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Barnsby-Greer L, Mabbitt PD, Dery MA, Squair DR, Wood NT, Lamoliatte F, Lange SM, Virdee S. UBE2A and UBE2B are recruited by an atypical E3 ligase module in UBR4. Nat Struct Mol Biol 2024; 31:351-363. [PMID: 38182926 PMCID: PMC10873205 DOI: 10.1038/s41594-023-01192-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 11/27/2023] [Indexed: 01/07/2024]
Abstract
UBR4 is a 574 kDa E3 ligase (E3) of the N-degron pathway with roles in neurodevelopment, age-associated muscular atrophy and cancer. The catalytic module that carries out ubiquitin (Ub) transfer remains unknown. Here we identify and characterize a distinct E3 module within human UBR4 consisting of a 'hemiRING' zinc finger, a helical-rich UBR zinc-finger interacting (UZI) subdomain, and an N-terminal region that can serve as an affinity factor for the E2 conjugating enzyme (E2). The structure of an E2-E3 complex provides atomic-level insight into the specificity determinants of the hemiRING toward the cognate E2s UBE2A/UBE2B. Via an allosteric mechanism, the UZI subdomain modestly activates the Ub-loaded E2 (E2∼Ub). We propose attenuated activation is complemented by the intrinsically high lysine reactivity of UBE2A, and their cooperation imparts a reactivity profile important for substrate specificity and optimal degradation kinetics. These findings reveal the mechanistic underpinnings of a neuronal N-degron E3, its specific recruitment of UBE2A, and highlight the underappreciated architectural diversity of cross-brace domains with Ub E3 activity.
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Affiliation(s)
- Lucy Barnsby-Greer
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Scotland, UK
| | - Peter D Mabbitt
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Scotland, UK
- Scion, Rotorua, New Zealand
| | - Marc-Andre Dery
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Scotland, UK
| | - Daniel R Squair
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Scotland, UK
| | - Nicola T Wood
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Scotland, UK
| | - Frederic Lamoliatte
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Scotland, UK
| | - Sven M Lange
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Scotland, UK
| | - Satpal Virdee
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Scotland, UK.
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2
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Laohavisit A. Wound-Induced Rooting in Plants-A big BIG ROle Emerges for Calcium and Auxin. PLANT & CELL PHYSIOLOGY 2023; 64:149-151. [PMID: 36688580 DOI: 10.1093/pcp/pcad007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/19/2023] [Accepted: 01/23/2023] [Indexed: 06/17/2023]
Affiliation(s)
- Anuphon Laohavisit
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 Japan
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3
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Modrego A, Pasternak T, Omary M, Albacete A, Cano A, Pérez-Pérez JM, Efroni I. Mapping of the Classical Mutation rosette Highlights a Role for Calcium in Wound-Induced Rooting. PLANT & CELL PHYSIOLOGY 2023; 64:152-164. [PMID: 36398993 DOI: 10.1093/pcp/pcac163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 11/14/2022] [Accepted: 11/17/2022] [Indexed: 06/16/2023]
Abstract
Removal of the root system induces the formation of new roots from the remaining shoot. This process is primarily controlled by the phytohormone auxin, which interacts with other signals in a yet unresolved manner. Here, we study the classical tomato mutation rosette (ro), which lacks shoot-borne roots. ro mutants were severely inhibited in formation of wound-induced roots (WiRs) and had reduced auxin transport rates. We mapped ro to the tomato ortholog of the Arabidopsis thaliana BIG and the mammalians UBR4/p600. RO/BIG is a large protein of unknown biochemical function. In A. thaliana, BIG was implicated in regulating auxin transport and calcium homeostasis. We show that exogenous calcium inhibits WiR formation in tomato and A. thaliana ro/big mutants. Exogenous calcium antagonized the root-promoting effects of the auxin indole-3-acetic-acid but not of 2,4-dichlorophenoxyacetic acid, an auxin analog that is not recognized by the polar transport machinery, and accumulation of the auxin transporter PIN-FORMED1 (PIN1) was sensitive to calcium levels in the ro/big mutants. Consistent with a role for calcium in mediating auxin transport, both ro/big mutants and calcium-treated wild-type plants were hypersensitive to treatment with polar auxin transport inhibitors. Subcellular localization of BIG suggests that, like its mammalian ortholog, it is associated with the endoplasmic reticulum. Analysis of subcellular morphology revealed that ro/big mutants exhibited disruption in cytoplasmic streaming. We suggest that RO/BIG maintains auxin flow by stabilizing PIN membrane localization, possibly by attenuating the inhibitory effect of Ca2+ on cytoplasmic streaming.
