated phosphorylation of phospholamban at Ser(16) was reduced by 27% in TG hearts. Thus, the increased PP2A-B56α activity in TG hearts is localized to specific subcellular sites leading to the dephosphorylation of important contractile proteins. This may result in higher myofilament Ca(2+) sensitivity and increased basal contractility in TG hearts. These effects were reversed by β-adrenergic stimulation.
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Affiliation(s)
- Uwe Kirchhefer
- From the Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, D-48149 Münster, Germany and
| | - Christiane Brekle
- From the Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, D-48149 Münster, Germany and
| | - John Eskandar
- From the Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, D-48149 Münster, Germany and
| | - Gunnar Isensee
- From the Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, D-48149 Münster, Germany and
| | - Dana Kučerová
- From the Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, D-48149 Münster, Germany and
| | - Frank U Müller
- From the Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, D-48149 Münster, Germany and
| | - Florence Pinet
- INSERM, U744, Institut Pasteur de Lille, 59019 Lille, France
| | - Jan S Schulte
- From the Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, D-48149 Münster, Germany and
| | - Matthias D Seidl
- From the Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, D-48149 Münster, Germany and
| | - Peter Boknik
- From the Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, D-48149 Münster, Germany and
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37
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Cytoplasmic SET induces tau hyperphosphorylation through a decrease of methylated phosphatase 2A. BMC Neurosci 2014; 15:82. [PMID: 24981783 PMCID: PMC4086270 DOI: 10.1186/1471-2202-15-82] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 06/25/2014] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND The neuronal cytoplasmic localization of SET, an inhibitor of the phosphatase 2A (PP2A), results in tau hyperphosphorylation in the brains of Alzheimer patients through mechanisms that are still not well defined. RESULTS We used primary neurons and mouse brain slices to show that SET is translocated to the cytoplasm in a manner independent of both its cleavage and over-expression. The localization of SET in the cytoplasm, either by the translocation of endogenous SET or by internalization of the recombinant full-length SET protein, induced tau hyperphosphorylation. Cytoplasmic recombinant full-length SET in mouse brain slices induced a decrease of PP2A activity through a decrease of methylated PP2A levels. The levels of methylated PP2A were negatively correlated with tau hyperphosphorylation at Ser-202 but not with the abnormal phosphorylation of tau at Ser-422. CONCLUSIONS The presence of full-length SET in the neuronal cytoplasm is sufficient to impair PP2A methylation and activity, leading to tau hyperphosphorylation. In addition, our data suggest that tau hyperphosphorylation is regulated by different mechanisms at distinct sites. The translocation of SET to the neuronal cytoplasm, the low activity of PP2A, and tau hyperphosphorylation are associated in the brains of Alzheimer patients. Our data show a link between the translocation of SET in the cytoplasm and the decrease of methylated PP2A levels leading to a decrease of PP2A activity and tau hyperphosphorylation. This chain of events may contribute to the pathogenesis of Alzheimer disease.
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38
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Sontag JM, Sontag E. Protein phosphatase 2A dysfunction in Alzheimer's disease. Front Mol Neurosci 2014; 7:16. [PMID: 24653673 PMCID: PMC3949405 DOI: 10.3389/fnmol.2014.00016] [Citation(s) in RCA: 212] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 02/22/2014] [Indexed: 01/26/2023] Open
Abstract
Protein phosphatase 2A (PP2A) is a large family of enzymes that account for the majority of brain Ser/Thr phosphatase activity. While PP2A enzymes collectively modulate most cellular processes, sophisticated regulatory mechanisms are ultimately responsible for ensuring isoform-specific substrate specificity. Of particular interest to the Alzheimer’s disease (AD) field, alterations in PP2A regulators and PP2A catalytic activity, subunit expression, methylation and/or phosphorylation, have been reported in AD-affected brain regions. “PP2A” dysfunction has been linked to tau hyperphosphorylation, amyloidogenesis and synaptic deficits that are pathological hallmarks of this neurodegenerative disorder. Deregulation of PP2A enzymes also affects the activity of many Ser/Thr protein kinases implicated in AD. This review will more specifically discuss the role of the PP2A/Bα holoenzyme and PP2A methylation in AD pathogenesis. The PP2A/Bα isoform binds to tau and is the primary tau phosphatase. Its deregulation correlates with increased tau phosphorylation in vivo and in AD. Disruption of PP2A/Bα-tau protein interactions likely contribute to tau deregulation in AD. Significantly, alterations in one-carbon metabolism that impair PP2A methylation are associated with increased risk for sporadic AD, and enhanced AD-like pathology in animal models. Experimental studies have linked deregulation of PP2A methylation with down-regulation of PP2A/Bα, enhanced phosphorylation of tau and amyloid precursor protein, tau mislocalization, microtubule destabilization and neuritic defects. While it remains unclear what are the primary events that underlie “PP2A” dysfunction in AD, deregulation of PP2A enzymes definitely affects key players in the pathogenic process. As such, there is growing interest in developing PP2A-centric therapies for AD, but this may be a daunting task without a better understanding of the regulation and function of specific PP2A enzymes.
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Affiliation(s)
- Jean-Marie Sontag
- Faculty of Health and Medicine, School of Biomedical Sciences and Pharmacy, The University of Newcastle Callaghan, NSW, Australia
| | - Estelle Sontag
- Faculty of Health and Medicine, School of Biomedical Sciences and Pharmacy, The University of Newcastle Callaghan, NSW, Australia
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