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Wu Y, Li X, Dong L, Liu T, Tang Z, Lin R, Norvienyeku J, Xing M. A New Insight into 6-Pentyl-2H-pyran-2-one against Peronophythora litchii via TOR Pathway. J Fungi (Basel) 2023; 9:863. [PMID: 37623635 PMCID: PMC10515317 DOI: 10.3390/jof9080863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/13/2023] [Accepted: 08/18/2023] [Indexed: 08/26/2023] Open
Abstract
The litchi downy blight disease of litchi caused by Peronophythora litchii accounts for severe losses in the field and during storage. While ample quantitative studies have shown that 6-pentyl-2H-pyran-2-one (6PP) possesses antifungal activities against multiple plant pathogenic fungi, the regulatory mechanisms of 6PP-mediated inhibition of fungal pathogenesis and growth are still unknown. Here, we investigated the potential molecular targets of 6PP in the phytopathogenic oomycetes P. litchii through integrated deployment of RNA-sequencing, functional genetics, and biochemical techniques to investigate the regulatory effects of 6PP against P. litchii. Previously we demonstrated that 6PP exerted significant oomyticidal activities. Also, comparative transcriptomic evaluation of P. litchii strains treated with 6PP Revealed significant up-regulations in the expression profile of TOR pathway-related genes, including PlCytochrome C and the transcription factors PlYY1. We also noticed that 6PP treatment down-regulated putative negative regulatory genes of the TOR pathway, including PlSpm1 and PlrhoH12 in P. litchii. Protein-ligand binding analyses revealed stable affinities between PlYY1, PlCytochrome C, PlSpm1, PlrhoH12 proteins, and the 6PP ligand. Phenotypic characterization of PlYY1 targeted gene deletion strains generated in this study using CRISPR/Cas9 and homologous recombination strategies significantly reduced the vegetative growth, sporangium, encystment, zoospore release, and pathogenicity of P. litchii. These findings suggest that 6PP-mediated activation of PlYY1 expression positively regulates TOR-related responses and significantly influences vegetative growth and the virulence of P. litchii. The current investigations revealed novel targets for 6PP and underscored the potential of deploying 6PP in developing management strategies for controlling the litchi downy blight pathogen.
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Affiliation(s)
- Yinggu Wu
- Key Laboratory of Green Prevention and Control of Tropical Diseases and Pests, Ministry of Education, School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China; (Y.W.); (X.L.); (L.D.); (T.L.); (Z.T.); (R.L.)
- Sanya Nanfan Research Institute, Hainan University, Sanya 572025, China
| | - Xinyu Li
- Key Laboratory of Green Prevention and Control of Tropical Diseases and Pests, Ministry of Education, School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China; (Y.W.); (X.L.); (L.D.); (T.L.); (Z.T.); (R.L.)
- Sanya Nanfan Research Institute, Hainan University, Sanya 572025, China
| | - Li Dong
- Key Laboratory of Green Prevention and Control of Tropical Diseases and Pests, Ministry of Education, School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China; (Y.W.); (X.L.); (L.D.); (T.L.); (Z.T.); (R.L.)
- Sanya Nanfan Research Institute, Hainan University, Sanya 572025, China
| | - Tong Liu
- Key Laboratory of Green Prevention and Control of Tropical Diseases and Pests, Ministry of Education, School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China; (Y.W.); (X.L.); (L.D.); (T.L.); (Z.T.); (R.L.)
- Sanya Nanfan Research Institute, Hainan University, Sanya 572025, China
| | - Zhengbin Tang
- Key Laboratory of Green Prevention and Control of Tropical Diseases and Pests, Ministry of Education, School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China; (Y.W.); (X.L.); (L.D.); (T.L.); (Z.T.); (R.L.)
- Sanya Nanfan Research Institute, Hainan University, Sanya 572025, China
| | - Runmao Lin
- Key Laboratory of Green Prevention and Control of Tropical Diseases and Pests, Ministry of Education, School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China; (Y.W.); (X.L.); (L.D.); (T.L.); (Z.T.); (R.L.)
- Sanya Nanfan Research Institute, Hainan University, Sanya 572025, China
| | - Justice Norvienyeku
- Key Laboratory of Green Prevention and Control of Tropical Diseases and Pests, Ministry of Education, School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China; (Y.W.); (X.L.); (L.D.); (T.L.); (Z.T.); (R.L.)
- Sanya Nanfan Research Institute, Hainan University, Sanya 572025, China
| | - Mengyu Xing
- Key Laboratory of Green Prevention and Control of Tropical Diseases and Pests, Ministry of Education, School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China; (Y.W.); (X.L.); (L.D.); (T.L.); (Z.T.); (R.L.)
- Sanya Nanfan Research Institute, Hainan University, Sanya 572025, China
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2
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Sutcu HH, Montagne B, Ricchetti M. DNA-PKcs regulates myogenesis in an Akt-dependent manner independent of induced DNA damage. Cell Death Differ 2023; 30:1900-1915. [PMID: 37400716 PMCID: PMC10406879 DOI: 10.1038/s41418-023-01177-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 04/26/2023] [Accepted: 05/03/2023] [Indexed: 07/05/2023] Open
Abstract
Skeletal muscle regeneration relies on muscle stem (satellite) cells. We previously demonstrated that satellite cells efficiently and accurately repair radiation-induced DNA double-strand breaks (DSBs) via the DNA-dependent kinase DNA-PKcs. We show here that DNA-PKcs affects myogenesis independently of its role in DSB repair. Consequently, this process does not require the accumulation of DSBs and it is also independent of caspase-induced DNA damage. We report that in myogenic cells DNA-PKcs is essential for the expression of the differentiation factor Myogenin in an Akt2-dependent manner. DNA-PKcs interacts with the p300-containing complex that activates Myogenin transcription. We show also that SCID mice that are deficient in DNA-PKcs, and are used for transplantation and muscle regeneration studies, display altered myofiber composition and delayed myogenesis upon injury. These defects are exacerbated after repeated injury/regeneration events resulting in reduced muscle size. We thus identify a novel, caspase-independent, regulation of myogenic differentiation, and define a differentiation phase that does not involve the DNA damage/repair process.
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Affiliation(s)
- Haser Hasan Sutcu
- Institut Pasteur, Team Stability of Nuclear & Mitochondrial DNA, Department of Developmental and Stem Cell Biology, CNRS UMR3738, 75015, Paris, France
- Université Pierre et Marie Curie (Sorbonne Universities, ED515), Paris, France
- Institut de Radioprotection et de Sûrété Nucléaire (IRSN), Radiobiology of Accidental Exposure Laboratory (PSE-SANTE/SERAMED/LRAcc), B.P. 17, 92262 Fontenay-aux-Roses, Cedex, France
| | - Benjamin Montagne
- Institut Pasteur, Team Stability of Nuclear & Mitochondrial DNA, Department of Developmental and Stem Cell Biology, CNRS UMR3738, 75015, Paris, France
- Institut Pasteur, Molecular Mechanisms of Pathological and Physiological Ageing, Department of Developmental and Stem Cell Biology, Paris, France
| | - Miria Ricchetti
- Institut Pasteur, Team Stability of Nuclear & Mitochondrial DNA, Department of Developmental and Stem Cell Biology, CNRS UMR3738, 75015, Paris, France.
- Institut Pasteur, Molecular Mechanisms of Pathological and Physiological Ageing, Department of Developmental and Stem Cell Biology, Paris, France.
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3
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Dylgjeri E, Knudsen KE. DNA-PKcs: A Targetable Protumorigenic Protein Kinase. Cancer Res 2022; 82:523-533. [PMID: 34893509 PMCID: PMC9306356 DOI: 10.1158/0008-5472.can-21-1756] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 08/17/2021] [Accepted: 11/10/2021] [Indexed: 01/07/2023]
Abstract
DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is a pleiotropic protein kinase that plays critical roles in cellular processes fundamental to cancer. DNA-PKcs expression and activity are frequently deregulated in multiple hematologic and solid tumors and have been tightly linked to poor outcome. Given the potentially influential role of DNA-PKcs in cancer development and progression, therapeutic targeting of this kinase is being tested in preclinical and clinical settings. This review summarizes the latest advances in the field, providing a comprehensive discussion of DNA-PKcs functions in cancer and an update on the clinical assessment of DNA-PK inhibitors in cancer therapy.
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Affiliation(s)
- Emanuela Dylgjeri
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, Pennsylvania.,Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Karen E. Knudsen
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, Pennsylvania.,Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania.,Department of Medical Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania.,Department of Urology, Thomas Jefferson University, Philadelphia, Pennsylvania.,Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania.,Corresponding Author: Karen E. Knudsen, Thomas Jefferson University, 233 South 10th Street, BLSB 1050, Philadelphia, PA 19107. Phone: 215-503-5692; E-mail:
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Shen J, Chen Q, Li Z, Zheng Q, Xu Y, Zhou H, Mao H, Shen Q, Liu P. Proteomic and metabolomic analysis of Nicotiana benthamiana under dark stress. FEBS Open Bio 2022; 12:231-249. [PMID: 34792288 PMCID: PMC8727940 DOI: 10.1002/2211-5463.13331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 10/15/2021] [Accepted: 11/13/2021] [Indexed: 11/08/2022] Open
Abstract
Exposure to extended periods of darkness is a common source of abiotic stress that significantly affects plant growth and development. To understand how Nicotiana benthamiana responds to dark stress, the proteomes and metabolomes of leaves treated with darkness were studied. In total, 5763 proteins and 165 primary metabolites were identified following dark treatment. Additionally, the expression of autophagy-related gene (ATG) proteins was transiently upregulated. Weighted gene coexpression network analysis (WGCNA) was utilized to find the protein modules associated with the response to dark stress. A total of four coexpression modules were obtained. The results indicated that heat-shock protein (HSP70), SnRK1-interacting protein 1, 2A phosphatase-associated protein of 46 kDa (Tap46), and glutamate dehydrogenase (GDH) might play crucial roles in N. benthamiana's response to dark stress. Furthermore, a protein-protein interaction (PPI) network was constructed and top-degreed proteins were predicted to identify potential key factors in the response to dark stress. These proteins include isopropylmalate isomerase (IPMI), eukaryotic elongation factor 5A (ELF5A), and ribosomal protein 5A (RPS5A). Finally, metabolic analysis suggested that some amino acids and sugars were involved in the dark-responsive pathways. Thus, these results provide a new avenue for understanding the defensive mechanism against dark stress at the protein and metabolic levels in N. benthamiana.