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Affiliation(s)
- Abelardo Modrego
- The Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, The Hebrew University, Rehovot 7610001, Israel
| | - Taras Pasternak
- Instituto de Bioingeniería, Universidad Miguel Hernández, Elche 03202, Spain
| | - Moutasem Omary
- The Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, The Hebrew University, Rehovot 7610001, Israel
| | - Alfonso Albacete
- Departamento de Nutrición Vegetal, CEBAS-CSIC, Murcia 30100, Spain
| | - Antonio Cano
- Departamento de Biología Vegetal (Fisiología Vegetal), Universidad de Murcia, Murcia 30100, Spain
| | | | - Idan Efroni
- The Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, The Hebrew University, Rehovot 7610001, Israel
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4
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Chen M, Zhao J, Ding X, Qin Y, Wu X, Li X, Wang L, Jiang G. Ketogenic diet and calorie-restricted diet attenuate ischemic brain injury via UBR4 and downstream CamkⅡ/TAK1/JNK signaling. J Funct Foods 2023. [DOI: 10.1016/j.jff.2022.105368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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5
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Hearn TJ, Marti Ruiz MC, Abdul-Awal SM, Wimalasekera R, Stanton CR, Haydon MJ, Theodoulou FL, Hannah MA, Webb AAR. BIG Regulates Dynamic Adjustment of Circadian Period in Arabidopsis thaliana. PLANT PHYSIOLOGY 2018; 178:358-371. [PMID: 29997180 PMCID: PMC6130016 DOI: 10.1104/pp.18.00571] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 06/28/2018] [Indexed: 05/26/2023]
Abstract
Circadian clocks drive rhythms with a period near 24 h, but the molecular basis of the regulation of the period of the circadian clockis poorly understood. We previously demonstrated that metabolites affect the free-running period of the circadian oscillator of Arabidopsis (Arabidopsis thaliana), with endogenous sugars acting as an accelerator and exogenous nicotinamide acting as a brake. Changes in circadian oscillator period are thought to adjust the timing of biological activities through the process of entrainment, in which the circadian oscillator becomes synchronized to rhythmic signals such as light and dark cycles as well as changes in internal metabolism. To identify the molecular components associated with the dynamic adjustment of circadian period, we performed a forward genetic screen. We identified Arabidopsis mutants that were either period insensitive to nicotinamide (sin) or period oversensitive to nicotinamide (son). We mapped son1 to BIG, a gene of unknown molecular function that was shown previously to play a role in light signaling. We found that son1 has an early entrained phase, suggesting that the dynamic alteration of circadian period contributes to the correct timing of biological events. Our data provide insight into how the dynamic period adjustment of circadian oscillators contributes to establishing a correct phase relationship with the environment and show that BIG is involved in this process.
