1
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Mayfield JE, Dixon JE. Emerging mechanisms of regulation for endoplasmic/sarcoplasmic reticulum Ca2+ stores by secretory pathway kinase FAM20C. Curr Opin Chem Biol 2023; 74:102279. [DOI: 10.1016/j.cbpa.2023.102279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 01/31/2023] [Accepted: 02/03/2023] [Indexed: 03/28/2023]
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2
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Mayfield JE, Newton AC, Dixon JE. Divalent cation driven liquid‐liquid phase separation of disordered acidic proteins. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r3785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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3
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Moreno R, Banerjee S, Jackson AW, Quinn J, Baillie G, Dixon JE, Dinkova-Kostova AT, Edwards J, de la Vega L. The stress-responsive kinase DYRK2 activates heat shock factor 1 promoting resistance to proteotoxic stress. Cell Death Differ 2021; 28:1563-1578. [PMID: 33268814 PMCID: PMC8166837 DOI: 10.1038/s41418-020-00686-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 11/16/2020] [Accepted: 11/17/2020] [Indexed: 12/23/2022] Open
Abstract
To survive proteotoxic stress, cancer cells activate the proteotoxic-stress response pathway, which is controlled by the transcription factor heat shock factor 1 (HSF1). This pathway supports cancer initiation, cancer progression and chemoresistance and thus is an attractive therapeutic target. As developing inhibitors against transcriptional regulators, such as HSF1 is challenging, the identification and targeting of upstream regulators of HSF1 present a tractable alternative strategy. Here we demonstrate that in triple-negative breast cancer (TNBC) cells, the dual specificity tyrosine-regulated kinase 2 (DYRK2) phosphorylates HSF1, promoting its nuclear stability and transcriptional activity. DYRK2 depletion reduces HSF1 activity and sensitises TNBC cells to proteotoxic stress. Importantly, in tumours from TNBC patients, DYRK2 levels positively correlate with active HSF1 and associates with poor prognosis, suggesting that DYRK2 could be promoting TNBC. These findings identify DYRK2 as a key modulator of the HSF1 transcriptional programme and a potential therapeutic target.
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Affiliation(s)
- Rita Moreno
- Division of Cellular Medicine, School of Medicine, University of Dundee, Dundee, Scotland, UK
| | - Sourav Banerjee
- Division of Cellular Medicine, School of Medicine, University of Dundee, Dundee, Scotland, UK
- Department of Pharmacology, University of California San Diego, La Jolla, CA, 92093-0721, USA
| | - Angus W Jackson
- Division of Cellular Medicine, School of Medicine, University of Dundee, Dundee, Scotland, UK
| | - Jean Quinn
- Unit of Gastrointestinal Oncology and Molecular Pathology, Institute of Cancer Sciences, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, UK
| | - Gregg Baillie
- Unit of Gastrointestinal Oncology and Molecular Pathology, Institute of Cancer Sciences, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, UK
| | - Jack E Dixon
- Department of Pharmacology, University of California San Diego, La Jolla, CA, 92093-0721, USA
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, 92093, USA
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA, 92093, USA
| | | | - Joanne Edwards
- Unit of Gastrointestinal Oncology and Molecular Pathology, Institute of Cancer Sciences, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, UK
| | - Laureano de la Vega
- Division of Cellular Medicine, School of Medicine, University of Dundee, Dundee, Scotland, UK.
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4
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Walimbe AS, Okuma H, Joseph S, Yang T, Yonekawa T, Hord JM, Venzke D, Anderson ME, Torelli S, Manzur A, Devereaux M, Cuellar M, Prouty S, Ocampo Landa S, Yu L, Xiao J, Dixon JE, Muntoni F, Campbell KP. POMK regulates dystroglycan function via LARGE1-mediated elongation of matriglycan. eLife 2020; 9:e61388. [PMID: 32975514 PMCID: PMC7556876 DOI: 10.7554/elife.61388] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 09/24/2020] [Indexed: 12/22/2022] Open
Abstract
Matriglycan [-GlcA-β1,3-Xyl-α1,3-]n serves as a scaffold in many tissues for extracellular matrix proteins containing laminin-G domains including laminin, agrin, and perlecan. Like-acetyl-glucosaminyltransferase 1 (LARGE1) synthesizes and extends matriglycan on α-dystroglycan (α-DG) during skeletal muscle differentiation and regeneration; however, the mechanisms which regulate matriglycan elongation are unknown. Here, we show that Protein O-Mannose Kinase (POMK), which phosphorylates mannose of core M3 (GalNAc-β1,3-GlcNAc-β1,4-Man) preceding matriglycan synthesis, is required for LARGE1-mediated generation of full-length matriglycan on α-DG (~150 kDa). In the absence of Pomk gene expression in mouse skeletal muscle, LARGE1 synthesizes a very short matriglycan resulting in a ~ 90 kDa α-DG which binds laminin but cannot prevent eccentric contraction-induced force loss or muscle pathology. Solution NMR spectroscopy studies demonstrate that LARGE1 directly interacts with core M3 and binds preferentially to the phosphorylated form. Collectively, our study demonstrates that phosphorylation of core M3 by POMK enables LARGE1 to elongate matriglycan on α-DG, thereby preventing muscular dystrophy.
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Affiliation(s)
- Ameya S Walimbe
- Howard Hughes Medical Institute, Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, Department of Molecular Physiology and Biophysics and Department of Neurology, Roy J. and Lucille A. Carver College of Medicine, The University of IowaIowa CityUnited States
| | - Hidehiko Okuma
- Howard Hughes Medical Institute, Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, Department of Molecular Physiology and Biophysics and Department of Neurology, Roy J. and Lucille A. Carver College of Medicine, The University of IowaIowa CityUnited States
| | - Soumya Joseph
- Howard Hughes Medical Institute, Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, Department of Molecular Physiology and Biophysics and Department of Neurology, Roy J. and Lucille A. Carver College of Medicine, The University of IowaIowa CityUnited States
| | - Tiandi Yang
- Howard Hughes Medical Institute, Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, Department of Molecular Physiology and Biophysics and Department of Neurology, Roy J. and Lucille A. Carver College of Medicine, The University of IowaIowa CityUnited States
| | - Takahiro Yonekawa
- Howard Hughes Medical Institute, Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, Department of Molecular Physiology and Biophysics and Department of Neurology, Roy J. and Lucille A. Carver College of Medicine, The University of IowaIowa CityUnited States
| | - Jeffrey M Hord
- Howard Hughes Medical Institute, Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, Department of Molecular Physiology and Biophysics and Department of Neurology, Roy J. and Lucille A. Carver College of Medicine, The University of IowaIowa CityUnited States
| | - David Venzke
- Howard Hughes Medical Institute, Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, Department of Molecular Physiology and Biophysics and Department of Neurology, Roy J. and Lucille A. Carver College of Medicine, The University of IowaIowa CityUnited States
| | - Mary E Anderson
- Howard Hughes Medical Institute, Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, Department of Molecular Physiology and Biophysics and Department of Neurology, Roy J. and Lucille A. Carver College of Medicine, The University of IowaIowa CityUnited States
| | - Silvia Torelli
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health & Great Ormond Street HospitalLondonUnited Kingdom
| | - Adnan Manzur
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health & Great Ormond Street HospitalLondonUnited Kingdom
| | - Megan Devereaux
- Howard Hughes Medical Institute, Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, Department of Molecular Physiology and Biophysics and Department of Neurology, Roy J. and Lucille A. Carver College of Medicine, The University of IowaIowa CityUnited States
| | - Marco Cuellar
- Howard Hughes Medical Institute, Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, Department of Molecular Physiology and Biophysics and Department of Neurology, Roy J. and Lucille A. Carver College of Medicine, The University of IowaIowa CityUnited States
| | - Sally Prouty
- Howard Hughes Medical Institute, Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, Department of Molecular Physiology and Biophysics and Department of Neurology, Roy J. and Lucille A. Carver College of Medicine, The University of IowaIowa CityUnited States
| | - Saul Ocampo Landa
- Howard Hughes Medical Institute, Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, Department of Molecular Physiology and Biophysics and Department of Neurology, Roy J. and Lucille A. Carver College of Medicine, The University of IowaIowa CityUnited States
| | - Liping Yu
- Medical Nuclear Magnetic Resonance Facility, University of Iowa Roy J. and Lucille A. Carver College of MedicineIowa CityUnited States
| | - Junyu Xiao
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking-Tsinghua Center for Life Sciences, Peking UniversityBeijingChina
| | - Jack E Dixon
- Department of Pharmacology, Department of Cellular and Molecular Medicine, Department of Chemistry and Biochemistry, University of California, San DiegoSan DiegoUnited States
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health & Great Ormond Street HospitalLondonUnited Kingdom
- National Institute for Health Research Great Ormond Street Hospital Biomedical Research Centre, UCL Great Ormond Street Institute of Child HealthLondonUnited Kingdom
| | - Kevin P Campbell
- Howard Hughes Medical Institute, Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, Department of Molecular Physiology and Biophysics and Department of Neurology, Roy J. and Lucille A. Carver College of Medicine, The University of IowaIowa CityUnited States
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5
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Banerjee S, Wei T, Wang J, Lee JJ, Gutierrez HL, Chapman O, Wiley SE, Mayfield JE, Tandon V, Juarez EF, Chavez L, Liang R, Sah RL, Costello C, Mesirov JP, de la Vega L, Cooper KL, Dixon JE, Xiao J, Lei X. Inhibition of dual-specificity tyrosine phosphorylation-regulated kinase 2 perturbs 26S proteasome-addicted neoplastic progression. Proc Natl Acad Sci U S A 2019; 116:24881-24891. [PMID: 31754034 PMCID: PMC6900511 DOI: 10.1073/pnas.1912033116] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Dependence on the 26S proteasome is an Achilles' heel for triple-negative breast cancer (TNBC) and multiple myeloma (MM). The therapeutic proteasome inhibitor, bortezomib, successfully targets MM but often leads to drug-resistant disease relapse and fails in breast cancer. Here we show that a 26S proteasome-regulating kinase, DYRK2, is a therapeutic target for both MM and TNBC. Genome editing or small-molecule mediated inhibition of DYRK2 significantly reduces 26S proteasome activity, bypasses bortezomib resistance, and dramatically delays in vivo tumor growth in MM and TNBC thereby promoting survival. We further characterized the ability of LDN192960, a potent and selective DYRK2-inhibitor, to alleviate tumor burden in vivo. The drug docks into the active site of DYRK2 and partially inhibits all 3 core peptidase activities of the proteasome. Our results suggest that targeting 26S proteasome regulators will pave the way for therapeutic strategies in MM and TNBC.
