1
|
Liu Z, Fan K, Abudukeremu A, Gao M, Tan X, Mao X, Li X, Ma W, Ma X, Li C, Yang Y, Tu K, Chen J, Zhang Y, Guan Y. LIMA1 links the E3 ubiquitin ligase RNF40 to lipid metabolism. Cell Death Discov 2024; 10:298. [PMID: 38909032 PMCID: PMC11193757 DOI: 10.1038/s41420-024-02072-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 06/11/2024] [Accepted: 06/13/2024] [Indexed: 06/24/2024] Open
Abstract
LIMA1 is a LIM domain and Actin binding 1 protein that acts as a skeleton protein to promote cholesterol absorption, which makes it an ideal target for interfering with lipid metabolism. However, the detailed regulation of LIMA1 remains unclear. Here, we identified that ring finger protein 40 (RNF40), an E3 ubiquitin ligase previously known as an epigenetic modifier to increase H2B ubiquitination, mediated the ubiquitination of LIMA1 and thereby promoted its degradation in a proteasome-dependent manner. Fraction studies revealed that the 1-166aa fragment of LIMA1 was indispensable for the interaction with RNF40, and at least two domains of RNF40 might mediate the association of RNF40 with LIMA1. Notably, treatment with simvastatin dramatically decreased the levels of CHO and TG in control cells rather than cells with overexpressed LIMA1. Moreover, RNF40 significantly decreased lipid content, which could be reversed by LIMA1 overexpression. These findings suggest that E3 ubiquitin ligase RNF40 could directly target LIMA1 and promote its protein degradation in cytoplasm, leading to the suppression of lipid accumulation mediated by LIMA1. Collectively, this study unveils that RNF40 is a novel E3 ubiquitin ligase of LIMA1, which underpins its high therapeutic value to combat dysregulation of lipid metabolism.
Collapse
Affiliation(s)
- Zhan Liu
- State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia, School of Basic Medical Sciences, Xinjiang Medical University, Urumqi, Xinjiang, China
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xinjiang Second Medical College, Karamay, Xinjiang, China
| | - Kexin Fan
- The Institute of Molecular and Translational Medicine, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Aikedaimu Abudukeremu
- State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia, School of Basic Medical Sciences, Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Min Gao
- The Institute of Molecular and Translational Medicine, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Xinyue Tan
- The Institute of Molecular and Translational Medicine, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Xiaojuan Mao
- The Institute of Molecular and Translational Medicine, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Xinyu Li
- State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia, School of Basic Medical Sciences, Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Wenting Ma
- State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia, School of Basic Medical Sciences, Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Xusheng Ma
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xinjiang Second Medical College, Karamay, Xinjiang, China
| | - Caolong Li
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xinjiang Second Medical College, Karamay, Xinjiang, China
| | - Yinglai Yang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xinjiang Second Medical College, Karamay, Xinjiang, China
| | - Kangsheng Tu
- Department of Hepatobiliary Surgery, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Jing Chen
- Department of Obstetrics, Xi 'an New Chang 'an Maternity Hospital, Xi'an, Shaanxi, China
| | - Yilei Zhang
- The Institute of Molecular and Translational Medicine, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, Shaanxi, China.
| | - Yaqun Guan
- State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia, School of Basic Medical Sciences, Xinjiang Medical University, Urumqi, Xinjiang, China.
| |
Collapse
|
2
|
Lin CT, Ting RT, Ou YH, Shao TL, Lee MC. Protein degradation of Lsd1 is mediated by Bre1 yet opposed by Lsd1-interacting lncRNAs during fly follicle development. iScience 2024; 27:109683. [PMID: 38655201 PMCID: PMC11035368 DOI: 10.1016/j.isci.2024.109683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 02/13/2024] [Accepted: 04/04/2024] [Indexed: 04/26/2024] Open
Abstract
Tissue development, homeostasis, and repair all require efficient progenitor expansion. Lysine-specific demethylase 1 (Lsd1) maintains plastic epigenetic states to promote progenitor proliferation while overexpressed Lsd1 protein causes oncogenic gene expression in cancer cells. However, the precise regulation of Lsd1 protein expression at the molecular level to drive progenitor differentiation remains unclear. Here, using Drosophila melanogaster oogenesis as our experimental system, we discovered molecular machineries that modify Lsd1 protein stability in vivo. Through genetic and biochemical analyses, an E3 ubiquitin ligase, Bre1, was identified as required for follicle progenitor differentiation, likely by mediating Lsd1 protein degradation. Interestingly, specific Lsd1-interacting long non-coding RNAs (LINRs) were found to antagonize Bre1-mediated Lsd1 protein degradation. The intricate interplay discovered among the Lsd1 complex, LINRs and Bre1 provides insight into how Lsd1 protein stability is fine-tuned to underlie progenitor differentiation in vivo.
Collapse
Affiliation(s)
- Chun Ting Lin
- Department of Life Sciences and Institute of Genome Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Info & Research Bldg, Rm 904, #155, Sec. 2, Li-Nong St, Taipei City 112, Taiwan
| | - Ruei-Teng Ting
- Department of Life Sciences and Institute of Genome Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Info & Research Bldg, Rm 904, #155, Sec. 2, Li-Nong St, Taipei City 112, Taiwan
| | - Yang-Hsuan Ou
- Department of Life Sciences and Institute of Genome Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Info & Research Bldg, Rm 904, #155, Sec. 2, Li-Nong St, Taipei City 112, Taiwan
| | - Tzu-Ling Shao
- Department of Life Sciences and Institute of Genome Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Info & Research Bldg, Rm 904, #155, Sec. 2, Li-Nong St, Taipei City 112, Taiwan
| | - Ming-Chia Lee
- Department of Life Sciences and Institute of Genome Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Info & Research Bldg, Rm 904, #155, Sec. 2, Li-Nong St, Taipei City 112, Taiwan
| |
Collapse
|
3
|
Ballin M, Griep W, Patel M, Karl M, Mentrup T, Rivera‐Monroy J, Foo B, Schwappach B, Schröder B. The intramembrane proteases
SPPL2a
and
SPPL2b
regulate the homeostasis of selected
SNARE
proteins. FEBS J 2022; 290:2320-2337. [PMID: 36047592 DOI: 10.1111/febs.16610] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 06/28/2022] [Accepted: 08/30/2022] [Indexed: 01/15/2023]
Abstract
Signal peptide peptidase (SPP) and SPP-like (SPPL) aspartyl intramembrane proteases are known to contribute to sequential processing of type II-oriented membrane proteins referred to as regulated intramembrane proteolysis. The ER-resident family members SPP and SPPL2c were shown to also cleave tail-anchored proteins, including selected SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins facilitating membrane fusion events. Here, we analysed whether the related SPPL2a and SPPL2b proteases, which localise to the endocytic or late secretory pathway, are also able to process SNARE proteins. Therefore, we screened 18 SNARE proteins for cleavage by SPPL2a and SPPL2b based on cellular co-expression assays, of which the proteins VAMP1, VAMP2, VAMP3 and VAMP4 were processed by SPPL2a/b demonstrating the capability of these two proteases to proteolyse tail-anchored proteins. Cleavage of the four SNARE proteins was scrutinised at the endogenous level upon SPPL2a/b inhibition in different cell lines as well as by analysing VAMP1-4 levels in tissues and primary cells of SPPL2a/b double-deficient (dKO) mice. Loss of SPPL2a/b activity resulted in an accumulation of VAMP1-4 in a cell type- and tissue-dependent manner, identifying these proteins as SPPL2a/b substrates validated in vivo. Therefore, we propose that SPPL2a/b control cellular levels of VAMP1-4 by initiating the degradation of these proteins, which might impact cellular trafficking.
Collapse
Affiliation(s)
- Moritz Ballin
- Biochemical Institute Christian Albrechts University Kiel Kiel Germany
- Institute of Physiological Chemistry Technische Universität Dresden Dresden Germany
| | - Wolfram Griep
- Biochemical Institute Christian Albrechts University Kiel Kiel Germany
- Institute of Physiological Chemistry Technische Universität Dresden Dresden Germany
| | - Mehul Patel
- Institute of Physiological Chemistry Technische Universität Dresden Dresden Germany
| | - Martin Karl
- Institute of Physiological Chemistry Technische Universität Dresden Dresden Germany
| | - Torben Mentrup
- Institute of Physiological Chemistry Technische Universität Dresden Dresden Germany
| | - Jhon Rivera‐Monroy
- Department of Molecular Biology University Medical Center Göttingen Göttingen Germany
| | - Brian Foo
- Department of Molecular Biology University Medical Center Göttingen Göttingen Germany
| | - Blanche Schwappach
- Department of Molecular Biology University Medical Center Göttingen Göttingen Germany
| | - Bernd Schröder
- Institute of Physiological Chemistry Technische Universität Dresden Dresden Germany
| |
Collapse
|
4
|
Keeping Synapses in Shape: Degradation Pathways in the Healthy and Aging Brain. Neuronal Signal 2022; 6:NS20210063. [PMID: 35813265 PMCID: PMC9208270 DOI: 10.1042/ns20210063] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/30/2022] [Accepted: 05/31/2022] [Indexed: 11/17/2022] Open
Abstract
Synapses maintain their molecular composition, plasticity and function through the concerted action of protein synthesis and removal. The complex and polarized neuronal architecture poses specific challenges to the logistics of protein and organelle turnover since protein synthesis and degradation mainly happen in the cell soma. In addition, post-mitotic neurons accumulate damage over a lifetime, challenging neuronal degradative pathways and making them particularly susceptible to the effects of aging. This review will summarize the current knowledge on neuronal protein turnover mechanisms with a particular focus on the presynapse, including the proteasome, autophagy and the endolysosomal route and their roles in regulating presynaptic proteostasis and function. In addition, the author will discuss how physiological brain aging, which entails a progressive decline in cognitive functions, affects synapses and the degradative machinery.
Collapse
|
5
|
Hasegawa Y, Huarancca Reyes T, Uemura T, Baral A, Fujimaki A, Luo Y, Morita Y, Saeki Y, Maekawa S, Yasuda S, Mukuta K, Fukao Y, Tanaka K, Nakano A, Takagi J, Bhalerao RP, Yamaguchi J, Sato T. The TGN/EE SNARE protein SYP61 and the ubiquitin ligase ATL31 cooperatively regulate plant responses to carbon/nitrogen conditions in Arabidopsis. THE PLANT CELL 2022; 34:1354-1374. [PMID: 35089338 PMCID: PMC8972251 DOI: 10.1093/plcell/koac014] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 12/30/2021] [Indexed: 05/23/2023]
Abstract
Ubiquitination is a post-translational modification involving the reversible attachment of the small protein ubiquitin to a target protein. Ubiquitination is involved in numerous cellular processes, including the membrane trafficking of cargo proteins. However, the ubiquitination of the trafficking machinery components and their involvement in environmental responses are not well understood. Here, we report that the Arabidopsis thaliana trans-Golgi network/early endosome localized SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) protein SYP61 interacts with the transmembrane ubiquitin ligase ATL31, a key regulator of resistance to disrupted carbon (C)/nitrogen/(N)-nutrient conditions. SYP61 is a key component of membrane trafficking in Arabidopsis. The subcellular localization of ATL31 was disrupted in knockdown mutants of SYP61, and the insensitivity of ATL31-overexpressing plants to high C/low N-stress was repressed in these mutants, suggesting that SYP61 and ATL31 cooperatively function in plant responses to nutrient stress. SYP61 is ubiquitinated in plants, and its ubiquitination level is upregulated under low C/high N-nutrient conditions. These findings provide important insights into the ubiquitin signaling and membrane trafficking machinery in plants.