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Affiliation(s)
- Timothy J Hearn
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
| | - Maria C Marti Ruiz
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
| | - S M Abdul-Awal
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
- Biotechnology and Genetic Engineering Discipline, Khulna University, Khulna-9208, Bangladesh
| | - Rinukshi Wimalasekera
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
| | - Camilla R Stanton
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
| | - Michael J Haydon
- School of BioSciences, University of Melbourne, Melbourne, Victoria 3010, Australia
| | | | | | - Alex A R Webb
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
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6
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Kim ST, Lee YJ, Tasaki T, Hwang J, Kang MJ, Yi EC, Kim BY, Kwon YT. The N-recognin UBR4 of the N-end rule pathway is required for neurogenesis and homeostasis of cell surface proteins. PLoS One 2018; 13:e0202260. [PMID: 30157281 PMCID: PMC6114712 DOI: 10.1371/journal.pone.0202260] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 07/05/2018] [Indexed: 12/21/2022] Open
Abstract
The N-end rule pathway is a proteolytic system in which single N-terminal amino acids of proteins act as a class of degrons (N-degrons) that determine the half-lives of proteins. We have previously identified a family of mammals N-recognins (termed UBR1, UBR2, UBR4/p600, and UBR5/EDD) whose conserved UBR boxes bind N-degrons to facilitate substrate ubiquitination and proteasomal degradation via the ubiquitin-proteasome system (UPS). Amongst these N-recognins, UBR1 and UBR2 mediate ubiquitination and proteolysis of short-lived regulators and misfolded proteins. Here, we characterized the null phenotypes of UBR4-deficient mice in which the UBR box of UBR4 was deleted. We show that the mutant mice die around embryonic days 9.5–10.5 (E9.5–E10.5) associated with abnormalities in various developmental processes such as neurogenesis and cardiovascular development. These developmental defects are significantly attributed to the inability to maintain cell integrity and adhesion, which significantly correlates to the severity of null phenotypes. UBR4-loss induces the depletion of many, but not all, proteins from the plasma membrane, suggesting that UBR4 is involved in proteome-wide turnover of cell surface proteins. Indeed, UBR4 is associated with and required to generate the multivesicular body (MVB) which transiently store endocytosed cell surface proteins before their targeting to autophagosomes and subsequently lysosomes. Our results suggest that the N-recognin UBR4 plays a role in the homeostasis of cell surface proteins and, thus, cell adhesion and integrity.
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Affiliation(s)
- Sung Tae Kim
- Protein Metabolism Medical Research Center and Department of Biomedical Sciences, College of Medicine, Seoul National University, Seoul, Republic of Korea
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Yoon Jee Lee
- Protein Metabolism Medical Research Center and Department of Biomedical Sciences, College of Medicine, Seoul National University, Seoul, Republic of Korea
| | - Takafumi Tasaki
- Medical Research Institute, Kanazawa Medical University, Ishikawa, Japan
| | - Joonsung Hwang
- World Class Institute, Anticancer Agents Research Center, Korea Research Institute of Bioscience and Biotechnology, Ochang, Cheongwon, Republic of Korea
| | - Min Jueng Kang
- Department of Molecular Medicine and Biopharmaceutical Sciences, School of Convergence Science and Technology and College of Medicine or College of Pharmacy, Seoul National University, Seoul, Republic of Korea
| | - Eugene C. Yi
- Department of Molecular Medicine and Biopharmaceutical Sciences, School of Convergence Science and Technology and College of Medicine or College of Pharmacy, Seoul National University, Seoul, Republic of Korea
| | - Bo Yeon Kim
- World Class Institute, Anticancer Agents Research Center, Korea Research Institute of Bioscience and Biotechnology, Ochang, Cheongwon, Republic of Korea
- * E-mail: (YTK); (BYK)
| | - Yong Tae Kwon
- Protein Metabolism Medical Research Center and Department of Biomedical Sciences, College of Medicine, Seoul National University, Seoul, Republic of Korea
- Ischemic/Hypoxic Disease Institute, College of Medicine, Seoul National University, Seoul, Republic of Korea
- * E-mail: (YTK); (BYK)
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7
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Maffioli E, Schulte C, Nonnis S, Grassi Scalvini F, Piazzoni C, Lenardi C, Negri A, Milani P, Tedeschi G. Proteomic Dissection of Nanotopography-Sensitive Mechanotransductive Signaling Hubs that Foster Neuronal Differentiation in PC12 Cells. Front Cell Neurosci 2018; 11:417. [PMID: 29354032 PMCID: PMC5758595 DOI: 10.3389/fncel.2017.00417] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 12/12/2017] [Indexed: 12/11/2022] Open
Abstract
Neuronal cells are competent in precisely sensing nanotopographical features of their microenvironment. The perceived microenvironmental information will be “interpreted” by mechanotransductive processes and impacts on neuronal functioning and differentiation. Attempts to influence neuronal differentiation by engineering substrates that mimic appropriate extracellular matrix (ECM) topographies are hampered by the fact that profound details of mechanosensing/-transduction complexity remain elusive. Introducing omics methods into these biomaterial approaches has the potential to provide a deeper insight into the molecular processes and signaling cascades underlying mechanosensing/-transduction but their exigence in cellular material is often opposed by technical limitations of major substrate top-down fabrication methods. Supersonic cluster beam deposition (SCBD) allows instead the bottom-up fabrication of nanostructured substrates over large areas characterized by a quantitatively controllable ECM-like nanoroughness that has been recently shown to foster neuron differentiation and maturation. Exploiting this capacity of SCBD, we challenged mechanosensing/-transduction and differentiative behavior of neuron-like PC12 cells with diverse nanotopographies and/or changes of their biomechanical status, and analyzed their phosphoproteomic profiles in these settings. Versatile proteins that can be associated to significant processes along the mechanotransductive signal sequence, i.e., cell/cell interaction, glycocalyx and ECM, membrane/f-actin linkage and integrin activation, cell/substrate interaction, integrin adhesion complex, actomyosin organization/cellular mechanics, nuclear organization, and transcriptional regulation, were affected. The phosphoproteomic data suggested furthermore an involvement of ILK, mTOR, Wnt, and calcium signaling in these nanotopography- and/or cell mechanics-related processes. Altogether, potential nanotopography-sensitive mechanotransductive signaling hubs participating in neuronal differentiation were dissected.
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Affiliation(s)
- Elisa Maffioli
- Department of Veterinary Medicine, Università degli Studi di Milano, Milan, Italy
| | - Carsten Schulte
- Centre for Nanostructured Materials and Interfaces, Università degli Studi di Milano, Milan, Italy.,Fondazione Filarete, Milan, Italy
| | - Simona Nonnis
- Department of Veterinary Medicine, Università degli Studi di Milano, Milan, Italy.,Fondazione Filarete, Milan, Italy
| | - Francesca Grassi Scalvini
- Department of Veterinary Medicine, Università degli Studi di Milano, Milan, Italy.,Fondazione Filarete, Milan, Italy
| | - Claudio Piazzoni
- Centre for Nanostructured Materials and Interfaces, Università degli Studi di Milano, Milan, Italy
| | - Cristina Lenardi
- Centre for Nanostructured Materials and Interfaces, Università degli Studi di Milano, Milan, Italy
| | - Armando Negri
- Department of Veterinary Medicine, Università degli Studi di Milano, Milan, Italy.,Fondazione Filarete, Milan, Italy
| | - Paolo Milani
- Centre for Nanostructured Materials and Interfaces, Università degli Studi di Milano, Milan, Italy
| | - Gabriella Tedeschi
- Department of Veterinary Medicine, Università degli Studi di Milano, Milan, Italy.,Fondazione Filarete, Milan, Italy
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8
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Avdoshina V, Caragher SP, Wenzel ED, Taraballi F, Mocchetti I, Harry GJ. The viral protein gp120 decreases the acetylation of neuronal tubulin: potential mechanism of neurotoxicity. J Neurochem 2017; 141:606-613. [PMID: 28295345 DOI: 10.1111/jnc.14015] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 02/10/2017] [Accepted: 02/28/2017] [Indexed: 01/18/2023]
Abstract
The human immunodeficiency virus (HIV) envelope protein gp120 promotes axonal damage and neurite pruning, similar to that observed in HIV-positive subjects with neurocognitive disorders. Thus, gp120 has been used to examine molecular and cellular pathways underlying HIV-mediated neuronal dysfunction. Gp120 binds to tubulin beta III, a component of neuronal microtubules. Microtubule function, which modulates the homeostasis of neurons, is regulated by polymerization and post-translational modifications. Based on these considerations, we tested the hypothesis that gp120 induces dynamic instability of neuronal microtubules. We first observed that gp120 prevents the normal polymerization of tubulin in vitro. We then tested whether gp120 alters the post-translational modifications in tubulin by examining the ability of gp120 to change the levels of acetylated tubulin in primary rat neuronal cultures. Gp120 elicited a time-dependent decrease in tubulin acetylation that was reversed by Helix-A peptide, a compound that competitively displaces the binding of gp120 to neuronal microtubules. To determine whether post-translational modifications in tubulin also occur in vivo, we measured acetylated tubulin in the cerebral cortex of HIV transgenic rats (HIV-tg). We observed a decrease in tubulin acetylation in 5- and 9-month-old HIV-tg rats when compared to age-matched wild type. Neither changes in microglia morphology nor alterations in mRNA levels for interleukin-1β and tumor necrosis factor α were detected in 5-month-old animals. Our findings propose neuronal microtubule instability as a novel mechanism of HIV neurotoxicity, without evidence of enhanced inflammation.