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Affiliation(s)
- Sourav Banerjee
- Department of Pharmacology, University of California San Diego, La Jolla, CA 92093
| | - Tiantian Wei
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, 100871 Beijing, China
- Peking-Tsinghua Center for Life Sciences, Peking University, 100871 Beijing, China
| | - Jue Wang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, 100871 Beijing, China
| | - Jenna J Lee
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093
| | - Haydee L Gutierrez
- Division of Biological Sciences, Section of Cellular and Developmental Biology, University of California San Diego, La Jolla, CA 92093
| | - Owen Chapman
- Department of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Sandra E Wiley
- Department of Pharmacology, University of California San Diego, La Jolla, CA 92093
| | - Joshua E Mayfield
- Department of Pharmacology, University of California San Diego, La Jolla, CA 92093
| | - Vasudha Tandon
- Department of Pharmacology, University of California San Diego, La Jolla, CA 92093
| | - Edwin F Juarez
- Department of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Lukas Chavez
- Department of Medicine, University of California San Diego, La Jolla, CA 92093
- Moores Cancer Center, University of California San Diego, La Jolla, CA 92093
| | - Ruqi Liang
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, 100871 Beijing, China
- Peking-Tsinghua Center for Life Sciences, Peking University, 100871 Beijing, China
| | - Robert L Sah
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093
| | - Caitlin Costello
- Moores Cancer Center, University of California San Diego, La Jolla, CA 92093
- Division of Blood and Marrow Transplant, University of California San Diego, La Jolla, CA 92093
| | - Jill P Mesirov
- Department of Medicine, University of California San Diego, La Jolla, CA 92093
- Moores Cancer Center, University of California San Diego, La Jolla, CA 92093
| | - Laureano de la Vega
- Division of Cellular Medicine, School of Medicine, University of Dundee, Dundee, DD1 9SY, United Kingdom
| | - Kimberly L Cooper
- Division of Biological Sciences, Section of Cellular and Developmental Biology, University of California San Diego, La Jolla, CA 92093
| | - Jack E Dixon
- Department of Pharmacology, University of California San Diego, La Jolla, CA 92093;
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093
| | - Junyu Xiao
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, 100871 Beijing, China;
- Peking-Tsinghua Center for Life Sciences, Peking University, 100871 Beijing, China
| | - Xiaoguang Lei
- Peking-Tsinghua Center for Life Sciences, Peking University, 100871 Beijing, China;
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, 100871 Beijing, China
- Department of Chemical Biology, Synthetic and Functional Biomolecules Center, Peking University, 100871 Beijing, China
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6
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Gerson-Gurwitz A, Worby CA, Lee KY, Khaliullin R, Bouffard J, Cheerambathur D, Oegema K, Cram EJ, Dixon JE, Desai A. Ancestral roles of the Fam20C family of secreted protein kinases revealed in C. elegans. J Cell Biol 2019; 218:3795-3811. [PMID: 31541016 PMCID: PMC6829671 DOI: 10.1083/jcb.201807041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 07/11/2019] [Accepted: 08/25/2019] [Indexed: 01/05/2023] Open
Abstract
Gerson-Gurwitz et al. show that FAMK-1, the sole Fam20-like secreted protein kinase in C. elegans, contributes to embryonic development and fertility, acts in the late secretory pathway, phosphorylates lectins, and is important in embryonic and tissue contexts where cells are subjected to mechanical strain. Fam20C is a secreted protein kinase mutated in Raine syndrome, a human skeletal disorder. In vertebrates, bone and enamel proteins are major Fam20C substrates. However, Fam20 kinases are conserved in invertebrates lacking bone and enamel, suggesting other ancestral functions. We show that FAMK-1, the Caenorhabditis elegans Fam20C orthologue, contributes to fertility, embryogenesis, and development. These functions are not fulfilled when FAMK-1 is retained in the early secretory pathway. During embryogenesis, FAMK-1 maintains intercellular partitions and prevents multinucleation; notably, temperature elevation or lowering cortical stiffness reduces requirement for FAMK-1 in these contexts. FAMK-1 is expressed in multiple adult tissues that undergo repeated mechanical strain, and selective expression in the spermatheca restores fertility. Informatic, biochemical, and functional analysis implicate lectins as FAMK-1 substrates. These findings suggest that FAMK-1 phosphorylation of substrates, including lectins, in the late secretory pathway is important in embryonic and tissue contexts where cells are subjected to mechanical strain.
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Affiliation(s)
- Adina Gerson-Gurwitz
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA.,Department of Cellular & Molecular Medicine, University of California, San Diego, La Jolla, CA
| | - Carolyn A Worby
- Department of Cellular & Molecular Medicine, University of California, San Diego, La Jolla, CA.,Department of Pharmacology, University of California, San Diego, La Jolla, CA
| | - Kian-Yong Lee
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA.,Department of Cellular & Molecular Medicine, University of California, San Diego, La Jolla, CA
| | - Renat Khaliullin
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA.,Department of Cellular & Molecular Medicine, University of California, San Diego, La Jolla, CA
| | - Jeff Bouffard
- Department of Bioengineering, Northeastern University, Boston, MA
| | - Dhanya Cheerambathur
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA.,Department of Cellular & Molecular Medicine, University of California, San Diego, La Jolla, CA
| | - Karen Oegema
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA.,Department of Cellular & Molecular Medicine, University of California, San Diego, La Jolla, CA
| | - Erin J Cram
- Department of Biology, Northeastern University, Boston, MA
| | - Jack E Dixon
- Department of Cellular & Molecular Medicine, University of California, San Diego, La Jolla, CA .,Department of Pharmacology, University of California, San Diego, La Jolla, CA
| | - Arshad Desai
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA .,Department of Cellular & Molecular Medicine, University of California, San Diego, La Jolla, CA
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7
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Abstract
Herb Tabor was the Editor-in-Chief of the Journal of Biological Chemistry (JBC) spanning the years 1971-2010. This year, Herb turns 100. What do you give a person turning 100? Our answer to this question was to dedicate two of our favorite JBC papers to Herb. Both of these papers focus on reversible phosphorylation, which we briefly review. In addition, we delve into a new finding that centers around a novel family of secreted kinases, suggesting that there are many new and exciting discoveries yet to explore.
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Affiliation(s)
- Carolyn A Worby
- Department of Pharmacology, University of California San Diego, La Jolla, California 92093
| | - Jack E Dixon
- Department of Pharmacology, University of California San Diego, La Jolla, California 92093; Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093; Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California 92093.
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8
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Pollak AJ, Liu C, Gudlur A, Mayfield JE, Dalton ND, Gu Y, Chen J, Heller Brown J, Hogan PG, Wiley SE, Peterson KL, Dixon JE. A secretory pathway kinase regulates sarcoplasmic reticulum Ca 2+ homeostasis and protects against heart failure. eLife 2018; 7:41378. [PMID: 30520731 PMCID: PMC6298778 DOI: 10.7554/elife.41378] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 12/03/2018] [Indexed: 12/17/2022] Open
Abstract
Ca2+ signaling is important for many cellular and physiological processes, including cardiac function. Although sarcoplasmic reticulum (SR) proteins involved in Ca2+ signaling have been shown to be phosphorylated, the biochemical and physiological roles of protein phosphorylation within the lumen of the SR remain essentially uncharacterized. Our laboratory recently identified an atypical protein kinase, Fam20C, which is uniquely localized to the secretory pathway lumen. Here, we show that Fam20C phosphorylates several SR proteins involved in Ca2+ signaling, including calsequestrin2 and Stim1, whose biochemical activities are dramatically regulated by Fam20C mediated phosphorylation. Notably, phosphorylation of Stim1 by Fam20C enhances Stim1 activation and store-operated Ca2+ entry. Physiologically, mice with Fam20c ablated in cardiomyocytes develop heart failure following either aging or induced pressure overload. We extended these observations to show that non-muscle cells lacking Fam20C display altered ER Ca2+ signaling. Overall, we show that Fam20C plays an overarching role in ER/SR Ca2+ homeostasis and cardiac pathophysiology.
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Affiliation(s)
- Adam J Pollak
- Department of Pharmacology, University of California, San Diego, San Diego, United States
| | - Canzhao Liu
- Department of Medicine, University of California, San Diego, San Diego, United States
| | - Aparna Gudlur
- Division of Signaling and Gene Expression, La Jolla Institute for Allergy and Immunology, San Diego, United States
| | - Joshua E Mayfield
- Department of Pharmacology, University of California, San Diego, San Diego, United States
| | - Nancy D Dalton
- Department of Medicine, University of California, San Diego, San Diego, United States
| | - Yusu Gu
- Department of Medicine, University of California, San Diego, San Diego, United States
| | - Ju Chen
- Department of Medicine, University of California, San Diego, San Diego, United States
| | - Joan Heller Brown
- Department of Pharmacology, University of California, San Diego, San Diego, United States
| | - Patrick G Hogan
- Division of Signaling and Gene Expression, La Jolla Institute for Allergy and Immunology, San Diego, United States.,Program in Immunology, University of California, San Diego, San Diego, United States.,Moores Cancer Center, University of California, San Diego, San Diego, United States
| | - Sandra E Wiley
- Department of Pharmacology, University of California, San Diego, San Diego, United States
| | - Kirk L Peterson
- Department of Medicine, University of California, San Diego, San Diego, United States
| | - Jack E Dixon
- Department of Pharmacology, University of California, San Diego, San Diego, United States.,Department of Cellular and Molecular Medicine, University of California, San Diego, San Diego, United States.,Department of Chemistry and Biochemistry, University of California, San Diego, San Diego, United States
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9
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Qiu Y, Poppleton E, Mekkat A, Yu H, Banerjee S, Wiley SE, Dixon JE, Kaplan DL, Lin YS, Brodsky B. Enzymatic Phosphorylation of Ser in a Type I Collagen Peptide. Biophys J 2018; 115:2327-2335. [PMID: 30527445 DOI: 10.1016/j.bpj.2018.11.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 10/12/2018] [Accepted: 11/08/2018] [Indexed: 01/13/2023] Open
Abstract
Phosphoproteomics studies have reported phosphorylation at multiple sites within collagen, raising the possibility that these post-translational modifications regulate the physical or biological properties of collagen. In this study, molecular dynamics simulations and experimental studies were carried out on model peptides to establish foundational principles of phosphorylation of Ser residues in collagen. A (Gly-Xaa-Yaa)11 peptide was designed to include a Ser-containing sequence from type I collagen that was reported to be phosphorylated. The physiological kinase involved in collagen phosphorylation is not known. In vitro studies showed that a model kinase ERK1 (extracellular signal-regulated protein kinase 1) would phosphorylate Ser within the consensus sequence if the collagen-like peptide is in the denatured state but not in the triple-helical state. The peptide was not a substrate for FAM20C, a kinase present in the secretory pathway, which has been shown to phosphorylate many extracellular matrix proteins. The unfolded single chain (Gly-Xaa-Yaa)11 peptide containing phosphoSer was able to refold to form a stable triple helix but at a reduced folding rate and with a small decrease in thermal stability relative to the nonphosphorylated peptide at neutral pH. These biophysical studies on model peptides provide a basis for investigations into the physiological consequences of collagen phosphorylation and the application of phosphorylation to regulate the properties of collagen biomaterials.
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Affiliation(s)
- Yimin Qiu
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts
| | - Erik Poppleton
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts
| | - Arya Mekkat
- Department of Chemistry, Tufts University, Medford, Massachusetts
| | - Hongtao Yu
- Department of Chemistry, Tufts University, Medford, Massachusetts
| | - Sourav Banerjee
- Department of Pharmacology, University of California, San Diego, La Jolla, California
| | - Sandra E Wiley
- Department of Pharmacology, University of California, San Diego, La Jolla, California
| | - Jack E Dixon
- Department of Pharmacology, University of California, San Diego, La Jolla, California
| | - David L Kaplan
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts.
| | - Yu-Shan Lin
- Department of Chemistry, Tufts University, Medford, Massachusetts
| | - Barbara Brodsky
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts.
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10
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Banerjee S, Ji C, Mayfield JE, Goel A, Xiao J, Dixon JE, Guo X. Ancient drug curcumin impedes 26S proteasome activity by direct inhibition of dual-specificity tyrosine-regulated kinase 2. Proc Natl Acad Sci U S A 2018; 115:8155-8160. [PMID: 29987021 PMCID: PMC6094102 DOI: 10.1073/pnas.1806797115] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Curcumin, the active ingredient in Curcuma longa, has been in medicinal use since ancient times. However, the therapeutic targets and signaling cascades modulated by curcumin have been enigmatic despite extensive research. Here we identify dual-specificity tyrosine-regulated kinase 2 (DYRK2), a positive regulator of the 26S proteasome, as a direct target of curcumin. Curcumin occupies the ATP-binding pocket of DYRK2 in the cocrystal structure, and it potently and specifically inhibits DYRK2 over 139 other kinases tested in vitro. As a result, curcumin diminishes DYRK2-mediated 26S proteasome phosphorylation in cells, leading to reduced proteasome activity and impaired cell proliferation. Interestingly, curcumin synergizes with the therapeutic proteasome inhibitor carfilzomib to induce apoptosis in a variety of proteasome-addicted cancer cells, while this drug combination exhibits modest to no cytotoxicity to noncancerous cells. In a breast cancer xenograft model, curcumin treatment significantly reduces tumor burden in immunocompromised mice, showing a similar antitumor effect as CRISPR/Cas9-mediated DYRK2 depletion. These results reveal an unexpected role of curcumin in DYRK2-proteasome inhibition and provide a proof-of-concept that pharmacological manipulation of proteasome regulators may offer new opportunities for anticancer treatment.