Collapse
Affiliation(s)
- Yoko Hasegawa
- Faculty of Science and Graduate School of Life Science, Hokkaido University, Kita-ku N10-W8, Sapporo 060-0810, Japan
| | - Thais Huarancca Reyes
- Faculty of Science and Graduate School of Life Science, Hokkaido University, Kita-ku N10-W8, Sapporo 060-0810, Japan
| | - Tomohiro Uemura
- Graduate School of Humanities and Sciences, Ochanomizu University, Bunkyo-ku, Tokyo 112-8610, Japan
| | - Anirban Baral
- Umeå Plant Science Centre, Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå S-901 83, Sweden
| | - Akari Fujimaki
- Faculty of Science and Graduate School of Life Science, Hokkaido University, Kita-ku N10-W8, Sapporo 060-0810, Japan
| | - Yongming Luo
- Faculty of Science and Graduate School of Life Science, Hokkaido University, Kita-ku N10-W8, Sapporo 060-0810, Japan
| | - Yoshie Morita
- Faculty of Science and Graduate School of Life Science, Hokkaido University, Kita-ku N10-W8, Sapporo 060-0810, Japan
| | - Yasushi Saeki
- Laboratory of Protein Metabolism, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo 156-8506, Japan
| | - Shugo Maekawa
- Faculty of Science and Graduate School of Life Science, Hokkaido University, Kita-ku N10-W8, Sapporo 060-0810, Japan
| | - Shigetaka Yasuda
- Faculty of Science and Graduate School of Life Science, Hokkaido University, Kita-ku N10-W8, Sapporo 060-0810, Japan
| | - Koki Mukuta
- Faculty of Science and Graduate School of Life Science, Hokkaido University, Kita-ku N10-W8, Sapporo 060-0810, Japan
| | - Yoichiro Fukao
- Department of Bioinformatics, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Keiji Tanaka
- Laboratory of Protein Metabolism, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo 156-8506, Japan
| | - Akihiko Nakano
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Wako, Saitama 351-0198, Japan
| | - Junpei Takagi
- Faculty of Science and Graduate School of Life Science, Hokkaido University, Kita-ku N10-W8, Sapporo 060-0810, Japan
| | - Rishikesh P Bhalerao
- Umeå Plant Science Centre, Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå S-901 83, Sweden
| | - Junji Yamaguchi
- Faculty of Science and Graduate School of Life Science, Hokkaido University, Kita-ku N10-W8, Sapporo 060-0810, Japan
| | - Takeo Sato
- Faculty of Science and Graduate School of Life Science, Hokkaido University, Kita-ku N10-W8, Sapporo 060-0810, Japan
| |
Collapse
|
6
|
Ike Y, Tomioka M, Iino Y. Involvement of HECT-type E3 ubiquitin ligase genes in salt chemotaxis learning in Caenorhabditis elegans. Genetics 2022; 220:6530289. [PMID: 35176147 PMCID: PMC8982016 DOI: 10.1093/genetics/iyac025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 01/27/2022] [Indexed: 11/14/2022] Open
Abstract
The ubiquitin-proteasome system is associated with various phenomena including learning and memory. In this study, we report that E3 ubiquitin ligase homologs and proteasome function are involved in taste avoidance learning, a type of associative learning between starvation and salt concentrations, in Caenorhabditis elegans. Pharmacological inhibition of proteasome function using bortezomib causes severe defects in taste avoidance learning. Among 9 HECT-type ubiquitin ligase genes, loss-of-function mutations of 6 ubiquitin ligase genes cause significant abnormalities in taste avoidance learning. Double mutations of those genes cause lethality or enhanced defects in taste avoidance learning, suggesting that the HECT-type ubiquitin ligases act in multiple pathways in the processes of learning. Furthermore, mutations of the ubiquitin ligase genes cause additive effects on taste avoidance learning defects of the insulin-like signaling mutants. Our findings unveil the consequences of aberrant functions of the proteasome and ubiquitin systems in learning behavior of Caenorhabditis elegans.
Collapse
Affiliation(s)
- Yasuaki Ike
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0032, Japan
| | - Masahiro Tomioka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0032, Japan,Corresponding author: Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Faculty of Science Building#3, Room 224, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan. ; Corresponding author: Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Faculty of Science Building#3, Room 224, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
| | - Yuichi Iino
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0032, Japan,Corresponding author: Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Faculty of Science Building#3, Room 224, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan. ; Corresponding author: Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Faculty of Science Building#3, Room 224, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
| |
Collapse
|
7
|
Robbins M, Clayton E, Kaminski Schierle GS. Synaptic tau: A pathological or physiological phenomenon? Acta Neuropathol Commun 2021; 9:149. [PMID: 34503576 PMCID: PMC8428049 DOI: 10.1186/s40478-021-01246-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 08/12/2021] [Indexed: 12/17/2022] Open
Abstract
In this review, we discuss the synaptic aspects of Tau pathology occurring during Alzheimer's disease (AD) and how this may relate to memory impairment, a major hallmark of AD. Whilst the clinical diagnosis of AD patients is a loss of working memory and long-term declarative memory, the histological diagnosis is the presence of neurofibrillary tangles of hyperphosphorylated Tau and Amyloid-beta plaques. Tau pathology spreads through synaptically connected neurons to impair synaptic function preceding the formation of neurofibrillary tangles, synaptic loss, axonal retraction and cell death. Alongside synaptic pathology, recent data suggest that Tau has physiological roles in the pre- or post- synaptic compartments. Thus, we have seen a shift in the research focus from Tau as a microtubule-stabilising protein in axons, to Tau as a synaptic protein with roles in accelerating spine formation, dendritic elongation, and in synaptic plasticity coordinating memory pathways. We collate here the myriad of emerging interactions and physiological roles of synaptic Tau, and discuss the current evidence that synaptic Tau contributes to pathology in AD.
Collapse
|
8
|
Massively parallel in vivo CRISPR screening identifies RNF20/40 as epigenetic regulators of cardiomyocyte maturation. Nat Commun 2021; 12:4442. [PMID: 34290256 PMCID: PMC8295283 DOI: 10.1038/s41467-021-24743-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 07/02/2021] [Indexed: 02/06/2023] Open
Abstract
The forward genetic screen is a powerful, unbiased method to gain insights into biological processes, yet this approach has infrequently been used in vivo in mammals because of high resource demands. Here, we use in vivo somatic Cas9 mutagenesis to perform an in vivo forward genetic screen in mice to identify regulators of cardiomyocyte (CM) maturation, the coordinated changes in phenotype and gene expression that occur in neonatal CMs. We discover and validate a number of transcriptional regulators of this process. Among these are RNF20 and RNF40, which form a complex that monoubiquitinates H2B on lysine 120. Mechanistic studies indicate that this epigenetic mark controls dynamic changes in gene expression required for CM maturation. These insights into CM maturation will inform efforts in cardiac regenerative medicine. More broadly, our approach will enable unbiased forward genetics across mammalian organ systems.
Collapse
|
9
|
Pinto MJ, Tomé D, Almeida RD. The Ubiquitinated Axon: Local Control of Axon Development and Function by Ubiquitin. J Neurosci 2021; 41:2796-2813. [PMID: 33789876 PMCID: PMC8018891 DOI: 10.1523/jneurosci.2251-20.2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 01/15/2021] [Accepted: 01/22/2021] [Indexed: 02/01/2023] Open
Abstract
Ubiquitin tagging sets protein fate. With a wide range of possible patterns and reversibility, ubiquitination can assume many shapes to meet specific demands of a particular cell across time and space. In neurons, unique cells with functionally distinct axons and dendrites harboring dynamic synapses, the ubiquitin code is exploited at the height of its power. Indeed, wide expression of ubiquitination and proteasome machinery at synapses, a diverse brain ubiquitome, and the existence of ubiquitin-related neurodevelopmental diseases support a fundamental role of ubiquitin signaling in the developing and mature brain. While special attention has been given to dendritic ubiquitin-dependent control, how axonal biology is governed by this small but versatile molecule has been considerably less discussed. Herein, we set out to explore the ubiquitin-mediated spatiotemporal control of an axon's lifetime: from its differentiation and growth through presynaptic formation, function, and pruning.
Collapse
Affiliation(s)
- Maria J Pinto
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, 3004-504, Portugal
| | - Diogo Tomé
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, 3004-504, Portugal
- Institute of Biomedicine, Department of Medical Sciences, University of Aveiro, Aveiro, 3810-193, Portugal
| | - Ramiro D Almeida
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, 3004-504, Portugal
- Institute of Biomedicine, Department of Medical Sciences, University of Aveiro, Aveiro, 3810-193, Portugal
| |
Collapse
|
10
|
Marsh DJ, Ma Y, Dickson KA. Histone Monoubiquitination in Chromatin Remodelling: Focus on the Histone H2B Interactome and Cancer. Cancers (Basel) 2020; 12:E3462. [PMID: 33233707 PMCID: PMC7699835 DOI: 10.3390/cancers12113462] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 11/13/2020] [Accepted: 11/17/2020] [Indexed: 12/21/2022] Open
Abstract
Chromatin remodelling is a major mechanism by which cells control fundamental processes including gene expression, the DNA damage response (DDR) and ensuring the genomic plasticity required by stem cells to enable differentiation. The post-translational modification of histone H2B resulting in addition of a single ubiquitin, in humans at lysine 120 (K120; H2Bub1) and in yeast at K123, has key roles in transcriptional elongation associated with the RNA polymerase II-associated factor 1 complex (PAF1C) and in the DDR. H2Bub1 itself has been described as having tumour suppressive roles and a number of cancer-related proteins and/or complexes are recognised as part of the H2Bub1 interactome. These include the RING finger E3 ubiquitin ligases RNF20, RNF40 and BRCA1, the guardian of the genome p53, the PAF1C member CDC73, subunits of the switch/sucrose non-fermenting (SWI/SNF) chromatin remodelling complex and histone methyltransferase complexes DOT1L and COMPASS, as well as multiple deubiquitinases including USP22 and USP44. While globally depleted in many primary human malignancies, including breast, lung and colorectal cancer, H2Bub1 is selectively enriched at the coding region of certain highly expressed genes, including at p53 target genes in response to DNA damage, functioning to exercise transcriptional control of these loci. This review draws together extensive literature to cement a significant role for H2Bub1 in a range of human malignancies and discusses the interplay between key cancer-related proteins and H2Bub1-associated chromatin remodelling.
Collapse
Affiliation(s)
- Deborah J. Marsh
- Translational Oncology Group, Faculty of Science, School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia; (Y.M.); (K.-A.D.)
- Kolling Institute, Faculty of Medicine and Health, Northern Clinical School, University of Sydney, Camperdown, NSW 2006, Australia
| | - Yue Ma
- Translational Oncology Group, Faculty of Science, School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia; (Y.M.); (K.-A.D.)
| | - Kristie-Ann Dickson
- Translational Oncology Group, Faculty of Science, School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia; (Y.M.); (K.-A.D.)
| |
Collapse
|
11
|
Epigenetic modification and a role for the E3 ligase RNF40 in cancer development and metastasis. Oncogene 2020; 40:465-474. [PMID: 33199825 PMCID: PMC7819849 DOI: 10.1038/s41388-020-01556-w] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 10/15/2020] [Accepted: 11/02/2020] [Indexed: 12/19/2022]
Abstract
RNF40 (OMIM: 607700) is a really interesting new gene (RING) finger E3 ubiquitin ligase containing multiple coiled-coil domains and a C-terminal RING finger motif, which engage in protein–DNA and protein–protein interactions. RNF40 encodes a polypeptide of 1001 amino acids with a predicted molecular mass of 113,678 Da. RNF40 and its paralog RNF20 form a stable heterodimer complex that can monoubiquitylate histone H2B at lysine 120 as well as other nonhistone proteins. Cancer is a major public health problem and the second leading cause of death. Through its protein ubiquitylation activity, RNF40 acts as a tumor suppressor or oncogene to play major epigenetic roles in cancer development, progression, and metastasis, highlighting the essential function of RNF40 and the importance of studying it. In this review, we summarize current knowledge about RNF40 gene structure and the role of RNF40 in histone H2B monoubiquitylation, DNA damage repair, apoptosis, cancer development, and metastasis. We also underscore challenges in applying this information to cancer prognosis and prevention and highlight the urgent need for additional investigations of RNF40 as a potential target for cancer therapeutics.