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Affiliation(s)
- Valeria Avdoshina
- Laboratory of Preclinical Neurobiology, Department of Neuroscience, Georgetown University Washington, Washington, District of Columbia, USA
| | - Seamus P Caragher
- Laboratory of Preclinical Neurobiology, Department of Neuroscience, Georgetown University Washington, Washington, District of Columbia, USA
| | - Erin D Wenzel
- Laboratory of Preclinical Neurobiology, Department of Neuroscience, Georgetown University Washington, Washington, District of Columbia, USA.,Department of Pharmacology and Physiology, Georgetown University Washington, Washington, District of Columbia, USA
| | - Francesca Taraballi
- Department of Regenerative Medicine, Houston Methodist Research Institute, Houston, Texas, USA
| | - Italo Mocchetti
- Laboratory of Preclinical Neurobiology, Department of Neuroscience, Georgetown University Washington, Washington, District of Columbia, USA
| | - Gaylia Jean Harry
- National Toxicology Program Laboratory, National Institute of Environmental Health Science, Research Triangle Park, North Carolina, USA
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9
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Park SE, Kim JM, Seok OH, Cho H, Wadas B, Kim SY, Varshavsky A, Hwang CS. Control of mammalian G protein signaling by N-terminal acetylation and the N-end rule pathway. Science 2015; 347:1249-1252. [PMID: 25766235 PMCID: PMC4748709 DOI: 10.1126/science.aaa3844] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Rgs2, a regulator of G proteins, lowers blood pressure by decreasing signaling through Gαq. Human patients expressing Met-Leu-Rgs2 (ML-Rgs2) or Met-Arg-Rgs2 (MR-Rgs2) are hypertensive relative to people expressing wild-type Met-Gln-Rgs2 (MQ-Rgs2). We found that wild-type MQ-Rgs2 and its mutant, MR-Rgs2, were destroyed by the Ac/N-end rule pathway, which recognizes N(α)-terminally acetylated (Nt-acetylated) proteins. The shortest-lived mutant, ML-Rgs2, was targeted by both the Ac/N-end rule and Arg/N-end rule pathways. The latter pathway recognizes unacetylated N-terminal residues. Thus, the Nt-acetylated Ac-MX-Rgs2 (X = Arg, Gln, Leu) proteins are specific substrates of the mammalian Ac/N-end rule pathway. Furthermore, the Ac/N-degron of Ac-MQ-Rgs2 was conditional, and Teb4, an endoplasmic reticulum (ER) membrane-embedded ubiquitin ligase, was able to regulate G protein signaling by targeting Ac-MX-Rgs2 proteins for degradation through their N(α)-terminal acetyl group.
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Affiliation(s)
- Sang-Eun Park
- Department of Life Sciences, Pohang University of Science and
Technology, Pohang, Gyeongbuk 790-784, South Korea
| | - Jeong-Mok Kim
- Department of Life Sciences, Pohang University of Science and
Technology, Pohang, Gyeongbuk 790-784, South Korea
| | - Ok-Hee Seok
- Department of Life Sciences, Pohang University of Science and
Technology, Pohang, Gyeongbuk 790-784, South Korea
| | - Hanna Cho
- Department of Life Sciences, Pohang University of Science and
Technology, Pohang, Gyeongbuk 790-784, South Korea
| | - Brandon Wadas
- Division of Biology and Biological Engineering, California Institute
of Technology, Pasadena, CA 91125, USA
| | - Seon-Young Kim
- Medical Genomics Research Center, KRIBB, Daejeon, South Korea
- Department of Functional Genomics, University of Science and
Technology, Daejeon, South Korea
| | - Alexander Varshavsky
- Division of Biology and Biological Engineering, California Institute
of Technology, Pasadena, CA 91125, USA
| | - Cheol-Sang Hwang
- Department of Life Sciences, Pohang University of Science and
Technology, Pohang, Gyeongbuk 790-784, South Korea
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10
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Parsons K, Nakatani Y, Nguyen MD. p600/UBR4 in the central nervous system. Cell Mol Life Sci 2015; 72:1149-60. [PMID: 25424645 PMCID: PMC11113099 DOI: 10.1007/s00018-014-1788-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 11/06/2014] [Accepted: 11/17/2014] [Indexed: 10/24/2022]
Abstract
A decade ago, the large 600 kDa mammalian protein p600 (also known as UBR4) was discovered as a multifunctional protein with roles in anoikis, viral transformation and protein degradation. Recently, p600 has emerged as a critical protein in the mammalian brain with roles in neurogenesis, neuronal migration, neuronal signaling and survival. How p600 integrates these apparently unrelated functions to maintain tissue homeostasis and murine survival remains unclear. The common molecular basis underlying many of the actions of p600 suggests, however, certain conservation and transposition of these functions across systems. In this review, we summarize the central nervous system functions of p600 and propose new perspectives on its biological complexity in neuronal physiology and neurological diseases.