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Affiliation(s)
- Sourav Banerjee
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093-0721
| | - Chenggong Ji
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, 100871 Beijing, China
| | - Joshua E Mayfield
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093-0721
| | - Apollina Goel
- Division of the Department of Radiation Oncology, The University of Iowa, Iowa City, IA 52242-1181
| | - Junyu Xiao
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, 100871 Beijing, China
| | - Jack E Dixon
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093-0721;
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093
| | - Xing Guo
- The Life Sciences Institute, Zhejiang University, 310058 Hangzhou, China
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11
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Zhang H, Zhu Q, Cui J, Wang Y, Chen MJ, Guo X, Tagliabracci VS, Dixon JE, Xiao J. Structure and evolution of the Fam20 kinases. Nat Commun 2018; 9:1218. [PMID: 29572475 PMCID: PMC5865150 DOI: 10.1038/s41467-018-03615-z] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 02/28/2018] [Indexed: 01/04/2023] Open
Abstract
The Fam20 proteins are novel kinases that phosphorylate secreted proteins and proteoglycans. Fam20C phosphorylates hundreds of secreted proteins and is activated by the pseudokinase Fam20A. Fam20B phosphorylates a xylose residue to regulate proteoglycan synthesis. Despite these wide-ranging and important functions, the molecular and structural basis for the regulation and substrate specificity of these kinases are unknown. Here we report molecular characterizations of all three Fam20 kinases, and show that Fam20C is activated by the formation of an evolutionarily conserved homodimer or heterodimer with Fam20A. Fam20B has a unique active site for recognizing Galβ1-4Xylβ1, the initiator disaccharide within the tetrasaccharide linker region of proteoglycans. We further show that in animals the monomeric Fam20B preceded the appearance of the dimeric Fam20C, and the dimerization trait of Fam20C emerged concomitantly with a change in substrate specificity. Our results provide comprehensive structural, biochemical, and evolutionary insights into the function of the Fam20 kinases.
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Affiliation(s)
- Hui Zhang
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, 100871, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China
| | - Qinyu Zhu
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, 100871, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China
| | - Jixin Cui
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Yuxin Wang
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, 100871, Beijing, China
| | - Mark J Chen
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, TN, 38015, USA
| | - Xing Guo
- The Life Sciences Institute, Zhejiang University, 310058, Hangzhou, China
| | - Vincent S Tagliabracci
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Jack E Dixon
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Junyu Xiao
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, 100871, Beijing, China.
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12
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Cui J, Zhu Q, Zhang H, Cianfrocco MA, Leschziner AE, Dixon JE, Xiao J. Structure of Fam20A reveals a pseudokinase featuring a unique disulfide pattern and inverted ATP-binding. eLife 2017; 6. [PMID: 28432788 PMCID: PMC5413348 DOI: 10.7554/elife.23990] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 04/20/2017] [Indexed: 12/19/2022] Open
Abstract
Mutations in FAM20A cause tooth enamel defects known as Amelogenesis Imperfecta (AI) and renal calcification. We previously showed that Fam20A is a secretory pathway pseudokinase and allosterically activates the physiological casein kinase Fam20C to phosphorylate secreted proteins important for biomineralization (Cui et al., 2015). Here we report the nucleotide-free and ATP-bound structures of Fam20A. Fam20A exhibits a distinct disulfide bond pattern mediated by a unique insertion region. Loss of this insertion due to abnormal mRNA splicing interferes with the structure and function of Fam20A, resulting in AI. Fam20A binds ATP in the absence of divalent cations, and strikingly, ATP is bound in an inverted orientation compared to other kinases. Fam20A forms a dimer in the crystal, and residues in the dimer interface are critical for Fam20C activation. Together, these results provide structural insights into the function of Fam20A and shed light on the mechanism by which Fam20A mutations cause disease. DOI:http://dx.doi.org/10.7554/eLife.23990.001
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Affiliation(s)
- Jixin Cui
- Department of Pharmacology, University of California, San Diego, United States
| | - Qinyu Zhu
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.,The State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Hui Zhang
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.,The State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Michael A Cianfrocco
- Department of Cellular and Molecular Medicine, University of California, San Diego, United States
| | - Andres E Leschziner
- Department of Cellular and Molecular Medicine, University of California, San Diego, United States
| | - Jack E Dixon
- Department of Pharmacology, University of California, San Diego, United States.,Department of Cellular and Molecular Medicine, University of California, San Diego, United States.,Department of Chemistry and Biochemistry, University of California, San Diego, United States
| | - Junyu Xiao
- The State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
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13
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14
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Wang X, Cimermancic P, Yu C, Schweitzer A, Chopra N, Engel JL, Greenberg C, Huszagh AS, Beck F, Sakata E, Yang Y, Novitsky EJ, Leitner A, Nanni P, Kahraman A, Guo X, Dixon JE, Rychnovsky SD, Aebersold R, Baumeister W, Sali A, Huang L. Molecular Details Underlying Dynamic Structures and Regulation of the Human 26S Proteasome. Mol Cell Proteomics 2017; 16:840-854. [PMID: 28292943 DOI: 10.1074/mcp.m116.065326] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Revised: 02/13/2017] [Indexed: 12/28/2022] Open
Abstract
The 26S proteasome is the macromolecular machine responsible for ATP/ubiquitin dependent degradation. As aberration in proteasomal degradation has been implicated in many human diseases, structural analysis of the human 26S proteasome complex is essential to advance our understanding of its action and regulation mechanisms. In recent years, cross-linking mass spectrometry (XL-MS) has emerged as a powerful tool for elucidating structural topologies of large protein assemblies, with its unique capability of studying protein complexes in cells. To facilitate the identification of cross-linked peptides, we have previously developed a robust amine reactive sulfoxide-containing MS-cleavable cross-linker, disuccinimidyl sulfoxide (DSSO). To better understand the structure and regulation of the human 26S proteasome, we have established new DSSO-based in vivo and in vitro XL-MS workflows by coupling with HB-tag based affinity purification to comprehensively examine protein-protein interactions within the 26S proteasome. In total, we have identified 447 unique lysine-to-lysine linkages delineating 67 interprotein and 26 intraprotein interactions, representing the largest cross-link dataset for proteasome complexes. In combination with EM maps and computational modeling, the architecture of the 26S proteasome was determined to infer its structural dynamics. In particular, three proteasome subunits Rpn1, Rpn6, and Rpt6 displayed multiple conformations that have not been previously reported. Additionally, cross-links between proteasome subunits and 15 proteasome interacting proteins including 9 known and 6 novel ones have been determined to demonstrate their physical interactions at the amino acid level. Our results have provided new insights on the dynamics of the 26S human proteasome and the methodologies presented here can be applied to study other protein complexes.
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Affiliation(s)
- Xiaorong Wang
- From the ‡Department of Physiology & Biophysics, University of California, Irvine, Irvine, California 92697
| | - Peter Cimermancic
- §Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, California 94143
| | - Clinton Yu
- From the ‡Department of Physiology & Biophysics, University of California, Irvine, Irvine, California 92697
| | - Andreas Schweitzer
- ¶Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Nikita Chopra
- §Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, California 94143
| | - James L Engel
- ‖Department of Pharmacology, University of California, San Diego, La Jolla, California, 92093
| | - Charles Greenberg
- §Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, California 94143
| | - Alexander S Huszagh
- From the ‡Department of Physiology & Biophysics, University of California, Irvine, Irvine, California 92697
| | - Florian Beck
- ¶Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Eri Sakata
- ¶Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Yingying Yang
- From the ‡Department of Physiology & Biophysics, University of California, Irvine, Irvine, California 92697
| | - Eric J Novitsky
- **Department of Chemistry, University of California, Irvine, Irvine, California 92697
| | - Alexander Leitner
- ‡‡Department of Biology, Institute of Molecular Systems Biology, Eidgenössische Technische Hochschule (ETH) Zürich, Zurich, Switzerland
| | - Paolo Nanni
- §§Functional Genomics Center Zurich (FGCZ), University of Zurich, ETH Zurich, CH-8057 Zurich, Switzerland
| | - Abdullah Kahraman
- ¶¶Institute of Molecular Life Sciences, University of Zurich, CH-8057 Zurich, Switzerland
| | - Xing Guo
- ‖Department of Pharmacology, University of California, San Diego, La Jolla, California, 92093
| | - Jack E Dixon
- ‖Department of Pharmacology, University of California, San Diego, La Jolla, California, 92093
| | - Scott D Rychnovsky
- **Department of Chemistry, University of California, Irvine, Irvine, California 92697
| | - Ruedi Aebersold
- ‡‡Department of Biology, Institute of Molecular Systems Biology, Eidgenössische Technische Hochschule (ETH) Zürich, Zurich, Switzerland.,Faculty of Science, University of Zurich, Zurich, Switzerland
| | - Wolfgang Baumeister
- ¶Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Andrej Sali
- §Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, California 94143
| | - Lan Huang
- From the ‡Department of Physiology & Biophysics, University of California, Irvine, Irvine, California 92697;
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15
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Zhu Q, Venzke D, Walimbe AS, Anderson ME, Fu Q, Kinch LN, Wang W, Chen X, Grishin NV, Huang N, Yu L, Dixon JE, Campbell KP, Xiao J. Structure of protein O-mannose kinase reveals a unique active site architecture. eLife 2016; 5. [PMID: 27879205 PMCID: PMC5142810 DOI: 10.7554/elife.22238] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 11/22/2016] [Indexed: 12/20/2022] Open
Abstract
The ‘pseudokinase’ SgK196 is a protein O-mannose kinase (POMK) that catalyzes an essential phosphorylation step during biosynthesis of the laminin-binding glycan on α-dystroglycan. However, the catalytic mechanism underlying this activity remains elusive. Here we present the crystal structure of Danio rerio POMK in complex with Mg2+ ions, ADP, aluminum fluoride, and the GalNAc-β3-GlcNAc-β4-Man trisaccharide substrate, thereby providing a snapshot of the catalytic transition state of this unusual kinase. The active site of POMK is established by residues located in non-canonical positions and is stabilized by a disulfide bridge. GalNAc-β3-GlcNAc-β4-Man is recognized by a surface groove, and the GalNAc-β3-GlcNAc moiety mediates the majority of interactions with POMK. Expression of various POMK mutants in POMK knockout cells further validated the functional requirements of critical residues. Our results provide important insights into the ability of POMK to function specifically as a glycan kinase, and highlight the structural diversity of the human kinome. DOI:http://dx.doi.org/10.7554/eLife.22238.001
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Affiliation(s)
- Qinyu Zhu
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China.,Academy for Advanced Interdisciplinary Studies, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - David Venzke
- Department of Molecular Physiology and Biophysics, Howard Hughes Medical Institute, University of Iowa Roy J and Lucille A Carver College of Medicine, Iowa City, United States.,Department of Neurology, University of Iowa Roy J and Lucille A Carver College of Medicine, Iowa, United States.,Department of Internal Medicine, University of Iowa Roy J and Lucille A Carver College of Medicine, Iowa, United States
| | - Ameya S Walimbe
- Department of Molecular Physiology and Biophysics, Howard Hughes Medical Institute, University of Iowa Roy J and Lucille A Carver College of Medicine, Iowa City, United States.,Department of Neurology, University of Iowa Roy J and Lucille A Carver College of Medicine, Iowa, United States.,Department of Internal Medicine, University of Iowa Roy J and Lucille A Carver College of Medicine, Iowa, United States
| | - Mary E Anderson
- Department of Molecular Physiology and Biophysics, Howard Hughes Medical Institute, University of Iowa Roy J and Lucille A Carver College of Medicine, Iowa City, United States.,Department of Neurology, University of Iowa Roy J and Lucille A Carver College of Medicine, Iowa, United States.,Department of Internal Medicine, University of Iowa Roy J and Lucille A Carver College of Medicine, Iowa, United States
| | - Qiuyu Fu
- National Institute of Biological Sciences, Beijing, China
| | - Lisa N Kinch
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, United States
| | - Wei Wang
- Academy for Advanced Interdisciplinary Studies, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China.,Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China.,Synthetic and Functional Biomolecules Center, Peking University, Beijing, China.,Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Peking University, Beijing, China
| | - Xing Chen
- Academy for Advanced Interdisciplinary Studies, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China.,Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China.,Synthetic and Functional Biomolecules Center, Peking University, Beijing, China.,Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Peking University, Beijing, China
| | - Nick V Grishin
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, United States
| | - Niu Huang
- National Institute of Biological Sciences, Beijing, China
| | - Liping Yu
- Medical Nuclear Magnetic Resonance Facility, University of Iowa Roy J and Lucille A Carver College of Medicine, Iowa, United States
| | - Jack E Dixon
- Department of Pharmacology, University of California, San Diego, La Jolla, United States.,Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, United States.,Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, United States
| | - Kevin P Campbell
- Department of Molecular Physiology and Biophysics, Howard Hughes Medical Institute, University of Iowa Roy J and Lucille A Carver College of Medicine, Iowa City, United States.,Department of Neurology, University of Iowa Roy J and Lucille A Carver College of Medicine, Iowa, United States.,Department of Internal Medicine, University of Iowa Roy J and Lucille A Carver College of Medicine, Iowa, United States
| | - Junyu Xiao
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China.,Academy for Advanced Interdisciplinary Studies, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
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16
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Affiliation(s)
- Xing Guo
- Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Jack E. Dixon
- Department of Pharmacology, University of California-San Diego School of Medicine, La Jolla, CA, USA
- Department of Chemistry and Biochemistry, University of California-San Diego School of Medicine, La Jolla, CA, USA
- Department of Cellular and Molecular Medicine, University of California-San Diego School of Medicine, La Jolla, CA, USA
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17
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Guo X, Wang X, Wang Z, Banerjee S, Yang J, Huang L, Dixon JE. Site-specific proteasome phosphorylation controls cell proliferation and tumorigenesis. Nat Cell Biol 2016; 18:202-12. [PMID: 26655835 PMCID: PMC4844191 DOI: 10.1038/ncb3289] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2015] [Accepted: 11/12/2015] [Indexed: 02/07/2023]
Abstract
Despite the fundamental importance of proteasomal degradation in cells, little is known about whether and how the 26S proteasome itself is regulated in coordination with various physiological processes. Here we show that the proteasome is dynamically phosphorylated during the cell cycle at Thr 25 of the 19S subunit Rpt3. CRISPR/Cas9-mediated genome editing, RNA interference and biochemical studies demonstrate that blocking Rpt3-Thr25 phosphorylation markedly impairs proteasome activity and impedes cell proliferation. Through a kinome-wide screen, we have identified dual-specificity tyrosine-regulated kinase 2 (DYRK2) as the primary kinase that phosphorylates Rpt3-Thr25, leading to enhanced substrate translocation and degradation. Importantly, loss of the single phosphorylation of Rpt3-Thr25 or knockout of DYRK2 significantly inhibits tumour formation by proteasome-addicted human breast cancer cells in mice. These findings define an important mechanism for proteasome regulation and demonstrate the biological significance of proteasome phosphorylation in regulating cell proliferation and tumorigenesis.