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Affiliation(s)
- Juan‐Juan Shen
- College of ChemistryZhengzhou UniversityZhengzhouChina
- Chemistry Research Institution of Henan Academy of SciencesZhengzhouChina
| | - Qian‐Si Chen
- Zhengzhou Tobacco Research Institute of CNTCZhengzhouChina
| | - Ze‐Feng Li
- Zhengzhou Tobacco Research Institute of CNTCZhengzhouChina
| | - Qing‐Xia Zheng
- Zhengzhou Tobacco Research Institute of CNTCZhengzhouChina
| | - Ya‐Long Xu
- Zhengzhou Tobacco Research Institute of CNTCZhengzhouChina
| | - Hui‐Na Zhou
- Zhengzhou Tobacco Research Institute of CNTCZhengzhouChina
| | - Hong‐Yan Mao
- College of ChemistryZhengzhou UniversityZhengzhouChina
| | - Qi Shen
- College of ChemistryZhengzhou UniversityZhengzhouChina
| | - Ping‐Ping Liu
- Zhengzhou Tobacco Research Institute of CNTCZhengzhouChina
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5
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Lees-Miller JP, Cobban A, Katsonis P, Bacolla A, Tsutakawa SE, Hammel M, Meek K, Anderson DW, Lichtarge O, Tainer JA, Lees-Miller SP. Uncovering DNA-PKcs ancient phylogeny, unique sequence motifs and insights for human disease. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 163:87-108. [PMID: 33035590 PMCID: PMC8021618 DOI: 10.1016/j.pbiomolbio.2020.09.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 09/12/2020] [Accepted: 09/29/2020] [Indexed: 01/26/2023]
Abstract
DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is a key member of the phosphatidylinositol-3 kinase-like (PIKK) family of protein kinases with critical roles in DNA-double strand break repair, transcription, metastasis, mitosis, RNA processing, and innate and adaptive immunity. The absence of DNA-PKcs from many model organisms has led to the assumption that DNA-PKcs is a vertebrate-specific PIKK. Here, we find that DNA-PKcs is widely distributed in invertebrates, fungi, plants, and protists, and that threonines 2609, 2638, and 2647 of the ABCDE cluster of phosphorylation sites are highly conserved amongst most Eukaryotes. Furthermore, we identify highly conserved amino acid sequence motifs and domains that are characteristic of DNA-PKcs relative to other PIKKs. These include residues in the Forehead domain and a novel motif we have termed YRPD, located in an α helix C-terminal to the ABCDE phosphorylation site loop. Combining sequence with biochemistry plus structural data on human DNA-PKcs unveils conserved sequence and conformational features with functional insights and implications. The defined generally progressive DNA-PKcs sequence diversification uncovers conserved functionality supported by Evolutionary Trace analysis, suggesting that for many organisms both functional sites and evolutionary pressures remain identical due to fundamental cell biology. The mining of cancer genomic data and germline mutations causing human inherited disease reveal that robust DNA-PKcs activity in tumors is detrimental to patient survival, whereas germline mutations compromising function are linked to severe immunodeficiency and neuronal degeneration. We anticipate that these collective results will enable ongoing DNA-PKcs functional analyses with biological and medical implications.
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Affiliation(s)
- James P Lees-Miller
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
| | - Alexander Cobban
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
| | - Panagiotis Katsonis
- Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Albino Bacolla
- Departments of Cancer Biology and of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, 6767 Bertner Avenue, Houston, TX, 77030, USA
| | - Susan E Tsutakawa
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Michal Hammel
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Katheryn Meek
- College of Veterinary Medicine, Department of Microbiology & Molecular Genetics, And Department of Pathobiology & Diagnostic Investigation, Michigan State University, East Lansing, MI, 48824, USA
| | - Dave W Anderson
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
| | - Olivier Lichtarge
- Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - John A Tainer
- Departments of Cancer Biology and of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, 6767 Bertner Avenue, Houston, TX, 77030, USA; Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
| | - Susan P Lees-Miller
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada.
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Douglas P, Ye R, Radhamani S, Cobban A, Jenkins NP, Bartlett E, Roveredo J, Kettenbach AN, Lees-Miller SP. Nocodazole-Induced Expression and Phosphorylation of Anillin and Other Mitotic Proteins Are Decreased in DNA-Dependent Protein Kinase Catalytic Subunit-Deficient Cells and Rescued by Inhibition of the Anaphase-Promoting Complex/Cyclosome with proTAME but Not Apcin. Mol Cell Biol 2020; 40:e00191-19. [PMID: 32284347 PMCID: PMC7296215 DOI: 10.1128/mcb.00191-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 05/15/2019] [Accepted: 03/31/2020] [Indexed: 11/23/2022] Open
Abstract
The DNA-dependent protein kinase catalytic subunit (DNA-PKcs) has well-established roles in DNA double-strand break repair, and recently, nonrepair functions have also been reported. To better understand its cellular functions, we deleted DNA-PKcs from HeLa and A549 cells using CRISPR/Cas9. The resulting cells were radiation sensitive, had reduced expression of ataxia-telangiectasia mutated (ATM), and exhibited multiple mitotic defects. Mechanistically, nocodazole-induced upregulation of cyclin B1, anillin, and securin was decreased in DNA-PKcs-deficient cells, as were phosphorylation of Aurora A on threonine 288, phosphorylation of Polo-like kinase 1 (PLK1) on threonine 210, and phosphorylation of targeting protein for Xenopus Klp2 (TPX2) on serine 121. Moreover, reduced nocodazole-induced expression of anillin, securin, and cyclin B1 and phosphorylation of PLK1, Aurora A, and TPX2 were rescued by inhibition of the anaphase-promoting complex/cyclosome (APC/C) by proTAME, which prevents binding of the APC/C-activating proteins Cdc20 and Cdh1 to the APC/C. Altogether, our studies suggest that loss of DNA-PKcs prevents inactivation of the APC/C in nocodazole-treated cells.
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Affiliation(s)
- Pauline Douglas
- Department of Biochemistry and Molecular Biology and Robson DNA Science Centre, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Ruiqiong Ye
- Department of Biochemistry and Molecular Biology and Robson DNA Science Centre, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Suraj Radhamani
- Department of Biochemistry and Molecular Biology and Robson DNA Science Centre, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Alexander Cobban
- Department of Biochemistry and Molecular Biology and Robson DNA Science Centre, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Nicole P Jenkins
- Norris Cotton Cancer Center, Geisel School of Medicine, Lebanon Campus at Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
| | - Edward Bartlett
- Department of Biochemistry and Molecular Biology and Robson DNA Science Centre, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Jonathan Roveredo
- Department of Biochemistry and Molecular Biology and Robson DNA Science Centre, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Arminja N Kettenbach
- Norris Cotton Cancer Center, Geisel School of Medicine, Lebanon Campus at Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
| | - Susan P Lees-Miller
- Department of Biochemistry and Molecular Biology and Robson DNA Science Centre, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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Macelignan inhibits the inflammatory response of microglia and regulates neuronal survival. J Neuroimmunol 2019; 339:577123. [PMID: 31838278 DOI: 10.1016/j.jneuroim.2019.577123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/24/2019] [Accepted: 12/05/2019] [Indexed: 01/19/2023]
Abstract
Neuroinflammation is an important pathological process of neurodegenerative diseases, and microglial contributes to chronic inflammation and neuronal loss in progressive neurodegenerative. Therefore, regulating the inflammatory response of microglia could lead to the discovery of promising treatments for neurodegenerative diseases. In this study, we investigated the effects of the nutmeg plant seed extract, macelignan, on the inflammatory response of microglia and neuronal cell survival. We detected NO and iNOS using the Griess test and Western blotting. We measured phosphoinositide 3 kinase (PI3K)/Akt expression by Western blotting. The release of NO and inflammatory cytokines and the expression of iNOS decreased in a concentration-dependent manner, with an increase in macelignan concentration. PI3K/Akt phosphorylation levels decreased in a dose-dependent manner in lipopolysaccharide (LPS)-activated microglial cells after exposure to macelignan. We also demonstrated that macelignan improved HT22 cell viability, following exposure to a microglial-conditioned medium. Furthermore, macelignan inhibited microglial cell near neurons treated with a hypoxic conditioned medium. Finally, macelignan treatment reduced the expression of p27 and cyclin D1 in neurons cultured in an LPS-activated microglia-conditioned medium. Therefore, these results imply that macelignan can inhibit the inflammatory response of microglia and regulate neuronal survival through the PI3K/Akt pathway.
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Macrophage Polarization Induced by Probiotic Bacteria: a Concise Review. Probiotics Antimicrob Proteins 2019; 12:798-808. [DOI: 10.1007/s12602-019-09612-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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9
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Abstract
Modulation of neurotransmitter exocytosis by activated Gi/o coupled G-protein coupled receptors (GPCRs) is a universal regulatory mechanism used both to avoid overstimulation and to influence circuitry. One of the known modulation mechanisms is the interaction between Gβγ and the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNAREs). There are 5 Gβ and 12 Gγ subunits, but specific Gβγs activated by a given GPCR and the specificity to effectors, such as SNARE, in vivo are not known. Although less studied, Gβγ binding to the exocytic fusion machinery (i.e. SNARE) provides a more direct regulatory mechanism for neurotransmitter release. Here, we review some recent insights in the architecture of the synaptic terminal, modulation of synaptic transmission, and implications of G protein modulation of synaptic transmission in diseases. Numerous presynaptic proteins are involved in the architecture of synaptic terminals, particularly the active zone, and their importance in the regulation of exocytosis is still not completely understood. Further understanding of the Gβγ-SNARE interaction and the architecture and mechanisms of exocytosis may lead to the discovery of novel therapeutic targets to help patients with various disorders such as hypertension, attention-deficit/hyperactivity disorder, post-traumatic stress disorder, and acute/chronic pain.