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Affiliation(s)
- Kari Parsons
- Department of Clinical Neurosciences, University of Calgary, Hotchkiss Brain Institute, 3330 Hospital Drive NW, Calgary, T2N 4N1, Canada,
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11
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Hong JH, Kaustov L, Coyaud E, Srikumar T, Wan J, Arrowsmith C, Raught B. KCMF1 (potassium channel modulatory factor 1) Links RAD6 to UBR4 (ubiquitin N-recognin domain-containing E3 ligase 4) and lysosome-mediated degradation. Mol Cell Proteomics 2015; 14:674-85. [PMID: 25582440 DOI: 10.1074/mcp.m114.042168] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
RAD6 is a ubiquitin E2 protein with roles in a number of different biological processes. Here, using affinity purification coupled with mass spectrometry, we identify a number of new RAD6 binding partners, including the poorly characterized ubiquitin E3 ligases KCMF1 (potassium channel modulatory factor 1) and UBR4 (ubiquitin N-recognin domain-containing E3 ligase 4), a protein that can bind N-end rule substrates, and which was recently linked to lysosome-mediated degradation and autophagy. NMR, combined with in vivo and in vitro interaction mapping, demonstrate that the KCMF1 C terminus binds directly to RAD6, whereas N-terminal domains interact with UBR4 and other intracellular vesicle- and mitochondria-associated proteins. KCMF1 and RAD6 colocalize at late endosomes and lysosomes, and cells disrupted for KCMF1 or RAD6 function display defects in late endosome vesicle dynamics. Notably, we also find that two different RAD6A point mutants (R7W and R11Q) found in X-linked intellectual disability (XLID) patients specifically lose the interaction with KCMF1 and UBR4, but not with other previously identified RAD6 interactors. We propose that RAD6-KCMF1-UBR4 represents a unique new E2-E3 complex that targets unknown N-end rule substrates for lysosome-mediated degradation, and that disruption of this complex via RAD6A mutations could negatively affect neuronal function in XLID patients.
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Affiliation(s)
- Jenny H Hong
- From the ‡Princess Margaret Cancer Centre, University Health Network and Department of Medical Biophysics, University of Toronto
| | - Lilia Kaustov
- §Structural Genomics Consortium, Toronto, Ontario Canada
| | - Etienne Coyaud
- From the ‡Princess Margaret Cancer Centre, University Health Network and Department of Medical Biophysics, University of Toronto
| | - Tharan Srikumar
- From the ‡Princess Margaret Cancer Centre, University Health Network and Department of Medical Biophysics, University of Toronto
| | - Janet Wan
- From the ‡Princess Margaret Cancer Centre, University Health Network and Department of Medical Biophysics, University of Toronto
| | - Cheryl Arrowsmith
- From the ‡Princess Margaret Cancer Centre, University Health Network and Department of Medical Biophysics, University of Toronto; §Structural Genomics Consortium, Toronto, Ontario Canada
| | - Brian Raught
- From the ‡Princess Margaret Cancer Centre, University Health Network and Department of Medical Biophysics, University of Toronto;
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12
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Karayannis T, Au E, Patel JC, Kruglikov I, Markx S, Delorme R, Héron D, Salomon D, Glessner J, Restituito S, Gordon A, Rodriguez-Murillo L, Roy NC, Gogos JA, Rudy B, Rice ME, Karayiorgou M, Hakonarson H, Keren B, Huguet G, Bourgeron T, Hoeffer C, Tsien RW, Peles E, Fishell G. Cntnap4 differentially contributes to GABAergic and dopaminergic synaptic transmission. Nature 2014; 511:236-40. [PMID: 24870235 PMCID: PMC4281262 DOI: 10.1038/nature13248] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 03/11/2014] [Indexed: 01/08/2023]
Abstract
Although considerable evidence suggests that the chemical synapse is a lynchpin underlying affective disorders, how molecular insults differentially affect specific synaptic connections remains poorly understood. For instance, Neurexin 1a and 2 (NRXN1 and NRXN2) and CNTNAP2 (also known as CASPR2), all members of the neurexin superfamily of transmembrane molecules, have been implicated in neuropsychiatric disorders. However, their loss leads to deficits that have been best characterized with regard to their effect on excitatory cells. Notably, other disease-associated genes such as BDNF and ERBB4 implicate specific interneuron synapses in psychiatric disorders. Consistent with this, cortical interneuron dysfunction has been linked to epilepsy, schizophrenia and autism. Using a microarray screen that focused upon synapse-associated molecules, we identified Cntnap4 (contactin associated protein-like 4, also known as Caspr4) as highly enriched in developing murine interneurons. In this study we show that Cntnap4 is localized presynaptically and its loss leads to a reduction in the output of cortical parvalbumin (PV)-positive GABAergic (γ-aminobutyric acid producing) basket cells. Paradoxically, the loss of Cntnap4 augments midbrain dopaminergic release in the nucleus accumbens. In Cntnap4 mutant mice, synaptic defects in these disease-relevant neuronal populations are mirrored by sensory-motor gating and grooming endophenotypes; these symptoms could be pharmacologically reversed, providing promise for therapeutic intervention in psychiatric disorders.
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Belzil C, Ramos T, Sanada K, Colicos MA, Nguyen MD. p600 stabilizes microtubules to prevent the aggregation of CaMKIIα during photoconductive stimulation. Cell Mol Biol Lett 2014; 19:381-92. [PMID: 25034033 PMCID: PMC6275876 DOI: 10.2478/s11658-014-0201-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Accepted: 07/07/2014] [Indexed: 11/21/2022] Open
Abstract
The large microtubule-associated/Ca(2+)-signalling protein p600 (also known as UBR4) is required for hippocampal neuronal survival upon Ca(2+) dyshomeostasis induced by glutamate treatment. During this process, p600 prevents aggregation of the Ca(2+)/calmodulin-dependent kinase IIα (CaMKIIα), a proxy of neuronal death, via direct binding to calmodulin in a microtubuleindependent manner. Using photoconductive stimulation coupled with live imaging of single neurons, we identified a distinct mechanism of prevention of CaMKIIα aggregation by p600. Upon direct depolarization, CaMKIIα translocates to microtubules. In the absence of p600, this translocation is interrupted in favour of a sustained self-aggregation that is prevented by the microtubule-stabilizing drug paclitaxel. Thus, during photoconductive stimulation, p600 prevents the aggregation of CaMKIIα by stabilizing microtubules. The effectiveness of this stabilization for preventing CaMKIIα aggregation during direct depolarization but not during glutamate treatment suggests a model wherein p600 has two modes of action depending on the source of cytosolic Ca(2+).