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Affiliation(s)
- Xing Guo
- Department of Pharmacology, University of California-San Diego, La Jolla, CA 92093
| | - Xiaorong Wang
- Departments of Physiology and Biophysics and of Developmental and Cell Biology, University of California, Irvine, CA 92697
| | - Zhiping Wang
- Division of Biological Sciences, University of California-San Diego, La Jolla, CA 92093
| | - Sourav Banerjee
- Department of Pharmacology, University of California-San Diego, La Jolla, CA 92093
| | - Jing Yang
- Department of Pharmacology, University of California-San Diego, La Jolla, CA 92093
| | - Lan Huang
- Departments of Physiology and Biophysics and of Developmental and Cell Biology, University of California, Irvine, CA 92697
| | - Jack E. Dixon
- Department of Pharmacology, University of California-San Diego, La Jolla, CA 92093
- Departments of Cellular and Molecular Medicine and of Chemistry and Biochemistry, University of California-San Diego, La Jolla, CA 92093
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18
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Cozza G, Salvi M, Banerjee S, Tibaldi E, Tagliabracci VS, Dixon JE, Pinna LA. A new role for sphingosine: Up-regulation of Fam20C, the genuine casein kinase that phosphorylates secreted proteins. Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics 2015; 1854:1718-26. [DOI: 10.1016/j.bbapap.2015.04.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 04/21/2015] [Indexed: 01/01/2023]
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19
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Tagliabracci VS, Wiley SE, Guo X, Kinch LN, Durrant E, Wen J, Xiao J, Cui J, Nguyen KB, Engel JL, Coon JJ, Grishin N, Pinna LA, Pagliarini DJ, Dixon JE. A Single Kinase Generates the Majority of the Secreted Phosphoproteome. Cell 2015; 161:1619-32. [PMID: 26091039 DOI: 10.1016/j.cell.2015.05.028] [Citation(s) in RCA: 223] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 03/05/2015] [Accepted: 05/06/2015] [Indexed: 01/12/2023]
Abstract
The existence of extracellular phosphoproteins has been acknowledged for over a century. However, research in this area has been undeveloped largely because the kinases that phosphorylate secreted proteins have escaped identification. Fam20C is a kinase that phosphorylates S-x-E/pS motifs on proteins in milk and in the extracellular matrix of bones and teeth. Here, we show that Fam20C generates the majority of the extracellular phosphoproteome. Using CRISPR/Cas9 genome editing, mass spectrometry, and biochemistry, we identify more than 100 secreted phosphoproteins as genuine Fam20C substrates. Further, we show that Fam20C exhibits broader substrate specificity than previously appreciated. Functional annotations of Fam20C substrates suggest roles for the kinase beyond biomineralization, including lipid homeostasis, wound healing, and cell migration and adhesion. Our results establish Fam20C as the major secretory pathway protein kinase and serve as a foundation for new areas of investigation into the role of secreted protein phosphorylation in human biology and disease.
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Affiliation(s)
- Vincent S Tagliabracci
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Sandra E Wiley
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Xiao Guo
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA; Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Lisa N Kinch
- Department of Biophysics, University of Texas, Southwestern Medical Center, Dallas, TX 75390-9050, USA
| | - Eric Durrant
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jianzhong Wen
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Junyu Xiao
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jixin Cui
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Kim B Nguyen
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - James L Engel
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Joshua J Coon
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA; Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Nick Grishin
- Department of Biophysics, University of Texas, Southwestern Medical Center, Dallas, TX 75390-9050, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Lorenzo A Pinna
- Department of Biomedical Sciences, University of Padova, 35121 Padova, Italy; Venetian Institute of Molecular Medicine, 35129 Padova, Italy
| | - David J Pagliarini
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Jack E Dixon
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA; Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA.
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20
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He Y, Guo X, Yu ZH, Wu L, Gunawan AM, Zhang Y, Dixon JE, Zhang ZY. A potent and selective inhibitor for the UBLCP1 proteasome phosphatase. Bioorg Med Chem 2015; 23:2798-809. [PMID: 25907364 DOI: 10.1016/j.bmc.2015.03.066] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 03/23/2015] [Accepted: 03/24/2015] [Indexed: 11/17/2022]
Abstract
The ubiquitin-like domain-containing C-terminal domain phosphatase 1 (UBLCP1) has been implicated as a negative regulator of the proteasome, a key mediator in the ubiquitin-dependent protein degradation. Small molecule inhibitors that block UBLCP1 activity would be valuable as research tools and potential therapeutics for human diseases caused by the cellular accumulation of misfold/damaged proteins. We report a salicylic acid fragment-based library approach aimed at targeting both the phosphatase active site and its adjacent binding pocket for enhanced affinity and selectivity. Screening of the focused libraries led to the identification of the first potent and selective UBLCP1 inhibitor 13. Compound 13 exhibits an IC50 of 1.0μM for UBLCP1 and greater than 5-fold selectivity against a large panel of protein phosphatases from several distinct families. Importantly, the inhibitor possesses efficacious cellular activity and is capable of inhibiting UBLCP1 function in cells, which in turn up-regulates nuclear proteasome activity. These studies set the groundwork for further developing compound 13 into chemical probes or potential therapeutic agents targeting the UBLCP1 phosphatase.
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Affiliation(s)
- Yantao He
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202, USA
| | - Xing Guo
- Department of Pharmacology, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Zhi-Hong Yu
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202, USA
| | - Li Wu
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202, USA
| | - Andrea M Gunawan
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202, USA
| | - Yan Zhang
- Department of Chemistry and Biochemistry, The University of Texas at Austin, 1 University Station A5300, Austin, TX 78712, USA
| | - Jack E Dixon
- Department of Pharmacology, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Department of Cellular and Molecular Medicine, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Department of Chemistry and Biochemistry, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Zhong-Yin Zhang
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202, USA.
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21
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Cui J, Xiao J, Tagliabracci VS, Wen J, Rahdar M, Dixon JE. A secretory kinase complex regulates extracellular protein phosphorylation. eLife 2015; 4:e06120. [PMID: 25789606 PMCID: PMC4421793 DOI: 10.7554/elife.06120] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 03/18/2015] [Indexed: 12/19/2022] Open
Abstract
Although numerous extracellular phosphoproteins have been identified, the protein kinases within the secretory pathway have only recently been discovered, and their regulation is virtually unexplored. Fam20C is the physiological Golgi casein kinase, which phosphorylates many secreted proteins and is critical for proper biomineralization. Fam20A, a Fam20C paralog, is essential for enamel formation, but the biochemical function of Fam20A is unknown. Here we show that Fam20A potentiates Fam20C kinase activity and promotes the phosphorylation of enamel matrix proteins in vitro and in cells. Mechanistically, Fam20A is a pseudokinase that forms a functional complex with Fam20C, and this complex enhances extracellular protein phosphorylation within the secretory pathway. Our findings shed light on the molecular mechanism by which Fam20C and Fam20A collaborate to control enamel formation, and provide the first insight into the regulation of secretory pathway phosphorylation. DOI:http://dx.doi.org/10.7554/eLife.06120.001 Some proteins must be modified in order to work effectively. One common modification is to add a phosphate group to the protein, which is performed by enzymes called protein kinases. Although most of the protein kinases work on proteins inside the cell, it was discovered recently that a small group of kinases work within the ‘secretory pathway’ and modify proteins that are released (or secreted) out of cells. One such secretory pathway kinase—called Fam20C—phosphorylates a wide range of secreted proteins and helps to ensure the proper development of bones and teeth. Specifically, Fam20C and a closely related protein called Fam20A are important for forming enamel, the hardest substance in human body, which makes up the outer surface of teeth. However, the exact role of Fam20A is unknown. Cui et al. now show that Fam20A binds to Fam20C, and this increases the ability of Fam20C to phosphorylate the proteins that form the ‘matrix’ that guides the deposition of the enamel minerals. Furthermore, mutations in Fam20A lead to the inefficient phosphorylation of enamel matrix proteins by Fam20C, and prevent proper enamel formation. The results raise the possibility that similar mechanisms of secretory kinase activation may also be important in other biological processes where many secreted proteins need to be phosphorylated rapidly. DOI:http://dx.doi.org/10.7554/eLife.06120.002
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Affiliation(s)
- Jixin Cui
- Department of Pharmacology, University of California, San Diego, La Jolla, United States
| | - Junyu Xiao
- Department of Pharmacology, University of California, San Diego, La Jolla, United States
| | - Vincent S Tagliabracci
- Department of Pharmacology, University of California, San Diego, La Jolla, United States
| | - Jianzhong Wen
- Department of Pharmacology, University of California, San Diego, La Jolla, United States
| | - Meghdad Rahdar
- Department of Pharmacology, University of California, San Diego, La Jolla, United States
| | - Jack E Dixon
- Department of Pharmacology, University of California, San Diego, La Jolla, United States
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22
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Bordoli MR, Yum J, Breitkopf SB, Thon JN, Italiano JE, Xiao J, Worby C, Wong SK, Lin G, Edenius M, Keller TL, Asara JM, Dixon JE, Yeo CY, Whitman M. A secreted tyrosine kinase acts in the extracellular environment. Cell 2015; 158:1033-1044. [PMID: 25171405 DOI: 10.1016/j.cell.2014.06.048] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 05/06/2014] [Accepted: 06/20/2014] [Indexed: 11/17/2022]
Abstract
Although tyrosine phosphorylation of extracellular proteins has been reported to occur extensively in vivo, no secreted protein tyrosine kinase has been identified. As a result, investigation of the potential role of extracellular tyrosine phosphorylation in physiological and pathological tissue regulation has not been possible. Here, we show that VLK, a putative protein kinase previously shown to be essential in embryonic development, is a secreted protein kinase, with preference for tyrosine, that phosphorylates a broad range of secreted and ER-resident substrate proteins. We find that VLK is rapidly and quantitatively secreted from platelets in response to stimuli and can tyrosine phosphorylate coreleased proteins utilizing endogenous as well as exogenous ATP sources. We propose that discovery of VLK activity provides an explanation for the extensive and conserved pattern of extracellular tyrosine phosphophorylation seen in vivo, and extends the importance of regulated tyrosine phosphorylation into the extracellular environment.
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Affiliation(s)
- Mattia R Bordoli
- Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA 02115, USA
| | - Jina Yum
- Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA 02115, USA; Department of Life Science and Global Top5 Research Program, Ewha Womans University, Seoul 120-750, Republic of Korea
| | - Susanne B Breitkopf
- Division of Signal Transduction, Beth Israel Deaconess Medical Center, Boston, MA 02115, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Jonathan N Thon
- Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Joseph E Italiano
- Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Harvard Medical School, Boston, MA 02115, USA; Vascular Biology Program, Department of Surgery, Children's Hospital, Boston, MA 02115, USA
| | - Junyu Xiao
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92031, USA
| | - Carolyn Worby
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92031, USA
| | - Swee-Kee Wong
- Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA 02115, USA
| | - Grace Lin
- Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA 02115, USA
| | - Maja Edenius
- Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA 02115, USA
| | - Tracy L Keller
- Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA 02115, USA
| | - John M Asara
- Division of Signal Transduction, Beth Israel Deaconess Medical Center, Boston, MA 02115, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Jack E Dixon
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92031, USA
| | - Chang-Yeol Yeo
- Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA 02115, USA; Department of Life Science and Global Top5 Research Program, Ewha Womans University, Seoul 120-750, Republic of Korea.
| | - Malcolm Whitman
- Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA 02115, USA.
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Abstract
The importance of PTEN in cellular function is underscored by the frequency of its deregulation in cancer. PTEN tumor-suppressor activity depends largely on its lipid phosphatase activity, which opposes PI3K/AKT activation. As such, PTEN regulates many cellular processes, including proliferation, survival, energy metabolism, cellular architecture, and motility. More than a decade of research has expanded our knowledge about how PTEN is controlled at the transcriptional level as well as by numerous posttranscriptional modifications that regulate its enzymatic activity, protein stability, and cellular location. Although the role of PTEN in cancers has long been appreciated, it is also emerging as an important factor in other diseases, such as diabetes and autism spectrum disorders. Our understanding of PTEN function and regulation will hopefully translate into improved prognosis and treatment for patients suffering from these ailments.
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Affiliation(s)
- Carolyn A Worby
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093-0721;
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24
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Abstract
This year, the Albert Lasker Basic Medical Research Award will be shared by Peter Walter and Kazutoshi Mori for discoveries revealing the molecular mechanism of the unfolded protein response, an intracellular quality control system that detects harmful misfolded proteins in the endoplasmic reticulum and then signals the nucleus to carry out corrective measures.
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Affiliation(s)
- Carolyn A Worby
- Departments of Pharmacology, Cellular and Molecular Medicine, and Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jack E Dixon
- Departments of Pharmacology, Cellular and Molecular Medicine, and Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA.
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25
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Tagliabracci VS, Pinna LA, Dixon JE. Response to Wang et al.: Secreted protein kinases? Trends Biochem Sci 2014; 38:425. [PMID: 23992948 DOI: 10.1016/j.tibs.2013.06.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 06/10/2013] [Indexed: 01/08/2023]
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26
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Tagliabracci VS, Engel JL, Wiley SE, Xiao J, Gonzalez DJ, Nidumanda Appaiah H, Koller A, Nizet V, White KE, Dixon JE. Dynamic regulation of FGF23 by Fam20C phosphorylation, GalNAc-T3 glycosylation, and furin proteolysis. Proc Natl Acad Sci U S A 2014; 111:5520-5. [PMID: 24706917 PMCID: PMC3992636 DOI: 10.1073/pnas.1402218111] [Citation(s) in RCA: 216] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The family with sequence similarity 20, member C (Fam20C) has recently been identified as the Golgi casein kinase. Fam20C phosphorylates secreted proteins on Ser-x-Glu/pSer motifs and loss-of-function mutations in the kinase cause Raine syndrome, an often-fatal osteosclerotic bone dysplasia. Fam20C is potentially an upstream regulator of the phosphate-regulating hormone fibroblast growth factor 23 (FGF23), because humans with FAM20C mutations and Fam20C KO mice develop hypophosphatemia due to an increase in full-length, biologically active FGF23. However, the mechanism by which Fam20C regulates FGF23 is unknown. Here we show that Fam20C directly phosphorylates FGF23 on Ser(180), within the FGF23 R(176)XXR(179)/S(180)AE subtilisin-like proprotein convertase motif. This phosphorylation event inhibits O-glycosylation of FGF23 by polypeptide N-acetylgalactosaminyltransferase 3 (GalNAc-T3), and promotes FGF23 cleavage and inactivation by the subtilisin-like proprotein convertase furin. Collectively, our results provide a molecular mechanism by which FGF23 is dynamically regulated by phosphorylation, glycosylation, and proteolysis. Furthermore, our findings suggest that cross-talk between phosphorylation and O-glycosylation of proteins in the secretory pathway may be an important mechanism by which secreted proteins are regulated.
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Affiliation(s)
| | | | | | | | | | - Hitesh Nidumanda Appaiah
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202; and
| | - Antonius Koller
- Stony Brook University Proteomics Center, School of Medicine, Stony Brook University, Stony Brook, NY 11794
| | - Victor Nizet
- Pediatrics
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093
| | - Kenneth E. White
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202; and
| | - Jack E. Dixon
- Departments of Pharmacology
- Cellular and Molecular Medicine, and
- Chemistry and Biochemistry and
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27
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Bahmanyar S, Biggs R, Schuh AL, Desai A, Müller-Reichert T, Audhya A, Dixon JE, Oegema K. Spatial control of phospholipid flux restricts endoplasmic reticulum sheet formation to allow nuclear envelope breakdown. Genes Dev 2014; 28:121-6. [PMID: 24449268 PMCID: PMC3909786 DOI: 10.1101/gad.230599.113] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The nuclear envelope is a subdomain of the endoplasmic reticulum (ER). Here, Oegema and colleagues characterize the conserved lipin-activating protein phosphatase CNEP-1, which is specifically enriched on the nuclear envelope. The data show that CNEP-1 spatially controls lipin-dependent phospholipid flux to limit phosphatidylinositol levels and restrict ER sheet formation in the vicinity of the nuclear envelope. This study reveals coupling between control of phospholipid synthesis and ER subdomain structure. The nuclear envelope is a subdomain of the endoplasmic reticulum (ER). Here we characterize CNEP-1 (CTD [C-terminal domain] nuclear envelope phosphatase-1), a nuclear envelope-enriched activator of the ER-associated phosphatidic acid phosphatase lipin that promotes synthesis of major membrane phospholipids over phosphatidylinositol (PI). CNEP-1 inhibition led to ectopic ER sheets in the vicinity of the nucleus that encased the nuclear envelope and interfered with nuclear envelope breakdown (NEBD) during cell division. Reducing PI synthesis suppressed these phenotypes, indicating that CNEP-1 spatially regulates phospholipid flux, biasing it away from PI production in the vicinity of the nuclear envelope to prevent excess ER sheet formation and NEBD defects.
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Affiliation(s)
- Shirin Bahmanyar
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093, USA
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28
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Gonzalez DJ, Vuong L, Gonzalez IS, Keller N, McGrosso D, Hwang JH, Hung J, Zinkernagel A, Dixon JE, Dorrestein PC, Nizet V. Phenol soluble modulin (PSM) variants of community-associated methicillin-resistant Staphylococcus aureus (MRSA) captured using mass spectrometry-based molecular networking. Mol Cell Proteomics 2014; 13:1262-72. [PMID: 24567418 DOI: 10.1074/mcp.m113.031336] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Molecular genetic analysis indicates that the problematic human bacterial pathogen methicillin-resistant Staphylococcus aureus possesses more than 2000 open reading frames in its genome. This number of potential gene products, coupled with intrinsic mechanisms of posttranslational modification, endows methicillin-resistant Staphylococcus aureus with a highly complex biochemical repertoire. Recent proteomic and metabolomic advances have provided methodologies to better understand and characterize the biosynthetic factors released by microbial organisms. Here, the emerging tool of mass spectrometry-based molecular networking was used to visualize and map the repertoire of biosynthetic factors produced by a community-associated methicillin-resistant Staphylococcus aureus strain representative of the epidemic USA300 clone. In particular, the study focused on elucidating the complexity of the recently discovered phenol soluble modulin family of peptides when placed under various antibiotic treatment stresses. Novel PSM truncated variant peptides were captured, and the type of variants that were clustered by the molecular networks platform changed in response to the different antibiotic treatment conditions. After discovery, a group of the peptides were selected for functional analysis in vitro. The peptides displayed bioactive properties including the ability to induce proinflammatory responses in human THP-1 monocytes. Additionally, the tested peptides did not display antimicrobial activity as previously reported for other phenol soluble modulin truncated variants. Our findings reveal that the PSM family of peptides are quite structurally diverse, and suggest a single phenol soluble modulin parent peptide can functionally spawn differential bioactivities in response to various external stimuli.
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29
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Weisberg SP, Smith-Raska MR, Esquilin JM, Zhang J, Arenzana TL, Lau CM, Churchill M, Pan H, Klinakis A, Dixon JE, Mirny LA, Mukherjee S, Reizis B. ZFX controls propagation and prevents differentiation of acute T-lymphoblastic and myeloid leukemia. Cell Rep 2014; 6:528-40. [PMID: 24485662 DOI: 10.1016/j.celrep.2014.01.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Revised: 12/20/2013] [Accepted: 01/07/2014] [Indexed: 11/18/2022] Open
Abstract
Tumor-propagating cells in acute leukemia maintain a stem/progenitor-like immature phenotype and proliferative capacity. Acute myeloid leukemia (AML) and acute T-lymphoblastic leukemia (T-ALL) originate from different lineages through distinct oncogenic events such as MLL fusions and Notch signaling, respectively. We found that Zfx, a transcription factor that controls hematopoietic stem cell self-renewal, controls the initiation and maintenance of AML caused by MLL-AF9 fusion and of T-ALL caused by Notch1 activation. In both leukemia types, Zfx prevents differentiation and activates gene sets characteristic of immature cells of the respective lineages. In addition, endogenous Zfx contributes to gene induction and transformation by Myc overexpression in myeloid progenitors. Key Zfx target genes include the mitochondrial enzymes Ptpmt1 and Idh2, whose overexpression partially rescues the propagation of Zfx-deficient AML. These results show that distinct leukemia types maintain their undifferentiated phenotype and self-renewal by exploiting a common stem-cell-related genetic regulator.
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Affiliation(s)
- Stuart P Weisberg
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY 10032, USA
| | - Matthew R Smith-Raska
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY 10032, USA
| | - Jose M Esquilin
- Division of Pediatric Hematology, Columbia University Medical Center, New York, NY 10032, USA
| | - Ji Zhang
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Teresita L Arenzana
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY 10032, USA
| | - Colleen M Lau
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY 10032, USA
| | - Michael Churchill
- Department of Medicine, Division of Hematology/Oncology, Columbia University Medical Center, New York, NY 10032, USA
| | - Haiyan Pan
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY 10032, USA
| | | | - Jack E Dixon
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Leonid A Mirny
- Institute for Medical Engineering and Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Siddhartha Mukherjee
- Department of Medicine, Division of Hematology/Oncology, Columbia University Medical Center, New York, NY 10032, USA
| | - Boris Reizis
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY 10032, USA.
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30
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Qi D, Dubiella U, Kim SH, Sloss DI, Dowen RH, Dixon JE, Innes RW. Recognition of the protein kinase AVRPPHB SUSCEPTIBLE1 by the disease resistance protein RESISTANCE TO PSEUDOMONAS SYRINGAE5 is dependent on s-acylation and an exposed loop in AVRPPHB SUSCEPTIBLE1. Plant Physiol 2014; 164:340-51. [PMID: 24225654 PMCID: PMC3875812 DOI: 10.1104/pp.113.227686] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 11/12/2013] [Indexed: 05/06/2023]
Abstract
The recognition of pathogen effector proteins by plants is typically mediated by intracellular receptors belonging to the nucleotide-binding leucine-rich repeat (NLR) family. NLR proteins often detect pathogen effector proteins indirectly by detecting modification of their targets. How NLR proteins detect such modifications is poorly understood. To address these questions, we have been investigating the Arabidopsis (Arabidopsis thaliana) NLR protein RESISTANCE TO PSEUDOMONAS SYRINGAE5 (RPS5), which detects the Pseudomonas syringae effector protein Avirulence protein Pseudomonas phaseolicolaB (AvrPphB). AvrPphB is a cysteine protease that specifically targets a subfamily of receptor-like cytoplasmic kinases, including the Arabidopsis protein kinase AVRPPHB Susceptible1 (PBS1). RPS5 is activated by the cleavage of PBS1 at the apex of its activation loop. Here, we show that RPS5 activation requires that PBS1 be localized to the plasma membrane and that plasma membrane localization of PBS1 is mediated by amino-terminal S-acylation. We also describe the development of a high-throughput screen for mutations in PBS1 that block RPS5 activation, which uncovered four new pbs1 alleles, two of which blocked cleavage by AvrPphB. Lastly, we show that RPS5 distinguishes among closely related kinases by the amino acid sequence (SEMPH) within an exposed loop in the C-terminal one-third of PBS1. The SEMPH loop is located on the opposite side of PBS1 from the AvrPphB cleavage site, suggesting that RPS5 associates with the SEMPH loop while leaving the AvrPphB cleavage site exposed. These findings provide support for a model of NLR activation in which NLR proteins form a preactivation complex with effector targets and then sense a conformational change in the target induced by effector modification.
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Affiliation(s)
| | | | | | - D. Isaiah Sloss
- Department of Biology, Indiana University, Bloomington, Indiana 47405 (D.Q., U.D., S.H.K., D.I.S., R.W.I.)
- Departments of Pharmacology, Cellular and Molecular Medicine, and Chemistry and Biochemistry and Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, California 92093 (R.H.D, J.E.D.); and
- Howard Hughes Medical Institute, Chevy Chase, Maryland 20815 (J.E.D.)
| | - Robert H. Dowen
- Department of Biology, Indiana University, Bloomington, Indiana 47405 (D.Q., U.D., S.H.K., D.I.S., R.W.I.)
- Departments of Pharmacology, Cellular and Molecular Medicine, and Chemistry and Biochemistry and Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, California 92093 (R.H.D, J.E.D.); and
- Howard Hughes Medical Institute, Chevy Chase, Maryland 20815 (J.E.D.)
| | - Jack E. Dixon
- Department of Biology, Indiana University, Bloomington, Indiana 47405 (D.Q., U.D., S.H.K., D.I.S., R.W.I.)
- Departments of Pharmacology, Cellular and Molecular Medicine, and Chemistry and Biochemistry and Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, California 92093 (R.H.D, J.E.D.); and
- Howard Hughes Medical Institute, Chevy Chase, Maryland 20815 (J.E.D.)
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31
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Wang Z, Hou Y, Guo X, van der Voet M, Boxem M, Dixon JE, Chisholm AD, Jin Y. The EBAX-type Cullin-RING E3 ligase and Hsp90 guard the protein quality of the SAX-3/Robo receptor in developing neurons. Neuron 2013; 79:903-16. [PMID: 24012004 PMCID: PMC3779136 DOI: 10.1016/j.neuron.2013.06.035] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/14/2013] [Indexed: 12/14/2022]
Abstract
Although protein quality control (PQC) is generally perceived as important for the development of the nervous system, the specific mechanisms of neuronal PQC have remained poorly understood. Here, we report that C. elegans Elongin BC-binding axon regulator (EBAX-1), a conserved BC-box protein, regulates axon guidance through PQC of the SAX-3/Robo receptor. EBAX-1 buffers guidance errors against temperature variations. As a substrate-recognition subunit in the Elongin BC-containing Cullin-RING ubiquitin ligase (CRL), EBAX-1 also binds to DAF-21, a cytosolic Hsp90 chaperone. The EBAX-type CRL and DAF-21 collaboratively regulate SAX-3-mediated axon pathfinding. Biochemical and imaging assays indicate that EBAX-1 specifically recognizes misfolded SAX-3 and promotes its degradation in vitro and in vivo. Importantly, vertebrate EBAX also shows substrate preference toward aberrant Robo3 implicated in horizontal gaze palsy with progressive scoliosis (HGPPS). Together, our findings demonstrate a triage PQC mechanism mediated by the EBAX-type CRL and DAF-21/Hsp90 that maintains the accuracy of neuronal wiring.
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Affiliation(s)
- Zhiping Wang
- Neurobiology Section, Division of Biological Sciences, UC San Diego, La Jolla, CA 92093
| | - Yanli Hou
- Department of Molecular, Cell, and Developmental Biology, UC Santa Cruz, CA 95064
| | - Xing Guo
- Department of Pharmacology, School of Medicine, UC San Diego, La Jolla, CA 92093
| | | | - Mike Boxem
- Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - Jack E. Dixon
- Department of Pharmacology, School of Medicine, UC San Diego, La Jolla, CA 92093
- Howard Hughes Medical Institute
| | - Andrew D. Chisholm
- Neurobiology Section, Division of Biological Sciences, UC San Diego, La Jolla, CA 92093
| | - Yishi Jin
- Neurobiology Section, Division of Biological Sciences, UC San Diego, La Jolla, CA 92093
- Howard Hughes Medical Institute
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32
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Wiley SE, Andreyev AY, Divakaruni AS, Karisch R, Perkins G, Wall EA, van der Geer P, Chen YF, Tsai TF, Simon MI, Neel BG, Dixon JE, Murphy AN. Wolfram Syndrome protein, Miner1, regulates sulphydryl redox status, the unfolded protein response, and Ca2+ homeostasis. EMBO Mol Med 2013; 5:904-18. [PMID: 23703906 PMCID: PMC3779451 DOI: 10.1002/emmm.201201429] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2012] [Revised: 03/26/2013] [Accepted: 03/27/2013] [Indexed: 01/21/2023] Open
Abstract
Miner1 is a redox-active 2Fe2S cluster protein. Mutations in Miner1 result in Wolfram Syndrome, a metabolic disease associated with diabetes, blindness, deafness, and a shortened lifespan. Embryonic fibroblasts from Miner1(-/-) mice displayed ER stress and showed hallmarks of the unfolded protein response. In addition, loss of Miner1 caused a depletion of ER Ca(2+) stores, a dramatic increase in mitochondrial Ca(2+) load, increased reactive oxygen and nitrogen species, an increase in the GSSG/GSH and NAD(+)/NADH ratios, and an increase in the ADP/ATP ratio consistent with enhanced ATP utilization. Furthermore, mitochondria in fibroblasts lacking Miner1 displayed ultrastructural alterations, such as increased cristae density and punctate morphology, and an increase in O2 consumption. Treatment with the sulphydryl anti-oxidant N-acetylcysteine reversed the abnormalities in the Miner1 deficient cells, suggesting that sulphydryl reducing agents should be explored as a treatment for this rare genetic disease.
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Affiliation(s)
- Sandra E Wiley
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA
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33
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Affiliation(s)
- Jack E. Dixon
- Department of ScienceHoward Hughes Medical InsituteChevy ChaseMD
- Department of PharmacologyUniversity of California San DiegoSan DiegoCA
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34
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Teh PG, Chen MJ, Engel JL, Worby CA, Manning G, Dixon JE, Zhang J. Identification of a mammalian-type phosphatidylglycerophosphate phosphatase in the Eubacterium Rhodopirellula baltica. J Biol Chem 2013; 288:5176-85. [PMID: 23293031 PMCID: PMC3576122 DOI: 10.1074/jbc.m112.413617] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cardiolipin is a glycerophospholipid found predominantly in the mitochondrial membranes of eukaryotes and in bacterial membranes. Cardiolipin interacts with protein complexes and plays pivotal roles in cellular energy metabolism, membrane dynamics, and stress responses. We recently identified the mitochondrial phosphatase, PTPMT1, as the enzyme that converts phosphatidylglycerolphosphate (PGP) to phosphatidylglycerol, a critical step in the de novo biosynthesis of cardiolipin. Upon examination of PTPMT1 evolutionary distribution, we found a PTPMT1-like phosphatase in the bacterium Rhodopirellula baltica. The purified recombinant enzyme dephosphorylated PGP in vitro. Moreover, its expression restored cardiolipin deficiency and reversed growth impairment in a Saccharomyces cerevisiae mutant lacking the yeast PGP phosphatase, suggesting that it is a bona fide PTPMT1 ortholog. When ectopically expressed, this bacterial PGP phosphatase was localized in the mitochondria of yeast and mammalian cells. Together, our results demonstrate the conservation of function between bacterial and mammalian PTPMT1 orthologs.
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Affiliation(s)
- Phildrich G Teh
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, USA
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35
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Abstract
Protein kinases constitute one of the largest gene families and control many aspects of cellular life. In retrospect, the first indication for their existence was reported 130 years ago when the secreted protein, casein, was shown to contain phosphate. Despite its identification as the first phosphoprotein, the responsible kinase has remained obscure. This conundrum was solved with the discovery of a novel family of atypical protein kinases that are secreted and appear to phosphorylate numerous extracellular proteins, including casein. Fam20C, the archetypical member, phosphorylates secreted proteins within Ser-x-Glu/pSer motifs. This discovery has solved a 130-year-old mystery and has shed light on several human disorders of biomineralization.
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Tagliabracci VS, Engel JL, Wen J, Wiley SE, Worby CA, Kinch LN, Xiao J, Grishin NV, Dixon JE. Secreted kinase phosphorylates extracellular proteins that regulate biomineralization. Science 2012; 336:1150-3. [PMID: 22582013 PMCID: PMC3754843 DOI: 10.1126/science.1217817] [Citation(s) in RCA: 339] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Protein phosphorylation is a fundamental mechanism regulating nearly every aspect of cellular life. Several secreted proteins are phosphorylated, but the kinases responsible are unknown. We identified a family of atypical protein kinases that localize within the Golgi apparatus and are secreted. Fam20C appears to be the Golgi casein kinase that phosphorylates secretory pathway proteins within S-x-E motifs. Fam20C phosphorylates the caseins and several secreted proteins implicated in biomineralization, including the small integrin-binding ligand, N-linked glycoproteins (SIBLINGs). Consequently, mutations in Fam20C cause an osteosclerotic bone dysplasia in humans known as Raine syndrome. Fam20C is thus a protein kinase dedicated to the phosphorylation of extracellular proteins.
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Affiliation(s)
- Vincent S. Tagliabracci
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093–0721, USA
| | - James L. Engel
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093–0721, USA
| | - Jianzhong Wen
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093–0721, USA
| | - Sandra E. Wiley
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093–0721, USA
| | - Carolyn A. Worby
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093–0721, USA
| | - Lisa N. Kinch
- University of Texas, Southwestern Medical Center, Dallas, TX 75390–9050, USA
| | - Junyu Xiao
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093–0721, USA
| | - Nick V. Grishin
- University of Texas, Southwestern Medical Center, Dallas, TX 75390–9050, USA
- Howard Hughes Medical Institute, Chevy Chase, MD 20815–6789, USA
| | - Jack E. Dixon
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093–0721, USA
- Howard Hughes Medical Institute, Chevy Chase, MD 20815–6789, USA
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Wiley SE, Andreyev A, Perkins G, Dixon JE, Murphy AN. Miner1, mutated in Wolfram Syndrome, is an endoplasmic reticulum protein that regulates cellular redox status and Ca2+ homeostasis. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.887.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Guy Perkins
- National Center for Microscopy and Imaging ResearchUCSDLa JollaCA
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38
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Gonzalez DJ, Okumura CY, Hollands A, Kersten R, Akong-Moore K, Pence MA, Malone CL, Derieux J, Moore BS, Horswill AR, Dixon JE, Dorrestein PC, Nizet V. Novel phenol-soluble modulin derivatives in community-associated methicillin-resistant Staphylococcus aureus identified through imaging mass spectrometry. J Biol Chem 2012; 287:13889-98. [PMID: 22371493 DOI: 10.1074/jbc.m112.349860] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Staphylococcus aureus causes a wide range of human disease ranging from localized skin and soft tissue infections to potentially lethal systemic infections. S. aureus has the biosynthetic ability to generate numerous virulence factors that assist in circumventing the innate immune system during disease pathogenesis. Recent studies have uncovered a set of extracellular peptides produced by community-associated methicillin-resistant S. aureus (CA-MRSA) with homology to the phenol-soluble modulins (PSMs) from Staphylococcus epidermidis. CA-MRSA PSMs contribute to skin infection and recruit and lyse neutrophils, and truncated versions of these peptides possess antimicrobial activity. In this study, novel CA-MRSA PSM derivatives were discovered by the use of microbial imaging mass spectrometry. The novel PSM derivatives are compared with their parent full-length peptides for changes in hemolytic, cytolytic, and neutrophil-stimulating activity. A potential contribution of the major S. aureus secreted protease aureolysin in processing PSMs is demonstrated. Finally, we show that PSM processing occurs in multiple CA-MRSA strains by structural confirmation of additional novel derivatives. This work demonstrates that IMS can serve as a useful tool to go beyond genome predictions and expand our understanding of the important family of small peptide virulence factors.
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Affiliation(s)
- David J Gonzalez
- Department of Pediatrics, University of California at San Diego, La Jolla, California 92093, USA
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Han S, Bahmanyar S, Zhang P, Grishin N, Oegema K, Crooke R, Graham M, Reue K, Dixon JE, Goodman JM. Nuclear envelope phosphatase 1-regulatory subunit 1 (formerly TMEM188) is the metazoan Spo7p ortholog and functions in the lipin activation pathway. J Biol Chem 2012; 287:3123-37. [PMID: 22134922 PMCID: PMC3283218 DOI: 10.1074/jbc.m111.324350] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Indexed: 11/06/2022] Open
Abstract
Lipin-1 catalyzes the formation of diacylglycerol from phosphatidic acid. Lipin-1 mutations cause lipodystrophy in mice and acute myopathy in humans. It is heavily phosphorylated, and the yeast ortholog Pah1p becomes membrane-associated and active upon dephosphorylation by the Nem1p-Spo7p membrane complex. A mammalian ortholog of Nem1p is the C-terminal domain nuclear envelope phosphatase 1 (CTDNEP1, formerly "dullard"), but its Spo7p-like partner is unknown, and the need for its existence is debated. Here, we identify the metazoan ortholog of Spo7p, TMEM188, renamed nuclear envelope phosphatase 1-regulatory subunit 1 (NEP1-R1). CTDNEP1 and NEP1-R1 together complement a nem1Δspo7Δ strain to block endoplasmic reticulum proliferation and restore triacylglycerol levels and lipid droplet number. The two human orthologs are in a complex in cells, and the amount of CTDNEP1 is increased in the presence of NEP1-R1. In the Caenorhabditis elegans embryo, expression of nematode CTDNEP1 and NEP1-R1, as well as lipin-1, is required for normal nuclear membrane breakdown after zygote formation. The expression pattern of NEP1-R1 and CTDNEP1 in human and mouse tissues closely mirrors that of lipin-1. CTDNEP1 can dephosphorylate lipins-1a, -1b, and -2 in human cells only in the presence of NEP1-R1. The nuclear fraction of lipin-1b is increased when CTDNEP1 and NEP1-R1 are co-expressed. Therefore, NEP1-R1 is functionally conserved from yeast to humans and functions in the lipin activation pathway.
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Affiliation(s)
| | - Shirin Bahmanyar
- the Ludwig Institute for Cancer Research, Department of Cell and Molecular Medicine, and
| | - Peixiang Zhang
- the Department of Human Genetics, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, and
| | - Nick Grishin
- Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Karen Oegema
- the Ludwig Institute for Cancer Research, Department of Cell and Molecular Medicine, and
| | | | - Mark Graham
- ISIS Pharmaceuticals, Inc., Carlsbad, California 92008
| | - Karen Reue
- the Department of Human Genetics, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, and
| | - Jack E. Dixon
- Department of Pharmacology, School of Medicine, University of California at San Diego, La Jolla, California 92093
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Mattoo S, Durrant E, Chen MJ, Xiao J, Lazar CS, Manning G, Dixon JE, Worby CA. Comparative analysis of Histophilus somni immunoglobulin-binding protein A (IbpA) with other fic domain-containing enzymes reveals differences in substrate and nucleotide specificities. J Biol Chem 2011; 286:32834-42. [PMID: 21795713 PMCID: PMC3173180 DOI: 10.1074/jbc.m111.227603] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 07/23/2011] [Indexed: 11/25/2022] Open
Abstract
A new family of adenylyltransferases, defined by the presence of a Fic domain, was recently discovered to catalyze the addition of adenosine monophosphate (AMP) to Rho GTPases (Yarbrough, M. L., Li, Y., Kinch, L. N., Grishin, N. V., Ball, H. L., and Orth, K. (2009) Science 323, 269-272; Worby, C. A., Mattoo, S., Kruger, R. P., Corbeil, L. B., Koller, A., Mendez, J. C., Zekarias, B., Lazar, C., and Dixon, J. E. (2009) Mol. Cell 34, 93-103). This adenylylation event inactivates Rho GTPases by preventing them from binding to their downstream effectors. We reported that the Fic domain(s) of the immunoglobulin-binding protein A (IbpA) from the pathogenic bacterium Histophilus somni adenylylates mammalian Rho GTPases, RhoA, Rac1, and Cdc42, thereby inducing host cytoskeletal collapse, which allows H. somni to breach alveolar barriers and cause septicemia. The IbpA-mediated adenylylation occurs on a functionally critical tyrosine in the switch 1 region of these GTPases. Here, we conduct a detailed characterization of the IbpA Fic2 domain and compare its activity with other known Fic adenylyltransferases, VopS (Vibrio outer protein S) from the bacterial pathogen Vibrio parahaemolyticus and the human protein HYPE (huntingtin yeast interacting protein E; also called FicD). We also included the Fic domains of the secreted protein, PfhB2, from the opportunistic pathogen Pasteurella multocida, in our analysis. PfhB2 shares a common domain architecture with IbpA and contains two Fic domains. We demonstrate that the PfhB2 Fic domains also possess adenylyltransferase activity that targets the switch 1 tyrosine of Rho GTPases. Comparative kinetic and phylogenetic analyses of IbpA-Fic2 with the Fic domains of PfhB2, VopS, and HYPE reveal important aspects of their specificities for Rho GTPases and nucleotide usage and offer mechanistic insights for determining nucleotide and substrate specificities for these enzymes. Finally, we compare the evolutionary lineages of Fic proteins with those of other known adenylyltransferases.
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Affiliation(s)
- Seema Mattoo
- From the Howard Hughes Medical Institute and Department of Pharmacology and
| | - Eric Durrant
- the Departments of Pharmacology, Cellular and Molecular Medicine, and Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0721 and
| | - Mark J. Chen
- the Razavi Newman Center for Bioinformatics, Salk Institute, La Jolla, California 92037
| | - Junyu Xiao
- the Departments of Pharmacology, Cellular and Molecular Medicine, and Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0721 and
| | - Cheri S. Lazar
- the Departments of Pharmacology, Cellular and Molecular Medicine, and Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0721 and
| | - Gerard Manning
- the Razavi Newman Center for Bioinformatics, Salk Institute, La Jolla, California 92037
| | - Jack E. Dixon
- From the Howard Hughes Medical Institute and Department of Pharmacology and
- the Departments of Pharmacology, Cellular and Molecular Medicine, and Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0721 and
| | - Carolyn A. Worby
- the Departments of Pharmacology, Cellular and Molecular Medicine, and Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0721 and
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41
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Abstract
Voltage-sensing phosphoinositide phosphatase (VSP) contains voltage sensor and cytoplasmic phosphatase domains. A unique feature of this protein is that depolarization-induced motions of the voltage sensor activate PtdIns(3,4,5)P(3) and PtdIns(4,5)P(2) phosphatase activities. VSP exhibits remarkable structural similarities with PTEN, the phosphatase and tensin homolog deleted on chromosome 10. These similarities include the cytoplasmic phosphatase region, the phosphoinositide binding region, and the putative membrane interacting C2 domain.
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Affiliation(s)
- Yasushi Okamura
- Department of Physiology, Graduate School of Medicine, Osaka University, Osaka, Japan.
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42
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Tallantyre EC, Dixon JE, Donaldson I, Owens T, Morgan PS, Morris PG, Evangelou N. Ultra-high-field imaging distinguishes MS lesions from asymptomatic white matter lesions. Neurology 2011; 76:534-9. [PMID: 21300968 DOI: 10.1212/wnl.0b013e31820b7630] [Citation(s) in RCA: 152] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVES To investigate whether multiple sclerosis (MS) and non-MS white matter brain lesions can be distinguished by their appearance on 7 T T2*-weighted MRI. METHODS This was an observational study of 28 patients with MS and 17 patients with cerebral white matter lesions who did not have MS. Subjects were imaged using 7 T T2*-weighted imaging. White matter lesions were identified and analyzed for volume, location, and perivenous appearance. RESULTS Out of 901 lesions identified in patients with MS, 80% were perivenous. In comparison, 19% of 428 lesions identified in patients without MS had a perivenous appearance. Seven-Tesla T2*-weighted MRI reliably distinguished all patients with clinically definite MS (>40% lesions appeared perivenous) from those without clinical MS (<40% lesions appeared perivenous). Perivenous lesion appearance was more predictive of MS (odds ratio [OR] 14, p < 0.001) than subcortical or periventricular lesion location (OR 4.5, p < 0.001, and OR 2.4, p = 0.009). Perivenous lesion appearance was observed with a similar frequency in patients with clinically isolated syndrome of demyelination and in early (gadolinium-enhancing) MS lesions. CONCLUSION Perivenous lesion location on 7 T T2*-weighted imaging is predictive of the presence of demyelination. Optimization of this imaging technique at lower magnetic resonance field strengths would offer benefit for the diagnosis of MS.
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Affiliation(s)
- E C Tallantyre
- Department of Clinical Neurology, Nottingham University Hospital NHS Trust, Nottingham, NG7 2UH, UK
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43
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Abstract
Phosphorylation of glycogen has been known for decades; however, the basic metabolic pathways responsible for this modification are unknown. In this issue, Tagliabracci et al. (2011) report the enzyme responsible for incorporating phosphate and the chemical nature of the phosphate linkage, providing a framework for expanding our understanding of a devastating form of epilepsy.
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Affiliation(s)
- Carolyn A Worby
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
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44
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Zhang M, Liu J, Kim Y, Dixon JE, Pfaff SL, Gill GN, Noel JP, Zhang Y. Structural and functional analysis of the phosphoryl transfer reaction mediated by the human small C-terminal domain phosphatase, Scp1. Protein Sci 2010; 19:974-86. [PMID: 20222012 DOI: 10.1002/pro.375] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Human small C-terminal domain phosphatase 1 (Scp1) modulates the phosphorylation state of the C-terminal domain (CTD) of eukaryotic RNA polymerase II (RNAP II), with preference for phosphorylated Ser5 in the tandem heptad repeats of the CTD. Additionally, Scp1 was identified as a conserved regulator of neuronal stem cell development. Scp1 is a member of haloacid dehalogenase (HAD) superfamily, whose catalysis depends on a Mg(2+) ion and a DXDX(T/V) motif. The first Asp of the motif is identified as the nucleophile that is subject to phosphorylation leading to a phosphoryl-aspartate intermediate. This high-energy mixed anhydride intermediate is subsequently hydrolyzed to regenerate the enzyme. In the present study, we successfully captured the phosphoryl-aspartate intermediate in the crystal structure of a Scp1D206A mutant soaked with para-nitrophenyl phosphate (pNPP), providing strong evidence for the proposed mechanism. Furthermore, steady-state kinetic analysis of a variety of Scp1 mutants revealed the importance of Asp206 in Mg(2+) coordination mediated by a water molecule. Overall, we captured the snapshots of the phosphoryl transfer reaction at each stage of Scp1-mediated catalysis. Through structural-based sequence alignment, we show that the spatial position of the D206 side chain is strictly conserved throughout HAD family. Our results strongly suggest that Asp206 and its equivalent residues in other HAD family members play important structural and possible mechanistic roles.
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Affiliation(s)
- Mengmeng Zhang
- Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas, USA
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45
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Gonzalez DJ, Lee SW, Hensler ME, Markley AL, Dahesh S, Mitchell DA, Bandeira N, Nizet V, Dixon JE, Dorrestein PC. Clostridiolysin S, a post-translationally modified biotoxin from Clostridium botulinum. J Biol Chem 2010; 285:28220-8. [PMID: 20581111 DOI: 10.1074/jbc.m110.118554] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Through elaboration of its botulinum toxins, Clostridium botulinum produces clinical syndromes of infant botulism, wound botulism, and other invasive infections. Using comparative genomic analysis, an orphan nine-gene cluster was identified in C. botulinum and the related foodborne pathogen Clostridium sporogenes that resembled the biosynthetic machinery for streptolysin S, a key virulence factor from group A Streptococcus responsible for its hallmark beta-hemolytic phenotype. Genetic complementation, in vitro reconstitution, mass spectral analysis, and plasmid intergrational mutagenesis demonstrate that the streptolysin S-like gene cluster from Clostridium sp. is responsible for the biogenesis of a novel post-translationally modified hemolytic toxin, clostridiolysin S.
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Affiliation(s)
- David J Gonzalez
- Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, California 92093, USA
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46
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Gleick PH, Adams RM, Amasino RM, Anders E, Anderson DJ, Anderson WW, Anselin LE, Arroyo MK, Asfaw B, Ayala FJ, Bax A, Bebbington AJ, Bell G, Bennett MVL, Bennetzen JL, Berenbaum MR, Berlin OB, Bjorkman PJ, Blackburn E, Blamont JE, Botchan MR, Boyer JS, Boyle EA, Branton D, Briggs SP, Briggs WR, Brill WJ, Britten RJ, Broecker WS, Brown JH, Brown PO, Brunger AT, Cairns J, Canfield DE, Carpenter SR, Carrington JC, Cashmore AR, Castilla JC, Cazenave A, Chapin FS, Ciechanover AJ, Clapham DE, Clark WC, Clayton RN, Coe MD, Conwell EM, Cowling EB, Cowling RM, Cox CS, Croteau RB, Crothers DM, Crutzen PJ, Daily GC, Dalrymple GB, Dangl JL, Darst SA, Davies DR, Davis MB, De Camilli PV, Dean C, DeFries RS, Deisenhofer J, Delmer DP, DeLong EF, DeRosier DJ, Diener TO, Dirzo R, Dixon JE, Donoghue MJ, Doolittle RF, Dunne T, Ehrlich PR, Eisenstadt SN, Eisner T, Emanuel KA, Englander SW, Ernst WG, Falkowski PG, Feher G, Ferejohn JA, Fersht A, Fischer EH, Fischer R, Flannery KV, Frank J, Frey PA, Fridovich I, Frieden C, Futuyma DJ, Gardner WR, Garrett CJR, Gilbert W, Goldberg RB, Goodenough WH, Goodman CS, Goodman M, Greengard P, Hake S, Hammel G, Hanson S, Harrison SC, Hart SR, Hartl DL, Haselkorn R, Hawkes K, Hayes JM, Hille B, Hökfelt T, House JS, Hout M, Hunten DM, Izquierdo IA, Jagendorf AT, Janzen DH, Jeanloz R, Jencks CS, Jury WA, Kaback HR, Kailath T, Kay P, Kay SA, Kennedy D, Kerr A, Kessler RC, Khush GS, Kieffer SW, Kirch PV, Kirk K, Kivelson MG, Klinman JP, Klug A, Knopoff L, Kornberg H, Kutzbach JE, Lagarias JC, Lambeck K, Landy A, Langmuir CH, Larkins BA, Le Pichon XT, Lenski RE, Leopold EB, Levin SA, Levitt M, Likens GE, Lippincott-Schwartz J, Lorand L, Lovejoy CO, Lynch M, Mabogunje AL, Malone TF, Manabe S, Marcus J, Massey DS, McWilliams JC, Medina E, Melosh HJ, Meltzer DJ, Michener CD, Miles EL, Mooney HA, Moore PB, Morel FMM, Mosley-Thompson ES, Moss B, Munk WH, Myers N, Nair GB, Nathans J, Nester EW, Nicoll RA, Novick RP, O'Connell JF, Olsen PE, Opdyke ND, Oster GF, Ostrom E, Pace NR, Paine RT, Palmiter RD, Pedlosky J, Petsko GA, Pettengill GH, Philander SG, Piperno DR, Pollard TD, Price PB, Reichard PA, Reskin BF, Ricklefs RE, Rivest RL, Roberts JD, Romney AK, Rossmann MG, Russell DW, Rutter WJ, Sabloff JA, Sagdeev RZ, Sahlins MD, Salmond A, Sanes JR, Schekman R, Schellnhuber J, Schindler DW, Schmitt J, Schneider SH, Schramm VL, Sederoff RR, Shatz CJ, Sherman F, Sidman RL, Sieh K, Simons EL, Singer BH, Singer MF, Skyrms B, Sleep NH, Smith BD, Snyder SH, Sokal RR, Spencer CS, Steitz TA, Strier KB, Südhof TC, Taylor SS, Terborgh J, Thomas DH, Thompson LG, Tjian RT, Turner MG, Uyeda S, Valentine JW, Valentine JS, Van Etten JL, van Holde KE, Vaughan M, Verba S, von Hippel PH, Wake DB, Walker A, Walker JE, Watson EB, Watson PJ, Weigel D, Wessler SR, West-Eberhard MJ, White TD, Wilson WJ, Wolfenden RV, Wood JA, Woodwell GM, Wright HE, Wu C, Wunsch C, Zoback ML. Climate change and the integrity of science. Science 2010; 328:689-90. [PMID: 20448167 DOI: 10.1126/science.328.5979.689] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Doughty-Shenton D, Joseph JD, Zhang J, Pagliarini DJ, Kim Y, Lu D, Dixon JE, Casey PJ. Pharmacological targeting of the mitochondrial phosphatase PTPMT1. J Pharmacol Exp Ther 2010; 333:584-92. [PMID: 20167843 DOI: 10.1124/jpet.109.163329] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The dual-specificity protein tyrosine phosphatases (PTPs) play integral roles in the regulation of cell signaling. There is a need for new tools to study these phosphatases, and the identification of inhibitors potentially affords not only new means for their study, but also possible therapeutics for the treatment of diseases caused by their dysregulation. However, the identification of selective inhibitors of the protein phosphatases has proven somewhat difficult. PTP localized to mitochondrion 1 (PTPMT1) is a recently discovered dual-specificity phosphatase that has been implicated in the regulation of insulin secretion. Screening of a commercially available small-molecule library yielded alexidine dihydrochloride, a dibiguanide compound, as an effective and selective inhibitor of PTPMT1 with an in vitro concentration that inhibits response by 50% of 1.08 microM. A related dibiguanide analog, chlorhexidine dihydrochloride, also significantly inhibited PTPMT1, albeit with lower potency, while a monobiguanide analog showed very weak inhibition. Treatment of isolated rat pancreatic islets with alexidine dihydrochloride resulted in a dose-dependent increase in insulin secretion, whereas treatment of a pancreatic beta-cell line with the drug affected the phosphorylation of mitochondrial proteins in a manner similar to genetic inhibition of PTPMT1. Furthermore, knockdown of PTPMT1 in rat islets rendered them insensitive to alexidine dihydrochloride treatment, providing evidence for mechanism-based activity of the inhibitor. Taken together, these studies establish alexidine dihydrochloride as an effective inhibitor of PTPMT1, both in vitro and in cells, and support the notion that PTPMT1 could serve as a pharmacological target in the treatment of type II diabetes.
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Affiliation(s)
- Dahlia Doughty-Shenton
- Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina 27710-3813, USA
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Gentry MS, Dixon JE, Worby CA. Lafora disease: insights into neurodegeneration from plant metabolism. Trends Biochem Sci 2009; 34:628-39. [PMID: 19818631 DOI: 10.1016/j.tibs.2009.08.002] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Revised: 07/30/2009] [Accepted: 08/04/2009] [Indexed: 12/30/2022]
Abstract
Reversible phosphorylation modulates nearly every step of glycogenesis and glycogenolysis. Multiple metabolic disorders are the result of defective enzymes that control these phosphorylation events, enzymes that were identified biochemically before the advent of the molecular biology era. Lafora disease is a metabolic disorder resulting in accumulation of water-insoluble glucan in the cytoplasm, and manifests as a debilitating neurodegeneration that ends with the death of the patient. Unlike most metabolic disorders, the link between Lafora disease and metabolism has not been defined in almost 100 years. The results of recent studies with mammalian cells, mouse models, eukaryotic algae, and plants have begun to define the molecular mechanisms that cause Lafora disease. The emerging theme identifies a new phosphorylation substrate in glycogen metabolism, the glucan itself.
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Affiliation(s)
- Matthew S Gentry
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, Lexington, KY 40536-0509, USA.
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49
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Dowen RH, Engel JL, Shao F, Ecker JR, Dixon JE. A family of bacterial cysteine protease type III effectors utilizes acylation-dependent and -independent strategies to localize to plasma membranes. J Biol Chem 2009; 284:15867-79. [PMID: 19346252 PMCID: PMC2708883 DOI: 10.1074/jbc.m900519200] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Bacterial phytopathogens employ a type III secretion system to deliver effector proteins into the plant cell to suppress defense pathways; however, the molecular mechanisms and subcellular localization strategies that drive effector function largely remain a mystery. Here, we demonstrate that the plant plasma membrane is the primary site for subcellular localization of the Pseudomonas syringae effector AvrPphB and five additional cysteine protease family members. AvrPphB and two AvrPphB-like effectors, ORF4 and NopT, autoproteolytically process following delivery into the plant cell to expose embedded sites for fatty acylation. Host-dependent lipidation of these three effectors directs plasma membrane localization and is required for the avirulence activity of AvrPphB. Surprisingly, the AvrPphB-like effectors RipT, HopC1, and HopN1 utilize an acylation-independent mechanism to localize to the cellular plasma membrane. Although some AvrPphB-like effectors employ acylation-independent localization strategies, others hijack the eukaryotic lipidation machinery to ensure plasma membrane localization, illustrating the diverse tactics employed by type III effectors to target specific subcellular compartments.
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Affiliation(s)
- Robert H Dowen
- Departments of Pharmacology, Cellular and Molecular Medicine, and Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0721, USA
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Rardin MJ, Wiley SE, Naviaux RK, Murphy AN, Dixon JE. Monitoring phosphorylation of the pyruvate dehydrogenase complex. Anal Biochem 2009; 389:157-64. [PMID: 19341700 DOI: 10.1016/j.ab.2009.03.040] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2009] [Revised: 03/26/2009] [Accepted: 03/26/2009] [Indexed: 12/27/2022]
Abstract
The pyruvate dehydrogenase multienzyme complex (PDC) is a key regulatory point in cellular metabolism linking glycolysis to the citric acid cycle and lipogenesis. Reversible phosphorylation of the pyruvate dehydrogenase enzyme is a critical regulatory mechanism and an important point for monitoring metabolic activity. To directly determine the regulation of the PDC by phosphorylation, we developed a complete set of phospho-antibodies against the three known phosphorylation sites on the E1 alpha subunit of pyruvate dehydrogenase (PDHE1alpha). We demonstrate phospho-site specificity of each antibody in a variety of cultured cells and tissue extracts. In addition, we show sensitivity of these antibodies to PDH activity using the pyruvate dehydrogenase kinase-specific inhibitor dichloroacetate. We go on to use these antibodies to assess PDH phosphorylation in a patient suffering from Leigh's syndrome. Finally, we observe changes in individual phosphorylation states following a small molecule screen, demonstrating that these reagents should be useful for monitoring phosphorylation of PDHE1alpha and, therefore, overall metabolism in the disease state as well as in response to a myriad of physiological and pharmacological stimuli.
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Affiliation(s)
- Matthew J Rardin
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
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