Collapse
|
12
|
Folci A, Mirabella F, Fossati M. Ubiquitin and Ubiquitin-Like Proteins in the Critical Equilibrium between Synapse Physiology and Intellectual Disability. eNeuro 2020; 7:ENEURO.0137-20.2020. [PMID: 32719102 PMCID: PMC7544190 DOI: 10.1523/eneuro.0137-20.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 06/08/2020] [Accepted: 06/17/2020] [Indexed: 01/04/2023] Open
Abstract
Posttranslational modifications (PTMs) represent a dynamic regulatory system that precisely modulates the functional organization of synapses. PTMs consist in target modifications by small chemical moieties or conjugation of lipids, sugars or polypeptides. Among them, ubiquitin and a large family of ubiquitin-like proteins (UBLs) share several features such as the structure of the small protein modifiers, the enzymatic cascades mediating the conjugation process, and the targeted aminoacidic residue. In the brain, ubiquitination and two UBLs, namely sumoylation and the recently discovered neddylation orchestrate fundamental processes including synapse formation, maturation and plasticity, and their alteration is thought to contribute to the development of neurological disorders. Remarkably, emerging evidence suggests that these pathways tightly interplay to modulate the function of several proteins that possess pivotal roles for brain homeostasis as well as failure of this crosstalk seems to be implicated in the development of brain pathologies. In this review, we outline the role of ubiquitination, sumoylation, neddylation, and their functional interplay in synapse physiology and discuss their implication in the molecular pathogenesis of intellectual disability (ID), a neurodevelopmental disorder that is frequently comorbid with a wide spectrum of brain pathologies. Finally, we propose a few outlooks that might contribute to better understand the complexity of these regulatory systems in regard to neuronal circuit pathophysiology.
Collapse
Affiliation(s)
- Alessandra Folci
- Humanitas Clinical and Research Center-IRCCS, via Manzoni 56, 20089, Rozzano (MI), Italy
| | - Filippo Mirabella
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20090 Pieve 9 Emanuele - Milan, Italy
| | - Matteo Fossati
- Humanitas Clinical and Research Center-IRCCS, via Manzoni 56, 20089, Rozzano (MI), Italy
- CNR-Institute of Neuroscience, via Manzoni 56, 20089, Rozzano (MI), Italy
| |
Collapse
|
13
|
Kumar D, Ambasta RK, Kumar P. Ubiquitin biology in neurodegenerative disorders: From impairment to therapeutic strategies. Ageing Res Rev 2020; 61:101078. [PMID: 32407951 DOI: 10.1016/j.arr.2020.101078] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 03/24/2020] [Accepted: 04/22/2020] [Indexed: 12/13/2022]
Abstract
The abnormal accumulation of neurotoxic proteins is the typical hallmark of various age-related neurodegenerative disorders (NDDs), including Alzheimer's disease, Parkinson's disease, Huntington's disease, Amyotrophic lateral sclerosis and Multiple sclerosis. The anomalous proteins, such as Aβ, Tau in Alzheimer's disease and α-synuclein in Parkinson's disease, perturb the neuronal physiology and cellular homeostasis in the brain thereby affecting the millions of human lives across the globe. Here, ubiquitin proteasome system (UPS) plays a decisive role in clearing the toxic metabolites in cells, where any aberrancy is widely reported to exaggerate the neurodegenerative pathologies. In spite of well-advancement in the ubiquitination research, their molecular markers and mechanisms for target-specific protein ubiquitination and clearance remained elusive. Therefore, this review substantiates the role of UPS in the brain signaling and neuronal physiology with their mechanistic role in the NDD's specific pathogenic protein clearance. Moreover, current and future promising therapies are discussed to target UPS-mediated neurodegeneration for better public health.
Collapse
|
14
|
The effects of proteasome on baseline and methamphetamine-dependent dopamine transmission. Neurosci Biobehav Rev 2019; 102:308-317. [DOI: 10.1016/j.neubiorev.2019.05.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 04/29/2019] [Accepted: 05/09/2019] [Indexed: 12/16/2022]
|
15
|
Petrov AM, Mast N, Li Y, Pikuleva IA. The key genes, phosphoproteins, processes, and pathways affected by efavirenz-activated CYP46A1 in the amyloid-decreasing paradigm of efavirenz treatment. FASEB J 2019; 33:8782-8798. [PMID: 31063705 DOI: 10.1096/fj.201900092r] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Efavirenz (EFV) is an anti-HIV drug, and cytochrome P450 46A1 (CYP46A1) is the major brain cholesterol hydroxylase. Previously, we discovered that EFV activates CYP46A1 and improves behavioral performance in 5XFAD mice, an Alzheimer's disease model. Herein, the unbiased omics and other approaches were used to study 5XFAD mice in the amyloid-decreasing paradigm of CYP46A1 activation by EFV. These approaches revealed increases in the brain levels of postsynaptic density protein 95, gephyrin, synaptophysin, synapsin, glial fibrillary acidic protein, and CYP46A1 and documented altered expression and phosphorylation of 66 genes and 77 proteins, respectively. The data obtained pointed to EFV effects at the synaptic level, plasmin-depended amyloid clearance, inflammation and microglia phenotype, oxidative stress and cellular hypoxia, autophagy and ubiquitin-proteasome systems as well as apoptosis. These effects could be realized in part via changes in the Ca2+-, small GTPase, and catenin signaling. A model is proposed, in which CYP46A1-dependent lipid raft rearrangement and subsequent decrease of protein phosphorylation are central in EFV effects and explain behavioral improvements in EFV-treated 5XFAD mice.-Petrov, A. M., Mast, N., Li, Y., Pikuleva, I. A. The key genes, phosphoproteins, processes, and pathways affected by efavirenz-activated CYP46A1 in the amyloid-decreasing paradigm of efavirenz treatment.
Collapse
Affiliation(s)
- Alexey M Petrov
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio, USA
| | - Natalia Mast
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio, USA
| | - Yong Li
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio, USA
| | - Irina A Pikuleva
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio, USA
| |
Collapse
|
16
|
Cell Clearing Systems Bridging Neuro-Immunity and Synaptic Plasticity. Int J Mol Sci 2019; 20:ijms20092197. [PMID: 31060234 PMCID: PMC6538995 DOI: 10.3390/ijms20092197] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 04/29/2019] [Accepted: 04/30/2019] [Indexed: 02/06/2023] Open
Abstract
In recent years, functional interconnections emerged between synaptic transmission, inflammatory/immune mediators, and central nervous system (CNS) (patho)-physiology. Such interconnections rose up to a level that involves synaptic plasticity, both concerning its molecular mechanisms and the clinical outcomes related to its behavioral abnormalities. Within this context, synaptic plasticity, apart from being modulated by classic CNS molecules, is strongly affected by the immune system, and vice versa. This is not surprising, given the common molecular pathways that operate at the cross-road between the CNS and immune system. When searching for a common pathway bridging neuro-immune and synaptic dysregulations, the two major cell-clearing cell clearing systems, namely the ubiquitin proteasome system (UPS) and autophagy, take center stage. In fact, just like is happening for the turnover of key proteins involved in neurotransmitter release, antigen processing within both peripheral and CNS-resident antigen presenting cells is carried out by UPS and autophagy. Recent evidence unravelling the functional cross-talk between the cell-clearing pathways challenged the traditional concept of autophagy and UPS as independent systems. In fact, autophagy and UPS are simultaneously affected in a variety of CNS disorders where synaptic and inflammatory/immune alterations concur. In this review, we discuss the role of autophagy and UPS in bridging synaptic plasticity with neuro-immunity, while posing a special emphasis on their interactions, which may be key to defining the role of immunity in synaptic plasticity in health and disease.
Collapse
|
17
|
Marsh DJ, Dickson KA. Writing Histone Monoubiquitination in Human Malignancy-The Role of RING Finger E3 Ubiquitin Ligases. Genes (Basel) 2019; 10:genes10010067. [PMID: 30669413 PMCID: PMC6356280 DOI: 10.3390/genes10010067] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 01/15/2019] [Accepted: 01/15/2019] [Indexed: 01/09/2023] Open
Abstract
There is growing evidence highlighting the importance of monoubiquitination as part of the histone code. Monoubiquitination, the covalent attachment of a single ubiquitin molecule at specific lysines of histone tails, has been associated with transcriptional elongation and the DNA damage response. Sites function as scaffolds or docking platforms for proteins involved in transcription or DNA repair; however, not all sites are equal, with some sites resulting in actively transcribed chromatin and others associated with gene silencing. All events are written by E3 ubiquitin ligases, predominantly of the RING (really interesting new gene) finger type. One of the most well-studied events is monoubiquitination of histone H2B at lysine 120 (H2Bub1), written predominantly by the RING finger complex RNF20-RNF40 and generally associated with active transcription. Monoubiquitination of histone H2A at lysine 119 (H2AK119ub1) is also well-studied, its E3 ubiquitin ligase constituting part of the Polycomb Repressor Complex 1 (PRC1), RING1B-BMI1, associated with transcriptional silencing. Both modifications are activated as part of the DNA damage response. Histone monoubiquitination is a key epigenomic event shaping the chromatin landscape of malignancy and influencing how cells respond to DNA damage. This review discusses a number of these sites and the E3 RING finger ubiquitin ligases that write them.
Collapse
Affiliation(s)
- Deborah J Marsh
- University of Technology Sydney, Translational Oncology Group, School of Life Sciences, Faculty of Science, Ultimo, NSW 2007, Australia.
| | - Kristie-Ann Dickson
- University of Technology Sydney, Translational Oncology Group, School of Life Sciences, Faculty of Science, Ultimo, NSW 2007, Australia.
| |
Collapse
|
18
|
Minaidou A, Nicolaou P, Christodoulou K. LRSAM1 Depletion Affects Neuroblastoma SH-SY5Y Cell Growth and Morphology: The LRSAM1 c.2047-1G>A Loss-of-Function Variant Fails to Rescue The Phenotype. CELL JOURNAL 2018; 20:340-347. [PMID: 29845787 PMCID: PMC6004992 DOI: 10.22074/cellj.2018.5352] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 10/25/2017] [Indexed: 12/13/2022]
Abstract
Objective Deleterious variants in LRSAM1, a RING finger ubiquitin ligase which is also known as TSG101-associated ligase
(TAL), have recently been associated with Charcot-Marie-Tooth disease type 2P (CMT2P). The mechanism by which mutant
LRSAM1 contributes to the development of neuropathy is currently unclear. The aim of this study was to induce LRSAM1
deficiency in a neuronal cell model, observe its effect on cell growth and morphology and attempt to rescue the phenotype with
ancestral and mutant LRSAM1 transfections.
Materials and Methods In this experimental study, we investigated the effect of LRSAM1 downregulation on
neuroblastoma SH-SY5Y cells by siRNA technology where cells were transfected with siRNA against LRSAM1.
The effects on the expression levels of TSG101, the only currently known LRSAM1 interacting molecule, were also
examined. An equal dosage of ancestral or mutant LRSAM1 construct was transfected in LRSAM1-downregulated cells
to investigate its effect on the phenotype of the cells and whether cell proliferation and morphology could be rescued.
Results A significant reduction in TSG101 levels was observed with the downregulation of LRSAM1. In addition,
LRSAM1 knockdown significantly decreased the growth rate of SH-SY5Y cells which is caused by a decrease in cell
proliferation. An effect on cell morphology was also observed. Furthermore, we overexpressed the ancestral and the
c.2047-1G>A mutant LRSAM1 in knocked down cells. Ancestral LRSAM1 recovered cell proliferation and partly the
morphology, however, the c.2047-1G>A mutant did not recover cell proliferation and further aggravated the observed
changes in cell morphology.
Conclusion Our findings suggest that depletion of LRSAM1 affects neuroblastoma cells growth and morphology and
that overexpression of the c.2047-1G>A mutant form, unlike the ancestral LRSAM1, fails to rescue the phenotype.
Collapse
Affiliation(s)
- Anna Minaidou
- Department of Neurogenetics, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.,Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Paschalis Nicolaou
- Department of Neurogenetics, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.,Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Kyproula Christodoulou
- Department of Neurogenetics, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.,Cyprus School of Molecular Medicine, Nicosia, Cyprus.Electronic Address:
| |
Collapse
|
19
|
Nakashima K, Takeuchi S, Iwama S, Kiyota A, Yasuda Y, Iwata N, Enomoto A, Arima H, Sugimura Y. Cullin-associated NEDD8-dissociated protein 1, a novel interactor of rabphilin-3A, deubiquitylates rabphilin-3A and regulates arginine vasopressin secretion in PC12 cells. Endocr J 2018; 65:325-334. [PMID: 29367474 DOI: 10.1507/endocrj.ej17-0399] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The molecular mechanism involved in the exocytosis of arginine vasopressin (AVP) is not fully known. Rabphilin-3A has been suggested as a novel autoantigen in infundibulo-neurohypophysitis (LINH), which leads to central diabetes insipidus through insufficient secretion of AVP. However, the role of rabphilin-3A in the pathogenesis of LINH remains unclear. Thus, the aim of the present study was to identify proteins binding rabphilin-3A in the posterior pituitary. Using glutathione S-transferase (GST)-pulldown assays and proteomic analyses, cullin-associated NEDD8-dissociated protein 1 (CAND1) was identified as a rabphilin-3A-binding protein in the posterior pituitary. Co-immunoprecipitation assays indicated that CAND1 interacted endogenously with rabphilin-3A. In addition, immunohistochemistry experiments showed that CAND1 immunoreactivity was detected mainly in the posterior pituitary, intermediate lobe, and the supraoptic nucleus in the hypothalamus, and less in the anterior lobe, partially co-localizing with rabphilin-3A. Overexpression of CAND1 resulted in deubiquitylation of rabphilin-3A in PC12 cells. Moreover, overexpression of CAND1 in PC12 cells co-transfected with AVP enhanced both basal and KCl-stimulated AVP secretion. The findings indicate that CAND1 inhibits the ubiquitylation of rabphilin-3A and positively regulates AVP secretion. These data shed light on a novel potential mechanism involving rabphilin-3A in AVP secretion, and suggest a new role of CAND1 as a regulator of hormone or neurotransmitter secretion.
Collapse
Affiliation(s)
- Kohtaro Nakashima
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
| | - Seiji Takeuchi
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
| | - Shintaro Iwama
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
| | - Atsushi Kiyota
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
| | - Yoshinori Yasuda
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
| | - Naoko Iwata
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
| | - Atsushi Enomoto
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
| | - Hiroshi Arima
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
| | - Yoshihisa Sugimura
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Fujita Health University, Toyoake, Aichi 470-1192 Japan
| |
Collapse
|
20
|
Giovannone AJ, Reales E, Bhattaram P, Fraile-Ramos A, Weimbs T. Monoubiquitination of syntaxin 3 leads to retrieval from the basolateral plasma membrane and facilitates cargo recruitment to exosomes. Mol Biol Cell 2017; 28:2843-2853. [PMID: 28814500 PMCID: PMC5638587 DOI: 10.1091/mbc.e17-07-0461] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 08/09/2017] [Accepted: 08/11/2017] [Indexed: 01/02/2023] Open
Abstract
Monoubiquitination of Stx3 leads to efficient endocytosis from the basolateral plasma membrane and trafficking into the multivesicular body/exosomal pathway. Stx3 plays a role in cargo recruitment into exosomes. This pathway is exploited by HCMV for virion excretion. Syntaxin 3 (Stx3), a SNARE protein located and functioning at the apical plasma membrane of epithelial cells, is required for epithelial polarity. A fraction of Stx3 is localized to late endosomes/lysosomes, although how it traffics there and its function in these organelles is unknown. Here we report that Stx3 undergoes monoubiquitination in a conserved polybasic domain. Stx3 present at the basolateral—but not the apical—plasma membrane is rapidly endocytosed, targeted to endosomes, internalized into intraluminal vesicles (ILVs), and excreted in exosomes. A nonubiquitinatable mutant of Stx3 (Stx3-5R) fails to enter this pathway and leads to the inability of the apical exosomal cargo protein GPRC5B to enter the ILV/exosomal pathway. This suggests that ubiquitination of Stx3 leads to removal from the basolateral membrane to achieve apical polarity, that Stx3 plays a role in the recruitment of cargo to exosomes, and that the Stx3-5R mutant acts as a dominant-negative inhibitor. Human cytomegalovirus (HCMV) acquires its membrane in an intracellular compartment and we show that Stx3-5R strongly reduces the number of excreted infectious viral particles. Altogether these results suggest that Stx3 functions in the transport of specific proteins to apical exosomes and that HCMV exploits this pathway for virion excretion.
Collapse
Affiliation(s)
- Adrian J Giovannone
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106
| | - Elena Reales
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106
| | - Pallavi Bhattaram
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106
| | - Alberto Fraile-Ramos
- Departamento de Biología Celular, Facultad de Medicina, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Thomas Weimbs
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106
| |
Collapse
|
21
|
Abstract
Maintaining synaptic integrity and function depends on the continuous removal and degradation of aged or damaged proteins. Synaptic protein degradation has received considerable attention in the context of synaptic plasticity and growing interest in relation to neurodegenerative and other disorders. Conversely, less attention has been given to constitutive, ongoing synaptic protein degradation and the roles canonical degradation pathways play in these processes. Here we briefly review recent progress on this topic and new experimental approaches which have expedited such progress and highlight several emerging principles. These include the realization that synaptic proteins typically have unusually long lifetimes, as might be expected from the remote locations of most synaptic sites; the possibility that degradation pathways can change with time from synthesis, cellular context, and physiological input; and that degradation pathways, other than ubiquitin-proteasomal-mediated degradation, might play key roles in constitutive protein degradation at synaptic sites. Finally, we point to the importance of careful experimental design and sufficiently sensitive techniques for studying synaptic protein degradation, which bring into account their slow turnover rates and complex life cycles.
Collapse
Affiliation(s)
- Laurie D Cohen
- Technion Faculty of Medicine, Rappaport Institute and Network Biology Research Laboratories, Technion City, Haifa, 32000, Israel
| | - Noam E Ziv
- Technion Faculty of Medicine, Rappaport Institute and Network Biology Research Laboratories, Technion City, Haifa, 32000, Israel
| |
Collapse
|
22
|
Wang YC, Lauwers E, Verstreken P. Presynaptic protein homeostasis and neuronal function. Curr Opin Genet Dev 2017; 44:38-46. [PMID: 28213157 DOI: 10.1016/j.gde.2017.01.015] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 01/30/2017] [Indexed: 01/15/2023]
Abstract
Proteome integrity is maintained by a coordinated network of molecular chaperones, by protein degradation machineries and by their regulators. Numerous human pathologies are considered as diseases of compromised protein homeostasis (proteostasis), including neurodegeneration. These are characterized by the accumulation of neuronal protein aggregates and by synaptic defects followed by loss of connectivity and cell death. While this suggests that synaptic terminals are particularly sensitive to proteostasis imbalance, our understanding of protein turnover mechanisms and regulation at the synapse remains limited. Recent reports show that different proteolytic pathways act at synapses, including several forms of autophagy. The role of chaperones in controlling the balance between synaptic protein refolding and degradation and how this complex network regulates neuronal function also begins to be unraveled.
Collapse
Affiliation(s)
- Yu-Chun Wang
- KU Leuven, Department of Neurosciences, Leuven Institute for Neurodegenerative Disease (LIND), Herestraat 49, bus 602, 3000 Leuven, Belgium; VIB Center for Brain & Disease Research, Herestraat 49, bus 602, 3000 Leuven, Belgium
| | - Elsa Lauwers
- KU Leuven, Department of Neurosciences, Leuven Institute for Neurodegenerative Disease (LIND), Herestraat 49, bus 602, 3000 Leuven, Belgium; VIB Center for Brain & Disease Research, Herestraat 49, bus 602, 3000 Leuven, Belgium.
| | - Patrik Verstreken
- KU Leuven, Department of Neurosciences, Leuven Institute for Neurodegenerative Disease (LIND), Herestraat 49, bus 602, 3000 Leuven, Belgium; VIB Center for Brain & Disease Research, Herestraat 49, bus 602, 3000 Leuven, Belgium.
| |
Collapse
|
23
|
Hakim V, Cohen LD, Zuchman R, Ziv T, Ziv NE. The effects of proteasomal inhibition on synaptic proteostasis. EMBO J 2016; 35:2238-2262. [PMID: 27613546 PMCID: PMC5069550 DOI: 10.15252/embj.201593594] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 08/08/2016] [Indexed: 01/03/2023] Open
Abstract
Synaptic function crucially depends on uninterrupted synthesis and degradation of synaptic proteins. While much has been learned on synaptic protein synthesis, little is known on the routes by which synaptic proteins are degraded. Here we systematically studied how inhibition of the ubiquitin-proteasome system (UPS) affects the degradation rates of thousands of neuronal and synaptic proteins. We identified a group of proteins, including several proteins related to glutamate receptor trafficking, whose degradation rates were significantly slowed by UPS inhibition. Unexpectedly, however, degradation rates of most synaptic proteins were not significantly affected. Interestingly, many of the differential effects of UPS inhibition were readily explained by a quantitative framework that considered known metabolic turnover rates for the same proteins. In contrast to the limited effects on protein degradation, UPS inhibition profoundly and preferentially suppressed the synthesis of a large number of synaptic proteins. Our findings point to the importance of the UPS in the degradation of certain synaptic proteins, yet indicate that under basal conditions most synaptic proteins might be degraded through alternative pathways.
Collapse
Affiliation(s)
- Vicky Hakim
- The Rappaport Faculty of Medicine and Research Institute, Haifa, Israel.,Network Biology Research Laboratories, Technion - Israel Institute of Technology, Haifa, Israel
| | - Laurie D Cohen
- The Rappaport Faculty of Medicine and Research Institute, Haifa, Israel.,Network Biology Research Laboratories, Technion - Israel Institute of Technology, Haifa, Israel
| | - Rina Zuchman
- Smoler Proteomics Center, Faculty of Biology, Technion, Haifa, Israel
| | - Tamar Ziv
- Smoler Proteomics Center, Faculty of Biology, Technion, Haifa, Israel
| | - Noam E Ziv
- The Rappaport Faculty of Medicine and Research Institute, Haifa, Israel .,Network Biology Research Laboratories, Technion - Israel Institute of Technology, Haifa, Israel
| |
Collapse
|
24
|
Hegde AN. Proteolysis, synaptic plasticity and memory. Neurobiol Learn Mem 2016; 138:98-110. [PMID: 27614141 DOI: 10.1016/j.nlm.2016.09.003] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 08/25/2016] [Accepted: 09/05/2016] [Indexed: 12/30/2022]
Abstract
Protein degradation has many critical functions in the nervous system such as refinement of synaptic connections during development and synaptic plasticity and memory in the adult organisms. A major cellular machinery of proteolysis is the ubiquitin-proteasome pathway (UPP). The UPP precisely regulates proteolysis by covalently attaching ubiquitin, a small protein, to substrates through sequential enzymatic reactions and the proteins marked with the ubiquitin tag are degraded by complex containing many subunits called the proteasome. Research over the years has shown a role for the UPP in regulating presynaptic and postsynaptic proteins critical for neurotransmission and synaptic plasticity. Studies have also revealed a role for the UPP in various forms of memory. Mechanistic investigations suggest that the function of the UPP in neurons is not homogenous and is subject to local regulation in different neuronal sub-compartments. In both invertebrate and vertebrate model systems, local roles have been found for enzymes that attach ubiquitin to substrate proteins as well as for enzymes that remove ubiquitin from substrates. The proteasome also has disparate functions in different parts of the neuron. In addition to the UPP, proteolysis by the lysosome and autophagy play a role in synaptic plasticity and memory. This review details the functions of proteolysis in synaptic plasticity and summarizes the findings on the connection between proteolysis and memory mainly focusing on the UPP including its local roles.
Collapse
Affiliation(s)
- Ashok N Hegde
- Department of Biological and Environmental Sciences, Georgia College and State University, Milledgeville, GA 31061, USA.
| |
Collapse
|
25
|
Craig TJ, Anderson D, Evans AJ, Girach F, Henley JM. SUMOylation of Syntaxin1A regulates presynaptic endocytosis. Sci Rep 2015; 5:17669. [PMID: 26635000 PMCID: PMC4669484 DOI: 10.1038/srep17669] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 11/03/2015] [Indexed: 12/27/2022] Open
Abstract
Neurotransmitter release from the presynaptic terminal is under very precise spatial and temporal control. Following neurotransmitter release, synaptic vesicles are recycled by endocytosis and refilled with neurotransmitter. During the exocytosis event leading to release, SNARE proteins provide most of the mechanical force for membrane fusion. Here, we show one of these proteins, Syntaxin1A, is SUMOylated near its C-terminal transmembrane domain in an activity-dependent manner. Preventing SUMOylation of Syntaxin1A reduces its interaction with other SNARE proteins and disrupts the balance of synaptic vesicle endo/exocytosis, resulting in an increase in endocytosis. These results indicate that SUMOylation regulates the emerging role of Syntaxin1A in vesicle endocytosis, which in turn, modulates neurotransmitter release and synaptic function.
Collapse
Affiliation(s)
- Tim J Craig
- School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, U.K
| | - Dina Anderson
- School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, U.K
| | - Ashley J Evans
- School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, U.K
| | - Fatima Girach
- School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, U.K
| | - Jeremy M Henley
- School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, U.K
| |
Collapse
|
26
|
Yung C, Sha D, Li L, Chin LS. Parkin Protects Against Misfolded SOD1 Toxicity by Promoting Its Aggresome Formation and Autophagic Clearance. Mol Neurobiol 2015; 53:6270-6287. [PMID: 26563499 DOI: 10.1007/s12035-015-9537-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 11/08/2015] [Indexed: 12/11/2022]
Abstract
Mutations in Cu/Zn superoxide dismutase (SOD1) cause autosomal dominant amyotrophic lateral sclerosis (ALS), a devastating neurodegenerative disease with no effective treatment. Despite ample evidence indicating involvement of mutation-induced SOD1 protein misfolding and aggregation in ALS pathogenesis, the molecular mechanisms that control cellular management of misfolded, aggregation-prone SOD1 mutant proteins remain unclear. Here, we report that parkin, an E3 ubiquitin-protein ligase which is linked to Parkinson's disease, is a novel regulator of cellular defense against toxicity induced by ALS-associated SOD1 mutant proteins. We find that parkin mediates K63-linked polyubiquitination of SOD1 mutants in cooperation with the UbcH13/Uev1a E2 enzyme and promotes degradation of these misfolded SOD1 proteins by the autophagy-lysosome system. In response to strong proteotoxic stress associated with proteasome impairment, parkin promotes sequestration of misfolded and aggregated SOD1 proteins to form perinuclear aggresomes, regulates positioning of lysosomes around misfolded SOD1 aggresomes, and facilitates aggresome clearance by autophagy. Our findings reveal parkin-mediated cytoprotective mechanisms against misfolded SOD1 toxicity and suggest that enhancing parkin-mediated cytoprotection may provide a novel therapeutic strategy for treating ALS.
Collapse
Affiliation(s)
- Cheryl Yung
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Di Sha
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Lian Li
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Lih-Shen Chin
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, 30322, USA.
| |
Collapse
|
27
|
Upadhyay A, Amanullah A, Chhangani D, Mishra R, Mishra A. Selective multifaceted E3 ubiquitin ligases barricade extreme defense: Potential therapeutic targets for neurodegeneration and ageing. Ageing Res Rev 2015; 24:138-59. [PMID: 26247845 DOI: 10.1016/j.arr.2015.07.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Revised: 06/24/2015] [Accepted: 07/30/2015] [Indexed: 12/24/2022]
Abstract
Efficient and regular performance of Ubiquitin Proteasome System and Autophagy continuously eliminate deleterious accumulation of nonnative protiens. In cellular quality control system, E3 ubiquitin ligases are significant employees for defense mechanism against abnormal toxic proteins. Few findings indicate that lack of functions of E3 ubiquitin ligases can be a causative factor of neurodevelopmental disorders, neurodegeneration, cancer and ageing. However, the detailed molecular pathomechanism implying E3 ubiquitin ligases in cellular functions in multifactorial disease conditions are not well understood. This article systematically represents the unique characteristics, molecular nature, and recent developments in the knowledge of neurobiological functions of few crucial E3 ubiquitin ligases. Here, we review recent literature on the roles of E6-AP, HRD1 and ITCH E3 ubiquitin ligases in the neuro-pathobiological mechanisms, with precise focus on the processes of neurodegeneration, and thereby propose new lines of potential targets for therapeutic interventions.
Collapse
|
28
|
Bachiller S, Rybkina T, Porras-García E, Pérez-Villegas E, Tabares L, Armengol JA, Carrión AM, Ruiz R. The HERC1 E3 Ubiquitin Ligase is essential for normal development and for neurotransmission at the mouse neuromuscular junction. Cell Mol Life Sci 2015; 72:2961-71. [PMID: 25746226 PMCID: PMC11113414 DOI: 10.1007/s00018-015-1878-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 02/15/2015] [Accepted: 02/27/2015] [Indexed: 12/14/2022]
Abstract
The ubiquitin-proteasome system (UPS) plays a fundamental role in protein degradation in neurons, and there is strong evidence that it fulfills a key role in synaptic transmission. The aim of the present work was to study the implication of one component of the UPS, the HERC1 E3 Ubiquitin Ligase, in motor function and neuromuscular transmission. The tambaleante (tbl) mutant mouse carries a spontaneous mutation in HERC1 E3 Ubiquitin Ligase, provoking an ataxic phenotype that develops in the second month of life. Our results show that motor performance in mutant mice is altered at postnatal day 30, before the cerebellar neurodegeneration takes place. This defect is associated with by: (a) a reduction of the motor end-plate area, (b) less efficient neuromuscular activity in vivo, and (c) an impaired evoked neurotransmitter release. Together, these data suggest that the HERC1 E3 Ubiquitin Ligase is fundamental for normal muscle function and that it is essential for neurotransmitter release at the mouse neuromuscular junction.
Collapse
Affiliation(s)
- S. Bachiller
- Department of Physiology, Anatomy and Cellular Biology, University of Pablo de Olavide, Carretera de Utrera Km 1, 41013 Seville, Spain
| | - T. Rybkina
- Department of Physiology, Anatomy and Cellular Biology, University of Pablo de Olavide, Carretera de Utrera Km 1, 41013 Seville, Spain
| | - E. Porras-García
- Department of Physiology, Anatomy and Cellular Biology, University of Pablo de Olavide, Carretera de Utrera Km 1, 41013 Seville, Spain
| | - E. Pérez-Villegas
- Department of Physiology, Anatomy and Cellular Biology, University of Pablo de Olavide, Carretera de Utrera Km 1, 41013 Seville, Spain
| | - L. Tabares
- Department of Medical Physiology and Biophysics, University of Seville, Seville, Spain
| | - J. A. Armengol
- Department of Physiology, Anatomy and Cellular Biology, University of Pablo de Olavide, Carretera de Utrera Km 1, 41013 Seville, Spain
- School of Medicine, University of Cartagena de Indias, Cartagena, Colombia
| | - A. M. Carrión
- Department of Physiology, Anatomy and Cellular Biology, University of Pablo de Olavide, Carretera de Utrera Km 1, 41013 Seville, Spain
| | - R. Ruiz
- Department of Physiology, Anatomy and Cellular Biology, University of Pablo de Olavide, Carretera de Utrera Km 1, 41013 Seville, Spain
| |
Collapse
|
29
|
Characterization of the Human Transcription Elongation Factor Rtf1: Evidence for Nonoverlapping Functions of Rtf1 and the Paf1 Complex. Mol Cell Biol 2015. [PMID: 26217014 DOI: 10.1128/mcb.00601-15] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Restores TBP function 1 (Rtf1) is generally considered to be a subunit of the Paf1 complex (PAF1C), a multifunctional protein complex involved in histone modification and transcriptional or posttranscriptional regulation. Rtf1, however, is not stably associated with the PAF1C in most species except Saccharomyces cerevisiae, and its biochemical functions are not well understood. Here, we show that human Rtf1 is a transcription elongation factor that may function independently of the PAF1C. Rtf1 requires "Rtf1 coactivator" activity, which is most likely unrelated to the PAF1C or DSIF, for transcriptional activation in vitro. A mutational study revealed that the Plus3 domain of human Rtf1 is critical for its coactivator-dependent function. Transcriptome sequencing (RNA-seq) and chromatin immunoprecipitation studies in HeLa cells showed that Rtf1 and the PAF1C play distinct roles in regulating the expression of a subset of genes. Moreover, contrary to the finding in S. cerevisiae, the PAF1C was apparently recruited to the genes examined in an Rtf1-independent manner. The present study establishes a role for human Rtf1 as a transcription elongation factor and highlights the similarities and differences between the S. cerevisiae and human Rtf1 proteins.
Collapse
|
30
|
Gupta P, Leahul L, Wang X, Wang C, Bakos B, Jasper K, Hansen D. Proteasome regulation of the chromodomain protein MRG-1 controls the balance between proliferative fate and differentiation in the C. elegans germ line. Development 2015; 142:291-302. [PMID: 25564623 DOI: 10.1242/dev.115147] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The level of stem cell proliferation must be tightly controlled for proper development and tissue homeostasis. Multiple levels of gene regulation are often employed to regulate stem cell proliferation to ensure that the amount of proliferation is aligned with the needs of the tissue. Here we focus on proteasome-mediated protein degradation as a means of regulating the activities of proteins involved in controlling the stem cell proliferative fate in the C. elegans germ line. We identify five potential E3 ubiquitin ligases, including the RFP-1 RING finger protein, as being involved in regulating proliferative fate. RFP-1 binds to MRG-1, a homologue of the mammalian chromodomain-containing protein MRG15 (MORF4L1), which has been implicated in promoting the proliferation of neural precursor cells. We find that C. elegans with reduced proteasome activity, or that lack RFP-1 expression, have increased levels of MRG-1 and a shift towards increased proliferation in sensitized genetic backgrounds. Likewise, reduction of MRG-1 partially suppresses stem cell overproliferation. MRG-1 levels are controlled independently of the spatially regulated GLP-1/Notch signalling pathway, which is the primary signal controlling the extent of stem cell proliferation in the C. elegans germ line. We propose a model in which MRG-1 levels are controlled, at least in part, by the proteasome, and that the levels of MRG-1 set a threshold upon which other spatially regulated factors act in order to control the balance between the proliferative fate and differentiation in the C. elegans germ line.
Collapse
Affiliation(s)
- Pratyush Gupta
- Department of Biological Sciences, University of Calgary, 2500 University Drive, Calgary, Alberta, Canada T2N 1N4
| | - Lindsay Leahul
- Department of Biological Sciences, University of Calgary, 2500 University Drive, Calgary, Alberta, Canada T2N 1N4
| | - Xin Wang
- Department of Biological Sciences, University of Calgary, 2500 University Drive, Calgary, Alberta, Canada T2N 1N4
| | - Chris Wang
- Department of Biological Sciences, University of Calgary, 2500 University Drive, Calgary, Alberta, Canada T2N 1N4
| | - Brendan Bakos
- Department of Biological Sciences, University of Calgary, 2500 University Drive, Calgary, Alberta, Canada T2N 1N4
| | - Katie Jasper
- Department of Biological Sciences, University of Calgary, 2500 University Drive, Calgary, Alberta, Canada T2N 1N4
| | - Dave Hansen
- Department of Biological Sciences, University of Calgary, 2500 University Drive, Calgary, Alberta, Canada T2N 1N4
| |
Collapse
|
31
|
Suga K, Saito A, Akagawa K. ER stress response in NG108-15 cells involves upregulation of syntaxin 5 expression and reduced amyloid β peptide secretion. Exp Cell Res 2015; 332:11-23. [DOI: 10.1016/j.yexcr.2015.01.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Revised: 01/05/2015] [Accepted: 01/07/2015] [Indexed: 01/24/2023]
|
32
|
Bhatnagar S, Soni MS, Wrighton LS, Hebert AS, Zhou AS, Paul PK, Gregg T, Rabaglia ME, Keller MP, Coon JJ, Attie AD. Phosphorylation and degradation of tomosyn-2 de-represses insulin secretion. J Biol Chem 2014; 289:25276-86. [PMID: 25002582 DOI: 10.1074/jbc.m114.575985] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The abundance and functional activity of proteins involved in the formation of the SNARE complex are tightly regulated for efficient exocytosis. Tomosyn proteins are negative regulators of exocytosis. Tomosyn causes an attenuation of insulin secretion by limiting the formation of the SNARE complex. We hypothesized that glucose-dependent stimulation of insulin secretion from β-cells must involve reversing the inhibitory action of tomosyn. Here, we show that glucose increases tomosyn protein turnover. Within 1 h of exposure to 15 mM glucose, ~50% of tomosyn was degraded. The degradation of tomosyn in response to high glucose was blocked by inhibitors of the proteasomal pathway. Using (32)P labeling and mass spectrometry, we showed that tomosyn-2 is phosphorylated in response to high glucose, phorbol esters, and analogs of cAMP, all key insulin secretagogues. We identified 11 phosphorylation sites in tomosyn-2. Site-directed mutagenesis was used to generate phosphomimetic (Ser → Asp) and loss-of-function (Ser → Ala) mutants. The Ser → Asp mutant had enhanced protein turnover compared with the Ser → Ala mutant and wild type tomosyn-2. Additionally, the Ser → Asp tomosyn-2 mutant was ineffective at inhibiting insulin secretion. Using a proteomic screen for tomosyn-2-binding proteins, we identified Hrd-1, an E3-ubiquitin ligase. We showed that tomosyn-2 ubiquitination is increased by Hrd-1, and knockdown of Hrd-1 by short hairpin RNA resulted in increased abundance in tomosyn-2 protein levels. Taken together, our results reveal a mechanism by which enhanced phosphorylation of a negative regulator of secretion, tomosyn-2, in response to insulin secretagogues targets it to degradation by the Hrd-1 E3-ubiquitin ligase.
Collapse
Affiliation(s)
| | | | | | - Alexander S Hebert
- Chemistry and Biomolecular Chemistry, University of Wisconsin, Madison, Wisconsin 53706
| | | | | | | | | | | | - Joshua J Coon
- Chemistry and Biomolecular Chemistry, University of Wisconsin, Madison, Wisconsin 53706
| | | |
Collapse
|
33
|
Kudryashova IV. Molecular mechanisms of short-term plasticity as a basis of frequency coding: The role of proteolytic systems. NEUROCHEM J+ 2014. [DOI: 10.1134/s1819712414010097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
34
|
Zhang Q, Li Y, Zhang L, Yang N, Meng J, Zuo P, Zhang Y, Chen J, Wang L, Gao X, Zhu D. E3 ubiquitin ligase RNF13 involves spatial learning and assembly of the SNARE complex. Cell Mol Life Sci 2013; 70:153-65. [PMID: 22890573 PMCID: PMC11113611 DOI: 10.1007/s00018-012-1103-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2012] [Revised: 07/01/2012] [Accepted: 07/19/2012] [Indexed: 11/26/2022]
Abstract
Changes in the structure and number of synapses modulate learning, memory and cognitive disorders. Ubiquitin-mediated protein modification is a key mechanism for regulating synaptic activity, though the precise control of this process remains poorly understood. RING finger protein 13 (RNF13) is a recently identified E3 ubiquitin ligase, and its in vivo function remains completely unknown. We show here that genetic deletion of RNF13 in mice leads to a significant deficit in spatial learning as determined by the Morris water maze test and Y-maze learning test. At the ultrastructral level, the synaptic vesicle density was decreased and the area of the active zone was increased at hippocampal synapses of RNF13-null mice compared with those of wild-type littermates. We found no change in the levels of SNARE (soluble N-ethylmaleimide-sensitive factor-attachment protein receptor) complex proteins in the hippocampus of RNF13-null mice, but impaired SNARE complex assembly. RNF13 directly interacted with snapin, a SNAP-25-interacting protein. Interestingly, snapin was ubiquitinated by RNF13 via the lysine-29 conjugated polyubiquitin chain, which in turn promoted the association of snapin with SNAP-25. Consistently, we found an attenuated interaction between snapin and SNAP-25 in the RNF13-null mice. Therefore, these results suggest that RNF13 is involved in the regulation of the SNARE complex, which thereby controls synaptic function.
Collapse
Affiliation(s)
- Qiang Zhang
- Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Tsinghua University, Beijing, 100005 China
| | - Yanfeng Li
- Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Tsinghua University, Beijing, 100005 China
| | - Lei Zhang
- Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Tsinghua University, Beijing, 100005 China
| | - Nan Yang
- Department of Pharmacology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Tsinghua University, Beijing, 100005 China
| | - Jiao Meng
- Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Tsinghua University, Beijing, 100005 China
| | - Pingping Zuo
- Department of Pharmacology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Tsinghua University, Beijing, 100005 China
| | - Yong Zhang
- Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Tsinghua University, Beijing, 100005 China
| | - Jie Chen
- Department of Pathology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tsinghua University, Beijing, 100730 China
| | - Li Wang
- Department of Epidemiology and Biostatistics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Tsinghua University, Beijing, 100005 China
| | - Xiang Gao
- Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Research, Nanjing University, Nanjing, 210061 China
| | - Dahai Zhu
- Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Tsinghua University, Beijing, 100005 China
| |
Collapse
|
35
|
Abstract
ISG15 is a ubiquitin-like modifier that is expressed in response to type 1 interferon signaling (IFN-α/β) and plays a role in antiviral responses. The core E1, E2, and E3 enzymes for ISG15 are Ube1L, UbcH8, and Herc5, respectively, and these are all also induced at the transcriptional level by IFN-α/β. We recently showed that Herc5 associates with polysomes and modifies target proteins in a cotranslational manner. Here, we describe the expression of the core conjugating enzymes in human cells, the detection of ISG15 conjugates, and the methods for fractionation of Herc5 with polysomes.
Collapse
Affiliation(s)
- R. Jürgen Dohmen
- Institut für Genetik, Universität Köln, Zülpicher Str. 47, Köln, 50674 Germany
| | | |
Collapse
|
36
|
Johnsen SA. The enigmatic role of H2Bub1 in cancer. FEBS Lett 2012; 586:1592-601. [PMID: 22564770 DOI: 10.1016/j.febslet.2012.04.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Revised: 04/02/2012] [Accepted: 04/03/2012] [Indexed: 12/19/2022]
Abstract
The post-translational modification of histone proteins plays an important role in controlling cell fate by directing essentially all DNA-associated nuclear processes. Misregulation and mutation of histone modifying enzymes is a hallmark of tumorigenesis. However, how these different epigenetic modifications lead to tumor initiation and/or progression remains poorly understood. Recent studies have uncovered a potential tumor suppressor role for histone H2B monoubiquitination (H2Bub1). Like many other histone modifications, H2Bub1 has diverse functions and plays roles both in transcriptional activation and repression as well as in controlling mRNA processing and directing DNA repair processes. Notably, H2Bub1 has been linked to transcriptional elongation and is preferentially found in the transcribed region of active genes. Its activity is intimately connected to active transcription and the transcriptional elongation regulatory protein cyclin-dependent kinase-9 (CDK9) and the facilitates chromatin transcription (FACT) complex. This review provides an overview of the current understanding of H2Bub1 function in mammalian systems with a particular emphasis on its role in cancer and potential options for exploiting this knowledge for the treatment of cancer.
Collapse
Affiliation(s)
- Steven A Johnsen
- Department of Tumor Biology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246 Hamburg, Germany.
| |
Collapse
|
37
|
The ubiquitin ligase Siah1 controls ELL2 stability and formation of super elongation complexes to modulate gene transcription. Mol Cell 2012; 46:325-34. [PMID: 22483617 DOI: 10.1016/j.molcel.2012.03.007] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Revised: 12/27/2011] [Accepted: 03/08/2012] [Indexed: 01/06/2023]
Abstract
Super elongation complexes (SECs) contain two different transcription elongation factors, P-TEFb and ELL1/2, linked by the scaffolding protein AFF4 or AFF1. They stimulate the expression of both normal and disease-related genes, especially those of HIV or those involved in leukemogenesis. Among all SEC subunits, ELL2 is stoichiometrically limiting and uniquely regulated at the level of protein stability. Here we identify the RING domain protein Siah1, but not the homologous Siah2, as the E3 ubiquitin ligase for ELL2 polyubiquitination and proteasomal degradation. Siah1 cannot access and ubiquitinate ELL2 bound to AFF4, although, at high concentrations, it also degrades AFF4/1 to destroy SECs. Prostratin and HMBA, two well-studied activators of HIV transcription and latency, enhance ELL2 accumulation and SECs formation largely through decreasing Siah1 expression and ELL2 polyubiquitination. Given its importance in formation of SECs, the Siah1 ubiquitination pathway provides a fresh avenue for developing strategies to control disease-related transcription.
Collapse
|
38
|
Chu KY, Li H, Wada K, Johnson JD. Ubiquitin C-terminal hydrolase L1 is required for pancreatic beta cell survival and function in lipotoxic conditions. Diabetologia 2012; 55:128-40. [PMID: 22038515 DOI: 10.1007/s00125-011-2323-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Accepted: 08/30/2011] [Indexed: 02/07/2023]
Abstract
AIMS/HYPOTHESIS Ubiquitin C-terminal hydrolase L1 (UCHL1) is associated with neurodegenerative diseases and has been suggested to have roles in pancreatic beta cells. Our proteomic analysis revealed that UCHL1 was the most increased protein in MIN6 cells exposed to palmitate. The present study used a genetic loss-of-function model to test the hypothesis that UCHL1 is required for normal beta cell function and fate under lipotoxic conditions. METHODS Human islets, mouse islets and MIN6 cells were used to analyse UCHL1 protein levels and regulation of UCHL1 by palmitate. The levels of free mono-ubiquitin and poly-ubiquitinated proteins were assessed. Gracile axonal dystrophy (GAD) mutant mice lacking UCHL1 were fed a normal or lipotoxic high-fat diet. Glucose tolerance, insulin tolerance and insulin secretion were assessed in vivo. Beta cell death and proliferation were assessed by TUNEL and proliferating cell nuclear antigen (PCNA) staining. Insulin secretion, calcium signalling, endoplasmic reticulum (ER) stress, apoptosis and SNARE protein levels were assessed in vitro. RESULTS UCHL1 protein, which was highly specific to beta cells, was increased by palmitate at basal glucose, but not in the context of hyperglycaemia associated with frank diabetes. Although islet development and function were initially normal in Uchl1 (-/-) mice, a 4-week high-fat diet caused glucose intolerance and impaired insulin secretion. Uchl1 (-/-) mice had increased ER stress and beta cell apoptosis. The levels of SNARE proteins were dysregulated in Uchl1 (-/-) islets. Palmitate-stimulated vesicle-associated membrane protein 2 (VAMP2) ubiquitination was modulated by a chemical UCHL1 inhibitor. CONCLUSIONS/INTERPRETATION Together, these data suggest that UCHL1 has essential functional and anti-apoptotic roles in beta cells under stress conditions associated with lipotoxicity.
Collapse
Affiliation(s)
- K Y Chu
- Laboratory of Molecular Signaling in Diabetes, Diabetes Research Group, Department of Cellular and Physiological Sciences, University of British Columbia, 5358 Life Sciences Building, 2350 Health Sciences Mall, Vancouver, BC, Canada V6T 1Z3
| | | | | | | |
Collapse
|
39
|
Lee YJ, Lee JE, Choi HJ, Lim JS, Jung HJ, Baek MC, Frøkiær J, Nielsen S, Kwon TH. E3 ubiquitin-protein ligases in rat kidney collecting duct: response to vasopressin stimulation and withdrawal. Am J Physiol Renal Physiol 2011; 301:F883-96. [PMID: 21734099 DOI: 10.1152/ajprenal.00117.2011] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The E3 ubiquitin (Ub)-protein ligases (E3s) play a role as regulators of protein trafficking and degradation. We aimed to integrate the profile of E3s in rat kidney and examine the changes in protein abundance of the selected E3s in response to 1-deamino-8-D-arginine vasopressin (dDAVP) stimulation/withdrawal. Sprague-Dawley rats were infused with vehicle (n = 13), dDAVP for 5 days (n = 13), or dDAVP was withdrawn for periods (15 min, 30 min, 1, 3, 6, 12, or 24 h) after 5-day infusion (n = 46). Total RNA was isolated from the inner medulla (IM) for transcriptome analysis. Plasma membrane (PM)- or intracellular vesicle (ICV)-enriched fractions of whole kidney were immunoisolated for liquid chromatography-tandem mass spectrometry analysis. dDAVP infusion for 5 days (D5d) significantly increased urine osmolality, which was maintained during 3-h withdrawal of dDAVP after 5-day infusion (D5d-3h). Consistent with this, aquaporin-2 (AQP2) expression in the PM fractions of D5d and D5d-3h increased, whereas AQP2 expression in the ICV fractions of D5d-3h was further increased, indicating internalization of AQP2. Transcriptome analysis revealed 86 genes of E3s and LC-MS/MS analysis demonstrated 16 proteins of E3s. Among these, seven E3s (BRCA1, UBR4, BRE1B, UHRF1, NEDD4, CUL5, and FBX6) were shared. RT-PCR demonstrated mRNA expressions of the seven identified E3s in the kidney, and immunoblotting demonstrated changes in protein abundance of the selected E3s (BRE1B, NEDD4, and CUL5) in response to dDAVP stimulation/withdrawal or lithium-induced nephrogenic diabetes insipidus. The rate of AQP2 degradation was retarded in mpkCCDc14 cells with small interfering RNA-mediated knockdown of NEDD4 or CUL5. Taken together, identified E3s could be involved in the degradation of proteins associated with vasopressin-induced urine concentration.
Collapse
Affiliation(s)
- Yu-Jung Lee
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, Korea
| | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Hogins J, Crawford DC, Jiang X, Mennerick S. Presynaptic silencing is an endogenous neuroprotectant during excitotoxic insults. Neurobiol Dis 2011; 43:516-25. [PMID: 21605675 DOI: 10.1016/j.nbd.2011.05.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 04/26/2011] [Accepted: 05/07/2011] [Indexed: 12/20/2022] Open
Abstract
Glutamate release is a root cause of acute and delayed neuronal damage in response to hypoxic/ischemic insults. Nevertheless, therapeutics that target the postsynaptic compartment have been disappointing clinically. Here we explored whether presynaptic silencing (muting) of glutamatergic terminals is sufficient to reduce excitotoxic damage resulting from hypoxia and oxygen/glucose deprivation. Our evidence suggests that strong depolarization, previously shown to mute glutamate synapses, protects neurons by a presynaptic mechanism that is sensitive to inhibition of the proteasome. Postsynaptic Ca2+ rises in response to glutamate application and toxicity in response to exogenous glutamate treatment were unaffected by depolarization preconditioning. These features strongly suggest that reduced glutamate release explains preconditioning protection. We addressed whether hypoxic depolarization itself induces presynaptic silencing, thereby participating in the damage threshold for hypoxic insult. Indeed, we found that the hypoxic insult increased the percentage of mute glutamate synapses in a proteasome-dependent manner. Furthermore, proteasome inhibition exacerbated neuronal loss to mild hypoxia and prevented hypoxia-induced muting. In total our results suggest that presynaptic silencing is an endogenous neuroprotective mechanism that could be exploited to reduce damage from insults involving excess synaptic glutamate release.
Collapse
Affiliation(s)
- Joshua Hogins
- Dept of Psychiatry, Washington University in St. Louis, 660 S. Euclid Ave., St. Louis, MO 63110, USA
| | | | | | | |
Collapse
|
41
|
Fioravante D, Byrne JH. Protein degradation and memory formation. Brain Res Bull 2011; 85:14-20. [PMID: 21078374 PMCID: PMC3079012 DOI: 10.1016/j.brainresbull.2010.11.002] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2010] [Revised: 10/21/2010] [Accepted: 11/03/2010] [Indexed: 11/16/2022]
Abstract
Long-term memories are created when labile short-term memory traces are converted to more enduring forms. This process, called consolidation, is associated with changes in the synthesis of proteins that alter the biophysical properties of neurons and the strength of their synaptic connections. Recently, it has become clear that the consolidation process requires not only protein synthesis but also degradation. Here, we discuss recent findings on the roles of ubiquitination and protein degradation in synaptic plasticity and learning and memory.
Collapse
Affiliation(s)
| | - John H. Byrne
- Dept. Neurobiology and Anatomy, W.M. Keck Center for the Neurobiology of Learning and Memory, The University of Texas Medical School at Houston, Houston TX 77030
| |
Collapse
|
42
|
Bingol B, Sheng M. Deconstruction for reconstruction: the role of proteolysis in neural plasticity and disease. Neuron 2011; 69:22-32. [PMID: 21220096 DOI: 10.1016/j.neuron.2010.11.006] [Citation(s) in RCA: 225] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2010] [Indexed: 12/17/2022]
Abstract
The brain changes in response to experience and altered environment. This neural plasticity is largely mediated by morphological and functional modification of synapses, a process that depends on both synthesis and degradation of proteins. It is now clear that regulated proteolysis plays a critical role in the remodeling of synapses, learning and memory, and neurodevelopment. Here, we highlight the mechanisms and functions of proteolysis in synaptic plasticity and discuss its alteration in disease states.
Collapse
Affiliation(s)
- Baris Bingol
- Department of Neuroscience, Genentech, Inc., South San Francisco, CA 94080, USA
| | | |
Collapse
|
43
|
Franco M, Seyfried NT, Brand AH, Peng J, Mayor U. A novel strategy to isolate ubiquitin conjugates reveals wide role for ubiquitination during neural development. Mol Cell Proteomics 2010; 10:M110.002188. [PMID: 20861518 PMCID: PMC3098581 DOI: 10.1074/mcp.m110.002188] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Ubiquitination has essential roles in neuronal development and function. Ubiquitin proteomics studies on yeast and HeLa cells have proven very informative, but there still is a gap regarding neuronal tissue-specific ubiquitination. In an organism context, direct evidence for the ubiquitination of neuronal proteins is even scarcer. Here, we report a novel proteomics strategy based on the in vivo biotinylation of ubiquitin to isolate ubiquitin conjugates from the neurons of Drosophila melanogaster embryos. We confidently identified 48 neuronal ubiquitin substrates, none of which was yet known to be ubiquitinated. Earlier proteomics and biochemical studies in non-neuronal cell types had identified orthologs to some of those but not to others. The identification here of novel ubiquitin substrates, those with no known ubiquitinated ortholog, suggests that proteomics studies must be performed on neuronal cells to identify ubiquitination pathways not shared by other cell types. Importantly, several of those newly found neuronal ubiquitin substrates are key players in synaptogenesis. Mass spectrometry results were validated by Western blotting to confirm that those proteins are indeed ubiquitinated in the Drosophila embryonic nervous system and to elucidate whether they are mono- or polyubiquitinated. In addition to the ubiquitin substrates, we also identified the ubiquitin carriers that are active during synaptogenesis. Identifying endogenously ubiquitinated proteins in specific cell types, at specific developmental stages, and within the context of a living organism will allow understanding how the tissue-specific function of those proteins is regulated by the ubiquitin system.
Collapse
Affiliation(s)
- Maribel Franco
- CIC Biogune, Bizkaia Teknologi Parkea, 48160 Derio, Spain
| | | | | | | | | |
Collapse
|
44
|
Abstract
Proteolysis by the ubiquitin-proteasome pathway (UPP) has emerged as a new molecular mechanism that controls wide-ranging functions in the nervous system, including fine-tuning of synaptic connections during development and synaptic plasticity in the adult organism. In the UPP, attachment of a small protein, ubiquitin, tags the substrates for degradation by a multisubunit complex called the proteasome. Linkage of ubiquitin to protein substrates is highly specific and occurs through a series of well-orchestrated enzymatic steps. The UPP regulates neurotransmitter receptors, protein kinases, synaptic proteins, transcription factors, and other molecules critical for synaptic plasticity. Accumulating evidence indicates that the operation of the UPP in neurons is not homogeneous and is subject to tightly managed local regulation in different neuronal subcompartments. Investigations on both invertebrate and vertebrate model systems have revealed local roles for enzymes that attach ubiquitin to substrate proteins, as well as for enzymes that remove ubiquitin from substrates. The proteasome also has been shown to possess disparate functions in different parts of the neuron. Here I give a broad overview of the role of the UPP in synaptic plasticity and highlight the local roles and regulation of the proteolytic pathway in neurons.
Collapse
Affiliation(s)
- Ashok N Hegde
- Department of Neurobiology and Anatomy, Wake Forest University Health Sciences, Winston-Salem, North Carolina 27157, USA
| |
Collapse
|
45
|
Jeon YJ, Yoo HM, Chung CH. ISG15 and immune diseases. Biochim Biophys Acta Mol Basis Dis 2010; 1802:485-96. [PMID: 20153823 PMCID: PMC7127291 DOI: 10.1016/j.bbadis.2010.02.006] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 02/08/2010] [Accepted: 02/09/2010] [Indexed: 12/22/2022]
Abstract
ISG15, the product of interferon (IFN)-stimulated gene 15, is the first identified ubiquitin-like protein, consisting of two ubiquitin-like domains. ISG15 is synthesized as a precursor in certain mammals and, therefore, needs to be processed to expose the C-terminal glycine residue before conjugation to target proteins. A set of three-step cascade enzymes, an E1 enzyme (UBE1L), an E2 enzyme (UbcH8), and one of several E3 ligases (e.g., EFP and HERC5), catalyzes ISG15 conjugation (ISGylation) of a specific protein. These enzymes are unique among the cascade enzymes for ubiquitin and other ubiquitin-like proteins in that all of them are induced by type I IFNs or other stimuli, such as exposure to viruses and lipopolysaccharide. Mass spectrometric analysis has led to the identification of several hundreds of candidate proteins that can be conjugated by ISG15. Some of them are type I IFN-induced proteins, such as PKR and RIG-I, and some are the key regulators that are involved in IFN signaling, such as JAK1 and STAT1, implicating the role of ISG15 and its conjugates in type I IFN-mediated innate immune responses. However, relatively little is known about the functional significance of ISG15 induction due to the lack of information on the consequences of its conjugation to target proteins. Here, we describe the recent progress made in exploring the biological function of ISG15 and its reversible modification of target proteins and thus in their implication in immune diseases.
Collapse
Affiliation(s)
- Young Joo Jeon
- School of Biological Sciences, Seoul National University, Seoul 151-742, Republic of Korea
| | | | | |
Collapse
|
46
|
Abstract
ISG15 is an interferon-induced ubiquitin-like protein (Ubl) that has antiviral properties. The core E1, E2 and E3 enzymes for conjugation of human ISG15 are Ube1L, UbcH8 and Herc5, all of which are induced at the transcriptional level by Type 1 interferon signaling. Several proteomics studies have, together, identified over 300 cellular proteins as ISG15 targets. These targets include a broad range of constitutively expressed proteins and approximately 15 interferon-induced proteins. This chapter provides an overview of the target identification process and the validation of these targets. We also discuss the limited number of examples where the biochemical effect of ISG15 conjugation on target proteins has been characterized.
Collapse
Affiliation(s)
| | - Jon M. Huibregtse
- Corresponding Author: Jon M. Huibregtse—Section of Molecular Genetics and Microbiology, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA.
| |
Collapse
|
47
|
Tada H, Okano HJ, Takagi H, Shibata S, Yao I, Matsumoto M, Saiga T, Nakayama KI, Kashima H, Takahashi T, Setou M, Okano H. Fbxo45, a novel ubiquitin ligase, regulates synaptic activity. J Biol Chem 2009; 285:3840-3849. [PMID: 19996097 DOI: 10.1074/jbc.m109.046284] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neurons communicate with each other through synapses. To establish the precise yet flexible connections that make up neural networks in the brain, continuous synaptic modulation is required. The ubiquitin-proteasome system of protein degradation is one of the critical mechanisms that underlie this process, playing crucial roles in the regulation of synaptic structure and function. We identified a novel ubiquitin ligase, Fbxo45, that functions at synapses. Fbxo45 is evolutionarily conserved and selectively expressed in the nervous system. We demonstrated that the knockdown of Fbxo45 in primary cultured hippocampal neurons resulted in a greater frequency of miniature excitatory postsynaptic currents. We also found that Fbxo45 induces the degradation of a synaptic vesicle-priming factor, Munc13-1. We propose that Fbxo45 plays an important role in the regulation of neurotransmission by modulating Munc13-1 at the synapse.
Collapse
Affiliation(s)
- Hirobumi Tada
- From the Department of Physiology, Keio University School of Medicine, Tokyo 160-8582; the Department of Physiology, Yokohama City University School of Medicine, Kanagawa 236-0004; the Bridgestone Laboratory of Developmental and Regenerative Neurobiology, Keio University School of Medicine, Tokyo 160-8582
| | - Hirotaka James Okano
- From the Department of Physiology, Keio University School of Medicine, Tokyo 160-8582; SORST (Solution Oriented Research for Science and Technology), the Japan Science and Technology Agency, Saitama 332-0012.
| | - Hiroshi Takagi
- the Laboratory for Molecular Gerontology, Mitsubishi Kagaku Institute of Life Sciences Setou Group, Tokyo 194-8511
| | - Shinsuke Shibata
- From the Department of Physiology, Keio University School of Medicine, Tokyo 160-8582
| | - Ikuko Yao
- the Laboratory for Molecular Gerontology, Mitsubishi Kagaku Institute of Life Sciences Setou Group, Tokyo 194-8511
| | - Masaki Matsumoto
- the Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, and; CREST (Core Research for Evolutional Science and Technology), the Japan Science and Technology Agency, Saitama 332-0012
| | - Toru Saiga
- the Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, and; CREST (Core Research for Evolutional Science and Technology), the Japan Science and Technology Agency, Saitama 332-0012
| | - Keiichi I Nakayama
- the Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, and; CREST (Core Research for Evolutional Science and Technology), the Japan Science and Technology Agency, Saitama 332-0012
| | - Haruo Kashima
- the Department of Neuropsychiatry, Keio University School of Medicine, Tokyo 160-8582
| | - Takuya Takahashi
- the Department of Physiology, Yokohama City University School of Medicine, Kanagawa 236-0004
| | - Mitsutoshi Setou
- the Laboratory for Molecular Gerontology, Mitsubishi Kagaku Institute of Life Sciences Setou Group, Tokyo 194-8511; the Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, and; the Department of Molecular Anatomy, Hamamatsu University School of Medicine, Shizuoka 431-3192, Japan.
| | - Hideyuki Okano
- From the Department of Physiology, Keio University School of Medicine, Tokyo 160-8582; the Bridgestone Laboratory of Developmental and Regenerative Neurobiology, Keio University School of Medicine, Tokyo 160-8582; SORST (Solution Oriented Research for Science and Technology), the Japan Science and Technology Agency, Saitama 332-0012.
| |
Collapse
|
48
|
Markson G, Kiel C, Hyde R, Brown S, Charalabous P, Bremm A, Semple J, Woodsmith J, Duley S, Salehi-Ashtiani K, Vidal M, Komander D, Serrano L, Lehner P, Sanderson CM. Analysis of the human E2 ubiquitin conjugating enzyme protein interaction network. Genome Res 2009; 19:1905-11. [PMID: 19549727 PMCID: PMC2765280 DOI: 10.1101/gr.093963.109] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Accepted: 05/27/2009] [Indexed: 11/25/2022]
Abstract
In eukaryotic cells the stability and function of many proteins are regulated by the addition of ubiquitin or ubiquitin-like peptides. This process is dependent upon the sequential action of an E1-activating enzyme, an E2-conjugating enzyme, and an E3 ligase. Different combinations of these proteins confer substrate specificity and the form of protein modification. However, combinatorial preferences within ubiquitination networks remain unclear. In this study, yeast two-hybrid (Y2H) screens were combined with true homology modeling methods to generate a high-density map of human E2/E3-RING interactions. These data include 535 experimentally defined novel E2/E3-RING interactions and >1300 E2/E3-RING pairs with more favorable predicted free-energy values than the canonical UBE2L3-CBL complex. The significance of Y2H predictions was assessed by both mutagenesis and functional assays. Significantly, 74/80 (>92%) of Y2H predicted complexes were disrupted by point mutations that inhibit verified E2/E3-RING interactions, and a approximately 93% correlation was observed between Y2H data and the functional activity of E2/E3-RING complexes in vitro. Analysis of the high-density human E2/E3-RING network reveals complex combinatorial interactions and a strong potential for functional redundancy, especially within E2 families that have undergone evolutionary expansion. Finally, a one-step extended human E2/E3-RING network, containing 2644 proteins and 5087 edges, was assembled to provide a resource for future functional investigations.
Collapse
Affiliation(s)
- Gabriel Markson
- Department of Medicine, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 OXY, United Kingdom
| | - Christina Kiel
- EMBL-CRG Systems Biology Research Unit and ICREA Centre de Regulacio Genomica, UPF, Barcelona 08003, Spain
| | - Russell Hyde
- Department of Physiology, School of Biomedical Sciences, University of Liverpool, Liverpool L69 3BX, United Kingdom
| | - Stephanie Brown
- Department of Medicine, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 OXY, United Kingdom
| | - Panagoula Charalabous
- Department of Physiology, School of Biomedical Sciences, University of Liverpool, Liverpool L69 3BX, United Kingdom
| | - Anja Bremm
- MRC Laboratory of Molecular Biology, Protein and Nucleic Acid Chemistry, Cambridge CB2 OQH, United Kingdom
| | - Jennifer Semple
- EMBL-CRG Systems Biology Research Unit and ICREA Centre de Regulacio Genomica, UPF, Barcelona 08003, Spain
| | - Jonathan Woodsmith
- Department of Physiology, School of Biomedical Sciences, University of Liverpool, Liverpool L69 3BX, United Kingdom
| | - Simon Duley
- Department of Medicine, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 OXY, United Kingdom
| | - Kourosh Salehi-Ashtiani
- Center for Cancer Systems Biology (CCSB) and Department of Cancer Biology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Marc Vidal
- Center for Cancer Systems Biology (CCSB) and Department of Cancer Biology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - David Komander
- MRC Laboratory of Molecular Biology, Protein and Nucleic Acid Chemistry, Cambridge CB2 OQH, United Kingdom
| | - Luis Serrano
- EMBL-CRG Systems Biology Research Unit and ICREA Centre de Regulacio Genomica, UPF, Barcelona 08003, Spain
- EMBL-CRG Systems Biology Research Unit and ICREA, Institució Catalana de Recerca i Estudis Avançats, Barcelona 08003, Spain
| | - Paul Lehner
- Department of Medicine, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 OXY, United Kingdom
| | - Christopher M. Sanderson
- Department of Physiology, School of Biomedical Sciences, University of Liverpool, Liverpool L69 3BX, United Kingdom
| |
Collapse
|
49
|
Giles LM, Li L, Chin LS. Printor, a novel torsinA-interacting protein implicated in dystonia pathogenesis. J Biol Chem 2009; 284:21765-75. [PMID: 19535332 DOI: 10.1074/jbc.m109.004838] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Early onset generalized dystonia (DYT1) is an autosomal dominant neurological disorder caused by deletion of a single glutamate residue (torsinA DeltaE) in the C-terminal region of the AAA(+) (ATPases associated with a variety of cellular activities) protein torsinA. The pathogenic mechanism by which torsinA DeltaE mutation leads to dystonia remains unknown. Here we report the identification and characterization of a 628-amino acid novel protein, printor, that interacts with torsinA. Printor co-distributes with torsinA in multiple brain regions and co-localizes with torsinA in the endoplasmic reticulum. Interestingly, printor selectively binds to the ATP-free form but not to the ATP-bound form of torsinA, supporting a role for printor as a cofactor rather than a substrate of torsinA. The interaction of printor with torsinA is completely abolished by the dystonia-associated torsinA DeltaE mutation. Our findings suggest that printor is a new component of the DYT1 pathogenic pathway and provide a potential molecular target for therapeutic intervention in dystonia.
Collapse
Affiliation(s)
- Lisa M Giles
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | | | | |
Collapse
|
50
|
Interferon-induced ISG15 conjugation inhibits influenza A virus gene expression and replication in human cells. J Virol 2009; 83:5971-7. [PMID: 19357168 DOI: 10.1128/jvi.01667-08] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ubiquitin-like ISG15 protein, as well as its conjugating enzymes, is induced by type I interferons (IFNs). Experiments using ISG15 knockout (ISG15(-/-)) mice established that ISG15 and/or its conjugation inhibits the replication of influenza A virus. However, in contrast to the virus inhibition results for mice, the rates of virus replication in ISG15(+/+) and ISG15(-/-) mouse embryo fibroblasts in tissue culture were similar. Here we focus on human tissue culture cells and on the effect of ISG15 and/or its conjugation on influenza A virus gene expression and replication in such cells. We demonstrate that IFN-induced antiviral activity against influenza A virus in human cells is significantly alleviated by inhibiting ISG15 conjugation using small interfering RNAs directed against ISG15-conjugating enzymes. IFN-induced antiviral activity against influenza A virus protein synthesis was reduced 5- to 20-fold by suppressing ISG15 conjugation. The amounts of the viral proteins that were restored by these siRNA treatments were approximately 40 to 50% of the amounts produced in cells that were not pretreated with IFN. Further, we show that ISG15 conjugation inhibits influenza A virus replication 10- to 20-fold at early times after infection in human cells. These results show that ISG15 conjugation plays a substantial role in the antiviral state induced by IFN in human cells. In contrast, we show that in mouse embryo fibroblasts ISG15 conjugation not only does not affect influenza A virus replication but also does not contribute to the IFN-induced antiviral activity against influenza A virus gene expression.
Collapse
|