1
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Noireterre A, Stutz F. Cdc48/p97 segregase: Spotlight on DNA-protein crosslinks. DNA Repair (Amst) 2024; 139:103691. [PMID: 38744091 DOI: 10.1016/j.dnarep.2024.103691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 04/30/2024] [Accepted: 05/01/2024] [Indexed: 05/16/2024]
Abstract
The ATP-dependent molecular chaperone Cdc48 (in yeast) and its human counterpart p97 (also known as VCP), are essential for a variety of cellular processes, including the removal of DNA-protein crosslinks (DPCs) from the DNA. Growing evidence demonstrates in the last years that Cdc48/p97 is pivotal in targeting ubiquitinated and SUMOylated substrates on chromatin, thereby supporting the DNA damage response. Along with its cofactors, notably Ufd1-Npl4, Cdc48/p97 has emerged as a central player in the unfolding and processing of DPCs. This review introduces the detailed structure, mechanism and cellular functions of Cdc48/p97 with an emphasis on the current knowledge of DNA-protein crosslink repair pathways across several organisms. The review concludes by discussing the potential therapeutic relevance of targeting p97 in DPC repair.
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Affiliation(s)
- Audrey Noireterre
- Department of Molecular and Cellular Biology, University of Geneva, Geneva 4 1211, Switzerland
| | - Françoise Stutz
- Department of Molecular and Cellular Biology, University of Geneva, Geneva 4 1211, Switzerland.
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2
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Thulasidharan A, Garg L, Tendulkar S, Ratnaparkhi GS. Age-dependent dynamics of neuronal VAPB ALS inclusions in the adult brain. Neurobiol Dis 2024; 196:106517. [PMID: 38679111 DOI: 10.1016/j.nbd.2024.106517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 04/01/2024] [Accepted: 04/25/2024] [Indexed: 05/01/2024] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a relentlessly progressive and fatal disease, caused by the degeneration of upper and lower motor neurons within the brain and spinal cord in the ageing human. The dying neurons contain cytoplasmic inclusions linked to the onset and progression of the disease. Here, we use a Drosophila model of ALS8 (VAPP58S) to understand the modulation of these inclusions in the ageing adult brain. The adult VAPP58S fly shows progressive deterioration in motor function till its demise 25 days post-eclosion. The density of VAPP58S-positive brain inclusions is stable for 5-15 days of age. In contrast, adding a single copy of VAPWT to the VAPP58S animal leads to a large decrease in inclusion density with concomitant rescue of motor function and lifespan. ER stress, a contributing factor in disease, shows reduction with ageing for the disease model. Autophagy, rather than the Ubiquitin Proteasome system, is the dominant mechanism for aggregate clearance. We explored the ability of Drosophila Valosin-containing protein (VCP/TER94), the ALS14 locus, which is involved in cellular protein clearance, to regulate age-dependent aggregation. Contrary to expectation, TER94 overexpression increased VAPP58S punctae density, while its knockdown led to enhanced clearance. Expression of a dominant positive allele, TER94R152H, further stabilised VAPP58S puncta, cementing roles for an ALS8-ALS14 axis. Our results are explained by a mechanism where autophagy is modulated by TER94 knockdown. Our study sheds light on the complex regulatory events involved in the neuronal maintenance of ALS8 aggregates, suggesting a context-dependent switch between proteasomal and autophagy-based mechanisms as the larvae develop into an adult. A deeper understanding of the nucleation and clearance of the inclusions, which affect cellular stress and function, is essential for understanding the initiation and progression of ALS.
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Affiliation(s)
- Aparna Thulasidharan
- Department of Biology, Indian Institute of Science Education & Research (IISER), Pune 411008, India
| | - Lovleen Garg
- Department of Biology, Indian Institute of Science Education & Research (IISER), Pune 411008, India
| | - Shweta Tendulkar
- Department of Biology, Indian Institute of Science Education & Research (IISER), Pune 411008, India
| | - Girish S Ratnaparkhi
- Department of Biology, Indian Institute of Science Education & Research (IISER), Pune 411008, India.
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3
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Batra S, Vaquer-Alicea JI, Valdez C, Taylor SP, Manon VA, Vega AR, Kashmer OM, Kolay S, Lemoff A, Cairns NJ, White CL, Diamond MI. VCP regulates early tau seed amplification via specific cofactors. RESEARCH SQUARE 2024:rs.3.rs-4307848. [PMID: 38826306 PMCID: PMC11142303 DOI: 10.21203/rs.3.rs-4307848/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Background Neurodegenerative tauopathies may progress based on seeding by pathological tau assemblies, whereby an aggregate is released from one cell, gains entry to an adjacent or connected cell, and serves as a specific template for its own replication in the cytoplasm. In vitro seeding reactions typically take days, yet seeding into the complex cytoplasmic milieu happens within hours, implicating a machinery with unknown players that controls this process in the acute phase. Methods We used proximity labeling to identify factors that control seed amplification within 5h of seed exposure. We fused split-APEX2 to the C-terminus of tau repeat domain (RD) to reconstitute peroxidase activity 5h after seeded intracellular tau aggregation. Valosin containing protein (VCP/p97) was the top hit. VCP harbors dominant mutations that underlie two neurodegenerative diseases, multisystem proteinopathy and vacuolar tauopathy, but its mechanistic role is unclear. We used immortalized cells and human neurons to study the effects of VCP on tau seeding. We exposed cells to fibrils or brain homogenates in cell culture media and measured effects on uptake and induction of intracellular tau aggregation following various genetic and chemical manipulations of VCP. Results VCP knockdown reduced tau seeding. Chemical inhibitors had opposing effects on aggregation in HEK293T tau biosensor cells and human neurons alike: ML-240 increased seeding efficiency, whereas NMS-873 decreased it. The inhibitors were effective only when administered within 8h of seed exposure, indicating a role for VCP early in seed processing. We screened 30 VCP co-factors in HEK293T biosensor cells by genetic knockout or knockdown. Reduction of ATXN3, NSFL1C, UBE4B, NGLY1, and OTUB1 decreased tau seeding, as did NPLOC4, which also uniquely increased soluble tau levels. By contrast, reduction of FAF2 increased tau seeding. Conclusions Divergent effects on tau seeding of chemical inhibitors and cofactor reduction indicate that VCP regulates this process. This is consistent with a dedicated cytoplasmic processing complex based on VCP that directs seeds acutely towards degradation vs. amplification.
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Affiliation(s)
- Sushobhna Batra
- UT Southwestern: The University of Texas Southwestern Medical Center
| | | | - Clarissa Valdez
- UT Southwestern: The University of Texas Southwestern Medical Center
| | - Skyler P Taylor
- UT Southwestern: The University of Texas Southwestern Medical Center
| | - Victor A Manon
- UT Southwestern: The University of Texas Southwestern Medical Center
| | - Anthony R Vega
- UT Southwestern: The University of Texas Southwestern Medical Center
| | - Omar M Kashmer
- UT Southwestern: The University of Texas Southwestern Medical Center
| | - Sourav Kolay
- UT Southwestern: The University of Texas Southwestern Medical Center
| | - Andrew Lemoff
- UT Southwestern: The University of Texas Southwestern Medical Center
| | - Nigel J Cairns
- University of Exeter Faculty of Health and Life Sciences
| | - Charles L White
- UT Southwestern: The University of Texas Southwestern Medical Center
| | - Marc I Diamond
- UT Southwestern: The University of Texas Southwestern Medical Center
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4
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Yu G, Bai Y, Zhang ZY. Valosin-Containing Protein (VCP)/p97 Oligomerization. Subcell Biochem 2024; 104:485-501. [PMID: 38963497 DOI: 10.1007/978-3-031-58843-3_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
Valosin-containing protein (VCP), also known as p97, is an evolutionarily conserved AAA+ ATPase essential for cellular homeostasis. Cooperating with different sets of cofactors, VCP is involved in multiple cellular processes through either the ubiquitin-proteasome system (UPS) or the autophagy/lysosomal route. Pathogenic mutations frequently found at the interface between the NTD domain and D1 ATPase domain have been shown to cause malfunction of VCP, leading to degenerative disorders including the inclusion body myopathy associated with Paget disease of bone and frontotemporal dementia (IBMPFD), amyotrophic lateral sclerosis (ALS), and cancers. Therefore, VCP has been considered as a potential therapeutic target for neurodegeneration and cancer. Most of previous studies found VCP predominantly exists and functions as a hexamer, which unfolds and extracts ubiquitinated substrates from protein complexes for degradation. However, recent studies have characterized a new VCP dodecameric state and revealed a controlling mechanism of VCP oligomeric states mediated by the D2 domain nucleotide occupancy. Here, we summarize our recent knowledge on VCP oligomerization, regulation, and potential implications of VCP in cellular function and pathogenic progression.
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Affiliation(s)
- Guimei Yu
- School of Pharmaceutical Science, Hengyang Medical School, University of South China, Hengyang, China
| | - Yunpeng Bai
- Borch Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA
| | - Zhong-Yin Zhang
- Borch Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA.