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Affiliation(s)
- Camille Belzil
- Hotchkiss Brain Institute, University of Calgary, Departments of Clinical Neurosciences, Cell Biology & Anatomy, Biochemistry & Molecular Biology, 3330 Hospital Drive NW, Calgary, Alberta Canada T2N 4N1
| | - Tim Ramos
- Hotchkiss Brain Institute, University of Calgary, Departments of Clinical Neurosciences, Cell Biology & Anatomy, Biochemistry & Molecular Biology, 3330 Hospital Drive NW, Calgary, Alberta Canada T2N 4N1
| | - Kamon Sanada
- Molecular Genetics Research Laboratory, Graduate School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo, 113-0033 Japan
| | - Michael A. Colicos
- Hotchkiss Brain Institute, University of Calgary, Departments of Clinical Neurosciences, Cell Biology & Anatomy, Biochemistry & Molecular Biology, 3330 Hospital Drive NW, Calgary, Alberta Canada T2N 4N1
| | - Minh Dang Nguyen
- Hotchkiss Brain Institute, University of Calgary, Departments of Clinical Neurosciences, Cell Biology & Anatomy, Biochemistry & Molecular Biology, 3330 Hospital Drive NW, Calgary, Alberta Canada T2N 4N1
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Belzil C, Asada N, Ishiguro KI, Nakaya T, Parsons K, Pendolino V, Neumayer G, Mapelli M, Nakatani Y, Sanada K, Nguyen MD. p600 regulates spindle orientation in apical neural progenitors and contributes to neurogenesis in the developing neocortex. Biol Open 2014; 3:475-85. [PMID: 24812355 PMCID: PMC4058081 DOI: 10.1242/bio.20147807] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Apical neural progenitors (aNPs) drive neurogenesis by means of a program consisting of self-proliferative and neurogenic divisions. The balance between these two manners of division sustains the pool of apical progenitors into late neurogenesis, thereby ensuring their availability to populate the brain with terminal cell types. Using knockout and in utero electroporation mouse models, we report a key role for the microtubule-associated protein 600 (p600) in the regulation of spindle orientation in aNPs, a cellular event that has been associated with cell fate and neurogenesis. We find that p600 interacts directly with the neurogenic protein Ndel1 and that aNPs knockout for p600, depleted of p600 by shRNA or expressing a Ndel1-binding p600 fragment all display randomized spindle orientation. Depletion of p600 by shRNA or expression of the Ndel1-binding p600 fragment also results in a decreased number of Pax6-positive aNPs and an increased number of Tbr2-positive basal progenitors destined to become neurons. These Pax6-positive aNPs display a tilted mitotic spindle. In mice wherein p600 is ablated in progenitors, the production of neurons is significantly impaired and this defect is associated with microcephaly. We propose a working model in which p600 controls spindle orientation in aNPs and discuss its implication for neurogenesis.
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Affiliation(s)
- Camille Belzil
- Hotchkiss Brain Institute, University of Calgary, Departments of Clinical Neurosciences, Cell Biology and Anatomy, and Biochemistry and Molecular Biology, 3330 Hospital Drive NW, Heritage Medical Research Building, Calgary, AB T2N 4N1, Canada
| | - Naoyuki Asada
- Molecular Genetics Research Laboratory, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Kei-Ichiro Ishiguro
- Dana Farber Cancer Institute, 44 Binney Street, Smith Building 836, Boston, MA 02115, USA Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Tokyo 113-0032, Japan
| | - Takeo Nakaya
- Dana Farber Cancer Institute, 44 Binney Street, Smith Building 836, Boston, MA 02115, USA
| | - Kari Parsons
- Hotchkiss Brain Institute, University of Calgary, Departments of Clinical Neurosciences, Cell Biology and Anatomy, and Biochemistry and Molecular Biology, 3330 Hospital Drive NW, Heritage Medical Research Building, Calgary, AB T2N 4N1, Canada
| | - Valentina Pendolino
- European Institute of Oncology, Department of Experimental Oncology, Via Adamello, 16-20139 Milan, Italy
| | - Gernot Neumayer
- Hotchkiss Brain Institute, University of Calgary, Departments of Clinical Neurosciences, Cell Biology and Anatomy, and Biochemistry and Molecular Biology, 3330 Hospital Drive NW, Heritage Medical Research Building, Calgary, AB T2N 4N1, Canada
| | - Marina Mapelli
- European Institute of Oncology, Department of Experimental Oncology, Via Adamello, 16-20139 Milan, Italy
| | - Yoshihiro Nakatani
- Dana Farber Cancer Institute, 44 Binney Street, Smith Building 836, Boston, MA 02115, USA
| | - Kamon Sanada
- Molecular Genetics Research Laboratory, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Minh Dang Nguyen
- Hotchkiss Brain Institute, University of Calgary, Departments of Clinical Neurosciences, Cell Biology and Anatomy, and Biochemistry and Molecular Biology, 3330 Hospital Drive NW, Heritage Medical Research Building, Calgary, AB T2N 4N1, Canada
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