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Affiliation(s)
- Yun Young Yim
- Department of Pharmacology, Vanderbilt University, Nashville 37232-6600, TN, United States
| | - Zack Zurawski
- Department of Pharmacology, Vanderbilt University, Nashville 37232-6600, TN, United States
| | - Heidi Hamm
- Department of Pharmacology, Vanderbilt University, Nashville 37232-6600, TN, United States.
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10
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Sugimoto K. Branching the Tel2 pathway for exact fit on phosphatidylinositol 3-kinase-related kinases. Curr Genet 2018; 64:965-970. [PMID: 29470645 DOI: 10.1007/s00294-018-0817-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 02/19/2018] [Accepted: 02/20/2018] [Indexed: 01/21/2023]
Abstract
Phosphatidylinositol 3-kinase-related kinases (PIKKs), are structurally related to phosphatidylinositol 3-kinase (lipid kinase), but possess protein kinase activities. PIKKs include ATM, ATR, DNA-PK, mTOR and SMG1, key regulators of cell proliferation and genome maintenance. TRRAP, which is devoid of protein kinase activity, is the sixth member of the PIKK family. PIKK family members are gigantic proteins in the range of 300-500 kDa. It has become apparent in the last decade that the stability or maturation of the PIKK family members depends on a molecular chaperone called the Tel2-Tti1-Tti2 (TTT) complex. Several lines of evidence have established a model in which TTT connects to the Hsp90 chaperone through the Rvb1-Rvb2-Tah1-Pih1 (R2TP) complex in mammalian and yeast cells. However, recent studies of yeast cells indicate that TTT is able to form different complexes. These observations raise a possibility that several different mechanisms regulate TTT-mediated protein stability of PIKKs.
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Affiliation(s)
- Katsunori Sugimoto
- Department of Microbiology, Biochemistry and Molecular Genetics, International Center for Public Health, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, 07103, USA.
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11
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Profile of Michael N. Hall, 2017 Albert Lasker Basic Medical Research Awardee: Target of rapamycin, cell growth, and translational control. Proc Natl Acad Sci U S A 2017; 114:11564-11567. [PMID: 29078415 DOI: 10.1073/pnas.1716203114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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12
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β 2 -adrenoceptor-induced modulation of transglutaminase 2 transamidase activity in cardiomyoblasts. Eur J Pharmacol 2017; 813:105-121. [DOI: 10.1016/j.ejphar.2017.07.043] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 07/24/2017] [Accepted: 07/24/2017] [Indexed: 12/12/2022]
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13
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Maheshwari S, Miller MS, O'Meally R, Cole RN, Amzel LM, Gabelli SB. Kinetic and structural analyses reveal residues in phosphoinositide 3-kinase α that are critical for catalysis and substrate recognition. J Biol Chem 2017; 292:13541-13550. [PMID: 28676499 DOI: 10.1074/jbc.m116.772426] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 06/30/2017] [Indexed: 12/26/2022] Open
Abstract
Phosphoinositide 3-kinases (PI3Ks) are ubiquitous lipid kinases that activate signaling cascades controlling cell survival, proliferation, protein synthesis, and vesicle trafficking. PI3Ks have dual kinase specificity: a lipid kinase activity that phosphorylates the 3'-hydroxyl of phosphoinositides and a protein-kinase activity that includes autophosphorylation. Despite the wealth of biochemical and structural information on PI3Kα, little is known about the identity and roles of individual active-site residues in catalysis. To close this gap, we explored the roles of residues of the catalytic domain and the regulatory subunit of human PI3Kα in lipid and protein phosphorylation. Using site-directed mutagenesis, kinetic assays, and quantitative mass spectrometry, we precisely mapped key residues involved in substrate recognition and catalysis by PI3Kα. Our results revealed that Lys-776, located in the P-loop of PI3Kα, is essential for the recognition of lipid and ATP substrates and also plays an important role in PI3Kα autophosphorylation. Replacement of the residues His-936 and His-917 in the activation and catalytic loops, respectively, with alanine dramatically changed PI3Kα kinetics. Although H936A inactivated the lipid kinase activity without affecting autophosphorylation, H917A abolished both the lipid and protein kinase activities of PI3Kα. On the basis of these kinetic and structural analyses, we propose possible mechanistic roles of these critical residues in PI3Kα catalysis.
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Affiliation(s)
- Sweta Maheshwari
- From the Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Michelle S Miller
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287
| | - Robert O'Meally
- Mass Spectrometry and Proteomics Facility, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, and
| | - Robert N Cole
- Mass Spectrometry and Proteomics Facility, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, and
| | - L Mario Amzel
- From the Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205,
| | - Sandra B Gabelli
- From the Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, .,Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287.,Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
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Reappraisal to the study of 4E-BP1 as an mTOR substrate – A normative critique. Eur J Cell Biol 2017; 96:325-336. [DOI: 10.1016/j.ejcb.2017.03.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 03/31/2017] [Accepted: 03/31/2017] [Indexed: 12/20/2022] Open
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15
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Andersen KR. Insights into Rad3 kinase recruitment from the crystal structure of the DNA damage checkpoint protein Rad26. J Biol Chem 2017; 292:8149-8157. [PMID: 28314775 DOI: 10.1074/jbc.m117.780189] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 03/14/2017] [Indexed: 12/30/2022] Open
Abstract
Metabolic products and environmental factors constantly damage DNA. To protect against these insults and maintain genome integrity, cells have evolved mechanisms to repair DNA lesions. One such mechanism involves Rad3, a master kinase coordinating the DNA damage response. Rad26 is a functional subunit of the Rad3-Rad26 complex and is responsible for bringing the kinase to sites of DNA damage. Here, I present the crystal structure of Rad26 and identify the elements important for recruiting Rad3. The structure suggests that Rad26 is a dimer with a conserved interface in the N-terminal part of the protein. Biochemical data showed that Rad26 uses its C-terminal domain and the flanking kinase-docking motif to bind specific HEAT repeats in Rad3. Analysis of the reconstituted Rad3-Rad26 heterotetrameric complex with electron microscopy enabled me to propose a structural model for its quaternary structure. In conclusion, these results suggest that Rad26 exists as a dimer and provide crucial insight into how Rad3 is recruited and incorporated into the Rad3-Rad26 DNA repair complex.
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Are Dynamic Mechanistic Explanations Still Mechanistic? HISTORY, PHILOSOPHY AND THEORY OF THE LIFE SCIENCES 2015. [DOI: 10.1007/978-94-017-9822-8_12] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
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17
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The DNA-dependent protein kinase: A multifunctional protein kinase with roles in DNA double strand break repair and mitosis. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 117:194-205. [PMID: 25550082 DOI: 10.1016/j.pbiomolbio.2014.12.003] [Citation(s) in RCA: 198] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 12/16/2014] [Accepted: 12/19/2014] [Indexed: 11/21/2022]
Abstract
The DNA-dependent protein kinase (DNA-PK) is a serine/threonine protein kinase composed of a large catalytic subunit (DNA-PKcs) and the Ku70/80 heterodimer. Over the past two decades, significant progress has been made in elucidating the role of DNA-PK in non-homologous end joining (NHEJ), the major pathway for repair of ionizing radiation-induced DNA double strand breaks in human cells and recently, additional roles for DNA-PK have been reported. In this review, we will describe the biochemistry, structure and function of DNA-PK, its roles in DNA double strand break repair and its newly described roles in mitosis and other cellular processes.
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Laurent PA, Severin S, Gratacap MP, Payrastre B. Class I PI 3-kinases signaling in platelet activation and thrombosis: PDK1/Akt/GSK3 axis and impact of PTEN and SHIP1. Adv Biol Regul 2014; 54:162-174. [PMID: 24095650 DOI: 10.1016/j.jbior.2013.09.006] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 09/05/2013] [Accepted: 09/06/2013] [Indexed: 06/02/2023]
Abstract
Class I phosphoinositide 3-kinases (PI3K) have been extensively studied in different models these last years and several isoforms are now promising drug targets to treat cancer and immune diseases. Blood platelets are non-nucleated cells critical for hemostasis and strongly involved in arterial thrombosis, a leading cause of death worldwide. Besides their role in hemostasis and thrombosis, platelets provide an interesting model to characterize the implication of the different isoforms of PI3K in signaling. They are specialized for regulated adhesion, particularly under high shear stress conditions found in arteries and use highly regulated signaling mechanisms to form and stabilize a thrombus. In this review we will highlight the role of class I PI3K in these processes and the pertinence of targeting them in the context of antithrombotic strategies but also the potential consequences on the bleeding risk of inhibiting the PI3K signaling in cancer therapy. The implication of upstream regulators of the most important isoforms of PI3K in platelets and their downstream effectors such as protein kinase B (PKB or Akt) and its target glycogen synthase kinase 3 (GSK3) will be discussed as well as the impact of PTEN and SHIP phosphatases as modulators of this pathway.
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Affiliation(s)
| | - Sonia Severin
- Inserm U1048, I2MC and Université Paul Sabatier, 31024 Toulouse Cedex 03, France
| | | | - Bernard Payrastre
- Inserm U1048, I2MC and Université Paul Sabatier, 31024 Toulouse Cedex 03, France; CHU de Toulouse, Laboratoire d'Hématologie, 31059 Toulouse Cedex 03, France.
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Fridman M, Williams GD, Muzamal U, Hunter H, Siu KWM, Golemi-Kotra D. Two unique phosphorylation-driven signaling pathways crosstalk in Staphylococcus aureus to modulate the cell-wall charge: Stk1/Stp1 meets GraSR. Biochemistry 2013; 52:7975-86. [PMID: 24102310 DOI: 10.1021/bi401177n] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Stk1/Stp1 and GraSR signal-transduction pathways are two distinct pathways in Staphylococcus aureus that rely on a reversible phosphorylation process in transducing external stimuli intracellularly. Stk1/Stp1 is an eukaryote-like Ser/Thr kinase phosphatase pair involved in purine biosynthesis, cell-wall metabolism, and autolysis. GraSR is a two-component system involved in resistance to cationic antimicrobial peptides. Both systems are implicated in S. aureus virulence and resistance to cell-wall inhibitors. Our study shows that the response regulator protein GraR undergoes phosphorylation by Stk1 at three threonine residues in the DNA-binding domain. Phosphorylation by Stk1 depends on the structural integrity of GraR as well as the amino acid sequences flanking the phosphorylation sites. Its homologue in Bacillus subtilis , BceR, which harbors two of the three phosphorylation sites in GraR, does not undergo Stk1-dependent phosphorylation. GraR is involved in regulation of the dltABCD operon, the gene products of which add the d-Ala on wall teichoic acid (WTA). Investigation of WTA isolated from the S. aureus RN6390 ΔgraR strain by NMR spectroscopy showed a clear negative effect that graR deletion has on the d-Ala content of WTA. Moreover, complementation of ΔgraR mutant with graR lacking the Stk1 phosphorylation sites mirrors this effect. These findings provide evidence that GraR is a target of Stk1 in vivo and suggest that modification of WTA by d-Ala is modulated by Stk1. The crosstalk between these two otherwise independent signaling pathways may facilitate S. aureus interaction with its environment to modulate processes such as cell growth and division and virulence.
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Affiliation(s)
- Michael Fridman
- Department of Biology and ‡Department of Chemistry, York University , Toronto, Ontario M3J 1P3, Canada
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20
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Abstract
Phosphoinositides (PIs) make up only a small fraction of cellular phospholipids, yet they control almost all aspects of a cell's life and death. These lipids gained tremendous research interest as plasma membrane signaling molecules when discovered in the 1970s and 1980s. Research in the last 15 years has added a wide range of biological processes regulated by PIs, turning these lipids into one of the most universal signaling entities in eukaryotic cells. PIs control organelle biology by regulating vesicular trafficking, but they also modulate lipid distribution and metabolism via their close relationship with lipid transfer proteins. PIs regulate ion channels, pumps, and transporters and control both endocytic and exocytic processes. The nuclear phosphoinositides have grown from being an epiphenomenon to a research area of its own. As expected from such pleiotropic regulators, derangements of phosphoinositide metabolism are responsible for a number of human diseases ranging from rare genetic disorders to the most common ones such as cancer, obesity, and diabetes. Moreover, it is increasingly evident that a number of infectious agents hijack the PI regulatory systems of host cells for their intracellular movements, replication, and assembly. As a result, PI converting enzymes began to be noticed by pharmaceutical companies as potential therapeutic targets. This review is an attempt to give an overview of this enormous research field focusing on major developments in diverse areas of basic science linked to cellular physiology and disease.
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Affiliation(s)
- Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
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21
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Thomas D, Powell JA, Green BD, Barry EF, Ma Y, Woodcock J, Fitter S, Zannettino ACW, Pitson SM, Hughes TP, Lopez AF, Shepherd PR, Wei AH, Ekert PG, Guthridge MA. Protein kinase activity of phosphoinositide 3-kinase regulates cytokine-dependent cell survival. PLoS Biol 2013; 11:e1001515. [PMID: 23526884 PMCID: PMC3601961 DOI: 10.1371/journal.pbio.1001515] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 02/07/2013] [Indexed: 12/20/2022] Open
Abstract
The protein kinase activity of PI3K phosphorylates specific serine residues in growth factor receptors to promote cell survival; these events are constitutively activated in some leukemias. The dual specificity protein/lipid kinase, phosphoinositide 3-kinase (PI3K), promotes growth factor-mediated cell survival and is frequently deregulated in cancer. However, in contrast to canonical lipid-kinase functions, the role of PI3K protein kinase activity in regulating cell survival is unknown. We have employed a novel approach to purify and pharmacologically profile protein kinases from primary human acute myeloid leukemia (AML) cells that phosphorylate serine residues in the cytoplasmic portion of cytokine receptors to promote hemopoietic cell survival. We have isolated a kinase activity that is able to directly phosphorylate Ser585 in the cytoplasmic domain of the interleukin 3 (IL-3) and granulocyte macrophage colony stimulating factor (GM-CSF) receptors and shown it to be PI3K. Physiological concentrations of cytokine in the picomolar range were sufficient for activating the protein kinase activity of PI3K leading to Ser585 phosphorylation and hemopoietic cell survival but did not activate PI3K lipid kinase signaling or promote proliferation. Blockade of PI3K lipid signaling by expression of the pleckstrin homology of Akt1 had no significant impact on the ability of picomolar concentrations of cytokine to promote hemopoietic cell survival. Furthermore, inducible expression of a mutant form of PI3K that is defective in lipid kinase activity but retains protein kinase activity was able to promote Ser585 phosphorylation and hemopoietic cell survival in the absence of cytokine. Blockade of p110α by RNA interference or multiple independent PI3K inhibitors not only blocked Ser585 phosphorylation in cytokine-dependent cells and primary human AML blasts, but also resulted in a block in survival signaling and cell death. Our findings demonstrate a new role for the protein kinase activity of PI3K in phosphorylating the cytoplasmic tail of the GM-CSF and IL-3 receptors to selectively regulate cell survival highlighting the importance of targeting such pathways in cancer. The ability of cells to survive in the absence of proliferation (cell division), differentiation (cell maturation) or activation allows tissues to maintain cell populations that are poised for rapid responses to damage, infections, or other physiological demands. While this “survival-only” response is fundamental to all physiological processes, the underlying mechanisms are not understood. Many growth factors are potent regulators of cell survival through their ability to bind specific cell surface receptors, which in turn activate specialized enzymes called kinases. Phosphoinositide 3-kinase (PI3K) is a dual specificity kinase that is known to be involved in cell survival and malignant transformation, and it is able to phosphorylate both lipid and protein substrates. While the PI3K lipid kinase activity has been extensively studied, the functional significance of its protein kinase activity remains unclear. Here we show that PI3K protein kinase activity can directly phosphorylate growth factor receptors on human hematopoietic (blood) cells to promote a “survival-only” response. We further show that the protein kinase activity of PI3K can be hijacked to result in uncontrolled growth factor receptor phosphorylation and the deregulated survival of leukemic cells. Our studies provide the first evidence that the protein kinase activity of PI3K can control cell survival and that this activity may be deregulated in cancer.
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Affiliation(s)
- Daniel Thomas
- Cell Growth and Differentiation Laboratory, Division of Human Immunology, Centre for Cancer Biology, SA Pathology, Adelaide, Australia
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22
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Izumi N, Yamashita A, Ohno S. Integrated regulation of PIKK-mediated stress responses by AAA+ proteins RUVBL1 and RUVBL2. Nucleus 2012; 3:29-43. [PMID: 22540023 PMCID: PMC3337166 DOI: 10.4161/nucl.18926] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Proteins of the phosphatidylinositol 3-kinase-related protein kinase (PIKK) family are activated by various cellular stresses, including DNA damage, premature termination codon and nutritional status, and induce appropriate cellular responses. The importance of PIKK functions in the maintenance of genome integrity, accurate gene expression and the proper control of cell growth/proliferation is established. Recently, ATPase associated diverse cellular activities (AAA+) proteins RUVBL1 and RUVBL2 (RUVBL1/2) have been shown to be common regulators of PIKKs. The RUVBL1/2 complex regulates PIKK-mediated stress responses through physical interactions with PIKKs and by controlling PIKK mRNA levels. In this review, the functions of PIKKs in stress responses are outlined and the physiological significance of the integrated regulation of PIKKs by the RUVBL1/2 complex is presented. We also discuss a putative "PIKK regulatory chaperone complex" including other PIKK regulators, Hsp90 and the Tel2 complex.
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Affiliation(s)
- Natsuko Izumi
- Department of Molecular Biology, Yokohama City University School of Medicine, Yokohama, Japan
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23
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Sample preparation and analytical strategies for large-scale phosphoproteomics experiments. Semin Cell Dev Biol 2012; 23:843-53. [DOI: 10.1016/j.semcdb.2012.05.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2012] [Accepted: 05/29/2012] [Indexed: 12/28/2022]
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24
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Saponaro C, Cianciulli A, Calvello R, Dragone T, Iacobazzi F, Panaro MA. The PI3K/Akt pathway is required for LPS activation of microglial cells. Immunopharmacol Immunotoxicol 2012; 34:858-65. [DOI: 10.3109/08923973.2012.665461] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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25
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Li X, Guo Z, Sheng Q, Xue X, Liang X. Sequential elution of multiply and singly phosphorylated peptides with polar-copolymerized mixed-mode RP18/SCX material. Analyst 2012; 137:2774-6. [DOI: 10.1039/c2an35247h] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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26
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Abstract
Plants have developed sophisticated mechanisms to survive when in unfavorable environments. Autophagy is a macromolecule degradation pathway that recycles damaged or unwanted cell materials upon encountering stress conditions or during specific developmental processes. Over the past decade, our molecular and physiological understanding of plant autophagy has greatly increased. Most of the essential machinery required for autophagy seems to be conserved from yeast to plants. Plant autophagy has been shown to function in various stress responses, pathogen defense, and senescence. Some of its potential upstream regulators have also been identified. Here, we describe recent advances in our understanding of autophagy in plants, discuss areas of controversy, and highlight potential future directions in autophagy research.
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Affiliation(s)
- Yimo Liu
- Department of Genetics, Development, and Cell Biology and Interdepartmental Genetics Program, Iowa State University, Ames, IA 50011, USA
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27
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Domains of Tra1 important for activator recruitment and transcription coactivator functions of SAGA and NuA4 complexes. Mol Cell Biol 2010; 31:818-31. [PMID: 21149579 DOI: 10.1128/mcb.00687-10] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The Tra1 protein is a direct transcription activator target that is essential for coactivator function of both the SAGA and NuA4 histone acetyltransferase (HAT) complexes. The ∼400-kDa Saccharomyces cerevisiae Tra1 polypeptide and its human counterpart TRRAP contain 67 or 68 tandem α-helical HEAT and TPR protein repeats that extend from the N terminus to the conserved yet catalytically inactive phosphatidylinositol 3-kinase (PI3K) domain. We generated a series of mutations spanning the length of the protein and assayed for defects in transcription, coactivator recruitment, and histone acetylation at SAGA- and NuA4-dependent genes. Inviable TRA1 mutants all showed defects in SAGA and NuA4 complex stability, suggesting that similar surfaces of Tra1 mediate assembly of these two very different coactivator complexes. Nearly all of the viable Tra1 mutants showed transcription defects that fell into one of three classes: (i) defective recruitment to promoters, (ii) reduced stability of the SAGA and NuA4 HAT modules, or (iii) normal recruitment of Tra1-associated subunits but reduced HAT activity in vivo. Our results show that Tra1 recruitment at Gcn4-dependent and Rap1-dependent promoters requires the same regions of Tra1 and that separate regions of Tra1 contribute to the HAT activity and stability of the SAGA and NuA4 HAT modules.
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Kan’shin ED, Nifant’ev IE, Pshezhetskii AV. Mass spectrometric analysis of protein phosphorylation. JOURNAL OF ANALYTICAL CHEMISTRY 2010. [DOI: 10.1134/s1061934810130010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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29
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Ha CW, Huh WK. Rapamycin increases rDNA stability by enhancing association of Sir2 with rDNA in Saccharomyces cerevisiae. Nucleic Acids Res 2010; 39:1336-50. [PMID: 20947565 PMCID: PMC3045593 DOI: 10.1093/nar/gkq895] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The target of rapamycin (TOR) kinase is an evolutionarily conserved key regulator of eukaryotic cell growth and proliferation. Recently, it has been reported that inhibition of TOR signaling pathway can delay aging and extend lifespan in several eukaryotic organisms, but how lifespan extension is mediated by inhibition of TOR signaling is poorly understood. Here we report that rapamycin treatment and nitrogen starvation, both of which cause inactivation of TOR complex 1 (TORC1), lead to enhanced association of Sir2 with ribosomal DNA (rDNA) in Saccharomyces cerevisiae. TORC1 inhibition increases transcriptional silencing of RNA polymerase II-transcribed gene integrated at the rDNA locus and reduces homologous recombination between rDNA repeats that causes formation of toxic extrachromosomal rDNA circles. In addition, TORC1 inhibition induces deacetylation of histones at rDNA. We also found that Pnc1 and Net1 are required for enhancement of association of Sir2 with rDNA under TORC1 inhibition. Taken together, our findings suggest that inhibition of TORC1 signaling stabilizes the rDNA locus by enhancing association of Sir2 with rDNA, thereby leading to extension of replicative lifespan in S. cerevisiae.
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Affiliation(s)
- Cheol Woong Ha
- School of Biological Sciences, Research Center for Functional Cellulomics, Institute of Microbiology, Seoul National University, Seoul 151-747, Republic of Korea
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30
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TOR is a negative regulator of autophagy in Arabidopsis thaliana. PLoS One 2010; 5:e11883. [PMID: 20686696 PMCID: PMC2912371 DOI: 10.1371/journal.pone.0011883] [Citation(s) in RCA: 189] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Accepted: 07/04/2010] [Indexed: 11/19/2022] Open
Abstract
Background Autophagy is a protein degradation process by which cells recycle cytoplasmic contents under stress conditions or during senescence; a basal level of housekeeping autophagy also occurs under non-stressed conditions. Although a number of genes that function in autophagy (ATG genes) have been identified in plants, the upstream components that regulate the plant autophagy pathway are still obscure. Target of rapamycin (TOR) is a negative regulator of autophagy in both yeast and animals, and homologs of TOR in plants control plant growth and protein synthesis. However, a role for TOR in regulation of autophagy in plants has not been demonstrated previously. Methodology/Principal Findings In this paper we used RNA interference (RNAi) to generate transgenic plants with reduced AtTOR transcript level. By observing monodansylcadaverine- (MDC) and GFP-AtATG8e-labeled autophagosomes, these plants were demonstrated to have constitutive AtATG18a-dependent autophagy. Reverse transcriptase-PCR also showed increased expression of some AtATG genes in the RNAi-AtTOR plants. Unlike autophagy induced by starvation or salt stress, an NADPH oxidase inhibitor did not inhibit the constitutive autophagy in the RNAi-AtTOR lines, indicating that AtTOR is either downstream of or in a parallel pathway to NADPH oxidase. Conclusions/Significance Together, our results provide evidence that TOR is a negative regulator of autophagy in plants.
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Wang H, Wang S, Shen L, Chen Y, Zhang X, Zhou J, Wang Z, Hu C, Yue W, Wang H. Chk2 down-regulation by promoter hypermethylation in human bulk gliomas. Life Sci 2009; 86:185-91. [PMID: 19969004 DOI: 10.1016/j.lfs.2009.11.023] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Revised: 10/29/2009] [Accepted: 11/30/2009] [Indexed: 12/11/2022]
Abstract
AIMS Gliomas account for 80% of malignant brain tumors. DNA damage response and subsequent checkpoint control pathways could maintain the integrity of the genome and thus defend tumorigenesis. Four kinases, ATM, ATR, ChK1 and Chk2 are the damage sensors and the early effectors in DNA damage responses. Given their importance, we investigated the transcriptional regulation of these four genes. MAIN METHODS Tissues from ten normal brains and thirty human gliomas were utilized for mRNA analysis via real-time PCR. Another twelve normal brain tissues and forty gliomas were used for confirmation. Methylation-specific PCR (MSP) was used to determine the methylation status of the Chk2 promoter. Quantitative chromatin immunoprecipitation (ChIP) was used to measure the influence of methylation on Sp1 binding. KEY FINDINGS We found that the expression of ATR, ChK1 and Chk2 in gliomas was significantly down-regulated relative to the normal brain tissues. The most significant reduction of expression was of the Chk2 gene, whose expression was approximately 10-fold decreased in gliomas (P<0.0001). Down-regulation of Chk2 was validated in the second real-time PCR analysis. This reduction in expression was partially due to promoter methylation. The Chk2 proximal promoter recruited Sp1 for transcriptional activation. We found that hypermethylation of the Chk2 promoter undermined the binding of the transcriptional factor Sp1. SIGNIFICANCE Our results indicate that Chk2 methylation could be involved in glioma carcinogenesis and Chk2 expression may potentially be used for the diagnosis of glioma.
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Affiliation(s)
- Hongwei Wang
- Harbin Medical University, Harbin 150001, China.
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Sustrova B, Novotna L, Kucerova Z, Ticha M. Immobilization of α-chymotrypsin to magnetic particles and their use for proteolytic cleavage of porcine pepsin A. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.molcatb.2009.03.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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33
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Shears SB. Molecular basis for the integration of inositol phosphate signaling pathways via human ITPK1. ACTA ACUST UNITED AC 2009; 49:87-96. [PMID: 19200440 DOI: 10.1016/j.advenzreg.2008.12.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Stephen B Shears
- Inositol Signaling Section, Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, NIH, DHSS, Research Triangle Park, NC 27709, USA.
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Peddinti D, Nanduri B, Kaya A, Feugang JM, Burgess SC, Memili E. Comprehensive proteomic analysis of bovine spermatozoa of varying fertility rates and identification of biomarkers associated with fertility. BMC SYSTEMS BIOLOGY 2008; 2:19. [PMID: 18294385 PMCID: PMC2291030 DOI: 10.1186/1752-0509-2-19] [Citation(s) in RCA: 191] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2007] [Accepted: 02/22/2008] [Indexed: 11/10/2022]
Abstract
BACKGROUND Male infertility is a major problem for mammalian reproduction. However, molecular details including the underlying mechanisms of male fertility are still not known. A thorough understanding of these mechanisms is essential for obtaining consistently high reproductive efficiency and to ensure lower cost and time-loss by breeder. RESULTS Using high and low fertility bull spermatozoa, here we employed differential detergent fractionation multidimensional protein identification technology (DDF-Mud PIT) and identified 125 putative biomarkers of fertility. We next used quantitative Systems Biology modeling and canonical protein interaction pathways and networks to show that high fertility spermatozoa differ from low fertility spermatozoa in four main ways. Compared to sperm from low fertility bulls, sperm from high fertility bulls have higher expression of proteins involved in: energy metabolism, cell communication, spermatogenesis, and cell motility. Our data also suggests a hypothesis that low fertility sperm DNA integrity may be compromised because cell cycle: G2/M DNA damage checkpoint regulation was most significant signaling pathway identified in low fertility spermatozoa. CONCLUSION This is the first comprehensive description of the bovine spermatozoa proteome. Comparative proteomic analysis of high fertility and low fertility bulls, in the context of protein interaction networks identified putative molecular markers associated with high fertility phenotype.
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Affiliation(s)
- Divyaswetha Peddinti
- Department of Basic Sciences, Mississippi State University, Mississippi State, MS 39762, USA.
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Murr R, Vaissière T, Sawan C, Shukla V, Herceg Z. Orchestration of chromatin-based processes: mind the TRRAP. Oncogene 2007; 26:5358-72. [PMID: 17694078 DOI: 10.1038/sj.onc.1210605] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Chromatin modifications at core histones including acetylation, methylation, phosphorylation and ubiquitination play an important role in diverse biological processes. Acetylation of specific lysine residues within the N terminus tails of core histones is arguably the most studied histone modification; however, its precise roles in different cellular processes and how it is disrupted in human diseases remain poorly understood. In the last decade, a number of histone acetyltransferases (HATs) enzymes responsible for histone acetylation, has been identified and functional studies have begun to unravel their biological functions. The activity of many HATs is dependent on HAT complexes, the multiprotein assemblies that contain one HAT catalytic subunit, adapter proteins, several other molecules of unknown function and a large protein called TRansformation/tRanscription domain-Associated Protein (TRRAP). As a common component of many HAT complexes, TRRAP appears to be responsible for the recruitment of these complexes to chromatin during transcription, replication and DNA repair. Recent studies have shed new light on the role of TRRAP in HAT complexes as well as mechanisms by which it mediates diverse cellular processes. Thus, TRRAP appears to be responsible for a concerted and context-dependent recruitment of HATs and coordination of distinct chromatin-based processes, suggesting that its deregulation may contribute to diseases. In this review, we summarize recent developments in our understanding of the function of TRRAP and TRRAP-containing HAT complexes in normal cellular processes and speculate on the mechanism underlying abnormal events that may lead to human diseases such as cancer.
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Affiliation(s)
- R Murr
- International Agency for Research on Cancer (IARC), Lyon, France
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36
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Liu X, Zheng XFS. Endoplasmic reticulum and Golgi localization sequences for mammalian target of rapamycin. Mol Biol Cell 2007; 18:1073-82. [PMID: 17215520 PMCID: PMC1805082 DOI: 10.1091/mbc.e06-05-0406] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Mammalian target of rapamycin (mTOR) forms two complexes, mTORC1 and mTORC2, that play central roles in cell growth and functions. Only mTORC1 is directly inhibited by the immunosuppressive drug rapamycin. Despite recent progress in identifying new components and functions of the mTOR pathway, relatively little is known about the spatial arrangement of mTOR signaling and the underlying mechanisms. In a previous study, we showed that a large proportion of mTOR is localized to the endoplasmic reticulum (ER) and Golgi in many common cell lines. Here, we report the identification of an internal mTOR sequence that contains two HEAT (HT) repeats, HT18 and HT19, and two intervening interunit spacers (IUSs), IUS17 and IUS18, which is sufficient to target enhanced green fluorescent protein to the Golgi. Surprisingly, deletion of IUS17 from this Golgi localization sequence (GLS) converts it to an ER localization sequence (ELS). Deletion of HT19, a common element of both GLS and ELS from the full-length mTOR, causes delocalization of mTOR and inhibits the ability of mTOR to promote S6 phosphorylation. Moreover, overexpression of GLS and ELS inhibits both mTOR complexes. Together, our results reveal unusual ER- and Golgi-targeting sequences and suggest that anchoring to these organelles is important for the functions of mTOR complexes.
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Affiliation(s)
- Xiangyu Liu
- Department of Pharmacology and Cancer Institute of New Jersey, Robert Wood Johnson Medical School, Piscataway, NJ 08854
| | - X. F. Steven Zheng
- Department of Pharmacology and Cancer Institute of New Jersey, Robert Wood Johnson Medical School, Piscataway, NJ 08854
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37
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Ha SH, Kim DH, Kim IS, Kim JH, Lee MN, Lee HJ, Kim JH, Jang SK, Suh PG, Ryu SH. PLD2 forms a functional complex with mTOR/raptor to transduce mitogenic signals. Cell Signal 2006; 18:2283-91. [PMID: 16837165 DOI: 10.1016/j.cellsig.2006.05.021] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2006] [Revised: 05/11/2006] [Accepted: 05/11/2006] [Indexed: 10/24/2022]
Abstract
Mammalian target-of-rapamycin (mTOR), which is a master controller of cell growth, senses a mitogenic signal in part through the lipid second messenger phosphatidic acid (PA), generated by phospholipase D (PLD). To understand further which isozymes of PLD are involved in this process, we compared the effect of PLD isozymes on mTOR activation. We found that PLD2 has an essential role in mitogen-induced mTOR activation as the siRNA-mediated knockdown of PLD2, not of PLD1, profoundly reduced the phosphorylations of S6K1 and 4EBP1, well-known mTOR effectors. Furthermore, exogenous PA-induced mTOR activation was abrogated by PLD2 knockdown, but not by PLD1 knockdown. This abrogation was found to be the result of complex formation between PLD2 and mTOR/raptor. PLD2 possesses a TOS-like motif (Phe-Glu-Val-Gln-Val, a.a. 265-269), through which it interacts with raptor independently of the other TOS motif-containing proteins, S6K1 and 4EBP1. PLD2-dependent mTOR activation appears to require PLD2 binding to mTOR/raptor with lipase activity, since lipase-inactive PLD2 cannot trigger mTOR activation despite its ability to interact with mTOR/raptor. Abrogation of mitogen-dependent mTOR activation by PLD2 knockdown was rescued only by wild type PLD2, but not by raptor binding-deficient and lipase-inactive PLD2. Our results demonstrate the importance of localized PA generation for the mitogen-induced activation of mTOR, which is achieved by a specific interaction between PLD2 and mTOR/raptor.
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Affiliation(s)
- Sang Hoon Ha
- Division of Molecular and Life Sciences, Pohang University of Science and Technology, Pohang, Kyungbook 790-784, Republic of Korea
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38
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Mishra NS, Tuteja R, Tuteja N. Signaling through MAP kinase networks in plants. Arch Biochem Biophys 2006; 452:55-68. [PMID: 16806044 DOI: 10.1016/j.abb.2006.05.001] [Citation(s) in RCA: 169] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2005] [Revised: 05/04/2006] [Accepted: 05/05/2006] [Indexed: 01/01/2023]
Abstract
Protein phosphorylation is the most important mechanism for controlling many fundamental cellular processes in all living organisms including plants. A specific class of serine/threonine protein kinases, the mitogen-activated protein kinases (MAP kinases) play a central role in the transduction of various extra- and intracellular signals and are conserved throughout eukaryotes. These generally function via a cascade of networks, where MAP kinase (MAPK) is phosphorylated and activated by MAPK kinase (MAPKK), which itself is activated by MAPKK kinase (MAPKKK). Signaling through MAP kinase cascade can lead to cellular responses including cell division, differentiation as well as response to various stresses. In plants, MAP kinases are represented by multigene families and are organized into a complex network for efficient transmission of specific stimuli. Putative plant MAP kinase cascades have been postulated based on experimental analysis of in vitro interactions between specific MAP kinase components. These cascades have been tested in planta following expression of epitope-tagged kinases in protoplasts. It is known that signaling for cell division and stress responses in plants are mediated through MAP kinases and even auxin, ABA and possibly ethylene and cytokinin also utilize a MAP kinase pathway. Most of the biotic (pathogens and pathogen-derived elicitors) including wounding and abiotic stresses (salinity, cold, drought, and oxidative) can induce defense responses in plants through MAP kinase pathways. In this article we have covered the historical background, biochemical assay, activation/inactivation, and targets of MAP kinases with emphasis on plant MAP kinases and the responses regulated by them. The cross-talk between plant MAP kinases is also discussed to bring out the complexity within this three-component module.
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Affiliation(s)
- Neeti Sanan Mishra
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India
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Li D, Wei Y, Babilonia E, Wang Z, Wang WH. Inhibition of phosphatidylinositol 3-kinase stimulates activity of the small-conductance K channel in the CCD. Am J Physiol Renal Physiol 2006; 290:F806-12. [PMID: 16204406 PMCID: PMC2847509 DOI: 10.1152/ajprenal.00352.2005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We used Western blotting to examine the expression of phosphatidylinositol 3-kinase (PI3K) in the renal cortex and outer medulla and employed the patch-clamp technique to study the effect of PI3K on the ROMK-like small-conductance K (SK) channels in the cortical collecting duct (CCD). Low K intake increased the expression of the 110-kDa alpha-subunit (p110alpha) of PI3K compared with rats on a normal-K diet. Because low K intake increases superoxide levels (2), the possibility that increases in superoxide anions may be responsible for the effect of low K intake on the expression of PI3K is supported by finding that addition of H(2)O(2) stimulates the expression of p110alpha in M1 cells. Inhibition of PI3K with either wortmannin or LY-294002 significantly increased channel activity in the CCD from rats on a K-deficient (KD) diet or on a normal-K diet. The stimulatory effect of wortmannin on ROMK channel activity cannot be mimicked by inhibition of phospholipase C with U-73122. This suggests that the effect of inhibiting PI3K was not the result of increasing the phosphatidylinositol 4,5-bisphosphate level. Moreover, application of the exogenous phosphatidylinositol 3,4,5-trisphosphate analog had no effect on channel activity in excised patches. Because low K intake has been shown to increase the activity of protein tyrosine kinase (PTK), we explored the role of the interaction between PTK and PI3K in the regulation of the SK channel activity. Inhibition of PTK increased SK channel activity in the CCD from rats on a KD diet. However, addition of wortmannin did not further increase ROMK channel activity. Also, the effect of wortmannin was abolished by treatment of CCD with phalloidin. We conclude that PI3K is involved in mediating the effect of low K intake on ROMK channel activity in the CCD and that the effect of PI3K on SK channels requires the involvement of PTK and the cytoskeleton.
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Affiliation(s)
- Dimin Li
- Department of Pharmacology, New York Medical College, Valhalla, NY 10595, USA
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40
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Kang S, Denley A, Vanhaesebroeck B, Vogt PK. Oncogenic transformation induced by the p110beta, -gamma, and -delta isoforms of class I phosphoinositide 3-kinase. Proc Natl Acad Sci U S A 2006; 103:1289-94. [PMID: 16432180 PMCID: PMC1360601 DOI: 10.1073/pnas.0510772103] [Citation(s) in RCA: 226] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Class I phosphoinositide 3-kinase contains four isoforms of the catalytic subunit, p110alpha, -beta, -gamma, and -delta. At physiological levels of expression, the wild-type p110alpha isoform lacks oncogenic potential, but gain-of-function mutations and overexpression of p110alpha are correlated with oncogenicity. The p110beta, -gamma, and -delta isoforms induce transformation of cultured cells as wild-type proteins. This oncogenic potential requires kinase activity and can be suppressed by the target of rapamycin inhibitor rapamycin. The p110delta isoform constitutively activates the Akt signaling pathway; p110gamma activates Akt only in the presence of serum. The isoforms differ in their requirements for upstream signaling. The transforming activity of the p110gamma isoform depends on rat sarcoma viral oncogene homolog (Ras) binding; preliminary data suggest the same for p110beta and indicate Ras-independent oncogenic potential of p110delta. The surprising oncogenic potential of the wild-type non-alpha isoforms of class I phosphoinositide 3-kinase may explain the dearth of cancer-specific mutations in these proteins, because these non-alpha isoforms could contribute to the oncogenic phenotype of the cell by differential expression.
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Affiliation(s)
- Sohye Kang
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, BCC 239, La Jolla, CA 92037, USA
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41
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Hsieh WT, Huang KY, Lin HY, Chung JG. Physalis angulata induced G2/M phase arrest in human breast cancer cells. Food Chem Toxicol 2006; 44:974-83. [PMID: 16427178 DOI: 10.1016/j.fct.2005.11.013] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2004] [Revised: 11/15/2005] [Accepted: 11/29/2005] [Indexed: 10/25/2022]
Abstract
Physalis angulata (PA) is employed in herbal medicine around the world. It is used to treat diabetes, hepatitis, asthma and malaria in Taiwan. We have evaluated PA as a cancer chemopreventive agent in vitro by studying the role of PA in regulation of proliferation, cell cycle and apoptosis in human breast cancer cell lines. PA inhibited cell proliferation and induced G2/M arrest and apoptosis in human breast cancer MAD-MB 231 and MCF-7 cell lines. In this study, under treatment with various concentrations of PA in MDA-MB 231 cell line, we checked mRNA levels for cyclin A and cyclin B1 and the protein levels of cyclin A and cyclin B1, Cdc2 (cyclin-dependent kinases), p21(waf1/cip1) and P27(Kip1) (cyclin-dependent kinase inhibitors), Cdc25C, Chk2 and Wee1 kinase (cyclin-dependent kinase relative factors) in cell cycle G2/M phase. From those results, we determined that PA arrests MDA-MB 231 cells at the G2/M phase by (i) inhibiting synthesis or stability of mRNA and their downstream protein levels of cyclin A and cyclin B1, (ii) increasing p21(waf1/cip1) and P27(kip1) levels, (iii) increasing Chk2, thus causing an increase in Cdc25C phosphorylation/inactivation and inducing a decrease in Cdc2 levels and an increase in Wee1 level. According to the results obtained, PA appears to possess anticarcinogenic properties; these results suggest that the effect of PA on the levels of phosphorylated/inactivated Cdc25C are mediated by Chk2 activation, at least in part, via p21(waf1/cip1) and P27(kip1) cyclin-dependent kinase inhibitors pathway to arrest cells at G2/M phase in breast cancer carcinoma cells.
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Affiliation(s)
- Wen-Tsong Hsieh
- Department of Pharmacology, China Medical University, 91 Hsueh-Shih Road, Taichung 404, Taiwan, ROC
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42
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Shinohara ET, Geng L, Tan J, Chen H, Shir Y, Edwards E, Halbrook J, Kesicki EA, Kashishian A, Hallahan DE. DNA-dependent protein kinase is a molecular target for the development of noncytotoxic radiation-sensitizing drugs. Cancer Res 2005; 65:4987-92. [PMID: 15958537 DOI: 10.1158/0008-5472.can-04-4250] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
DNA-dependent protein kinase (DNA-PK)-defective severe combined immunodeficient (SCID) mice have a greater sensitivity to ionizing radiation compared with wild-type mice due to deficient repair of DNA double-strand break. SCID cells were therefore studied to determine whether radiosensitization by the specific inhibitor of DNA-PK, IC87361, is eliminated in the absence of functional DNA-PK. IC87361 enhanced radiation sensitivity in wild-type C57BL6 endothelial cells but not in SCID cells. The tumor vascular window model was used to assess IC87361-induced radiosensitization of SCID and wild-type tumor microvasculature. Vascular density was 5% in irradiated SCID host compared with 50% in C57BL6 mice (P < 0.05). IC87361 induced radiosensitization of tumor microvasculature in wild-type mice that resembled the radiosensitive phenotype of tumor vessels in SCID mice. Radiosensitization by IC87361 was eliminated in SCID tumor vasculature, which lack functional DNA-PK. Irradiated LLC and B16F0 tumors implanted into SCID mice showed greater tumor growth delay compared with tumors implanted into either wild-type C57BL6 or nude mice. Furthermore, LLC tumors treated with radiation and IC87361 showed tumor growth delay that was significantly greater than tumors treated with radiation alone (P < 0.01 for 3 Gy alone versus 3 Gy + IC87361). DNA-PK inhibitors induced no cytotoxicity and no toxicity in mouse normal tissues. Mouse models deficient in enzyme activity are useful to assess the specificity of novel kinase inhibitors. DNA-PK is an important target for the development of novel radiation-sensitizing drugs that have little intrinsic cytotoxicity.
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MESH Headings
- Animals
- Carcinoma, Lewis Lung/blood supply
- Carcinoma, Lewis Lung/drug therapy
- Carcinoma, Lewis Lung/enzymology
- Carcinoma, Lewis Lung/radiotherapy
- Cell Growth Processes/drug effects
- Cell Growth Processes/radiation effects
- Cell Line, Tumor
- Combined Modality Therapy
- DNA-Activated Protein Kinase
- DNA-Binding Proteins/antagonists & inhibitors
- Endothelial Cells/cytology
- Endothelial Cells/drug effects
- Endothelial Cells/radiation effects
- Melanoma, Experimental/blood supply
- Melanoma, Experimental/drug therapy
- Melanoma, Experimental/enzymology
- Melanoma, Experimental/radiotherapy
- Mice
- Mice, Nude
- Mice, SCID
- Neovascularization, Pathologic/drug therapy
- Neovascularization, Pathologic/enzymology
- Neovascularization, Pathologic/pathology
- Neovascularization, Pathologic/radiotherapy
- Protein Kinase Inhibitors/pharmacology
- Protein Serine-Threonine Kinases/antagonists & inhibitors
- Radiation-Sensitizing Agents/pharmacology
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Affiliation(s)
- Eric T Shinohara
- Department of Radiation Oncology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-5671, USA
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43
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Soghoian D, Jayaraman V, Silane M, Berenstein A, Jayaraman T. Inositol 1,4,5-trisphosphate receptor phosphorylation in breast cancer. Tumour Biol 2005; 26:207-12. [PMID: 16006774 DOI: 10.1159/000086954] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2005] [Indexed: 11/19/2022] Open
Abstract
The aim of this study was to establish the type(s) of inositol 1,4,5-trisphosphate receptors (IP3Rs) in T47D breast cancer cells that regulate intracellular calcium (Ca2+) and whether they interact with cyclin (Cy), an important regulator of cyclin-dependent kinases (cdk), during cell cycle progression. Immunoblotting, immunoprecipitation, and pull-down assays were used to identify IP3R expression and interaction with Cy. The relative IP3R3 expression, as compared to IP3R1, was higher in these cells. Pull-down analysis showed that IP3R3 interacted with both CyA and CyB. The interaction with Cys and the phosphorylation of IP3Rs by Cy/cdk complexes provide a novel mechanism of regulating intracellular Ca2+ release and Ca2+-dependent signaling events in breast cancer.
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Affiliation(s)
- Damien Soghoian
- Vascular Biology Laboratory, Department of Neurosurgery, St. Luke's Roosevelt Hospital Center, New York, N.Y. 10025, USA
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44
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Holgersson A, Heiden T, Castro J, Edgren MR, Lewensohn R, Meijer AE. Different G2/M accumulation in M059J and M059K cells after exposure to DNA double-strand break-inducing agents. Int J Radiat Oncol Biol Phys 2005; 61:915-21. [PMID: 15708275 DOI: 10.1016/j.ijrobp.2004.10.036] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2004] [Revised: 09/27/2004] [Accepted: 10/14/2004] [Indexed: 11/22/2022]
Abstract
PURPOSE To investigate and compare the cell cycle progression in relation to cell death in the human glioma cell lines, M059J and M059K, after exposure to DNA double-strand break-inducing agents. METHODS AND MATERIALS The M059J and M059K cells, deficient and proficient in the catalytic subunit of the DNA-dependent protein kinase, respectively, were exposed to 1 and 4 Gy of photons or accelerated nitrogen ions. In addition, M059J and M059K cells were treated with 10 and 40 mug/mL of bleomycin for 30 min, respectively. Cell cycle progression, monitored by DNA flow cytometry, was measured up to 72 h after treatment. RESULTS M059J, but not M059K, cells displayed G(2)/M accumulation after low linear energy transfer irradiation. High linear energy transfer radiation exposure however, resulted in a substantial increase of M059K cells in the G(2)/M phase detected at 48 h. At 72 h, the number of cells in the G(2)/M phase was equivalent to its control. M059J cells accumulated mainly in S phase after high linear energy transfer irradiation. In contrast to M059K, M059J cells were still blocked at 72 h. Bleomycin induced G(2)/M accumulation for both M059J and M059K cells detected 24 h after treatment. At 48 h, the percentage of bleomycin-treated M059J cells in G(2)/M phase remained high, and the number of M059K cells had decreased to control levels. Neither cell line showed cell cycle arrest (< or =10 h) after exposure to these agents. CONCLUSION Distinct cell cycle block and release is dependent on the complexity of the induced DNA damage and the presence of the DNA-dependent protein kinase catalytic subunit.
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Affiliation(s)
- Asa Holgersson
- Department of Oncology-Pathology, Unit of Medical Radiation Biology, Karolinska Institutet, SE-171 76 Stockholm, Sweden
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45
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Griffin RJ, Fontana G, Golding BT, Guiard S, Hardcastle IR, Leahy JJJ, Martin N, Richardson C, Rigoreau L, Stockley M, Smith GCM. Selective benzopyranone and pyrimido[2,1-a]isoquinolin-4-one inhibitors of DNA-dependent protein kinase: synthesis, structure-activity studies, and radiosensitization of a human tumor cell line in vitro. J Med Chem 2005; 48:569-85. [PMID: 15658870 DOI: 10.1021/jm049526a] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A diverse range of chromen-2-one, chromen-4-one and pyrimidoisoquinolin-4-one derivatives was synthesized and evaluated for inhibitory activity against the DNA repair enzyme DNA-dependent protein kinase (DNA-PK), with a view to elucidating structure-activity relationships for potency and kinase selectivity. DNA-PK inhibitory activity varied widely over the series of compounds evaluated (IC(50) values ranged from 0.19 to >10 microM), with excellent activity being observed for the 7,8-benzochromen-4-one and pyrimido[2,1-a]isoquinolin-4-one templates. By contrast, inhibitors based on the benzochromen-2-one (coumarin) or 2-aryl-7,8-benzochromen-4-one (flavone) scaffolds were less potent. Crucially, these studies revealed a very constrained structure-activity relationship at the 2-position of the benzopyranone and pyrimido[2,1-a]isoquinolin-4-one pharmacophore, with only a 2-morpholino or 2-(2'-methylmorpholino) group being tolerated at this position. More detailed biological studies conducted with the most potent inhibitor NU7163 (48; IC(50) = 0.19 microM) demonstrated ATP-competitive DNA-PK inhibition, with a K(i) value of 24 nM, and 48 exhibited selectivity for DNA-PK compared with the related enzymes ATM, ATR, mTOR, and PI 3-K (p110alpha). Compound 48 sensitized the HeLa human tumor cell line to the cytotoxic effects of ionizing radiation in vitro, a dose modification factor of 2.3 at 10% survival being observed with an inhibitor concentration of 5 microM. This study identified these structural classes as novel DNA-PK inhibitors and delineated initial structure-activity relationships against DNA-PK.
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Affiliation(s)
- Roger J Griffin
- Northern Institute for Cancer Research, School of Natural Sciences-Chemistry, Bedson Building, The University, Newcastle upon Tyne NE1 7RU, UK
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46
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Abstract
The phosphoinositide 3-kinase related kinases (PIKKs) comprise a family of high molecular mass signaling proteins that play central roles in the control of cell growth, gene expression, and genome surveillance and repair in eukaryotic cells. Mammalian cells express six PIKK family members, five of which-ATM, ATR, mTOR, DNA-PK, and hSMG-1-function as protein serine-threosine kinases. This overview provides some general insights into the pharmacology, biochemistry, and function of this nonconventional group of protein kinases.
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Affiliation(s)
- Robert T Abraham
- Program in Signal Transduction Research, The Burnham Institute, 10901 North Torrey Pines Road, La Jolla, CA 92130, USA.
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47
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Viniegra JG, Martínez N, Modirassari P, Hernández Losa J, Parada Cobo C, Sánchez-Arévalo Lobo VJ, Aceves Luquero CI, Alvarez-Vallina L, Ramón y Cajal S, Rojas JM, Sánchez-Prieto R. Full Activation of PKB/Akt in Response to Insulin or Ionizing Radiation Is Mediated through ATM. J Biol Chem 2005; 280:4029-36. [PMID: 15546863 DOI: 10.1074/jbc.m410344200] [Citation(s) in RCA: 202] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The gene mutated in ataxia telangiectasia, ATM, has been implicated in several cell functions such as cell cycle control and response to DNA damage and insulin. PKB/Akt has also been implicated in the cellular response to insulin, gamma-radiation, and cell cycle control. Interestingly, lack of PKB/Akt function in vivo is able to mimic some phenotypic abnormalities associated with ataxia telangiectasia (AT). Here we show that ATM is a major determinant of full PKB/Akt activation in response to insulin or gamma-radiation. This effect is mediated through the phosphatidylinositol 3-kinase domain of ATM that specifically affects Akt serine 473 phosphorylation. This conclusion was inferred from the results obtained in transient transfection assays using exogenous PKB/Akt and ATM in Cos cells. Moreover, the use of ATM inhibitors or small interfering RNA confirmed our observation. Further supporting these results, we also observed that biological responses tightly regulated by Akt, such as transcription factor of the forkhead family activity after insulin treatment or gamma-radiation response, were altered in cell lines derived from AT patients and knockout mice for ATM in which phosphorylation in serine 473 was almost abolished. This study proposes new clues in the search of the unknown PDK2 and new explanations for the radiosensitivity or insulin intolerance described more than 30 years ago in AT patients.
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Affiliation(s)
- Juan Guinea Viniegra
- CRIB/Facultad de Medicina, Universidad de Castilla la Mancha, 02071 Albacete, Spain
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48
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Abstract
Efficient repair of DNA double-strand breaks is essential for the maintenance of chromosomal integrity. In higher eukaryotes, non-homologous end-joining (NHEJ) DNA is the primary pathway that repairs these breaks. NHEJ also functions in developing lymphocytes to repair strand breaks that occur during V(D)J recombination, the site-specific recombination process that provides for the assembly of functional antigen-receptor genes. If V(D)J recombination is impaired, B- and T-lymphocyte development is blocked resulting in severe combined immunodeficiency disease. In the last decade, an intensive research effort has focused on NHEJ resulting in a reasonable understanding of how double-strand breaks are resolved. Six distinct gene products have been identified that function in this pathway (Ku70, Ku86, XRCC4, DNA ligase IV, Artemis, and DNA-PKcs). Three of these comprise one complex, the DNA-dependent protein kinase (DNA-PK). This protein complex is central during NHEJ, because DNA-PK initially recognizes and binds to the damaged DNA and then targets the other repair activities to the site of DNA damage. In this review, we discuss recent developments that have provided insight into how DNA-PK functions, once bound to DNA ends.
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Affiliation(s)
- Katheryn Meek
- College of Veterinary Medicine and Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, MI 48824, USA
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49
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Birmingham EC, Lee SA, McCulloch RD, Baker MD. Testing predictions of the double-strand break repair model relating to crossing over in Mammalian cells. Genetics 2004; 168:1539-55. [PMID: 15579705 PMCID: PMC1448801 DOI: 10.1534/genetics.104.029215] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2004] [Accepted: 07/22/2004] [Indexed: 11/18/2022] Open
Abstract
In yeast, four-stranded, biparental "joint molecules" containing a pair of Holliday junctions are demonstrated intermediates in the repair of meiotic double-strand breaks (DSBs). Genetic and physical evidence suggests that when joint molecules are resolved by the cutting of each of the two Holliday junctions, crossover products result at least most of the time. The double-strand break repair (DSBR) model is currently accepted as a paradigm for acts of DSB repair that lead to crossing over. In this study, a well-defined mammalian gene-targeting assay was used to test predictions that the DSBR model makes about the frequency and position of hDNA in recombinants generated by crossing over. The DSBR model predicts that hDNA will frequently form on opposite sides of the DSB in the two homologous sequences undergoing recombination [half conversion (HC); 5:3, 5:3 segregation]. By examining the segregation patterns of poorly repairable small palindrome genetic markers, we show that this configuration of hDNA is rare. Instead, in a large number of recombinants, full conversion (FC) events in the direction of the unbroken chromosomal sequence (6:2 segregation) were observed on one side of the DSB. A conspicuous fraction of the unidirectional FC events was associated with normal 4:4 marker segregation on the other side of the DSB. In addition, a large number of recombinants displayed evidence of hDNA formation. In several, hDNA was symmetrical on one side of the DSB, suggesting that the two homologous regions undergoing recombination swapped single strands of the same polarity. These data are considered within the context of modified versions of the DSBR model.
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Affiliation(s)
- Erin C Birmingham
- Department of Molecular Biology and Genetics, College of Biological Science, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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50
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Grimson A, O'Connor S, Newman CL, Anderson P. SMG-1 is a phosphatidylinositol kinase-related protein kinase required for nonsense-mediated mRNA Decay in Caenorhabditis elegans. Mol Cell Biol 2004; 24:7483-90. [PMID: 15314158 PMCID: PMC506987 DOI: 10.1128/mcb.24.17.7483-7490.2004] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Eukaryotic messenger RNAs containing premature stop codons are selectively and rapidly degraded, a phenomenon termed nonsense-mediated mRNA decay (NMD). Previous studies with both Caenohabditis elegans and mammalian cells indicate that SMG-2/human UPF1, a central regulator of NMD, is phosphorylated in an SMG-1-dependent manner. We report here that smg-1, which is required for NMD in C. elegans, encodes a protein kinase of the phosphatidylinositol kinase superfamily of protein kinases. We identify null alleles of smg-1 and demonstrate that SMG-1 kinase activity is required in vivo for NMD and in vitro for SMG-2 phosphorylation. SMG-1 and SMG-2 coimmunoprecipitate from crude extracts, and this interaction is maintained in smg-3 and smg-4 mutants, both of which are required for SMG-2 phosphorylation in vivo and in vitro. SMG-2 is located diffusely through the cytoplasm, and its location is unaltered in mutants that disrupt the cycle of SMG-2 phosphorylation. We discuss the role of SMG-2 phosphorylation in NMD.
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Affiliation(s)
- Andrew Grimson
- Department of Genetics, University of Wisconsin, 445 Henry Mall, Madison, WI 53706, USA
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