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5
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Braxton JR, Southworth DR. Structural insights of the p97/VCP AAA+ ATPase: How adapter interactions coordinate diverse cellular functionality. J Biol Chem 2023; 299:105182. [PMID: 37611827 PMCID: PMC10641518 DOI: 10.1016/j.jbc.2023.105182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 08/05/2023] [Accepted: 08/14/2023] [Indexed: 08/25/2023] Open
Abstract
p97/valosin-containing protein is an essential eukaryotic AAA+ ATPase with diverse functions including protein homeostasis, membrane remodeling, and chromatin regulation. Dysregulation of p97 function causes severe neurodegenerative disease and is associated with cancer, making this protein a significant therapeutic target. p97 extracts polypeptide substrates from macromolecular assemblies by hydrolysis-driven translocation through its central pore. Growing evidence indicates that this activity is highly coordinated by "adapter" partner proteins, of which more than 30 have been identified and are commonly described to facilitate translocation through substrate recruitment or modification. In so doing, these adapters enable critical p97-dependent functions such as extraction of misfolded proteins from the endoplasmic reticulum or mitochondria, and are likely the reason for the extreme functional diversity of p97 relative to other AAA+ translocases. Here, we review the known functions of adapter proteins and highlight recent structural and biochemical advances that have begun to reveal the diverse molecular bases for adapter-mediated regulation of p97 function. These studies suggest that the range of mechanisms by which p97 activity is controlled is vastly underexplored with significant advances possible for understanding p97 regulation by the most known adapters.
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Affiliation(s)
- Julian R Braxton
- Graduate Program in Chemistry and Chemical Biology, University of California, San Francisco, San Francisco, California, USA; Department of Biochemistry and Biophysics and Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, California, USA
| | - Daniel R Southworth
- Department of Biochemistry and Biophysics and Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, California, USA.
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6
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Tsioras K, Smith KC, Edassery SL, Garjani M, Li Y, Williams C, McKenna ED, Guo W, Wilen AP, Hark TJ, Marklund SL, Ostrow LW, Gilthorpe JD, Ichida JK, Kalb RG, Savas JN, Kiskinis E. Analysis of proteome-wide degradation dynamics in ALS SOD1 iPSC-derived patient neurons reveals disrupted VCP homeostasis. Cell Rep 2023; 42:113160. [PMID: 37776851 PMCID: PMC10785776 DOI: 10.1016/j.celrep.2023.113160] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 07/18/2023] [Accepted: 09/06/2023] [Indexed: 10/02/2023] Open
Abstract
Mutations in SOD1 cause amyotrophic lateral sclerosis (ALS) through gain-of-function effects, yet the mechanisms by which misfolded mutant SOD1 (mutSOD1) protein impairs human motor neurons (MNs) remain unclear. Here, we use induced-pluripotent-stem-cell-derived MNs coupled to metabolic stable isotope labeling and mass spectrometry to investigate proteome-wide degradation dynamics. We find several proteins, including the ALS-causal valosin-containing protein (VCP), which predominantly acts in proteasome degradation and autophagy, that degrade slower in mutSOD1 relative to isogenic control MNs. The interactome of VCP is altered in mutSOD1 MNs in vitro, while VCP selectively accumulates in the affected motor cortex of ALS-SOD1 patients. Overexpression of VCP rescues mutSOD1 toxicity in MNs in vitro and in a C. elegans model in vivo, in part due to its ability to modulate the degradation of insoluble mutSOD1. Our results demonstrate that VCP contributes to mutSOD1-dependent degeneration, link two distinct ALS-causal genes, and highlight selective protein degradation impairment in ALS pathophysiology.
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Affiliation(s)
- Konstantinos Tsioras
- The Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Kevin C Smith
- The Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Seby L Edassery
- The Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Mehraveh Garjani
- The Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Yichen Li
- Department of Stem Cell Biology and Regenerative Medicine, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, Zilkha Neurogenetic Institute, University of Southern California, Keck School of Medicine, Los Angeles, CA 90033, USA
| | - Chloe Williams
- Department of Integrative Medical Biology, Umeå University, 90187 Umeå, Sweden
| | - Elizabeth D McKenna
- The Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Wenxuan Guo
- Department of Stem Cell Biology and Regenerative Medicine, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, Zilkha Neurogenetic Institute, University of Southern California, Keck School of Medicine, Los Angeles, CA 90033, USA
| | - Anika P Wilen
- The Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Timothy J Hark
- The Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Stefan L Marklund
- Department of Medical Biosciences, Clinical Chemistry, Umeå University, 90187 Umeå, Sweden
| | - Lyle W Ostrow
- Department of Neurology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | | | - Justin K Ichida
- Department of Stem Cell Biology and Regenerative Medicine, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, Zilkha Neurogenetic Institute, University of Southern California, Keck School of Medicine, Los Angeles, CA 90033, USA
| | - Robert G Kalb
- The Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Jeffrey N Savas
- The Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Evangelos Kiskinis
- The Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA; Simpson Querrey Institute, Northwestern University, Chicago, IL 60611, USA; Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
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7
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Batra S, Vaquer-Alicea J, Manon VA, Kashmer OM, Lemoff A, Cairns NJ, White CL, Diamond MI. VCP increases or decreases tau seeding using specific cofactors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.30.555637. [PMID: 37693404 PMCID: PMC10491269 DOI: 10.1101/2023.08.30.555637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Background Neurodegenerative tauopathies may progress based on seeding by pathological tau assemblies, whereby an aggregate is released from one cell, gains entry to an adjacent or connected cell, and serves as a specific template for its own replication in the cytoplasm. In vitro seeding reactions typically take days, yet seeding into the complex cytoplasmic milieu can happen within hours. A cellular machinery might regulate this process, but potential players are unknown. Methods We used proximity labeling to identify factors that control seed amplification. We fused split-APEX2 to the C-terminus of tau repeat domain (RD) to reconstitute peroxidase activity upon seeded intracellular tau aggregation. We identified valosin containing protein (VCP/p97) 5h after seeding. Mutations in VCP underlie two neurodegenerative diseases, multisystem proteinopathy and vacuolar tauopathy, but its mechanistic role is unclear. We utilized tau biosensors, a cellular model for tau aggregation, to study the effects of VCP on tau seeding. Results VCP knockdown reduced tau seeding. However, distinct chemical inhibitors of VCP and the proteasome had opposing effects on aggregation, but only when given <8h of seed exposure. ML-240 increased seeding efficiency ~40x, whereas NMS-873 decreased seeding efficiency by 50%, and MG132 increased seeding ~10x. We screened VCP co-factors in HEK293 biosensor cells by genetic knockout or knockdown. Reduction of ATXN3, NSFL1C, UBE4B, NGLY1, and OTUB1 decreased tau seeding, as did NPLOC4, which also uniquely increased soluble tau levels. Reduction of FAF2 and UBXN6 increased tau seeding. Conclusions VCP uses distinct cofactors to determine seed replication efficiency, consistent with a dedicated cytoplasmic processing complex that directs seeds towards dissolution vs. amplification.
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Affiliation(s)
- Sushobhna Batra
- Center for Alzheimer's and Neurodegenerative Diseases, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX
| | - Jaime Vaquer-Alicea
- Center for Alzheimer's and Neurodegenerative Diseases, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX
| | - Victor A Manon
- Center for Alzheimer's and Neurodegenerative Diseases, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX
| | - Omar M Kashmer
- Center for Alzheimer's and Neurodegenerative Diseases, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX
| | - Andrew Lemoff
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX
| | - Nigel J Cairns
- Department of Clinical and Biological Sciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Charles L White
- Department of Pathology, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX
| | - Marc I Diamond
- Center for Alzheimer's and Neurodegenerative Diseases, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX
- Department of Neurology, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX
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8
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Kochenova OV, Mukkavalli S, Raman M, Walter JC. Cooperative assembly of p97 complexes involved in replication termination. Nat Commun 2022; 13:6591. [PMID: 36329031 PMCID: PMC9633789 DOI: 10.1038/s41467-022-34210-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 10/18/2022] [Indexed: 11/06/2022] Open
Abstract
The p97 ATPase extracts polyubiquitylated proteins from diverse cellular structures in preparation for destruction by the proteasome. p97 functions with Ufd1-Npl4 and a variety of UBA-UBX co-factors, but how p97 complexes assemble on ubiquitylated substrates is unclear. To address this, we investigated how p97 disassembles the CMG helicase after it is ubiquitylated during replication termination. We show that p97Ufd1-Npl4 recruitment to CMG requires the UBA-UBX protein Ubxn7, and conversely, stable Ubxn7 binding to CMG requires p97Ufd1-Npl4. This cooperative assembly involves interactions between Ubxn7, p97, Ufd1-Npl4, and ubiquitin. Another p97 co-factor, Faf1, partially compensates for the loss of Ubxn7. Surprisingly, p97Ufd1-Npl4-Ubxn7 and p97Ufd1-Npl4-Faf1 also assemble cooperatively on unanchored ubiquitin chains. We propose that cooperative and substrate-independent recognition of ubiquitin chains allows p97 to recognize an unlimited number of polyubiquitylated proteins while avoiding the formation of partial, inactive complexes.
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Affiliation(s)
- Olga V Kochenova
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute, Boston, MA, 02115, USA
- Howard Hughes Medical Institute, Boston, MA, USA
| | - Sirisha Mukkavalli
- Department of Developmental Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA, 02111, USA
| | - Malavika Raman
- Department of Developmental Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA, 02111, USA
| | - Johannes C Walter
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute, Boston, MA, 02115, USA.
- Howard Hughes Medical Institute, Boston, MA, USA.
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9
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Fujisawa R, Polo Rivera C, Labib KPM. Multiple UBX proteins reduce the ubiquitin threshold of the mammalian p97-UFD1-NPL4 unfoldase. eLife 2022; 11:e76763. [PMID: 35920641 PMCID: PMC9377798 DOI: 10.7554/elife.76763] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 08/02/2022] [Indexed: 11/17/2022] Open
Abstract
The p97/Cdc48 ATPase and its ubiquitin receptors Ufd1-Npl4 are essential to unfold ubiquitylated proteins in many areas of eukaryotic cell biology. In yeast, Cdc48-Ufd1-Npl4 is controlled by a quality control mechanism, whereby substrates must be conjugated to at least five ubiquitins. Here, we show that mammalian p97-UFD1-NPL4 is governed by a complex interplay between additional p97 cofactors and the number of conjugated ubiquitins. Using reconstituted assays for the disassembly of ubiquitylated CMG (Cdc45-MCM-GINS) helicase by human p97-UFD1-NPL4, we show that the unfoldase has a high ubiquitin threshold for substrate unfolding, which can be reduced by the UBX proteins UBXN7, FAF1, or FAF2. Our data indicate that the UBX proteins function by binding to p97-UFD1-NPL4 and stabilising productive interactions between UFD1-NPL4 and K48-linked chains of at least five ubiquitins. Stimulation by UBXN7 is dependent upon known ubiquitin-binding motifs, whereas FAF1 and FAF2 use a previously uncharacterised coiled-coil domain to reduce the ubiquitin threshold of p97-UFD1-NPL4. We show that deleting the Ubnx7 and Faf1 genes impairs CMG disassembly during S-phase and mitosis and sensitises cells to reduced ubiquitin ligase activity. These findings indicate that multiple UBX proteins are important for the efficient unfolding of ubiquitylated proteins by p97-UFD1-NPL4 in mammalian cells.
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Affiliation(s)
- Ryo Fujisawa
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of DundeeDundeeUnited Kingdom
| | - Cristian Polo Rivera
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of DundeeDundeeUnited Kingdom
| | - Karim PM Labib
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of DundeeDundeeUnited Kingdom
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10
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Shibuya K, Ebihara K, Ebihara C, Sawayama N, Isoda M, Yamamuro D, Takahashi M, Nagashima S, Ishibashi S. AAA-ATPase valosin-containing protein binds the transcription factor SREBP1 and promotes its proteolytic activation by rhomboid protease RHBDL4. J Biol Chem 2022; 298:101936. [PMID: 35430252 PMCID: PMC9127370 DOI: 10.1016/j.jbc.2022.101936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 03/29/2022] [Accepted: 04/01/2022] [Indexed: 11/24/2022] Open
Abstract
Valosin-containing protein (VCP) is a member of AAA-ATPase superfamily involved in various cellular functions. To investigate the pathophysiological role of VCP in metabolic disorders, we generated knock-in mice bearing an A232E mutation in VCP, a known human VCP pathogenic variant. When heterozygous mutant mice (A232E/+) were fed a high-fat diet, we observed that fatty liver was ameliorated and the proteolytic processing of the transcription factor sterol regulatory element-binding protein 1 (SREBP1) was impaired. Further co-immunoprecipitation analysis in wildtype mice revealed interactions of VCP with SREBP1 and a rhomboid protease, RHBDL4, in the liver, and these interactions were attenuated in A232E/+ mice. Consistent with these results, we show that knockdown or chemical inhibition of VCP or RHBDL4 in human hepatocytes impaired the proteolytic processing of SREBP1. Finally, we found that knockdown of E3 ligases such as glycoprotein 78 and HMG-CoA reductase degradation protein 1 disrupted the interaction of VCP with SREBP1 and impaired the proteolytic processing of SREBP1. These results suggest that VCP recognizes ubiquitinylated SREBP1 and recruits it to RHBDL4 to promote its proteolytic processing. The present study reveals a novel proteolytic processing pathway of SREBP1 and may lead to development of new therapeutic strategies to treat fatty liver diseases.
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Affiliation(s)
- Koji Shibuya
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University School of Medicine, Shimotsuke, Tochigi, Japan
| | - Ken Ebihara
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University School of Medicine, Shimotsuke, Tochigi, Japan.
| | - Chihiro Ebihara
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University School of Medicine, Shimotsuke, Tochigi, Japan
| | - Nagisa Sawayama
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University School of Medicine, Shimotsuke, Tochigi, Japan
| | - Masayo Isoda
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University School of Medicine, Shimotsuke, Tochigi, Japan
| | - Daisuke Yamamuro
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University School of Medicine, Shimotsuke, Tochigi, Japan
| | - Manabu Takahashi
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University School of Medicine, Shimotsuke, Tochigi, Japan
| | - Shuichi Nagashima
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University School of Medicine, Shimotsuke, Tochigi, Japan
| | - Shun Ishibashi
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University School of Medicine, Shimotsuke, Tochigi, Japan
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11
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Kim BS, Song JA, Jang KH, Jang T, Jung B, Yoo SE, Lee JM, Kim E. Pharmacological Intervention Targeting FAF1 Restores Autophagic Flux for α-Synuclein Degradation in the Brain of a Parkinson's Disease Mouse Model. ACS Chem Neurosci 2022; 13:806-817. [PMID: 35230076 DOI: 10.1021/acschemneuro.1c00828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
α-Synuclein accumulation is implicated in the pathogenesis of neurodegenerative diseases, including Parkinson's disease (PD). Previously, we reported that Fas-associated factor 1 (FAF1), which plays a role in PD pathogenesis, potentiates α-synuclein accumulation through autophagy impairment in dopaminergic neurons. In this study, we show that KM-819, a FAF1-targeting compound, which has completed phase I clinical trials, interferes with α-synuclein accumulation in the mouse brain, as well as in human neuronal cells (SH-SY5Ys). KM-819 suppressed the accumulation of monomeric, oligomeric, and aggregated forms of α-synuclein in neuronal cells. Furthermore, KM-819 restored the turnover rate of α-synuclein in FAF1-overexpressing SH-SY5Y cells, implicating KM-819-mediated reconstitution of the α-synuclein degradative pathway. In addition, KM-819 reconstituted autophagic flux in FAF1-transfected SH-SY5Y cells, also suppressing α-synuclein-induced mitochondrial dysfunction. Moreover, oral administration of KM-819 also interfered with α-synuclein accumulation in the midbrain of mice overexpressing FAF1 via an adeno-associated virus system. Consistently, KM-819 reduced α-synuclein accumulation in both the hippocampus and the midbrain of human A53T α-synuclein transgenic mice. Collectively, these data imply that KM-819 may have therapeutic potential for patients with PD.
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Affiliation(s)
- Bok-Seok Kim
- Department of Biological Sciences, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Korea
| | - Jin-A Song
- Department of Biological Sciences, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Korea
| | - Ki-Hong Jang
- Department of Biological Sciences, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Korea
| | - Taeik Jang
- Department of Biological Sciences, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Korea
| | - Bumjun Jung
- Department of Biological Sciences, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Korea
| | | | | | - Eunhee Kim
- Department of Biological Sciences, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Korea
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12
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Franz A, Valledor P, Ubieto-Capella P, Pilger D, Galarreta A, Lafarga V, Fernández-Llorente A, de la Vega-Barranco G, den Brave F, Hoppe T, Fernandez-Capetillo O, Lecona E. USP7 and VCP FAF1 define the SUMO/Ubiquitin landscape at the DNA replication fork. Cell Rep 2021; 37:109819. [PMID: 34644576 PMCID: PMC8527565 DOI: 10.1016/j.celrep.2021.109819] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 07/20/2021] [Accepted: 09/21/2021] [Indexed: 12/16/2022] Open
Abstract
The AAA+ ATPase VCP regulates the extraction of SUMO and ubiquitin-modified DNA replication factors from chromatin. We have previously described that active DNA synthesis is associated with a SUMO-high/ubiquitin-low environment governed by the deubiquitylase USP7. Here, we unveil a functional cooperation between USP7 and VCP in DNA replication, which is conserved from Caenorhabditis elegans to mammals. The role of VCP in chromatin is defined by its cofactor FAF1, which facilitates the extraction of SUMOylated and ubiquitylated proteins that accumulate after the block of DNA replication in the absence of USP7. The inactivation of USP7 and FAF1 is synthetically lethal both in C. elegans and mammalian cells. In addition, USP7 and VCP inhibitors display synergistic toxicity supporting a functional link between deubiquitylation and extraction of chromatin-bound proteins. Our results suggest that USP7 and VCPFAF1 facilitate DNA replication by controlling the balance of SUMO/Ubiquitin-modified DNA replication factors on chromatin.
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Affiliation(s)
- André Franz
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Pablo Valledor
- Genomic Instability Group, Spanish National Cancer Research Centre (CNIO), Madrid 28029, Spain
| | - Patricia Ubieto-Capella
- Genomic Instability Group, Spanish National Cancer Research Centre (CNIO), Madrid 28029, Spain
| | - Domenic Pilger
- The Wellcome Trust and Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Cambridge CB2 1QN, UK
| | - Antonio Galarreta
- Genomic Instability Group, Spanish National Cancer Research Centre (CNIO), Madrid 28029, Spain
| | - Vanesa Lafarga
- Genomic Instability Group, Spanish National Cancer Research Centre (CNIO), Madrid 28029, Spain
| | - Alejandro Fernández-Llorente
- Chromatin, Cancer and the Ubiquitin System lab, Centre for Molecular Biology Severo Ochoa (CBMSO, CSIC-UAM), Department of Genome Dynamics and Function, Madrid 28049, Spain
| | - Guillermo de la Vega-Barranco
- Chromatin, Cancer and the Ubiquitin System lab, Centre for Molecular Biology Severo Ochoa (CBMSO, CSIC-UAM), Department of Genome Dynamics and Function, Madrid 28049, Spain
| | - Fabian den Brave
- Institute of Biochemistry and Molecular Biology, University of Bonn, 53115 Bonn, Germany
| | - Thorsten Hoppe
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany.
| | - Oscar Fernandez-Capetillo
- Genomic Instability Group, Spanish National Cancer Research Centre (CNIO), Madrid 28029, Spain; Science for Life Laboratory, Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, 171 21 Stockholm, Sweden.
| | - Emilio Lecona
- Chromatin, Cancer and the Ubiquitin System lab, Centre for Molecular Biology Severo Ochoa (CBMSO, CSIC-UAM), Department of Genome Dynamics and Function, Madrid 28049, Spain.
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13
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Thery F, Martina L, Asselman C, Zhang Y, Vessely M, Repo H, Sedeyn K, Moschonas GD, Bredow C, Teo QW, Zhang J, Leandro K, Eggermont D, De Sutter D, Boucher K, Hochepied T, Festjens N, Callewaert N, Saelens X, Dermaut B, Knobeloch KP, Beling A, Sanyal S, Radoshevich L, Eyckerman S, Impens F. Ring finger protein 213 assembles into a sensor for ISGylated proteins with antimicrobial activity. Nat Commun 2021; 12:5772. [PMID: 34599178 PMCID: PMC8486878 DOI: 10.1038/s41467-021-26061-w] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 09/14/2021] [Indexed: 12/20/2022] Open
Abstract
ISG15 is an interferon-stimulated, ubiquitin-like protein that can conjugate to substrate proteins (ISGylation) to counteract microbial infection, but the underlying mechanisms remain elusive. Here, we use a virus-like particle trapping technology to identify ISG15-binding proteins and discover Ring Finger Protein 213 (RNF213) as an ISG15 interactor and cellular sensor of ISGylated proteins. RNF213 is a poorly characterized, interferon-induced megaprotein that is frequently mutated in Moyamoya disease, a rare cerebrovascular disorder. We report that interferon induces ISGylation and oligomerization of RNF213 on lipid droplets, where it acts as a sensor for ISGylated proteins. We show that RNF213 has broad antimicrobial activity in vitro and in vivo, counteracting infection with Listeria monocytogenes, herpes simplex virus 1, human respiratory syncytial virus and coxsackievirus B3, and we observe a striking co-localization of RNF213 with intracellular bacteria. Together, our findings provide molecular insights into the ISGylation pathway and reveal RNF213 as a key antimicrobial effector.
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Affiliation(s)
- Fabien Thery
- VIB-UGent Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Lia Martina
- VIB-UGent Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Caroline Asselman
- VIB-UGent Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Yifeng Zhang
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Madeleine Vessely
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Heidi Repo
- VIB-UGent Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Koen Sedeyn
- VIB-UGent Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - George D Moschonas
- VIB-UGent Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Clara Bredow
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Biochemistry, Berlin, Germany
| | - Qi Wen Teo
- HKU-Pasteur Research Pole, School of Public Health, University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Jingshu Zhang
- HKU-Pasteur Research Pole, School of Public Health, University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Kevin Leandro
- VIB-UGent Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Denzel Eggermont
- VIB-UGent Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Delphine De Sutter
- VIB-UGent Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Katie Boucher
- VIB-UGent Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
- VIB Proteomics Core, VIB, Ghent, Belgium
| | - Tino Hochepied
- VIB Center for Inflammation Research, VIB, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Nele Festjens
- VIB-UGent Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Nico Callewaert
- VIB-UGent Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Xavier Saelens
- VIB-UGent Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Bart Dermaut
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Klaus-Peter Knobeloch
- Institute of Neuropathology, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Antje Beling
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Biochemistry, Berlin, Germany
- Deutsches Zentrum für Herz-Kreislauf-Forschung (DZHK), partner side Berlin, Berlin, Germany
| | - Sumana Sanyal
- HKU-Pasteur Research Pole, School of Public Health, University of Hong Kong, Pok Fu Lam, Hong Kong
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK
| | - Lilliana Radoshevich
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA, USA.
| | - Sven Eyckerman
- VIB-UGent Center for Medical Biotechnology, VIB, Ghent, Belgium.
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium.
| | - Francis Impens
- VIB-UGent Center for Medical Biotechnology, VIB, Ghent, Belgium.
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium.
- VIB Proteomics Core, VIB, Ghent, Belgium.
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14
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Borgese N, Iacomino N, Colombo SF, Navone F. The Link between VAPB Loss of Function and Amyotrophic Lateral Sclerosis. Cells 2021; 10:1865. [PMID: 34440634 PMCID: PMC8392409 DOI: 10.3390/cells10081865] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/16/2021] [Accepted: 07/16/2021] [Indexed: 02/06/2023] Open
Abstract
The VAP proteins are integral adaptor proteins of the endoplasmic reticulum (ER) membrane that recruit a myriad of interacting partners to the ER surface. Through these interactions, the VAPs mediate a large number of processes, notably the generation of membrane contact sites between the ER and essentially all other cellular membranes. In 2004, it was discovered that a mutation (p.P56S) in the VAPB paralogue causes a rare form of dominantly inherited familial amyotrophic lateral sclerosis (ALS8). The mutant protein is aggregation-prone, non-functional and unstable, and its expression from a single allele appears to be insufficient to support toxic gain-of-function effects within motor neurons. Instead, loss-of-function of the single wild-type allele is required for pathological effects, and VAPB haploinsufficiency may be the main driver of the disease. In this article, we review the studies on the effects of VAPB deficit in cellular and animal models. Several basic cell physiological processes are affected by downregulation or complete depletion of VAPB, impinging on phosphoinositide homeostasis, Ca2+ signalling, ion transport, neurite extension, and ER stress. In the future, the distinction between the roles of the two VAP paralogues (A and B), as well as studies on motor neurons generated from induced pluripotent stem cells (iPSC) of ALS8 patients will further elucidate the pathogenic basis of p.P56S familial ALS, as well as of other more common forms of the disease.
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Affiliation(s)
- Nica Borgese
- CNR Institute of Neuroscience, Via Follereau 3, Bldg U28, 20854 Vedano al Lambro, Italy; (N.I.); (S.F.C.)
| | | | | | - Francesca Navone
- CNR Institute of Neuroscience, Via Follereau 3, Bldg U28, 20854 Vedano al Lambro, Italy; (N.I.); (S.F.C.)
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15
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Aguiar BG, Dumas C, Maaroufi H, Padmanabhan PK, Papadopoulou B. The AAA + ATPase valosin-containing protein (VCP)/p97/Cdc48 interaction network in Leishmania. Sci Rep 2020; 10:13135. [PMID: 32753747 PMCID: PMC7403338 DOI: 10.1038/s41598-020-70010-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 07/14/2020] [Indexed: 12/11/2022] Open
Abstract
Valosin-containing protein (VCP)/p97/Cdc48 is an AAA + ATPase associated with many ubiquitin-dependent cellular pathways that are central to protein quality control. VCP binds various cofactors, which determine pathway selectivity and substrate processing. Here, we used co-immunoprecipitation and mass spectrometry studies coupled to in silico analyses to identify the Leishmania infantum VCP (LiVCP) interactome and to predict molecular interactions between LiVCP and its major cofactors. Our data support a largely conserved VCP protein network in Leishmania including known but also novel interaction partners. Network proteomics analysis confirmed LiVCP-cofactor interactions and provided novel insights into cofactor-specific partners and the diversity of LiVCP complexes, including the well-characterized VCP-UFD1-NPL4 complex. Gene Ontology analysis coupled with digitonin fractionation and immunofluorescence studies support cofactor subcellular compartmentalization with either cytoplasmic or organellar or vacuolar localization. Furthermore, in silico models based on 3D homology modeling and protein-protein docking indicated that the conserved binding modules of LiVCP cofactors, except for NPL4, interact with specific binding sites in the hexameric LiVCP protein, similarly to their eukaryotic orthologs. Altogether, these results allowed us to build the first VCP protein interaction network in parasitic protozoa through the identification of known and novel interacting partners potentially associated with distinct VCP complexes.
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Affiliation(s)
- Bruno Guedes Aguiar
- Division of Infectious Disease and Immunity, CHU de Quebec Research Center-Laval University, 2705 Laurier Blvd, Quebec, QC, G1V 4G2, Canada
- Department of Microbiology-Infectious Disease and Immunology, Faculty of Medicine, University Laval, Quebec, QC, G1V 4G2, Canada
- Department of Community Medicine, Federal University of Piauí, Teresina, Brazil
| | - Carole Dumas
- Division of Infectious Disease and Immunity, CHU de Quebec Research Center-Laval University, 2705 Laurier Blvd, Quebec, QC, G1V 4G2, Canada
- Department of Microbiology-Infectious Disease and Immunology, Faculty of Medicine, University Laval, Quebec, QC, G1V 4G2, Canada
| | - Halim Maaroufi
- Institut de Biologie Intégrative Et Des Systèmes (IBIS), Laval University, Quebec, QC, Canada
| | - Prasad K Padmanabhan
- Division of Infectious Disease and Immunity, CHU de Quebec Research Center-Laval University, 2705 Laurier Blvd, Quebec, QC, G1V 4G2, Canada
- Department of Microbiology-Infectious Disease and Immunology, Faculty of Medicine, University Laval, Quebec, QC, G1V 4G2, Canada
| | - Barbara Papadopoulou
- Division of Infectious Disease and Immunity, CHU de Quebec Research Center-Laval University, 2705 Laurier Blvd, Quebec, QC, G1V 4G2, Canada.
- Department of Microbiology-Infectious Disease and Immunology, Faculty of Medicine, University Laval, Quebec, QC, G1V 4G2, Canada.
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16
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Abstract
p97 belongs to the functional diverse superfamily of AAA+ (ATPases Associated with diverse cellular Activities) ATPases and is characterized by an N-terminal regulatory domain and two stacked hexameric ATPase domains forming a central protein conducting channel. p97 is highly versatile and has key functions in maintaining protein homeostasis including protein quality control mechanisms like the ubiquitin proteasome system (UPS) and autophagy to disassemble polyubiquitylated proteins from chromatin, membranes, macromolecular protein complexes and aggregates which are either degraded by the proteasome or recycled. p97 can use energy derived from ATP hydrolysis to catalyze substrate unfolding and threading through its central channel. The function of p97 in a large variety of different cellular contexts is reflected by its simultaneous association with different cofactors, which are involved in substrate recognition and processing, thus leading to the formation of transient multi-protein complexes. Dysregulation in protein homeostasis and proteotoxic stress are often involved in the development of cancer and neurological diseases and targeting the UPS including p97 in cancer is a well-established pharmacological strategy. In this chapter we will describe structural and functional aspects of the p97 interactome in regulating diverse cellular processes and will discuss the role of p97 in targeted cancer therapy.
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17
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Motahari Z, Moody SA, Maynard TM, LaMantia AS. In the line-up: deleted genes associated with DiGeorge/22q11.2 deletion syndrome: are they all suspects? J Neurodev Disord 2019; 11:7. [PMID: 31174463 PMCID: PMC6554986 DOI: 10.1186/s11689-019-9267-z] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 04/21/2019] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND 22q11.2 deletion syndrome (22q11DS), a copy number variation (CNV) disorder, occurs in approximately 1:4000 live births due to a heterozygous microdeletion at position 11.2 (proximal) on the q arm of human chromosome 22 (hChr22) (McDonald-McGinn and Sullivan, Medicine 90:1-18, 2011). This disorder was known as DiGeorge syndrome, Velo-cardio-facial syndrome (VCFS) or conotruncal anomaly face syndrome (CTAF) based upon diagnostic cardiovascular, pharyngeal, and craniofacial anomalies (McDonald-McGinn and Sullivan, Medicine 90:1-18, 2011; Burn et al., J Med Genet 30:822-4, 1993) before this phenotypic spectrum was associated with 22q11.2 CNVs. Subsequently, 22q11.2 deletion emerged as a major genomic lesion associated with vulnerability for several clinically defined behavioral deficits common to a number of neurodevelopmental disorders (Fernandez et al., Principles of Developmental Genetics, 2015; Robin and Shprintzen, J Pediatr 147:90-6, 2005; Schneider et al., Am J Psychiatry 171:627-39, 2014). RESULTS The mechanistic relationships between heterozygously deleted 22q11.2 genes and 22q11DS phenotypes are still unknown. We assembled a comprehensive "line-up" of the 36 protein coding loci in the 1.5 Mb minimal critical deleted region on hChr22q11.2, plus 20 protein coding loci in the distal 1.5 Mb that defines the 3 Mb typical 22q11DS deletion. We categorized candidates based upon apparent primary cell biological functions. We analyzed 41 of these genes that encode known proteins to determine whether haploinsufficiency of any single 22q11.2 gene-a one gene to one phenotype correspondence due to heterozygous deletion restricted to that locus-versus complex multigenic interactions can account for single or multiple 22q11DS phenotypes. CONCLUSIONS Our 22q11.2 functional genomic assessment does not support current theories of single gene haploinsufficiency for one or all 22q11DS phenotypes. Shared molecular functions, convergence on fundamental cell biological processes, and related consequences of individual 22q11.2 genes point to a matrix of multigenic interactions due to diminished 22q11.2 gene dosage. These interactions target fundamental cellular mechanisms essential for development, maturation, or homeostasis at subsets of 22q11DS phenotypic sites.
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Affiliation(s)
- Zahra Motahari
- The Institute for Neuroscience, and Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, Washington DC, 20037 USA
| | - Sally Ann Moody
- The Institute for Neuroscience, and Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, Washington DC, 20037 USA
| | - Thomas Michael Maynard
- The Institute for Neuroscience, and Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, Washington DC, 20037 USA
| | - Anthony-Samuel LaMantia
- The Institute for Neuroscience, and Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, Washington DC, 20037 USA
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18
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Identification of two independent SUMO-interacting motifs in Fas-associated factor 1 (FAF1): Implications for mineralocorticoid receptor (MR)-mediated transcriptional regulation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:1282-1297. [PMID: 30935967 DOI: 10.1016/j.bbamcr.2019.03.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 03/19/2019] [Accepted: 03/26/2019] [Indexed: 01/23/2023]
Abstract
Fas-associated factor 1 (FAF1) was originally isolated as a Fas-associated factor and was subsequently found to interact with numerous other proteins that are involved in various cellular events including Fas-mediated apoptosis, nuclear factor (NF)-κB, Wnt/β-catenin, and transforming growth factor (TGF)-β signaling pathways, mineralocorticoid receptor (MR)-mediated transactivation, and ubiquitin-dependent processes. Herein, we defined two small ubiquitin-like modifier (SUMO)-interacting motifs (SIMs) within FAF1 and demonstrated to be crucial for transcriptional modulation of the MR. Our study demonstrated that the SIMs of FAF1 do not play a significant role in regulating its subcellular localization, Fas-mediated apoptosis, or NF-κB or Wnt/β-catenin pathways. Remarkably, FAF1 interacts with the sumoylated MR and represses aldosterone-activated MR transactivation in a SIM-dependent manner. Moreover, silencing of endogenous FAF1 in cells resulted in an increase in the induction of MR target genes by aldosterone, indicating that FAF1 functions as an MR co-repressor. We further provide evidence to suggest that the mechanisms of FAF1/SIM-mediated MR transrepression involve inhibition of MR N/C interactions and promotion of MR polyubiquitination and degradation. Sumoylation has been linked to impacting of repressive properties on several transcription factors and cofactors. Our findings therefore provide mechanistic insights underlying SUMO-dependent transcriptional repression of the MR.
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19
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Dai T, Wu L, Wang S, Wang J, Xie F, Zhang Z, Fang X, Li J, Fang P, Li F, Jin K, Dai J, Yang B, Zhou F, van Dam H, Cai D, Huang H, Zhang L. FAF1 Regulates Antiviral Immunity by Inhibiting MAVS but Is Antagonized by Phosphorylation upon Viral Infection. Cell Host Microbe 2018; 24:776-790.e5. [PMID: 30472208 DOI: 10.1016/j.chom.2018.10.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Revised: 09/04/2018] [Accepted: 10/15/2018] [Indexed: 11/20/2022]
Abstract
Mitochondrial antiviral signaling protein (MAVS) is an adaptor of the innate immune receptor retinoic acid-inducible gene 1 (RIG-I) that links recognition of viral RNA to antiviral signaling. Upon interacting with RIG-I, MAVS undergoes lysine 63-linked poly-ubiquitination by the E3 ligase TRIM31 and subsequently aggregates to activate downstream signaling effectors. We find that the scaffold protein FAF1 forms aggregates that negatively regulate MAVS. FAF1 antagonizes the poly-ubiquitination and aggregation of MAVS by competing with TRIM31 for MAVS association. FAF1 knockout mice are more resistant to RNA virus infection, and FAF1 deficiency in myeloid cells results in enhanced innate signaling and reduced viral load and morbidity in vivo. Upon virus infection, the kinase IKKɛ directly phosphorylates FAF1 at Ser556 and triggers FAF1 de-aggregation. Moreover, Ser556 phosphorylation promotes FAF1 lysosomal degradation, consequently relieving FAF1-dependent suppression of MAVS. These findings establish FAF1 as a modulator of MAVS and uncover mechanisms that regulate FAF1 to insure timely activation of antiviral defense.
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Affiliation(s)
- Tong Dai
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China; Institutes of Biology and Medical Science, Soochow University, Suzhou 215123, China
| | - Liming Wu
- The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Shuai Wang
- Institutes of Biology and Medical Science, Soochow University, Suzhou 215123, China
| | - Jing Wang
- The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Feng Xie
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China; Institutes of Biology and Medical Science, Soochow University, Suzhou 215123, China
| | - Zhengkui Zhang
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China; Institutes of Biology and Medical Science, Soochow University, Suzhou 215123, China
| | - Xiuwu Fang
- Institutes of Biology and Medical Science, Soochow University, Suzhou 215123, China
| | - Jingxian Li
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Pengfei Fang
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Fang Li
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Ke Jin
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Jianfeng Dai
- Institutes of Biology and Medical Science, Soochow University, Suzhou 215123, China
| | - Bing Yang
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China; Department of Pharmaceutical Chemistry and the Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Fangfang Zhou
- Institutes of Biology and Medical Science, Soochow University, Suzhou 215123, China
| | - Hans van Dam
- Department of Molecular Cell Biology, Cancer Genomics Centre Netherlands, Leiden University Medical Center, Postbus 9600, 2300 RC Leiden, the Netherlands
| | - Dachuan Cai
- Department for Infectious Diseases, The Second Affiliated Hospital of Chonqing Medical University, Chongqing 400016, China
| | - Huizhe Huang
- Faculty of Basic Medical Sciences, Chonqing Medical University, Chongqing 400016, China
| | - Long Zhang
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China.
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Sane S, Hafner A, Srinivasan R, Masood D, Slunecka JL, Noldner CJ, Hanson AD, Kruisselbrink T, Wang X, Wang Y, Yin J, Rezvani K. UBXN2A enhances CHIP-mediated proteasomal degradation of oncoprotein mortalin-2 in cancer cells. Mol Oncol 2018; 12:1753-1777. [PMID: 30107089 PMCID: PMC6166003 DOI: 10.1002/1878-0261.12372] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 07/12/2018] [Accepted: 08/02/2018] [Indexed: 01/07/2023] Open
Abstract
Overexpression of oncoproteins is a major cause of treatment failure using current chemotherapeutic drugs. Drug-induced degradation of oncoproteins is feasible and can improve clinical outcomes in diverse types of cancers. Mortalin-2 (mot-2) is a dominant oncoprotein in several tumors, including colorectal cancer (CRC). In addition to inactivating the p53 tumor suppressor protein, mot-2 enhances tumor cell invasion and migration. Thus, mot-2 is considered a potential therapeutic target in several cancer types. The current study investigated the biological role of a ubiquitin-like protein called UBXN2A in the regulation of mot-2 turnover. An orthogonal ubiquitin transfer technology followed by immunoprecipitation, in vitro ubiquitination, and Magnetic Beads TUBE2 pull-down experiments revealed that UBXN2A promotes carboxyl terminus of the HSP70-interacting protein (CHIP)-dependent ubiquitination of mot-2. We subsequently showed that UBXN2A increases proteasomal degradation of mot-2. A subcellular compartmentalization experiment revealed that induced UBXN2A decreases the level of mot-2 and its chaperone partner, HSP60. Pharmacological upregulation of UBXN2A using a small molecule, veratridine (VTD), decreases the level of mot-2 in cancer cells. Consistent with the in vitro results, UBXN2A+/- mice exhibited selective elevation of mot-2 in colon tissues. An in vitro Anti-K48 TUBE isolation approach showed that recombinant UBXN2A enhances proteasomal degradation of mot-2 in mouse colon tissues. Finally, we observed enhanced association of CHIP with the UBXN2A-mot-2 complex in tumors in an azoxymethane/dextran sulfate sodium-induced mouse CRC model. The existence of a multiprotein complex containing UBXN2A, CHIP, and mot-2 suggests a synergistic tumor suppressor activity of UBXN2A and CHIP in mot-2-enriched tumors. This finding validates the UBXN2A-CHIP axis as a novel and potential therapeutic target in CRC.
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Affiliation(s)
- Sanam Sane
- Division of Basic Biomedical SciencesSanford School of MedicineThe University of South DakotaVermillionSDUSA
| | - Andre Hafner
- Division of Basic Biomedical SciencesSanford School of MedicineThe University of South DakotaVermillionSDUSA
| | - Rekha Srinivasan
- Division of Basic Biomedical SciencesSanford School of MedicineThe University of South DakotaVermillionSDUSA
| | - Daniall Masood
- Division of Basic Biomedical SciencesSanford School of MedicineThe University of South DakotaVermillionSDUSA
| | - John l. Slunecka
- Division of Basic Biomedical SciencesSanford School of MedicineThe University of South DakotaVermillionSDUSA
| | - Collin J. Noldner
- Division of Basic Biomedical SciencesSanford School of MedicineThe University of South DakotaVermillionSDUSA
| | - Alex D. Hanson
- Division of Basic Biomedical SciencesSanford School of MedicineThe University of South DakotaVermillionSDUSA
| | - Taylor Kruisselbrink
- Division of Basic Biomedical SciencesSanford School of MedicineThe University of South DakotaVermillionSDUSA
| | - Xuejun Wang
- Division of Basic Biomedical SciencesSanford School of MedicineThe University of South DakotaVermillionSDUSA
| | - Yiyang Wang
- Department of ChemistryCenter for Diagnostics & TherapeuticsGeorgia State UniversityAtlantaGAUSA
| | - Jun Yin
- Department of ChemistryCenter for Diagnostics & TherapeuticsGeorgia State UniversityAtlantaGAUSA
| | - Khosrow Rezvani
- Division of Basic Biomedical SciencesSanford School of MedicineThe University of South DakotaVermillionSDUSA
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Yu C, Kim BS, Park M, Do YJ, Kong YY, Kim E. FAF1 mediates necrosis through JNK1-mediated mitochondrial dysfunction leading to retinal degeneration in the ganglion cell layer upon ischemic insult. Cell Commun Signal 2018; 16:56. [PMID: 30200976 PMCID: PMC6131785 DOI: 10.1186/s12964-018-0265-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 08/21/2018] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Aberrant cell death induced by ischemic stress is implicated in the pathogenesis of ischemic diseases. Fas-associated factor 1 (FAF1) has been identified as a death-promoting protein. This study demonstrates that FAF1 functions in death signaling triggered by ischemic insult. METHODS The expression changes of FAF1 and phophorylated JNK1 were detected by Western blotting. Immunoprecipitation was employed to investigate protein-protein interaction. We determined the cell death using flow cytometry and lactate dehydrogenase release measurement. To validate the death-promoting role of FAF1 in the retina, we generated conditional retinal FAF1 knockout mice. We used hematoxylin and eosin staining to detect retinal cell death in retinal ganglion cell layer. RESULTS FAF1 was found to function upstream of c-Jun N-terminal kinase 1 (JNK1), followed by mitochondrial dysregulation and necrotic cell death processes upon ischemic insult. We investigated whether FAF1 is involved in the pathogenesis of ischemic diseases using a retinal ischemia model. Indeed, FAF1 potentiated necrosis through JNK1 activation upon ischemic stress in retinal cells demonstrating retinal ganglion-like character. Conditional FAF1 depletion attenuated JNK1 activation in the retinas of Dkk3-Cre;Faf1flox/flox mice and ameliorated death of retinal cells due to elevated intraocular pressure (IOP). CONCLUSIONS Our results show that FAF1 plays a key role in ischemic retinal damage and may be implicated in the pathogenesis of retinal ischemic disease.
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Affiliation(s)
- Changsun Yu
- Department of Biological Sciences, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon, 34134 South Korea
- MOGAM Institute for Biomedical Research, 93, 30beon-gil, Ihyeon-ro, Gilheung-gu, Yongin-si, Gyeonggi-do 16924 South Korea
| | - Bok-seok Kim
- Department of Biological Sciences, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon, 34134 South Korea
| | - Minyoung Park
- Department of Biological Sciences, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon, 34134 South Korea
- BeyondBio Inc., Daejeon BioVenture Town, 1662, Yuseong-daero, Yuseong-gu, Daejeon, 34134 South Korea
| | - Yun-Ju Do
- Department of Biological Sciences, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon, 34134 South Korea
| | - Young-Yun Kong
- School of Biological Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826 South Korea
| | - Eunhee Kim
- Department of Biological Sciences, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon, 34134 South Korea
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22
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Do YJ, Yun SY, Park MY, Kim E. The M458L missense mutation disrupts the catalytic properties of Parkin. FEBS Lett 2017; 592:78-88. [PMID: 29223129 DOI: 10.1002/1873-3468.12934] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Revised: 11/21/2017] [Accepted: 11/30/2017] [Indexed: 11/09/2022]
Abstract
Parkin encodes an E3 ubiquitin ligase, and mutations affecting its catalytic potential are implicated in autosomal recessive Parkinson's disease (PD). The M458L mutation of parkin and its enzymatic effects require characterization. Therefore, we examined the enzymatic activity of Parkin with M458L mutation. We show that the M458L mutant retains its autoubiquitination potential in vitro but not in cells. Fas-associated factor 1 and p38 (substrates of Parkin) are able to bind to the M458L mutant in cells; however, these Parkin substrates are not ubiquitinated and degraded in M458L mutant-transfected cells. Moreover, M458L mutant fails to protect the mitochondria against hydrogen peroxide, leading to cell death. Considering the role of mitochondrial dysfunction in PD pathogenesis, our results imply a causative role for the M458L mutation in neurodegeneration.
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Affiliation(s)
- Yun-Ju Do
- Department of Biological Sciences, Chungnam National University, Daejeon, Korea
| | - Seo Young Yun
- Department of Biological Sciences, Chungnam National University, Daejeon, Korea
| | - Min-Young Park
- Department of Biological Sciences, Chungnam National University, Daejeon, Korea
| | - Eunhee Kim
- Department of Biological Sciences, Chungnam National University, Daejeon, Korea
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23
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The AAA+ ATPase p97, a cellular multitool. Biochem J 2017; 474:2953-2976. [PMID: 28819009 PMCID: PMC5559722 DOI: 10.1042/bcj20160783] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 07/17/2017] [Accepted: 07/21/2017] [Indexed: 12/17/2022]
Abstract
The AAA+ (ATPases associated with diverse cellular activities) ATPase p97 is essential to a wide range of cellular functions, including endoplasmic reticulum-associated degradation, membrane fusion, NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) activation and chromatin-associated processes, which are regulated by ubiquitination. p97 acts downstream from ubiquitin signaling events and utilizes the energy from ATP hydrolysis to extract its substrate proteins from cellular structures or multiprotein complexes. A multitude of p97 cofactors have evolved which are essential to p97 function. Ubiquitin-interacting domains and p97-binding domains combine to form bi-functional cofactors, whose complexes with p97 enable the enzyme to interact with a wide range of ubiquitinated substrates. A set of mutations in p97 have been shown to cause the multisystem proteinopathy inclusion body myopathy associated with Paget's disease of bone and frontotemporal dementia. In addition, p97 inhibition has been identified as a promising approach to provoke proteotoxic stress in tumors. In this review, we will describe the cellular processes governed by p97, how the cofactors interact with both p97 and its ubiquitinated substrates, p97 enzymology and the current status in developing p97 inhibitors for cancer therapy.
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24
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Kim JH, Park ME, Nikapitiya C, Kim TH, Uddin MB, Lee HC, Kim E, Ma JY, Jung JU, Kim CJ, Lee JS. FAS-associated factor-1 positively regulates type I interferon response to RNA virus infection by targeting NLRX1. PLoS Pathog 2017; 13:e1006398. [PMID: 28542569 PMCID: PMC5456407 DOI: 10.1371/journal.ppat.1006398] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 06/02/2017] [Accepted: 05/04/2017] [Indexed: 12/25/2022] Open
Abstract
FAS-associated factor-1 (FAF1) is a component of the death-inducing signaling complex involved in Fas-mediated apoptosis. It regulates NF-κB activity, ubiquitination, and proteasomal degradation. Here, we found that FAF1 positively regulates the type I interferon pathway. FAF1gt/gt mice, which deficient in FAF1, and FAF1 knockdown immune cells were highly susceptible to RNA virus infection and showed low levels of inflammatory cytokines and type I interferon (IFN) production. FAF1 was bound competitively to NLRX1 and positively regulated type I IFN signaling by interfering with the interaction between NLRX1 and MAVS, thereby freeing MAVS to bind RIG-I, which switched on the MAVS-RIG-I-mediated antiviral signaling cascade. These results highlight a critical role of FAF1 in antiviral responses against RNA virus infection.
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Affiliation(s)
- Jae-Hoon Kim
- College of Veterinary Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Min-Eun Park
- College of Veterinary Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Chamilani Nikapitiya
- College of Veterinary Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Tae-Hwan Kim
- College of Veterinary Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Md Bashir Uddin
- College of Veterinary Medicine, Chungnam National University, Daejeon, Republic of Korea
- Faculty of Veterinary & Animal Science, Sylhet Agricultural University, Sylhet, Bangladesh
| | - Hyun-Cheol Lee
- College of Veterinary Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Eunhee Kim
- College of Biological Sciences and Biotechnology, Chungnam National University, Daejeon, Korea
| | - Jin Yeul Ma
- Korean Medicine (KM)-Application Center, Korea Institute of Oriental Medicine (KIOM), Daegu, Republic of Korea
| | - Jae U. Jung
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, California, United States of America
| | - Chul-Joong Kim
- College of Veterinary Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Jong-Soo Lee
- College of Veterinary Medicine, Chungnam National University, Daejeon, Republic of Korea
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Hänzelmann P, Schindelin H. The Interplay of Cofactor Interactions and Post-translational Modifications in the Regulation of the AAA+ ATPase p97. Front Mol Biosci 2017; 4:21. [PMID: 28451587 PMCID: PMC5389986 DOI: 10.3389/fmolb.2017.00021] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 03/24/2017] [Indexed: 12/18/2022] Open
Abstract
The hexameric type II AAA ATPase (ATPase associated with various activities) p97 (also referred to as VCP, Cdc48, and Ter94) is critically involved in a variety of cellular activities including pathways such as DNA replication and repair which both involve chromatin remodeling, and is a key player in various protein quality control pathways mediated by the ubiquitin proteasome system as well as autophagy. Correspondingly, p97 has been linked to various pathophysiological states including cancer, neurodegeneration, and premature aging. p97 encompasses an N-terminal domain, two highly conserved ATPase domains and an unstructured C-terminal tail. This enzyme hydrolyzes ATP and utilizes the resulting energy to extract or disassemble protein targets modified with ubiquitin from stable protein assemblies, chromatin and membranes. p97 participates in highly diverse cellular processes and hence its activity is tightly controlled. This is achieved by multiple regulatory cofactors, which either associate with the N-terminal domain or interact with the extreme C-terminus via distinct binding elements and target p97 to specific cellular pathways, sometimes requiring the simultaneous association with more than one cofactor. Most cofactors are recruited to p97 through conserved binding motifs/domains and assist in substrate recognition or processing by providing additional molecular properties. A tight control of p97 cofactor specificity and diversity as well as the assembly of higher-order p97-cofactor complexes is accomplished by various regulatory mechanisms, which include bipartite binding, binding site competition, changes in oligomeric assemblies, and nucleotide-induced conformational changes. Furthermore, post-translational modifications (PTMs) like acetylation, palmitoylation, phosphorylation, SUMOylation, and ubiquitylation of p97 have been reported which further modulate its diverse molecular activities. In this review, we will describe the molecular basis of p97-cofactor specificity/diversity and will discuss how PTMs can modulate p97-cofactor interactions and affect the physiological and patho-physiological functions of p97.
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Affiliation(s)
- Petra Hänzelmann
- Rudolf Virchow Center for Experimental Biomedicine, University of WürzburgWürzburg, Germany
| | - Hermann Schindelin
- Rudolf Virchow Center for Experimental Biomedicine, University of WürzburgWürzburg, Germany
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26
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XIAP Interacts with and Regulates the Activity of FAF1. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:1335-1348. [PMID: 28414080 DOI: 10.1016/j.bbamcr.2017.04.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 03/26/2017] [Accepted: 04/12/2017] [Indexed: 12/19/2022]
Abstract
Cell death depends on the balance between the activities of pro- and anti-apoptotic factors. X-linked inhibitor of apoptosis protein (XIAP) plays an important role in the cytoprotective process by inhibiting the caspase cascade and regulating pro-survival signaling pathways. While searching for novel interacting partners of XIAP, we identified Fas-associated factor 1 (FAF1). Contrary to XIAP, FAF1 is a pro-apoptotic factor that also regulates several signaling pathways in which XIAP is involved. However, the functional relationship between FAF1 and XIAP is unknown. Here, we describe a new interaction between XIAP and FAF1 and describe the functional implications of their opposing roles in cell death and NF-κB signaling. Our results clearly demonstrate the interaction of XIAP with FAF1 and define the specific region of the interaction. We observed that XIAP is able to block FAF1-mediated cell death by interfering with the caspase cascade and directly interferes in NF-κB pathway inhibition by FAF1. Furthermore, we show that XIAP promotes ubiquitination of FAF1. Conversely, FAF1 does not interfere with the anti-apoptotic activity of XIAP, despite binding to the BIR domains of XIAP; however, FAF1 does attenuate XIAP-mediated NF-κB activation. Altered expression of both factors has been implicated in degenerative and cancerous processes; therefore, studying the balance between XIAP and FAF1 in these pathologies will aid in the development of novel therapies.
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27
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Sonneville R, Moreno SP, Knebel A, Johnson C, Hastie CJ, Gartner A, Gambus A, Labib K. CUL-2 LRR-1 and UBXN-3 drive replisome disassembly during DNA replication termination and mitosis. Nat Cell Biol 2017; 19:468-479. [PMID: 28368371 PMCID: PMC5410169 DOI: 10.1038/ncb3500] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 02/27/2017] [Indexed: 02/06/2023]
Abstract
Replisome disassembly is the final step of DNA replication in eukaryotes, involving the ubiquitylation and CDC48-dependent dissolution of the CMG helicase (CDC45-MCM-GINS). Using Caenorhabditis elegans early embryos and Xenopus laevis egg extracts, we show that the E3 ligase CUL-2LRR-1 associates with the replisome and drives ubiquitylation and disassembly of CMG, together with the CDC-48 cofactors UFD-1 and NPL-4. Removal of CMG from chromatin in frog egg extracts requires CUL2 neddylation, and our data identify chromatin recruitment of CUL2LRR1 as a key regulated step during DNA replication termination. Interestingly, however, CMG persists on chromatin until prophase in worms that lack CUL-2LRR-1, but is then removed by a mitotic pathway that requires the CDC-48 cofactor UBXN-3, orthologous to the human tumour suppressor FAF1. Partial inactivation of lrr-1 and ubxn-3 leads to synthetic lethality, suggesting future approaches by which a deeper understanding of CMG disassembly in metazoa could be exploited therapeutically.
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Affiliation(s)
- Remi Sonneville
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Sara Priego Moreno
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Axel Knebel
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Clare Johnson
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - C James Hastie
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Anton Gartner
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Agnieszka Gambus
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Karim Labib
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
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28
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Gambus A. Termination of Eukaryotic Replication Forks. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1042:163-187. [DOI: 10.1007/978-981-10-6955-0_8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Rezvani K. UBXD Proteins: A Family of Proteins with Diverse Functions in Cancer. Int J Mol Sci 2016; 17:ijms17101724. [PMID: 27754413 PMCID: PMC5085755 DOI: 10.3390/ijms17101724] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 09/24/2016] [Accepted: 10/08/2016] [Indexed: 12/15/2022] Open
Abstract
The UBXD family is a diverse group of UBX (ubiquitin-regulatory X) domain-containing proteins in mammalian cells. Members of this family contain a UBX domain typically located at the carboxyl-terminal of the protein. In contrast to the UBX domain shared by all members of UBXD family, the amino-terminal domains are diverse and appear to carry out different roles in a subcellular localization-dependent manner. UBXD proteins are principally associated with the endoplasmic reticulum (ER), where they positively or negatively regulate the ER-associated degradation machinery (ERAD). The distinct protein interaction networks of UBXD proteins allow them to have specific functions independent of the ERAD pathway in a cell type- and tissue context-dependent manner. Recent reports have illustrated that a number of mammalian members of the UBXD family play critical roles in several proliferation and apoptosis pathways dysregulated in selected types of cancer. This review covers recent advances that elucidate the therapeutic potential of selected members of the UBXD family that can contribute to tumor growth.
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Affiliation(s)
- Khosrow Rezvani
- Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota, 414 E. Clark Street, Lee Medical Building, Vermillion, SD 57069, USA.
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30
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Structural insights into the interaction of p97 N-terminus domain and VBM in rhomboid protease, RHBDL4. Biochem J 2016; 473:2863-80. [DOI: 10.1042/bcj20160237] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 07/12/2016] [Indexed: 01/20/2023]
Abstract
RHBDL4 is an active rhomboid that specifically recognizes and cleaves atypical, positively charged transmembrane endoplasmic reticulum-associated degradation (ERAD) substrates. Interaction of valosin-containing protein (p97/VCP) and RHBDL4 is crucial to retrotranslocate polyubiquitinated substrates for ERAD pathway. Here, we report the first complex structure of VCP-binding motif (VBM) with p97 N-terminal domain (p97N) at 1.88 Å resolution. Consistent with p97 adaptor proteins including p47-ubiquitin regulatory X (UBX), gp78-VCP-interacting motif (VIM), OTU1-UBX-like element, and FAF1-UBX, RHBDL4 VBM also binds at the interface between the two lobes of p97N. Notably, the RF residues in VBM are involved in the interaction with p97N, showing a similar interaction pattern with that of FPR signature motif in the UBX domain, although the directionality is opposite. Comparison of VBM interaction with VIM of gp78, another α-helical motif that interacts with p97N, revealed that the helix direction is inversed. Nevertheless, the conserved arginine residues in both motifs participate in the majority of the interface via extensive hydrogen bonds and ionic interactions with p97N. We identified novel VBM-binding mode to p97N that involves a combination of two types of p97–cofactor specificities observed in the UBX and VIM interactions. This highlights the induced fit model of p97N interdomain cleft upon cofactor binding to form stable p97–cofactor complexes. Our mutational and biochemical analyses in defining the specific interaction between VBM and p97N have elucidated the importance of the highly conserved VBM, applicable to other VBM-containing proteins. We also showed that RHBDL4, ubiquitins, and p97 co-operate for efficient substrate dislocation.
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31
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Xia D, Tang WK, Ye Y. Structure and function of the AAA+ ATPase p97/Cdc48p. Gene 2016. [DOI: 10.1016/j.gene.2016.02.042 and 21=21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/01/2022]
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32
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Xia D, Tang WK, Ye Y. Structure and function of the AAA+ ATPase p97/Cdc48p. Gene 2016. [DOI: 10.1016/j.gene.2016.02.042 and 67=89] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/30/2022]
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Xia D, Tang WK, Ye Y. Structure and function of the AAA+ ATPase p97/Cdc48p. Gene 2016; 583:64-77. [PMID: 26945625 DOI: 10.1016/j.gene.2016.02.042] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 02/23/2016] [Accepted: 02/25/2016] [Indexed: 11/29/2022]
Abstract
p97 (also known as valosin-containing protein (VCP) in mammals or Cdc48p in Saccharomyces cerevisiae) is an evolutionarily conserved ATPase present in all eukaryotes and archaebacteria. In conjunction with a collection of cofactors and adaptors, p97/Cdc48p performs an array of biological functions mostly through modulating the stability of 'client' proteins. Using energy from ATP hydrolysis, p97/Cdc48p segregates these molecules from immobile cellular structures such as protein assemblies, membrane organelles, and chromatin. Consequently, the released polypeptides can be efficiently degraded by the ubiquitin proteasome system or recycled. This review summarizes our current understanding of the structure and function of this essential cellular chaperoning system.
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Affiliation(s)
- Di Xia
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, United States.
| | - Wai Kwan Tang
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, United States
| | - Yihong Ye
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, United States.
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Merched AJ, Daret D, Li L, Franzl N, Sauvage-Merched M. Specific autoantigens in experimental autoimmunity-associated atherosclerosis. FASEB J 2016; 30:2123-34. [PMID: 26891734 DOI: 10.1096/fj.201500131] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Accepted: 02/01/2016] [Indexed: 12/22/2022]
Abstract
Higher cardiovascular morbidity in patients with a wide range of autoimmune diseases highlights the importance of autoimmunity in promoting atherosclerosis. Our purpose was to investigate the mechanisms of accelerated atherosclerosis and identified vascular autoantigens targeted by autoimmunity. We created a mouse model of autoimmunity-associated atherosclerosis by transplanting bone marrow from FcγRIIB knockout (FcRIIB(-/-)) mice into LDL receptor knockout mice. We characterized the cellular and molecular mechanisms of atherogenesis and identified specific aortic autoantigens using serologic proteomic studies. En face lesion area analysis showed more aggressive atherosclerosis in autoimmune mice compared with control mice (0.64 ± 0.12 vs 0.32 ± 0.05 mm(2); P < 0.05, respectively). At the cellular level, FcRIIB(-/-) macrophages showed significant reduction (46-72%) in phagocytic capabilities. Proteomic analysis revealed circulating autoantibodies in autoimmune mice that targeted 25 atherosclerotic lesion proteins, including essential components of adhesion complex, cytoskeleton, and extracellular matrix, and proteins involved in critical functions and pathways. Microscopic examination of atherosclerotic plaques revealed essential colocalization of autoantibodies with endothelial cells, their adherence to basement membranes, the internal elastica lamina, and necrotic cores. The new vascular autoimmunosome may be a useful target for diagnostic and immunotherapeutic interventions in autoimmunity-associated diseases that have accelerated atherosclerosis.-Merched, A. J., Daret, D., Li, L., Franzl, N., Sauvage-Merched, M. Specific autoantigens in experimental autoimmunity-associated atherosclerosis.
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Affiliation(s)
- Aksam J Merched
- Department of Pharmaceutical Sciences, and INSERM U1053, University of Bordeaux, Bordeaux, France Department of Cell Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Danièle Daret
- Department of Cell Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Lan Li
- Department of Cell Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Nathalie Franzl
- Department of Cell Biology, Baylor College of Medicine, Houston, Texas, USA
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Fas-Associated Factor 1 Negatively Regulates the Antiviral Immune Response by Inhibiting Translocation of Interferon Regulatory Factor 3 to the Nucleus. Mol Cell Biol 2016; 36:1136-51. [PMID: 26811330 PMCID: PMC4800795 DOI: 10.1128/mcb.00744-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 01/16/2016] [Indexed: 01/12/2023] Open
Abstract
This study is designed to examine the cellular functions of human Fas-associated factor 1 (FAF1) containing multiple ubiquitin-related domains. Microarray analyses revealed that interferon-stimulated genes related to the antiviral response are significantly increased in FAF1-knockdown HeLa cells. Silencing FAF1 enhanced the poly(I·C)- and respiratory syncytial virus (RSV)-induced production of type I interferons (IFNs), the target genes of interferon regulator factor 3 (IRF3). IRF3 is a key transcription factor in IFN-β signaling responsible for the host innate immune response. This study also found that FAF1 and IRF3 physically associate with IPO5/importin-β3 and that overexpression of FAF1 reduces the interaction between IRF3 and IPO5/importin-β3. These findings suggest that FAF1 negatively regulates IRF3-mediated IFN-β production and the antiviral innate immune response by regulating nuclear translocation of IRF3. We conclude that FAF1 plays a novel role in negatively regulating virus-induced IFN-β production and the antiviral response by inhibiting the translocation of active, phosphorylated IRF3 from the cytosol to the nucleus.
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36
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Ernst WL, Shome K, Wu CC, Gong X, Frizzell RA, Aridor M. VAMP-associated Proteins (VAP) as Receptors That Couple Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Proteostasis with Lipid Homeostasis. J Biol Chem 2016; 291:5206-20. [PMID: 26740627 DOI: 10.1074/jbc.m115.692749] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Indexed: 12/27/2022] Open
Abstract
Unesterified cholesterol accumulates in late endosomes in cells expressing the misfolded cystic fibrosis transmembrane conductance regulator (CFTR). CFTR misfolding in the endoplasmic reticulum (ER) or general activation of ER stress led to dynein-mediated clustering of cholesterol-loaded late endosomes at the Golgi region, a process regulated by ER-localized VAMP-associated proteins (VAPs). We hypothesized that VAPs serve as intracellular receptors that couple lipid homeostasis through interactions with two phenylalanines in an acidic track (FFAT) binding signals (found in lipid sorting and sensing proteins, LSS) with proteostasis regulation. VAPB inhibited the degradation of ΔF508-CFTR. The activity was mapped to the ligand-binding major sperm protein (MSP) domain, which was sufficient in regulating CFTR biogenesis. We identified mutations in an unstructured loop within the MSP that uncoupled VAPB-regulated CFTR biogenesis from basic interactions with FFAT. Using this information, we defined functional and physical interactions between VAPB and proteostasis regulators (ligands), including the unfolded protein response sensor ATF6 and the ER degradation cluster that included FAF1, VCP, BAP31, and Derlin-1. VAPB inhibited the degradation of ΔF508-CFTR in the ER through interactions with the RMA1-Derlin-BAP31-VCP pathway. Analysis of pseudoligands containing tandem FFAT signals supports a competitive model for VAP interactions that direct CFTR biogenesis. The results suggest a model in which VAP-ligand binding couples proteostasis and lipid homeostasis leading to observed phenotypes of lipid abnormalities in protein folding diseases.
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Affiliation(s)
- Wayne L Ernst
- From the Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Kuntala Shome
- From the Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Christine C Wu
- From the Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Xiaoyan Gong
- From the Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Raymond A Frizzell
- From the Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Meir Aridor
- From the Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
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Lee JH, Park KJ, Jang JK, Jeon YH, