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Jaime-Garza M, Nowotny CA, Coutandin D, Wang F, Tabios M, Agard DA. Hsp90 provides a platform for kinase dephosphorylation by PP5. Nat Commun 2023; 14:2197. [PMID: 37069154 PMCID: PMC10110553 DOI: 10.1038/s41467-023-37659-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 03/23/2023] [Indexed: 04/19/2023] Open
Abstract
The Hsp90 molecular chaperone collaborates with the phosphorylated Cdc37 cochaperone for the folding and activation of its many client kinases. As with many kinases, the Hsp90 client kinase CRaf is activated by phosphorylation at specific regulatory sites. The cochaperone phosphatase PP5 dephosphorylates CRaf and Cdc37 in an Hsp90-dependent manner. Although dephosphorylating Cdc37 has been proposed as a mechanism for releasing Hsp90-bound kinases, here we show that Hsp90 bound kinases sterically inhibit Cdc37 dephosphorylation indicating kinase release must occur before Cdc37 dephosphorylation. Our cryo-EM structure of PP5 in complex with Hsp90:Cdc37:CRaf reveals how Hsp90 both activates PP5 and scaffolds its association with the bound CRaf to dephosphorylate phosphorylation sites neighboring the kinase domain. Thus, we directly show how Hsp90's role in maintaining protein homeostasis goes beyond folding and activation to include post translationally modifying its client kinases.
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Affiliation(s)
- Maru Jaime-Garza
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, 94143, USA
| | - Carlos A Nowotny
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, 94143, USA
| | - Daniel Coutandin
- Novartis Institutes for BioMedical Research, San Diego, CA, 92121, USA
| | - Feng Wang
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, 94143, USA
| | - Mariano Tabios
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, 94143, USA
| | - David A Agard
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, 94143, USA.
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2
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Zhang H, Zhang Q, Tu J, You Q, Wang L. Dual function of protein phosphatase 5 (PPP5C): An emerging therapeutic target for drug discovery. Eur J Med Chem 2023; 254:115350. [PMID: 37054560 DOI: 10.1016/j.ejmech.2023.115350] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/21/2023] [Accepted: 03/28/2023] [Indexed: 04/15/2023]
Abstract
Phosphorylation of proteins is reversibly controlled by the kinases and phosphatases in many posttranslational regulation patterns. Protein phosphatase 5 (PPP5C) is a serine/threonine protein phosphatase showing dual function by simultaneously exerting dephosphorylation and co-chaperone functions. Due to this special role, PPP5C was found to participate in many signal transductions related to various diseases. Abnormal expression of PPP5C results in cancers, obesity, and Alzheimer's disease, making it a potential drug target. However, the design of small molecules targeting PPP5C is struggling due to its special monomeric enzyme form and low basal activity by a self-inhibition mechanism. Through realizing the PPP5C's dual function as phosphatase and co-chaperone, more and more small molecules were found to regulate PPP5C with a different mechanism. This review aims to provide insights into PPP5C's dual function from structure to function, which could provide efficient design strategies for small molecules targeting PPP5C as therapeutic candidates.
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Affiliation(s)
- Hengheng Zhang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing, 210009, China; Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
| | - Qiuyue Zhang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing, 210009, China; Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
| | - Jiaqi Tu
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing, 210009, China; Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
| | - Qidong You
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing, 210009, China; Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China.
| | - Lei Wang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing, 210009, China; Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China.
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3
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Plk4 Is a Novel Substrate of Protein Phosphatase 5. Int J Mol Sci 2023; 24:ijms24032033. [PMID: 36768356 PMCID: PMC9917060 DOI: 10.3390/ijms24032033] [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: 11/30/2022] [Revised: 01/13/2023] [Accepted: 01/17/2023] [Indexed: 01/21/2023] Open
Abstract
The conserved Ser/Thr protein phosphatase 5 (PP5) is involved in the regulation of key cellular processes, including DNA damage repair and cell division in eukaryotes. As a co-chaperone of Hsp90, PP5 has been shown to modulate the maturation and activity of numerous oncogenic kinases. Here, we identify a novel substrate of PP5, the Polo-like kinase 4 (Plk4), which is the master regulator of centriole duplication in animal cells. We show that PP5 specifically interacts with Plk4, and is able to dephosphorylate the kinase in vitro and in vivo, which affects the interaction of Plk4 with its partner proteins. In addition, we provide evidence that PP5 and Plk4 co-localize to the centrosomes in Drosophila embryos and cultured cells. We demonstrate that PP5 is not essential; the null mutant flies are viable without a severe mitotic phenotype; however, its loss significantly reduces the fertility of the animals. Our results suggest that PP5 is a novel regulator of the Plk4 kinase in Drosophila.
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Multi-Level Control of the ATM/ATR-CHK1 Axis by the Transcription Factor E4F1 in Triple-Negative Breast Cancer. Int J Mol Sci 2022; 23:ijms23169217. [PMID: 36012478 PMCID: PMC9409040 DOI: 10.3390/ijms23169217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 08/10/2022] [Accepted: 08/12/2022] [Indexed: 12/01/2022] Open
Abstract
E4F1 is essential for early embryonic mouse development and for controlling the balance between proliferation and survival of actively dividing cells. We previously reported that E4F1 is essential for the survival of murine p53-deficient cancer cells by controlling the expression of genes involved in mitochondria functions and metabolism, and in cell-cycle checkpoints, including CHEK1, a major component of the DNA damage and replication stress responses. Here, combining ChIP-Seq and RNA-Seq approaches, we identified the transcriptional program directly controlled by E4F1 in Human Triple-Negative Breast Cancer cells (TNBC). E4F1 binds and regulates a limited list of direct target genes (57 genes) in these cells, including the human CHEK1 gene and, surprisingly, also two other genes encoding post-transcriptional regulators of the ATM/ATR-CHK1 axis, namely, the TTT complex component TTI2 and the phosphatase PPP5C, that are essential for the folding and stability, and the signaling of ATM/ATR kinases, respectively. Importantly, E4F1 also binds the promoter of these genes in vivo in Primary Derived Xenograft (PDX) of human TNBC. Consequently, the protein levels and signaling of CHK1 but also of ATM/ATR kinases are strongly downregulated in E4F1-depleted TNBC cells resulting in a deficiency of the DNA damage and replicative stress response in these cells. The E4F1-depleted cells fail to arrest into S-phase upon treatment with the replication-stalling agent Gemcitabine, and are highly sensitized to this drug, as well as to other DNA-damaging agents, such as Cisplatin. Altogether, our data indicate that in breast cancer cells the ATM/ATR-CHK1 signaling pathway and DNA damage-stress response are tightly controlled at the transcriptional and post-transcriptional level by E4F1.
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Fielder SM, Rosenfeld JA, Burrage LC, Emrick L, Lalani S, Attali R, Bembenek JN, Hoang H, Baldridge D, Silverman GA, Schedl T, Pak SC. Functional analysis of a novel de novo variant in PPP5C associated with microcephaly, seizures, and developmental delay. Mol Genet Metab 2022; 136:65-73. [PMID: 35361529 DOI: 10.1016/j.ymgme.2022.03.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 03/13/2022] [Indexed: 11/27/2022]
Abstract
We describe a proband evaluated through the Undiagnosed Diseases Network (UDN) who presented with microcephaly, developmental delay, and refractory epilepsy with a de novo p.Ala47Thr missense variant in the protein phosphatase gene, PPP5C. This gene has not previously been associated with a Mendelian disease, and based on the population database, gnomAD, the gene has a low tolerance for loss-of-function variants (pLI = 1, o/e = 0.07). We functionally evaluated the PPP5C variant in C. elegans by knocking the variant into the orthologous gene, pph-5, at the corresponding residue, Ala48Thr. We employed assays in three different biological processes where pph-5 was known to function through opposing the activity of genes, mec-15 and sep-1. We demonstrated that, in contrast to control animals, the pph-5 Ala48Thr variant suppresses the neurite growth phenotype and the GABA signaling defects of mec-15 mutants, and the embryonic lethality of sep-1 mutants. The Ala48Thr variant did not display dominance and behaved similarly to the reference pph-5 null, indicating that the variant is likely a strong hypomorph or complete loss-of-function. We conclude that pph-5 Ala48Thr is damaging in C. elegans. By extension in the proband, PPP5C p.Ala47Thr is likely damaging, the de novo dominant presentation is consistent with haplo-insufficiency, and the PPP5C variant is likely responsible for one or more of the proband's phenotypes.
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Affiliation(s)
- Sara M Fielder
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, MO 63110, USA
| | - Jill A Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lindsay C Burrage
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA
| | - Lisa Emrick
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA
| | - Seema Lalani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA
| | - Ruben Attali
- Genomic Research Department, Emedgene Technologies, 6744332 Tel Aviv, Israel
| | - Joshua N Bembenek
- Department of Obstetrics and Gynecology, C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Hieu Hoang
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, MO 63110, USA
| | - Dustin Baldridge
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, MO 63110, USA
| | - Gary A Silverman
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, MO 63110, USA
| | - Tim Schedl
- Department of Genetics, Washington University in St Louis School of Medicine, St Louis, MO 63110, USA
| | - Stephen C Pak
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, MO 63110, USA.
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6
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Cancer mutation profiles predict ICIs efficacy in patients with non-small cell lung cancer. Expert Rev Mol Med 2022; 24:e16. [PMID: 35373730 DOI: 10.1017/erm.2022.9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Although immune checkpoint inhibitors (ICIs) have produced remarkable responses in non-small cell lung cancer (NSCLC) patients, receivers still have a relatively low response rate. Initial response assessment by conventional imaging and evaluation criteria is often unable to identify whether patients can achieve durable clinical benefit from ICIs. Overall, there are sparse effective biomarkers identified to screen NSCLC patients responding to this therapy. A lot of studies have reported that patients with specific gene mutations may benefit from or resist to immunotherapy. However, the single gene mutation may be not effective enough to predict the benefit from immunotherapy for patients. With the advancement in sequencing technology, further studies indicate that many mutations often co-occur and suggest a drastic transformation of tumour microenvironment phenotype. Moreover, co-mutation events have been reported to synergise to activate or suppress signalling pathways of anti-tumour immune response, which also indicates a potential target for combining intervention. Thus, the different mutation profile (especially co-mutation) of patients may be an important concern for predicting or promoting the efficacy of ICIs. However, there is a lack of comprehensive knowledge of this field until now. Therefore, in this study, we reviewed and elaborated the value of cancer mutation profile in predicting the efficacy of immunotherapy and analysed the underlying mechanisms, to provide an alternative way for screening dominant groups, and thereby, optimising individualised therapy for NSCLC patients.
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Cheng J, Tsuda M, Okolotowicz K, Dwyer M, Bushway PJ, Colas AR, Lancman JJ, Schade D, Perea-Gil I, Bruyneel AAN, Lee J, Vadgama N, Quach J, McKeithan WL, Biechele TL, Wu JC, Moon RT, Si Dong PD, Karakikes I, Cashman JR, Mercola M. Small-molecule probe reveals a kinase cascade that links stress signaling to TCF/LEF and Wnt responsiveness. Cell Chem Biol 2021; 28:625-635.e5. [PMID: 33503403 PMCID: PMC8140986 DOI: 10.1016/j.chembiol.2021.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 08/02/2020] [Accepted: 01/04/2021] [Indexed: 12/13/2022]
Abstract
Wnt signaling plays a central role in tissue maintenance and cancer. Wnt activates downstream genes through β-catenin, which interacts with TCF/LEF transcription factors. A major question is how this signaling is coordinated relative to tissue organization and renewal. We used a recently described class of small molecules that binds tubulin to reveal a molecular cascade linking stress signaling through ATM, HIPK2, and p53 to the regulation of TCF/LEF transcriptional activity. These data suggest a mechanism by which mitotic and genotoxic stress can indirectly modulate Wnt responsiveness to exert coherent control over cell shape and renewal. These findings have implications for understanding tissue morphogenesis and small-molecule anticancer therapeutics.
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Affiliation(s)
- Jiongjia Cheng
- Human BioMolecular Research Institute, 5310 Eastgate Mall, San Diego, CA 92121, USA
| | - Masanao Tsuda
- Sanford-Burnham-Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Karl Okolotowicz
- Human BioMolecular Research Institute, 5310 Eastgate Mall, San Diego, CA 92121, USA
| | - Mary Dwyer
- Human BioMolecular Research Institute, 5310 Eastgate Mall, San Diego, CA 92121, USA
| | - Paul J Bushway
- Sanford-Burnham-Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA; University of California, San Diego, San Diego, CA 92093, USA
| | - Alexandre R Colas
- Sanford-Burnham-Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Joseph J Lancman
- Sanford-Burnham-Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Dennis Schade
- Human BioMolecular Research Institute, 5310 Eastgate Mall, San Diego, CA 92121, USA; Institute of Pharmacy, Christian-Albrechts-University of Kiel, Gutenbergstrasse 76, Kiel, Germany
| | - Isaac Perea-Gil
- Cardiovascular Institute, Stanford University, 240 Pasteur Drive, Palo Alto, CA 94305, USA
| | - Arne A N Bruyneel
- Cardiovascular Institute, Stanford University, 240 Pasteur Drive, Palo Alto, CA 94305, USA
| | - Jaechol Lee
- Cardiovascular Institute, Stanford University, 240 Pasteur Drive, Palo Alto, CA 94305, USA
| | - Nirmal Vadgama
- Cardiovascular Institute, Stanford University, 240 Pasteur Drive, Palo Alto, CA 94305, USA
| | - Justine Quach
- Human BioMolecular Research Institute, 5310 Eastgate Mall, San Diego, CA 92121, USA
| | - Wesley L McKeithan
- Sanford-Burnham-Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA; Cardiovascular Institute, Stanford University, 240 Pasteur Drive, Palo Alto, CA 94305, USA
| | - Travis L Biechele
- Department of Pharmacology, University of Washington, Seattle, WA 98105, USA
| | - Joseph C Wu
- Cardiovascular Institute, Stanford University, 240 Pasteur Drive, Palo Alto, CA 94305, USA; Department of Medicine, Stanford University, 240 Pasteur Drive, Palo Alto, CA 94305, USA
| | - Randall T Moon
- Department of Pharmacology, University of Washington, Seattle, WA 98105, USA
| | - P Duc Si Dong
- Sanford-Burnham-Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Ioannis Karakikes
- Cardiovascular Institute, Stanford University, 240 Pasteur Drive, Palo Alto, CA 94305, USA; Department of Cardiothoracic Surgery, Stanford University, 240 Pasteur Drive, Palo Alto, CA 94305, USA
| | - John R Cashman
- Sanford-Burnham-Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Mark Mercola
- Sanford-Burnham-Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA; University of California, San Diego, San Diego, CA 92093, USA; Cardiovascular Institute, Stanford University, 240 Pasteur Drive, Palo Alto, CA 94305, USA; Department of Medicine, Stanford University, 240 Pasteur Drive, Palo Alto, CA 94305, USA.
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Neumann J, Boknik P, Kirchhefer U, Gergs U. The role of PP5 and PP2C in cardiac health and disease. Cell Signal 2021; 85:110035. [PMID: 33964402 DOI: 10.1016/j.cellsig.2021.110035] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 04/16/2021] [Accepted: 05/03/2021] [Indexed: 02/08/2023]
Abstract
Protein phosphatases are important, for example, as functional antagonists of β-adrenergic stimulation of the mammalian heart. While β-adrenergic stimulations increase the phosphorylation state of regulatory proteins and therefore force of contraction in the heart, these phosphorylations are reversed and thus force is reduced by the activity of protein phosphatases. In this context the role of PP5 and PP2C is starting to unravel. They do not belong to the same family of phosphatases with regard to sequence homology, many similarities with regard to location, activation by lipids and putative substrates have been worked out over the years. We also suggest which pathways for regulation of PP5 and/or PP2C described in other tissues and not yet in the heart might be useful to look for in cardiac tissue. Both phosphatases might play a role in signal transduction of sarcolemmal receptors in the heart. Expression of PP5 and PP2C can be increased by extracellular stimuli in the heart. Because PP5 is overexpressed in failing animal and human hearts, and because overexpression of PP5 or PP2C leads to cardiac hypertrophy and KO of PP5 leads to cardiac hypotrophy, one might argue for a role of PP5 and PP2C in heart failure. Because PP5 and PP2C can reduce, at least in vitro, the phosphorylation state of proteins thought to be relevant for cardiac arrhythmias, a role of these phosphatases for cardiac arrhythmias is also probable. Thus, PP5 and PP2C might be druggable targets to treat important cardiac diseases like heart failure, cardiac hypertrophy and cardiac arrhythmias.
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Affiliation(s)
- Joachim Neumann
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, Magdeburger Str. 4, D-06097 Halle, Germany.
| | - Peter Boknik
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Westfälische Wilhelms-Universität, Domagkstraße 12, D-48149 Münster, Germany.
| | - Uwe Kirchhefer
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Westfälische Wilhelms-Universität, Domagkstraße 12, D-48149 Münster, Germany.
| | - Ulrich Gergs
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, Magdeburger Str. 4, D-06097 Halle, Germany.
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9
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Bertucci EM, Mason MW, Camus AC, Rhodes OE, Parrott BB. Chronic low dose irradiation alters hepatic transcriptional profiles, but not global DNA methylation in medaka (Oryzias latipes). THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 729:138680. [PMID: 32361431 DOI: 10.1016/j.scitotenv.2020.138680] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 03/26/2020] [Accepted: 04/11/2020] [Indexed: 06/11/2023]
Abstract
Ionizing radiation (IR) resulting from both natural and anthropogenic sources is ubiquitous throughout the environment. Historically, studies on the biological impacts of radiation primarily focused on responses to acute doses of radiation, with little advancement in our understanding of environmentally relevant exposures. Epigenetic mechanisms are capable of mediating organismal responses to environmental stressors and DNA methylation plays important roles in gene regulation and promoting chromosomal stability. Here, we assess broad-scale transcriptional and epigenetic variation resulting from chronic exposure to low doses of ionizing radiation (LDIR; 5.78, 53.76, or 520.23 mGy/day) using Japanese medaka fish (Oryzias latipes) in a replicated mesocosm design. We observed significant changes to the hepatic transcriptome induced by a 3-month chronic exposure to IR, whereas global DNA methylation appeared largely unaffected. Our findings reveal a set of genes, including those involved in immune function, responding to environmentally relevant IR exposures, which do not appear to be mediated by a systemic global shift in DNA methylation.
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Affiliation(s)
- Emily M Bertucci
- Odum School of Ecology, University of Georgia, 140 E. Green St., Athens 30602, GA, USA; Savannah River Ecology Laboratory, University of Georgia, P.O. Drawer E, Aiken 29802, SC, USA.
| | - Marilyn W Mason
- Savannah River Ecology Laboratory, University of Georgia, P.O. Drawer E, Aiken 29802, SC, USA.
| | - Alvin C Camus
- College of Veterinary Medicine Department of Pathology, University of Georgia, 501 D.W. Brooks Drive, Athens 30602, GA, USA.
| | - Olin E Rhodes
- Odum School of Ecology, University of Georgia, 140 E. Green St., Athens 30602, GA, USA; Savannah River Ecology Laboratory, University of Georgia, P.O. Drawer E, Aiken 29802, SC, USA.
| | - Benjamin B Parrott
- Odum School of Ecology, University of Georgia, 140 E. Green St., Athens 30602, GA, USA; Savannah River Ecology Laboratory, University of Georgia, P.O. Drawer E, Aiken 29802, SC, USA.
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10
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Sager RA, Dushukyan N, Woodford M, Mollapour M. Structure and function of the co-chaperone protein phosphatase 5 in cancer. Cell Stress Chaperones 2020; 25:383-394. [PMID: 32239474 PMCID: PMC7193036 DOI: 10.1007/s12192-020-01091-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 03/04/2020] [Accepted: 03/12/2020] [Indexed: 12/12/2022] Open
Abstract
Protein phosphatase 5 (PP5) is a serine/threonine protein phosphatase that regulates many cellular functions including steroid hormone signaling, stress response, proliferation, apoptosis, and DNA repair. PP5 is also a co-chaperone of the heat shock protein 90 molecular chaperone machinery that assists in regulation of cellular signaling pathways essential for cell survival and growth. PP5 plays a significant role in survival and propagation of multiple cancers, which makes it a promising target for cancer therapy. Though there are several naturally occurring PP5 inhibitors, none is specific for PP5. Here, we review the roles of PP5 in cancer progression and survival and discuss the unique features of the PP5 structure that differentiate it from other phosphoprotein phosphatase (PPP) family members and make it an attractive therapeutic target.
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Affiliation(s)
- Rebecca A Sager
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
- Upstate Cancer Center, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
- College of Medicine, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
| | - Natela Dushukyan
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
- Upstate Cancer Center, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
| | - Mark Woodford
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
- Upstate Cancer Center, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
| | - Mehdi Mollapour
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY, 13210, USA.
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, 13210, USA.
- Upstate Cancer Center, SUNY Upstate Medical University, Syracuse, NY, 13210, USA.
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11
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Profile of Dr. Xiao-Fan Wang. SCIENCE CHINA-LIFE SCIENCES 2020; 63:329-331. [PMID: 32060862 DOI: 10.1007/s11427-020-1636-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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12
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Cell Cycle and DNA Repair Regulation in the Damage Response: Protein Phosphatases Take Over the Reins. Int J Mol Sci 2020; 21:ijms21020446. [PMID: 31936707 PMCID: PMC7014277 DOI: 10.3390/ijms21020446] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 12/29/2019] [Accepted: 01/02/2020] [Indexed: 12/14/2022] Open
Abstract
Cells are constantly suffering genotoxic stresses that affect the integrity of our genetic material. Genotoxic insults must be repaired to avoid the loss or inappropriate transmission of the genetic information, a situation that could lead to the appearance of developmental abnormalities and tumorigenesis. To combat this threat, eukaryotic cells have evolved a set of sophisticated molecular mechanisms that are collectively known as the DNA damage response (DDR). This surveillance system controls several aspects of the cellular response, including the detection of lesions, a temporary cell cycle arrest, and the repair of the broken DNA. While the regulation of the DDR by numerous kinases has been well documented over the last decade, the complex roles of protein dephosphorylation have only recently begun to be investigated. Here, we review recent progress in the characterization of DDR-related protein phosphatases during the response to a DNA lesion, focusing mainly on their ability to modulate the DNA damage checkpoint and the repair of the damaged DNA. We also discuss their protein composition and structure, target specificity, and biochemical regulation along the different stages encompassed in the DDR. The compilation of this information will allow us to better comprehend the physiological significance of protein dephosphorylation in the maintenance of genome integrity and cell viability in response to genotoxic stress.
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13
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Chauhan N, Wagh V, Joshi P, Jariyal H. ATM and ATR checkpoint kinase pathways: A concise review. ADVANCES IN HUMAN BIOLOGY 2020. [DOI: 10.4103/aihb.aihb_78_19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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14
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Li Z, Chen Y, Tang M, Li Y, Zhu WG. Regulation of DNA damage-induced ATM activation by histone modifications. ACTA ACUST UNITED AC 2019. [DOI: 10.1007/s42764-019-00004-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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15
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Song Q, Yi F, Zhang Y, Jun Li DK, Wei Y, Yu H, Zhang Y. CRKL regulates alternative splicing of cancer-related genes in cervical cancer samples and HeLa cell. BMC Cancer 2019; 19:499. [PMID: 31133010 PMCID: PMC6537309 DOI: 10.1186/s12885-019-5671-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 05/02/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Aberrant spliced isoforms are specifically associated with cancer progression and metastasis. The cytoplasmic adaptor CRKL (v-crk avian sarcoma virus CT10 oncogene homolog-like) is a CRK like proto-oncogene, which encodes a SH2 and SH3 (src homology) domain-containing adaptor protein. CRKL is tightly linked to leukemia via its binding partners BCR-ABL and TEL-ABL, upregulated in multiple types of human cancers, and induce cancer cell proliferation and invasion. However, it remains unclear whether signaling adaptors such as CRKL could regulate alternative splicing. METHODS We analyzed the expression level of CRKL in 305 cervical cancer tissue samples available in TCGA database, and then selected two groups of cancer samples with CRKL differentially expressed to analyzed potential CRKL-regulated alternative splicing events (ASEs). CRKL was knocked down by shRNA to further study CRKL-regulated alternative splicing and the activity of SR protein kinases in HeLa cells using RNA-Seq and Western blot techniques. We validated 43 CRKL-regulated ASEs detected by RNA-seq in HeLa cells, using RT-qPCR analysis of HeLa cell samples and using RNA-seq data of the two group of clinical cervical samples. RESULTS The expression of CRKL was mostly up-regulated in stage I cervical cancer samples. Knock-down of CRKL led to a reduced cell proliferation. CRKL-regulated alternative splicing of a large number of genes were enriched in cancer-related functional pathways, among which DNA repair and G2/M mitotic cell cycle, GnRH signaling were shared among the top 10 enriched GO terms and KEGG pathways by results from clinical samples and HeLa cell model. We showed that CRKL-regulated ASEs revealed by computational analysis using ABLas software in HeLa cell were highly validated by RT-qPCR, and also validated by cervical cancer clinical samples. CONCLUSIONS This is the first report of CRKL-regulation of the alternative splicing of a number of genes critical in tumorigenesis and cancer progression, which is consistent with CRKL reported role as a signaling adaptor and a kinase. Our results underline that the signaling adaptor CRKL might integrate the external and intrinsic cellular signals and coordinate the dynamic activation of cellular signaling pathways including alternative splicing regulation.
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Affiliation(s)
- Qingling Song
- Department of Oncology and Radiotherapy, Wuhan General Hospital of Guangzhou Military Command, Wuhan, 430070, Hubei Province, China
| | - Fengtao Yi
- Department of Oncology and Radiotherapy, Wuhan General Hospital of Guangzhou Military Command, Wuhan, 430070, Hubei Province, China.
| | - Yuhong Zhang
- Laboratory of Human Health and Genome Regulation, Wuhan, 430075, Hubei, China.,Center for Genome Analysis, ABLife Inc, Wuhan, 430075, Hubei, China
| | - Daniel K Jun Li
- Center for Genome Analysis, ABLife Inc, Wuhan, 430075, Hubei, China.,Department of Biology and Biotechnology, School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan, 430070, Hubei, China
| | - Yaxun Wei
- Center for Genome Analysis, ABLife Inc, Wuhan, 430075, Hubei, China
| | - Han Yu
- Laboratory of Human Health and Genome Regulation, Wuhan, 430075, Hubei, China
| | - Yi Zhang
- Laboratory of Human Health and Genome Regulation, Wuhan, 430075, Hubei, China. .,Center for Genome Analysis, ABLife Inc, Wuhan, 430075, Hubei, China.
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16
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The protein phosphatase gene MaPpt1 acts as a programmer of microcycle conidiation and a negative regulator of UV-B tolerance in Metarhizium acridum. Appl Microbiol Biotechnol 2019; 103:1351-1362. [DOI: 10.1007/s00253-018-9567-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 12/04/2018] [Accepted: 12/07/2018] [Indexed: 12/18/2022]
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17
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Mi Y, Gurumurthy RK, Zadora PK, Meyer TF, Chumduri C. Chlamydia trachomatis Inhibits Homologous Recombination Repair of DNA Breaks by Interfering with PP2A Signaling. mBio 2018; 9:e01465-18. [PMID: 30401777 PMCID: PMC6222135 DOI: 10.1128/mbio.01465-18] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 10/01/2018] [Indexed: 12/05/2022] Open
Abstract
Cervical and ovarian cancers exhibit characteristic mutational signatures that are reminiscent of mutational processes, including defective homologous recombination (HR) repair. How these mutational processes are initiated during carcinogenesis is largely unclear. Chlamydia trachomatis infections are epidemiologically associated with cervical and ovarian cancers. Previously, we showed that C. trachomatis induces DNA double-strand breaks (DSBs) but suppresses Ataxia-telangiectasia mutated (ATM) activation and cell cycle checkpoints. The mechanisms by which ATM regulation is modulated and its consequences for the repair pathway in C. trachomatis-infected cells remain unknown. Here, we found that Chlamydia bacteria interfere with the usual response of PP2A to DSBs. As a result, PP2A activity remains high, as the level of inhibitory phosphorylation at Y307 remains unchanged following C. trachomatis-induced DSBs. Protein-protein interaction analysis revealed that C. trachomatis facilitates persistent interactions of PP2A with ATM, thus suppressing ATM activation. This correlated with a remarkable lack of homologous recombination (HR) repair in C. trachomatis-infected cells. Chemical inhibition of PP2A activity in infected cells released ATM from PP2A, resulting in ATM phosphorylation. Activated ATM was then recruited to DSBs and initiated downstream signaling, including phosphorylation of MRE11 and NBS1 and checkpoint kinase 2 (Chk2)-mediated activation of the G2/M cell cycle checkpoint in C. trachomatis-infected cells. Further, PP2A inhibition led to the restoration of C. trachomatis-suppressed HR DNA repair function. Taking the data together, this study revealed that C. trachomatis modulates PP2A signaling to suppress ATM activation to prevent cell cycle arrest, thus contributing to a deficient high-fidelity HR pathway and a conducive environment for mutagenesis.IMPORTANCEChlamydia trachomatis induces DNA double-strand breaks in host cells but simultaneously inhibits proper DNA damage response and repair mechanisms. This may render host cells prone to loss of genetic integrity and transformation. Here we show that C. trachomatis prevents activation of the key DNA damage response mediator ATM by preventing the release from PP2A, leading to a complete absence of homologous recombination repair in host cells.
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Affiliation(s)
- Yang Mi
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
- Key Laboratory of H. pylori and Gastrointestinal Microecology of Henan Province, The Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | | | - Piotr K Zadora
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Thomas F Meyer
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Cindrilla Chumduri
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
- Department of Hepatology and Gastroenterology, Charité University Medicine, Berlin, Germany
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18
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Wang J, Shen T, Zhu W, Dou L, Gu H, Zhang L, Yang Z, Chen H, Zhou Q, Sánchez ER, Field LJ, Mayo LD, Xie Z, Xiao D, Lin X, Shou W, Yong W. Protein phosphatase 5 and the tumor suppressor p53 down-regulate each other's activities in mice. J Biol Chem 2018; 293:18218-18229. [PMID: 30262665 DOI: 10.1074/jbc.ra118.004256] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 09/17/2018] [Indexed: 12/20/2022] Open
Abstract
Protein phosphatase 5 (PP5), a serine/threonine phosphatase, has a wide range of biological functions and exhibits elevated expression in tumor cells. We previously reported that pp5-deficient mice have altered ataxia-telangiectasia mutated (ATM)-mediated signaling and function. However, this regulation was likely indirect, as ATM is not a known PP5 substrate. In the current study, we found that pp5-deficient mice are hypersensitive to genotoxic stress. This hypersensitivity was associated with the marked up-regulation of the tumor suppressor tumor protein p53 and its downstream targets cyclin-dependent kinase inhibitor 1A (p21), MDM2 proto-oncogene (MDM2), and phosphatase and tensin homolog (PTEN) in pp5-deficient tissues and cells. These observations suggested that PP5 plays a role in regulating p53 stability and function. Experiments conducted with p53 +/- pp5 +/- or p53 +/- pp5 -/- mice revealed that complete loss of PP5 reduces tumorigenesis in the p53 +/- mice. Biochemical analyses further revealed that PP5 directly interacts with and dephosphorylates p53 at multiple serine/threonine residues, resulting in inhibition of p53-mediated transcriptional activity. Interestingly, PP5 expression was significantly up-regulated in p53-deficient cells, and further analysis of pp5 promoter activity revealed that p53 strongly represses PP5 transcription. Our results suggest a reciprocal regulatory interplay between PP5 and p53, providing an important feedback mechanism for the cellular response to genotoxic stress.
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Affiliation(s)
- Jun Wang
- From the Comparative Medical Center, Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences, Beijing 100021, China,; School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Tao Shen
- DeBakey Department of Surgery, Baylor College of Medicine, Houston, Texas 77030
| | - Wuqiang Zhu
- Herman B. Wells Center for Pediatric Research, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Longyu Dou
- From the Comparative Medical Center, Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences, Beijing 100021, China
| | - Hao Gu
- From the Comparative Medical Center, Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences, Beijing 100021, China
| | - Lingling Zhang
- From the Comparative Medical Center, Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences, Beijing 100021, China
| | - Zhenyun Yang
- Herman B. Wells Center for Pediatric Research, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Hanying Chen
- Herman B. Wells Center for Pediatric Research, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Qi Zhou
- Herman B. Wells Center for Pediatric Research, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Edwin R Sánchez
- Department of Physiology and Pharmacology, College of Medicine, University of Toledo, Toledo, Ohio 43614, and
| | - Loren J Field
- Herman B. Wells Center for Pediatric Research, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Lindsey D Mayo
- Herman B. Wells Center for Pediatric Research, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Zhongwen Xie
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Deyong Xiao
- Fountain Valley Institute of Life Sciences and Fountain Valley Biomedical Technology Company, Dalian Hi-Tech Industrial Zone, Dalian 116023, China
| | - Xia Lin
- DeBakey Department of Surgery, Baylor College of Medicine, Houston, Texas 77030
| | - Weinian Shou
- Herman B. Wells Center for Pediatric Research, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana 46202,.
| | - Weidong Yong
- From the Comparative Medical Center, Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences, Beijing 100021, China,; Herman B. Wells Center for Pediatric Research, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana 46202,.
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19
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Lv JM, Chen L, Gao Y, Huang H, Pan XW, Liu X, Chen M, Qu FJ, Li L, Wang JK, Cui XG, Xu DF. PPP5C promotes cell proliferation and survival in human prostate cancer by regulating of the JNK and ERK1/2 phosphorylation. Onco Targets Ther 2018; 11:5797-5809. [PMID: 30254472 PMCID: PMC6140725 DOI: 10.2147/ott.s161280] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Background Prostate cancer (PCa) is one of the most common malignancies and a major leading cause of cancer-related deaths in males. And it is necessary to explore new molecular targets to enhance diagnosis and treatment level of the PCa. Serine/threonine protein phosphatase 5 (PPP5C) is a vital molecule that Involve in complex cell physiological activity. Purpose The objective of this study was to detecte the expression level of PPP5C in the tissue of prostate cancer patients and further discussed the PPP5C biological function and mechanisms on the PCa. Methods The expression level of PPP5C was analyzed by immunohistochemistry and ONCOM-INE datasets. Lentivirus-mediated short hairpin RNA (shRNA) was constructed to silence the expression of PPP5C in prostate cancer cell. Cell viability and proliferation were measured using MTT and colony formation, and the cell cycle and apoptosis was analyszed by flow cytometry. The changes of downstream protein level and protein phosphorylation level were detected by western blot. Results PPP5C was highly expressed in PCa tissue as analyzed by immunohistochemistry and ONCOMINE datasets. PPP5C Knockdown inhibited cell proliferation and colony formation in PCa cells. Flow cytometry analysis showed that DU145, PC3 and 22RV1 PCa cells deprived of PPP5C were arrested in G0/G1 phase and became apoptotic. Western blot analysis indicated that PPP5C knockdown could promote JNK and ERK phosphorylation. Conclusion Our study indicated that the PPP5C may become a new potential diagnostic biomarker and therapeutic target for the PCa.
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Affiliation(s)
- Jian-Min Lv
- Department of Urinary Surgery, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China, .,Department of Urinary Surgery, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China.,Department of Urinary Surgery, Third Affiliated Hospital, Second Military Medical University, Shanghai 201805, China,
| | - Lu Chen
- Department of Urinary Surgery, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China,
| | - Yi Gao
- Department of Urinary Surgery, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China,
| | - Hai Huang
- Department of Urinary Surgery, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China, .,Department of Urinary Surgery, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China.,Department of Urinary Surgery, Third Affiliated Hospital, Second Military Medical University, Shanghai 201805, China,
| | - Xiu-Wu Pan
- Department of Urinary Surgery, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China.,Department of Urinary Surgery, Third Affiliated Hospital, Second Military Medical University, Shanghai 201805, China,
| | - Xi Liu
- Department of Urinary Surgery, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China,
| | - Ming Chen
- Department of Urinary Surgery, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
| | - Fa-Jun Qu
- Department of Urinary Surgery, Third Affiliated Hospital, Second Military Medical University, Shanghai 201805, China,
| | - Lin Li
- Department of Urinary Surgery, Third Affiliated Hospital, Second Military Medical University, Shanghai 201805, China,
| | - Jun-Kai Wang
- Department of Urinary Surgery, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
| | - Xin-Gang Cui
- Department of Urinary Surgery, Third Affiliated Hospital, Second Military Medical University, Shanghai 201805, China, .,Department of Urinary Surgery, Gongli Hospital, Second Military Medical University, Shanghai 200135, China,
| | - Dan-Feng Xu
- Department of Urinary Surgery, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China,
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20
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Huang CY, Hsieh FS, Wang CY, Chen LJ, Chang SS, Tsai MH, Hung MH, Kuo CW, Shih CT, Chao TI, Chen KF. Palbociclib enhances radiosensitivity of hepatocellular carcinoma and cholangiocarcinoma via inhibiting ataxia telangiectasia-mutated kinase-mediated DNA damage response. Eur J Cancer 2018; 102:10-22. [PMID: 30103095 DOI: 10.1016/j.ejca.2018.07.010] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 07/12/2018] [Accepted: 07/13/2018] [Indexed: 12/15/2022]
Abstract
AIM Palbociclib is an oral cyclin-dependent kinase 4/6 inhibitor, which is efficacious in treating breast cancer. Currently, there are numerous active clinical trials testing palbociclib alone or in combination with other medications for treating various types of malignancies. Here, we evaluated the anti-cancer effect of palbociclib in combination with radiation therapy (RT) for treating human hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) and addressed the molecular mechanism behind the combination therapy. METHODS Immunofluorescence staining of γH2AX or 53BP1 was used to determine the effect of palbociclib on double-strand break (DSB) repair. Clonogenic assays, sphere formation and cell death ELISA were performed to study the sensitising effect of palbociclib on radiation-induced cytotoxicity. Signal alteration in DSB repair pathways was examined by Western blot analysis. Finally, we evaluated the in vivo anti-cancer activity and the associated molecular events of the combination therapy in a preclinical HCC xenograft model. RESULTS Palbociclib affected the kinetics of DNA repair and enhanced the radiation sensitivity of HCC and CCA cells. Importantly, we found that palbociclib inhibits ataxia telangiectasia-mutated (ATM) kinase, the key upstream kinase responding to RT-induced DSBs. Furthermore, we showed that the inhibitory effect of palbociclib on RT-induced ATM kinase activation is mediated by protein phosphatase 5 (PP5). Both in vitro and in vivo investigations revealed that the inhibition of the PP5-ATM axis by palbociclib after DNA damage is responsible for the synergism between palbociclib and RT. CONCLUSION Our findings provide a novel combination strategy against liver cancer cells. Clinical trials using palbociclib as an adjuvant in RT are warranted.
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Affiliation(s)
- Chao-Yuan Huang
- Division of Radiation Oncology, Department of Oncology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan; Department of Medical Imaging and Radiological Technology, Yuanpei University, Hsinchu, Taiwan
| | - Feng-Shu Hsieh
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan.
| | - Cheng-Yi Wang
- Department of Internal Medicine, Cardinal Tien Hospital, Fu Jen Catholic University, New Taipei City, Taiwan
| | - Li-Ju Chen
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan
| | - Shih-Shin Chang
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan
| | - Ming-Hsien Tsai
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan
| | - Man-Hsin Hung
- Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan; School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Chiung-Wen Kuo
- Department of Medical Imaging and Radiological Technology, Yuanpei University, Hsinchu, Taiwan
| | - Chi-Ting Shih
- Institute of Biopharmaceutical Sciences, National Yang-Ming University, Taipei, Taiwan
| | | | - Kuen-Feng Chen
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan; National Center of Excellence for Clinical Trial and Research, National Taiwan University Hospital, Taipei, Taiwan.
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21
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Gil RS, Vagnarelli P. Protein phosphatases in chromatin structure and function. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:90-101. [PMID: 30036566 PMCID: PMC6227384 DOI: 10.1016/j.bbamcr.2018.07.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 06/29/2018] [Accepted: 07/18/2018] [Indexed: 12/19/2022]
Abstract
Chromatin structure and dynamics are highly controlled and regulated processes that play an essential role in many aspects of cell biology. The chromatin transition stages and the factors that control this process are regulated by post-translation modifications, including phosphorylation. While the role of protein kinases in chromatin dynamics has been quite well studied, the nature and regulation of the counteracting phosphatases represent an emerging field but are still at their infancy. In this review we summarize the current literature on phosphatases involved in the regulation of chromatin structure and dynamics, with emphases on the major knowledge gaps that should require attention and more investigation.
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Affiliation(s)
- Raquel Sales Gil
- Colleges of Health and Life Science, Research Institute for Environment Health and Society, Brunel University London, London UB8 3PH, UK
| | - Paola Vagnarelli
- Colleges of Health and Life Science, Research Institute for Environment Health and Society, Brunel University London, London UB8 3PH, UK.
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22
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Zhu S, Fisher LA, Bessho T, Peng A. Protein phosphatase 1 and phosphatase 1 nuclear targeting subunit-dependent regulation of DNA-dependent protein kinase and non-homologous end joining. Nucleic Acids Res 2017; 45:10583-10594. [PMID: 28985363 PMCID: PMC5737533 DOI: 10.1093/nar/gkx686] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Accepted: 07/28/2017] [Indexed: 12/29/2022] Open
Abstract
DNA-dependent protein kinase catalytic subunit (DNA-PKcs) plays a key role in mediating non-homologous end joining (NHEJ), a major repair pathway for DNA double-strand breaks (DSBs). The activation, function and dynamics of DNA-PKcs is regulated largely by its reversible phosphorylation at numerous residues, many of which are targeted by DNA-PKcs itself. Interestingly, these DNA-PKcs phosphorylation sites function in a distinct, and sometimes opposing manner, suggesting that they are differentially regulated via complex actions of both kinases and phosphatases. In this study we identified several phosphatase subunits as potential DSB-associated proteins. In particular, protein phosphatase 1 (PP1) is recruited to a DSB-mimicking substrate in Xenopus egg extracts and sites of laser microirradiation in human cells. Depletion of PP1 impairs NHEJ in both Xenopus egg extracts and human cells. PP1 binds multiple motifs of DNA-PKcs, regulates DNA-PKcs phosphorylation, and is required for DNA-PKcs activation after DNA damage. Interestingly, phosphatase 1 nuclear targeting subunit (PNUTS), an inhibitory regulator of PP1, is also recruited to DNA damage sites to promote NHEJ. PNUTS associates with the DNA-PK complex and is required for DNA-PKcs phosphorylation at Ser-2056 and Thr-2609. Thus, PNUTS and PP1 together fine-tune the dynamic phosphorylation of DNA-PKcs after DNA damage to mediate NHEJ.
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Affiliation(s)
- Songli Zhu
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, NE 68583, USA
| | - Laura A Fisher
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, NE 68583, USA
| | - Tadayoshi Bessho
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Aimin Peng
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, NE 68583, USA
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23
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Abstract
The NBN component of the MRE11-RAD50-NBN (MRN) complex and the ATM kinase have been identified as clients of the HSP90α chaperone. Inhibition of HSP90 leads to reduced stability of NBN and ATM and an impaired DNA damage response. These results identify new regulatory details of the DNA damage response and further explain the chemosensitizing effects of HSP90 inhibitors.
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Affiliation(s)
- Travis H Stracker
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Spain
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24
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Hong SY. DNA damage response is hijacked by human papillomaviruses to complete their life cycle. J Zhejiang Univ Sci B 2017; 18:215-232. [PMID: 28271657 DOI: 10.1631/jzus.b1600306] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The DNA damage response (DDR) is activated when DNA is altered by intrinsic or extrinsic agents. This pathway is a complex signaling network and plays important roles in genome stability, tumor transformation, and cell cycle regulation. Human papillomaviruses (HPVs) are the main etiological agents of cervical cancer. Cervical cancer ranks as the fourth most common cancer among women and the second most frequent cause of cancer-related death worldwide. Over 200 types of HPVs have been identified and about one third of these infect the genital tract. The HPV life cycle is associated with epithelial differentiation. Recent studies have shown that HPVs deregulate the DDR to achieve a productive life cycle. In this review, I summarize current findings about how HPVs mediate the ataxia-telangiectasia mutated kinase (ATM) and the ATM-and RAD3-related kinase (ATR) DDRs, and focus on the roles that ATM and ATR signalings play in HPV viral replication. In addition, I demonstrate that the signal transducer and activator of transcription-5 (STAT)-5, an important immune regulator, can promote ATM and ATR activations through different mechanisms. These findings may provide novel opportunities for development of new therapeutic targets for HPV-related cancers.
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Affiliation(s)
- Shi-Yuan Hong
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
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25
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Lazo PA. Reverting p53 activation after recovery of cellular stress to resume with cell cycle progression. Cell Signal 2017; 33:49-58. [PMID: 28189587 DOI: 10.1016/j.cellsig.2017.02.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Revised: 01/23/2017] [Accepted: 02/06/2017] [Indexed: 11/17/2022]
Abstract
The activation of p53 in response to different types of cellular stress induces several protective reactions including cell cycle arrest, senescence or cell death. These protective effects are a consequence of the activation of p53 by specific phosphorylation performed by several kinases. The reversion of the cell cycle arrest, induced by p53, is a consequence of the phosphorylated and activated p53, which triggers its own downregulation and that of its positive regulators. The different down-regulatory processes have a sequential and temporal order of events. The mechanisms implicated in p53 down-regulation include phosphatases, deacetylases, and protein degradation by the proteasome or autophagy, which also affect different p53 protein targets and functions. The necessary first step is the dephosphorylation of p53 to make it available for interaction with mdm2 ubiquitin-ligase, which requires the activation of phosphatases targeting both p53 and p53-activating kinases. In addition, deacetylation of p53 is required to make lysine residues accessible to ubiquitin ligases. The combined action of these downregulatory mechanisms brings p53 protein back to its basal levels, and cell cycle progression can resume if cells have overcome the stress or damage situation. The specific targeting of these down-regulatory mechanisms can be exploited for therapeutic purposes in cancers harbouring wild-type p53.
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Affiliation(s)
- Pedro A Lazo
- Experimental Therapeutics and Translational Oncology Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, Salamanca, Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, Salamanca, Spain.
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26
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Zhou Y, Lee JH, Jiang W, Crowe JL, Zha S, Paull TT. Regulation of the DNA Damage Response by DNA-PKcs Inhibitory Phosphorylation of ATM. Mol Cell 2017; 65:91-104. [PMID: 27939942 PMCID: PMC5724035 DOI: 10.1016/j.molcel.2016.11.004] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 09/29/2016] [Accepted: 10/31/2016] [Indexed: 12/17/2022]
Abstract
Ataxia-telangiectasia mutated (ATM) regulates the DNA damage response as well as DNA double-strand break repair through homologous recombination. Here we show that ATM is hyperactive when the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs) is chemically inhibited or when the DNA-PKcs gene is deleted in human cells. Pre-incubation of ATM protein with active DNA-PKcs also significantly reduces ATM activity in vitro. We characterize several phosphorylation sites in ATM that are targets of DNA-PKcs and show that phospho-mimetic mutations at these residues significantly inhibit ATM activity and impair ATM signaling upon DNA damage. In contrast, phospho-blocking mutations at one cluster of sites increase the frequency of apoptosis during normal cell growth. DNA-PKcs, which is integral to the non-homologous end joining pathway, thus negatively regulates ATM activity through phosphorylation of ATM. These observations illuminate an important regulatory mechanism for ATM that also controls DNA repair pathway choice.
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Affiliation(s)
- Yi Zhou
- Howard Hughes Medical Institute, University of Texas at Austin, Austin, TX 78712, USA; Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Ji-Hoon Lee
- Howard Hughes Medical Institute, University of Texas at Austin, Austin, TX 78712, USA; Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Wenxia Jiang
- Institute for Cancer Genetics, Columbia University Medical Center, New York, NY 10032, USA; Department of Pathology and Cell Biology, Department of Pediatrics, Columbia University Medical Center, New York, NY 10032, USA
| | - Jennie L Crowe
- Institute for Cancer Genetics, Columbia University Medical Center, New York, NY 10032, USA; Department of Pathology and Cell Biology, Department of Pediatrics, Columbia University Medical Center, New York, NY 10032, USA
| | - Shan Zha
- Institute for Cancer Genetics, Columbia University Medical Center, New York, NY 10032, USA; Department of Pathology and Cell Biology, Department of Pediatrics, Columbia University Medical Center, New York, NY 10032, USA
| | - Tanya T Paull
- Howard Hughes Medical Institute, University of Texas at Austin, Austin, TX 78712, USA; Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA.
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27
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Graham ME, Lavin MF, Kozlov SV. Identification of ATM Protein Kinase Phosphorylation Sites by Mass Spectrometry. Methods Mol Biol 2017; 1599:127-144. [PMID: 28477116 DOI: 10.1007/978-1-4939-6955-5_10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
ATM (ataxia-telangiectasia mutated) protein kinase is a key regulator of cellular responses to DNA damage and oxidative stress. DNA damage triggers complex cascade of signaling events leading to numerous posttranslational modification on multitude of proteins. Understanding the regulation of ATM kinase is therefore critical not only for understanding the human genetic disorder ataxia-telangiectasia and potential treatment strategies, but essential for deciphering physiological responses of cells to stress. These responses play an important role in carcinogenesis, neurodegeneration, and aging. We focus here on the identification of DNA damage inducible ATM phosphorylation sites to understand the importance of autophosphorylation in the mechanism of ATM kinase activation. We demonstrate the utility of using immunoprecipitated ATM in quantitative LC-MS/MS workflow with stable isotope dimethyl labeling of ATM peptides for identification of phosphorylation sites.
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Affiliation(s)
- Mark E Graham
- Children's Medical Research Institute, University of Sydney, Westmead, NSW, 2145, Australia
| | - Martin F Lavin
- University of Queensland Centre for Clinical Research (UQCCR), University of Queensland, Building 71/918, Royal Brisbane & Women's Hospital Campus, Herston, Brisbane, QLD4029, Australia
| | - Sergei V Kozlov
- University of Queensland Centre for Clinical Research (UQCCR), University of Queensland, Building 71/918, Royal Brisbane & Women's Hospital Campus, Herston, Brisbane, QLD4029, Australia.
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28
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Walkowiak-Przybyło M, Komorowski P, Walkowiak B. Differences in the expression of cell cycle genes in osteoblasts and endothelial cells cultured on the surfaces of Ti6Al4V and Ti6Al7Nb alloys. J Biomed Mater Res A 2016; 105:1607-1617. [PMID: 28002653 DOI: 10.1002/jbm.a.35972] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 11/22/2016] [Accepted: 11/28/2016] [Indexed: 11/11/2022]
Abstract
Three medically used alloys (Ti6Al4V, Ti6Al7Nb, and AISI 316 L) are compared due to proliferative potential and metabolic response of human cells (osteoblasts line Saos-2 and endothelial cells line EA.hy-926) seeded on the surfaces of these alloys. Although no statistically significant difference in the proliferative potential of the cells cultured on the surfaces of examined biomaterials was observed, it does not exclude relevant differences in metabolic response of these cells assessed as changes in genes' expression. As a result of our studies it was demonstrated that the changes in the expression of examined genes were very common. Our observation suggests the presence of the process of selective recognition of the contacted biomaterials by the cells seeded on their surfaces. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1607-1617, 2017.
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Affiliation(s)
- M Walkowiak-Przybyło
- Division of Biophysics, Institute of Materials Engineering, Lodz University of Technology, Stefanowskiego 1/15, Lodz, 90-924, Poland
| | - P Komorowski
- Division of Biophysics, Institute of Materials Engineering, Lodz University of Technology, Stefanowskiego 1/15, Lodz, 90-924, Poland.,BioNanoPark Laboratories, Lodz Regional Park of Science and Technologies, Dubois 114/116, 93-465 Lodz, Poland
| | - B Walkowiak
- Division of Biophysics, Institute of Materials Engineering, Lodz University of Technology, Stefanowskiego 1/15, Lodz, 90-924, Poland.,BioNanoPark Laboratories, Lodz Regional Park of Science and Technologies, Dubois 114/116, 93-465 Lodz, Poland
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29
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Jiang Y, Chen HC, Su X, Thompson PA, Liu X, Do KA, Wierda W, Keating MJ, Plunkett W. ATM function and its relationship with ATM gene mutations in chronic lymphocytic leukemia with the recurrent deletion (11q22.3-23.2). Blood Cancer J 2016; 6:e465. [PMID: 27588518 PMCID: PMC5056966 DOI: 10.1038/bcj.2016.69] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 07/06/2016] [Indexed: 01/02/2023] Open
Abstract
Approximately 10–20% of chronic lymphocytic leukemia (CLL) patients exhibit del(11q22–23) before treatment, this cohort increases to over 40% upon progression following chemoimmunotherapy. The coding sequence of the DNA damage response gene, ataxia-telangiectasia-mutated (ATM), is contained in this deletion. The residual ATM allele is frequently mutated, suggesting a relationship between gene function and clinical response. To investigate this possibility, we sought to develop and validate an assay for the function of ATM protein in these patients. SMC1 (structural maintenance of chromosomes 1) and KAP1 (KRAB-associated protein 1) were found to be unique substrates of ATM kinase by immunoblot detection following ionizing radiation. Using a pool of eight fluorescence in situ hybridization-negative CLL samples as a standard, the phosphorylation of SMC1 and KAP1 from 46 del (11q22–23) samples was analyzed using normal mixture model-based clustering. This identified 13 samples (28%) that were deficient in ATM function. Targeted sequencing of the ATM gene of these samples, with reference to genomic DNA, revealed 12 somatic mutations and 15 germline mutations in these samples. No strong correlation was observed between ATM mutation and function. Therefore, mutation status may not be taken as an indicator of ATM function. Rather, a direct assay of the kinase activity should be used in the development of therapies.
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Affiliation(s)
- Y Jiang
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - H-C Chen
- Department of Biostatistics, Houston, TX, USA
| | - X Su
- Department of Bioinformatics and Computational Biology, Houston, TX, USA
| | - P A Thompson
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - X Liu
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - K-A Do
- Department of Biostatistics, Houston, TX, USA
| | - W Wierda
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - M J Keating
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - W Plunkett
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.,Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
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Kozlov SV, Waardenberg AJ, Engholm-Keller K, Arthur JW, Graham ME, Lavin M. Reactive Oxygen Species (ROS)-Activated ATM-Dependent Phosphorylation of Cytoplasmic Substrates Identified by Large-Scale Phosphoproteomics Screen. Mol Cell Proteomics 2016; 15:1032-47. [PMID: 26699800 PMCID: PMC4813686 DOI: 10.1074/mcp.m115.055723] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 12/08/2015] [Indexed: 01/06/2023] Open
Abstract
Ataxia-telangiectasia, mutated (ATM) protein plays a central role in phosphorylating a network of proteins in response to DNA damage. These proteins function in signaling pathways designed to maintain the stability of the genome and minimize the risk of disease by controlling cell cycle checkpoints, initiating DNA repair, and regulating gene expression. ATM kinase can be activated by a variety of stimuli, including oxidative stress. Here, we confirmed activation of cytoplasmic ATM by autophosphorylation at multiple sites. Then we employed a global quantitative phosphoproteomics approach to identify cytoplasmic proteins altered in their phosphorylation state in control and ataxia-telangiectasia (A-T) cells in response to oxidative damage. We demonstrated that ATM was activated by oxidative damage in the cytoplasm as well as in the nucleus and identified a total of 9,833 phosphorylation sites, including 6,686 high-confidence sites mapping to 2,536 unique proteins. A total of 62 differentially phosphorylated peptides were identified; of these, 43 were phosphorylated in control but not in A-T cells, and 19 varied in their level of phosphorylation. Motif enrichment analysis of phosphopeptides revealed that consensus ATM serine glutamine sites were overrepresented. When considering phosphorylation events, only observed in control cells (not observed in A-T cells), with predicted ATM sites phosphoSerine/phosphoThreonine glutamine, we narrowed this list to 11 candidate ATM-dependent cytoplasmic proteins. Two of these 11 were previously described as ATM substrates (HMGA1 and UIMCI/RAP80), another five were identified in a whole cell extract phosphoproteomic screens, and the remaining four proteins had not been identified previously in DNA damage response screens. We validated the phosphorylation of three of these proteins (oxidative stress responsive 1 (OSR1), HDGF, and ccdc82) as ATM dependent after H2O2 exposure, and another protein (S100A11) demonstrated ATM-dependence for translocation from the cytoplasm to the nucleus. These data provide new insights into the activation of ATM by oxidative stress through identification of novel substrates for ATM in the cytoplasm.
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Affiliation(s)
- Sergei V Kozlov
- From the ‡University of Queensland Centre for Clinical Research, University of Queensland, Royal Brisbane & Women's Hospital Campus, Herston, Brisbane, QLD 4029 Australia
| | - Ashley J Waardenberg
- §Bioinformatics Unit, Children's Medical Research Institute, University of Sydney, 214 Hawkesbury Road, Westmead, NSW, 2145, Australia
| | - Kasper Engholm-Keller
- ¶Synapse Proteomics Group, Children's Medical Research Institute, University of Sydney, 214 Hawkesbury Road, Westmead, NSW, 2145, Australia; ‖Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Jonathan W Arthur
- §Bioinformatics Unit, Children's Medical Research Institute, University of Sydney, 214 Hawkesbury Road, Westmead, NSW, 2145, Australia
| | - Mark E Graham
- ¶Synapse Proteomics Group, Children's Medical Research Institute, University of Sydney, 214 Hawkesbury Road, Westmead, NSW, 2145, Australia
| | - Martin Lavin
- From the ‡University of Queensland Centre for Clinical Research, University of Queensland, Royal Brisbane & Women's Hospital Campus, Herston, Brisbane, QLD 4029 Australia;
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31
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Liu Y, Li Y, Lu X. Regulators in the DNA damage response. Arch Biochem Biophys 2016; 594:18-25. [PMID: 26882840 DOI: 10.1016/j.abb.2016.02.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 02/11/2016] [Accepted: 02/12/2016] [Indexed: 01/05/2023]
Abstract
Maintenance of genome integrity is essential for the proper function of all cells and organisms. In response to both endogenous and exogenous DNA damaging agents, mammalian cells have evolved a delicate system to sense DNA damage, stop cell cycle progression, modulate cell metabolism, repair damaged DNA, and induce programmed cell death if the damage is too severe. This coordinated global signaling network, namely the DNA damage response (DDR), ensures the genome stability under DNA damaging stress. A variety of regulators have been shown to modulate the activity and levels of key proteins in the DDR, including kinases, phosphatases, ubiquitin ligases, deubiquitinases, and other protein modifying enzymes. Epigenetic regulators, particularly microRNAs and long noncoding RNAs, have been emerging as an important payer of regulation in addition to canonical DNA damage signaling proteins. In this review, we will discuss the functional interaction between the regulators and their targets in the DDR.
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Affiliation(s)
- Yunhua Liu
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
| | - Yujing Li
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
| | - Xiongbin Lu
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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32
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ATM kinase: Much more than a DNA damage responsive protein. DNA Repair (Amst) 2015; 39:1-20. [PMID: 26777338 DOI: 10.1016/j.dnarep.2015.12.009] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Revised: 12/21/2015] [Accepted: 12/21/2015] [Indexed: 11/22/2022]
Abstract
ATM, mutation of which causes Ataxia telangiectasia, has emerged as a cardinal multifunctional protein kinase during past two decades as evidenced by various studies from around the globe. Further to its well established and predominant role in DNA damage response, ATM has also been understood to help in maintaining overall functional integrity of cells; since its mutation, inactivation or deficiency results in a variety of pathological manifestations besides DNA damage. These include oxidative stress, metabolic syndrome, mitochondrial dysfunction as well as neurodegeneration. Recently, high throughput screening using proteomics, metabolomics and transcriptomic studies revealed several proteins which might be acting as substrates of ATM. Studies that can help in identifying effective regulatory controls within the ATM-mediated pathways/mechanisms can help in developing better therapeutics. In fact, more in-depth understanding of ATM-dependent cellular signals could also help in the treatment of variety of other disease conditions since these pathways seem to control many critical cellular functions. In this review, we have attempted to put together a detailed yet lucid picture of the present-day understanding of ATM's role in various pathophysiological conditions involving DNA damage and beyond.
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Abstract
ATM and ATR signaling pathways are well conserved throughout evolution and are central to the maintenance of genome integrity. Although the role of both ATM and ATR in DNA repair, cell cycle regulation and apoptosis have been well studied, both still remain in the focus of current research activities owing to their role in cancer. Recent advances in the field suggest that these proteins have an additional function in maintaining cellular homeostasis under both stressed and non-stressed conditions. In this Cell Science at a Glance article and the accompanying poster, we present an overview of recent advances in ATR and ATM research with emphasis on that into the modes of ATM and ATR activation, the different signaling pathways they participate in - including those that do not involve DNA damage - and highlight their relevance in cancer.
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Affiliation(s)
- Poorwa Awasthi
- Developmental Toxicology Laboratory, Systems Toxicology and Health Risk Assessment Group, CSIR-Indian Institute of Toxicology Research, M.G. Marg 80, Lucknow 226001, India Academy of Scientific and Innovative Research (AcSIR), CSIR-IITR campus, Lucknow 226001, India
| | - Marco Foiani
- IFOM (Fondazione Istituto FIRC di Oncologia Molecolare), IFOM-IEO Campus Via Adamello 16, Milan 20139, Italy DSBB-Università degli Studi di Milano, Milan 20133, Italy
| | - Amit Kumar
- Developmental Toxicology Laboratory, Systems Toxicology and Health Risk Assessment Group, CSIR-Indian Institute of Toxicology Research, M.G. Marg 80, Lucknow 226001, India Academy of Scientific and Innovative Research (AcSIR), CSIR-IITR campus, Lucknow 226001, India
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34
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Selective activators of protein phosphatase 5 target the auto-inhibitory mechanism. Biosci Rep 2015; 35:BSR20150042. [PMID: 26182372 PMCID: PMC4721540 DOI: 10.1042/bsr20150042] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 03/06/2015] [Indexed: 12/18/2022] Open
Abstract
This paper describes the identification of compounds, which stimulate the activity of the protein phosphatase PPH-5 and addresses the influence of the identified compounds on the enzymatic properties and the potential mechanism of their action. Protein phosphatase 5 (PP5) is an evolutionary conserved serine/threonine phosphatase. Its dephosphorylation activity modulates a diverse set of cellular factors including protein kinases and the microtubule-associated tau protein involved in neurodegenerative disorders. It is auto-regulated by its heat-shock protein (Hsp90)-interacting tetratricopeptide repeat (TPR) domain and its C-terminal α-helix. In the present study, we report the identification of five specific PP5 activators [PP5 small-molecule activators (P5SAs)] that enhance the phosphatase activity up to 8-fold. The compounds are allosteric modulators accelerating efficiently the turnover rate of PP5, but do barely affect substrate binding or the interaction between PP5 and the chaperone Hsp90. Enzymatic studies imply that the compounds bind to the phosphatase domain of PP5. For the most promising compound crystallographic comparisons of the apo PP5 and the PP5–P5SA-2 complex indicate a relaxation of the auto-inhibited state of PP5. Residual electron density and mutation analyses in PP5 suggest activator binding to a pocket in the phosphatase/TPR domain interface, which may exert regulatory functions. These compounds thus may expose regulatory mechanisms in the PP5 enzyme and serve to develop optimized activators based on these scaffolds.
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35
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Doherty K, Meere M, Piiroinen PT. Some mathematical models of intermolecular autophosphorylation. J Theor Biol 2015; 370:27-38. [PMID: 25636493 DOI: 10.1016/j.jtbi.2015.01.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 01/08/2015] [Accepted: 01/15/2015] [Indexed: 11/26/2022]
Abstract
Intermolecular autophosphorylation refers to the process whereby a molecule of an enzyme phosphorylates another molecule of the same enzyme. The enzyme thereby catalyses its own phosphorylation. In the present paper, we develop two generic models of intermolecular autophosphorylation that also include dephosphorylation by a phosphatase of constant concentration. The first of these, a solely time-dependent model, is written as one ordinary differential equation that relies upon mass-action and Michaelis-Menten kinetics. Beginning with the enzyme in its dephosphorylated state, it predicts a lag before the enzyme becomes significantly phosphorylated, for suitable parameter values. It also predicts that there exists a threshold concentration for the phosphorylation of enzyme and that for suitable parameter values, a continuous or discontinuous switch in the phosphorylation of enzyme are possible. The model developed here has the advantage that it is relatively easy to analyse compared with most existing models for autophosphorylation and can qualitatively describe many different systems. We also extend our time-dependent model of autophosphorylation to include a spatial dependence, as well as localised binding reactions. This spatio-temporal model consists of a system of partial differential equations that describe a soluble autophosphorylating enzyme in a spherical geometry. We use the spatio-temporal model to describe the phosphorylation of an enzyme throughout the cell due to an increase in local concentration by binding. Using physically realistic values for model parameters, our results provide a proof-of-concept of the process of activation by local concentration and suggest that, in the presence of a phosphatase, this activation can be irreversible.
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Affiliation(s)
- Kevin Doherty
- School of Mathematics, Statistics and Applied Mathematics, National University of Ireland, Galway, University Road, Galway, Ireland; AgroParisTech, CRNH-IdF, UMR914, Nutrition Physiology and Ingestive Behavior, F-75005 Paris, France; INRA, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, F-75005 Paris, France.
| | - Martin Meere
- School of Mathematics, Statistics and Applied Mathematics, National University of Ireland, Galway, University Road, Galway, Ireland.
| | - Petri T Piiroinen
- School of Mathematics, Statistics and Applied Mathematics, National University of Ireland, Galway, University Road, Galway, Ireland.
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36
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Abstract
The ataxia-telangiectasia mutated (ATM) protein kinase is a master regulator of the DNA damage response, and it coordinates checkpoint activation, DNA repair, and metabolic changes in eukaryotic cells in response to DNA double-strand breaks and oxidative stress. Loss of ATM activity in humans results in the pleiotropic neurodegeneration disorder ataxia-telangiectasia. ATM exists in an inactive state in resting cells but can be activated by the Mre11-Rad50-Nbs1 (MRN) complex and other factors at sites of DNA breaks. In addition, oxidation of ATM activates the kinase independently of the MRN complex. This review discusses these mechanisms of activation, as well as the posttranslational modifications that affect this process and the cellular factors that affect the efficiency and specificity of ATM activation and substrate phosphorylation. I highlight functional similarities between the activation mechanisms of ATM, phosphatidylinositol 3-kinases (PI3Ks), and the other PI3K-like kinases, as well as recent structural insights into their regulation.
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Affiliation(s)
- Tanya T Paull
- Howard Hughes Medical Institute, Department of Molecular Biosciences, and Institute for Cellular and Molecular Biology, University of Texas, Austin, Texas 78712;
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37
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Kawasumi M, Bradner JE, Tolliday N, Thibodeau R, Sloan H, Brummond KM, Nghiem P. Identification of ATR-Chk1 pathway inhibitors that selectively target p53-deficient cells without directly suppressing ATR catalytic activity. Cancer Res 2014; 74:7534-45. [PMID: 25336189 DOI: 10.1158/0008-5472.can-14-2650] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Resistance to DNA-damaging chemotherapy is a barrier to effective treatment that appears to be augmented by p53 functional deficiency in many cancers. In p53-deficient cells in which the G1-S checkpoint is compromised, cell viability after DNA damage relies upon intact intra-S and G2-M checkpoints mediated by the ATR (ataxia telangiectasia and Rad3 related) and Chk1 kinases. Thus, a logical rationale to sensitize p53-deficient cancers to DNA-damaging chemotherapy is through the use of ATP-competitive inhibitors of ATR or Chk1. To discover small molecules that may act on uncharacterized components of the ATR pathway, we performed a phenotype-based screen of 9,195 compounds for their ability to inhibit hydroxyurea-induced phosphorylation of Ser345 on Chk1, known to be a critical ATR substrate. This effort led to the identification of four small-molecule compounds, three of which were derived from known bioactive library (anthothecol, dihydrocelastryl, and erysolin) and one of which was a novel synthetic compound termed MARPIN. These compounds all inhibited ATR-selective phosphorylation and sensitized p53-deficient cancer cells to DNA-damaging agents in vitro and in vivo. Notably, these compounds did not inhibit ATR catalytic activity in vitro, unlike typical ATP-competitive inhibitors, but acted in a mechanistically distinct manner to disable ATR-Chk1 function. Our results highlight a set of novel molecular probes to further elucidate druggable mechanisms to improve cancer therapeutic responses produced by DNA-damaging drugs.
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Affiliation(s)
- Masaoki Kawasumi
- Division of Dermatology, Department of Medicine, University of Washington, Seattle, Washington.
| | - James E Bradner
- The Broad Institute of MIT and Harvard, Cambridge, Massachusetts. Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts. Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Nicola Tolliday
- The Broad Institute of MIT and Harvard, Cambridge, Massachusetts
| | - Renee Thibodeau
- Division of Dermatology, Department of Medicine, University of Washington, Seattle, Washington
| | - Heather Sloan
- Division of Dermatology, Department of Medicine, University of Washington, Seattle, Washington
| | - Kay M Brummond
- University of Pittsburgh Center for Chemical Methodologies and Library Development, Pittsburgh, Pennsylvania
| | - Paul Nghiem
- Division of Dermatology, Department of Medicine, University of Washington, Seattle, Washington. Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington.
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38
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Knockdown of PPP5C inhibits growth of hepatocellular carcinoma cells in vitro. Appl Biochem Biotechnol 2014; 175:526-34. [PMID: 25326185 DOI: 10.1007/s12010-014-1281-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 09/30/2014] [Indexed: 02/07/2023]
Abstract
Ser/Thr protein phosphatase 5 (PPP5C) has been reported to participate in tumor progression. However, its functional role in hepatocellular carcinoma (HCC) remains unknown yet. In this study, we firstly evaluated the expression levels of PPP5C in six HCC cell lines by real-time PCR and found that PPP5C was widely expressed in HCC cells. To explore the role of PPP5C in HCC cell growth, lentivirus-mediated short hairpin RNA (shRNA) was employed to silence PPP5C expression in HepG2 and Bel-7404 cells. The expression of PPP5C was significantly downregulated in PPP5C knockdown cells. Knockdown of PPP5C markedly suppressed the proliferation and colony formation ability of HCC cells. Moreover, cell cycle analysis showed that PPP5C depletion in HepG2 cells led to G0/G1 phase and G2/M phase arrest. We demonstrate for the first time that PPP5C is essential for growth of HCC cells, which suggests that inhibition of PPP5C by RNAi may be a potential therapeutic strategy for the treatment of HCC.
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Multifunctional role of ATM/Tel1 kinase in genome stability: from the DNA damage response to telomere maintenance. BIOMED RESEARCH INTERNATIONAL 2014; 2014:787404. [PMID: 25247188 PMCID: PMC4163350 DOI: 10.1155/2014/787404] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 07/28/2014] [Accepted: 08/07/2014] [Indexed: 12/19/2022]
Abstract
The mammalian protein kinase ataxia telangiectasia mutated (ATM) is a key regulator of the DNA double-strand-break response and belongs to the evolutionary conserved phosphatidylinositol-3-kinase-related protein kinases. ATM deficiency causes ataxia telangiectasia (AT), a genetic disorder that is characterized by premature aging, cerebellar neuropathy, immunodeficiency, and predisposition to cancer. AT cells show defects in the DNA damage-response pathway, cell-cycle control, and telomere maintenance and length regulation. Likewise, in Saccharomyces cerevisiae, haploid strains defective in the TEL1 gene, the ATM ortholog, show chromosomal aberrations and short telomeres. In this review, we outline the complex role of ATM/Tel1 in maintaining genomic stability through its control of numerous aspects of cellular survival. In particular, we describe how ATM/Tel1 participates in the signal transduction pathways elicited by DNA damage and in telomere homeostasis and its importance as a barrier to cancer development.
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40
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Hu K, Li W, Gao J, Liu Q, Wang H, Wang Y, Sang J. Role of Ppt1 in multiple stress responses in Candida albicans. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s11434-014-0552-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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41
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Abstract
The prevalence of diabetes is increasing rapidly worldwide. A cardinal feature of most forms of diabetes is the lack of insulin-producing capability, due to the loss of insulin-producing β-cells, impaired glucose-sensitive insulin secretion from the β-cell, or a combination thereof, the reasons for which largely remain elusive. Reversible phosphorylation is an important and versatile mechanism for regulating the biological activity of many intracellular proteins, which, in turn, controls a variety of cellular functions. For instance, significant changes in protein kinase activities and in protein phosphorylation patterns occur subsequent to the stimulation of insulin release by glucose. Therefore, the molecular mechanisms regulating the phosphorylation of proteins involved in the insulin secretory process by the β-cell have been extensively investigated. However, far less is known about the role and regulation of protein dephosphorylation by various protein phosphatases. Herein, we review extant data implicating serine/threonine and tyrosine phosphatases in various aspects of healthy and diabetic islet biology, ranging from control of hormonal stimulus-secretion coupling to mitogenesis and apoptosis.
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Affiliation(s)
- Henrik Ortsäter
- Biovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, SwedenBiovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, Sweden
| | - Nina Grankvist
- Biovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, Sweden
| | - Richard E Honkanen
- Biovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, Sweden
| | - Åke Sjöholm
- Biovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, SwedenBiovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, SwedenBiovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, Sweden
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Mazalouskas MD, Godoy-Ruiz R, Weber DJ, Zimmer DB, Honkanen RE, Wadzinski BE. Small G proteins Rac1 and Ras regulate serine/threonine protein phosphatase 5 (PP5)·extracellular signal-regulated kinase (ERK) complexes involved in the feedback regulation of Raf1. J Biol Chem 2013; 289:4219-32. [PMID: 24371145 DOI: 10.1074/jbc.m113.518514] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Serine/threonine protein phosphatase 5 (PP5, PPP5C) is known to interact with the chaperonin heat shock protein 90 (HSP90) and is involved in the regulation of multiple cellular signaling cascades that control diverse cellular processes, such as cell growth, differentiation, proliferation, motility, and apoptosis. Here, we identify PP5 in stable complexes with extracellular signal-regulated kinases (ERKs). Studies using mutant proteins reveal that the formation of PP5·ERK1 and PP5·ERK2 complexes partially depends on HSP90 binding to PP5 but does not require PP5 or ERK1/2 activity. However, PP5 and ERK activity regulates the phosphorylation state of Raf1 kinase, an upstream activator of ERK signaling. Whereas expression of constitutively active Rac1 promotes the assembly of PP5·ERK1/2 complexes, acute activation of ERK1/2 fails to influence the phosphatase-kinase interaction. Introduction of oncogenic HRas (HRas(V12)) has no effect on PP5-ERK1 binding but selectively decreases the interaction of PP5 with ERK2, in a manner that is independent of PP5 and MAPK/ERK kinase (MEK) activity, yet paradoxically requires ERK2 activity. Additional studies conducted with oncogenic variants of KRas4B reveal that KRas(L61), but not KRas(V12), also decreases the PP5-ERK2 interaction. The expression of wild type HRas or KRas proteins fails to reduce PP5-ERK2 binding, indicating that the effect is specific to HRas(V12) and KRas(L61) gain-of-function mutations. These findings reveal a novel, differential responsiveness of PP5-ERK1 and PP5-ERK2 interactions to select oncogenic Ras variants and also support a role for PP5·ERK complexes in regulating the feedback phosphorylation of PP5-associated Raf1.
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Affiliation(s)
- Matthew D Mazalouskas
- From the Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-6600
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43
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The ATM-mediated DNA-damage response. Mol Oncol 2013. [DOI: 10.1017/cbo9781139046947.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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44
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Connarn JN, Assimon VA, Reed RA, Tse E, Southworth DR, Zuiderweg ERP, Gestwicki JE, Sun D. The molecular chaperone Hsp70 activates protein phosphatase 5 (PP5) by binding the tetratricopeptide repeat (TPR) domain. J Biol Chem 2013; 289:2908-17. [PMID: 24327656 DOI: 10.1074/jbc.m113.519421] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Protein phosphatase 5 (PP5) is auto-inhibited by intramolecular interactions with its tetratricopeptide repeat (TPR) domain. Hsp90 has been shown to bind PP5 to activate its phosphatase activity. However, the functional implications of binding Hsp70 to PP5 are not yet clear. In this study, we find that both Hsp90 and Hsp70 bind to PP5 using a luciferase fragment complementation assay. A fluorescence polarization assay shows that Hsp90 (MEEVD motif) binds to the TPR domain of PP5 almost 3-fold higher affinity than Hsp70 (IEEVD motif). However, Hsp70 binding to PP5 stimulates higher phosphatase activity of PP5 than the binding of Hsp90. We find that PP5 forms a stable 1:1 complex with Hsp70, but the interaction appears asymmetric with Hsp90, with one PP5 binding the dimer. Solution NMR studies reveal that Hsc70 and PP5 proteins are dynamically independent in complex, tethered by a disordered region that connects the Hsc70 core and the IEEVD-TPR contact area. This tethered binding is expected to allow PP5 to carry out multi-site dephosphorylation of Hsp70-bound clients with a range of sizes and shapes. Together, these results demonstrate that Hsp70 recruits PP5 and activates its phosphatase activity which suggests dual roles for PP5 that might link chaperone systems with signaling pathways in cancer and development.
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45
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Eliaš J, Dimitrio L, Clairambault J, Natalini R. The p53 protein and its molecular network: modelling a missing link between DNA damage and cell fate. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1844:232-47. [PMID: 24113167 DOI: 10.1016/j.bbapap.2013.09.019] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 09/23/2013] [Accepted: 09/25/2013] [Indexed: 12/29/2022]
Abstract
Various molecular pharmacokinetic-pharmacodynamic (PK-PD) models have been proposed in the last decades to represent and predict drug effects in anticancer chemotherapies. Most of these models are cell population based since clearly measurable effects of drugs can be seen much more easily on populations of cells, healthy and tumour, than in individual cells. The actual targets of drugs are, however, cells themselves. The drugs in use either disrupt genome integrity by causing DNA strand breaks, and consequently initiate programmed cell death, or block cell proliferation mainly by inhibiting factors that enable cells to proceed from one cell cycle phase to the next through checkpoints in the cell division cycle. DNA damage caused by cytotoxic drugs (and also cytostatic drugs at high concentrations) activates, among others, the p53 protein-modulated signalling pathways that directly or indirectly force the cell to make a decision between survival and death. The paper aims to become the first-step in a larger scale enterprise that should bridge the gap between intracellular and population PK-PD models, providing oncologists with a rationale to predict and optimise the effects of anticancer drugs in the clinic. So far, it only sticks at describing p53 activation and regulation in single cells following their exposure to DNA damaging stress agents. We show that p53 oscillations that have been observed in individual cells can be reconstructed and predicted by compartmentalising cellular events occurring after DNA damage, either in the nucleus or in the cytoplasm, and by describing network interactions, using ordinary differential equations (ODEs), between the ATM, p53, Mdm2 and Wip1 proteins, in each compartment, nucleus or cytoplasm, and between the two compartments. This article is part of a Special Issue entitled: Computational Proteomics, Systems Biology & Clinical Implications.
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Affiliation(s)
- Ján Eliaš
- UPMC, Laboratoire Jacques-Louis Lions, 4 Place Jussieu, F-75005 Paris, France; INRIA Paris-Rocquencourt, Bang project-team, Paris and Rocquencourt, France.
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46
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Rodriguez-Hernandez CJ, Llorens-Agost M, Calbó J, Murguia JR, Guinovart JJ. Sodium tungstate modulates ATM function upon DNA damage. FEBS Lett 2013; 587:1579-86. [PMID: 23587483 DOI: 10.1016/j.febslet.2013.04.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 04/02/2013] [Indexed: 11/20/2022]
Abstract
Both radiotherapy and most effective chemotherapeutic agents induce different types of DNA damage. Here we show that tungstate modulates cell response to DNA damaging agents. Cells treated with tungstate were more sensitive to etoposide, phleomycin and ionizing radiation (IR), all of which induce DNA double-strand breaks (DSBs). Tungstate also modulated the activation of the central DSB signalling kinase, ATM, in response to these agents. These effects required the functionality of the Mre11-Nbs1-Rad50 (MRN) complex and were mimicked by the inhibition of PP2A phosphatase. Therefore, tungstate may have adjuvant activity when combined with DNA-damaging agents in the treatment of several malignancies.
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47
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Stracker TH, Roig I, Knobel PA, Marjanović M. The ATM signaling network in development and disease. Front Genet 2013; 4:37. [PMID: 23532176 PMCID: PMC3607076 DOI: 10.3389/fgene.2013.00037] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 03/04/2013] [Indexed: 12/15/2022] Open
Abstract
The DNA damage response (DDR) rapidly recognizes DNA lesions and initiates the appropriate cellular programs to maintain genome integrity. This includes the coordination of cell cycle checkpoints, transcription, translation, DNA repair, metabolism, and cell fate decisions, such as apoptosis or senescence (Jackson and Bartek, 2009). DNA double-strand breaks (DSBs) represent one of the most cytotoxic DNA lesions and defects in their metabolism underlie many human hereditary diseases characterized by genomic instability (Stracker and Petrini, 2011; McKinnon, 2012). Patients with hereditary defects in the DDR display defects in development, particularly affecting the central nervous system, the immune system and the germline, as well as aberrant metabolic regulation and cancer predisposition. Central to the DDR to DSBs is the ataxia-telangiectasia mutated (ATM) kinase, a master controller of signal transduction. Understanding how ATM signaling regulates various aspects of the DDR and its roles in vivo is critical for our understanding of human disease, its diagnosis and its treatment. This review will describe the general roles of ATM signaling and highlight some recent advances that have shed light on the diverse roles of ATM and related proteins in human disease.
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Affiliation(s)
- Travis H. Stracker
- Oncology Programme, Institute for Research in Biomedicine (IRB Barcelona)Barcelona, Spain
| | - Ignasi Roig
- Departament de Biologia Cellular, Fisiologia i Immunologia, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de BarcelonBarcelona, Spain
| | - Philip A. Knobel
- Oncology Programme, Institute for Research in Biomedicine (IRB Barcelona)Barcelona, Spain
| | - Marko Marjanović
- Oncology Programme, Institute for Research in Biomedicine (IRB Barcelona)Barcelona, Spain
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48
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Shiloh Y, Ziv Y. The ATM protein kinase: regulating the cellular response to genotoxic stress, and more. Nat Rev Mol Cell Biol 2013; 14:197-210. [DOI: 10.1038/nrm3546] [Citation(s) in RCA: 1170] [Impact Index Per Article: 106.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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49
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Shimada M, Nakanishi M. Response to DNA damage: why do we need to focus on protein phosphatases? Front Oncol 2013; 3:8. [PMID: 23386996 PMCID: PMC3560363 DOI: 10.3389/fonc.2013.00008] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Accepted: 01/09/2013] [Indexed: 01/07/2023] Open
Abstract
Eukaryotic cells are continuously threatened by unavoidable errors during normal DNA replication or various sources of genotoxic stresses that cause DNA damage or stalled replication. To maintain genomic integrity, cells have developed a coordinated signaling network, known as the DNA damage response (DDR). Following DNA damage, sensor molecules detect the presence of DNA damage and transmit signals to downstream transducer molecules. This in turn conveys the signals to numerous effectors, which initiate a large number of specific biological responses, including transient cell cycle arrest mediated by checkpoints, DNA repair, and apoptosis. It is recently becoming clear that dephosphorylation events are involved in keeping DDR factors inactive during normal cell growth. Moreover, dephosphorylation is required to shut off checkpoint arrest following DNA damage and has been implicated in the activation of the DDR. Spatial and temporal regulation of phosphorylation events is essential for the DDR, and fine-tuning of phosphorylation is partly mediated by protein phosphatases. While the role of kinases in the DDR has been well documented, the complex roles of protein dephosphorylation have only recently begun to be investigated. Therefore, it is important to focus on the role of phosphatases and to determine how their activity is regulated upon DNA damage. In this work, we summarize current knowledge on the involvement of serine/threonine phosphatases, especially the protein phosphatase 1, protein phosphatase 2A, and protein phosphatase Mg2+/Mn2+-dependent families, in the DDR.
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Affiliation(s)
- Midori Shimada
- Department of Cell Biology, Graduate School of Medical Sciences, Nagoya City University Nagoya, Japan
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50
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Bruce DL, Macartney T, Yong W, Shou W, Sapkota GP. Protein phosphatase 5 modulates SMAD3 function in the transforming growth factor-β pathway. Cell Signal 2012; 24:1999-2006. [PMID: 22781750 DOI: 10.1016/j.cellsig.2012.07.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 07/03/2012] [Indexed: 02/02/2023]
Abstract
Protein phosphatases play a key role in balancing the cellular responses to the transforming growth factor-β (TGFβ) signals. Several protein phosphatases have been attributed roles in the regulation of the TGFβ pathway. Among these, PPM1A is the only phosphatase reported to dephosphorylate SMAD2/3 in the nucleus. However we observed PPM1A exclusively in the cytoplasmic fractions independently of TGFβ treatment in all cells tested. These observations imply that a bona fide nuclear SMAD2/3 phosphatase remains elusive. In this study, we report a role for protein phosphatase 5 (PP5) in the TGFβ pathway. We identified PP5 as an interactor of SMAD2/3. Interestingly, in mouse embryonic fibroblast cells derived from PP5-null mice, TGFβ-induced transcriptional responses were significantly enhanced. Rather surprisingly, this enhancement is due to the increased levels of SMAD3 protein observed in PP5-null MEFs compared to the wild type. No differences in the levels of SMAD3 transcripts were observed between the wild-type and PP5-null MEFs. While PP5 is capable of dephosphorylating SMAD3-tail in overexpression assays, we demonstrate that its activity is essential in controlling SMAD3 protein levels in MEFs. We propose that PP5 regulates the TGFβ pathway in MEFs by regulating the expression of SMAD3 protein levels.
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Affiliation(s)
- David L Bruce
- MRC Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dundee, UK
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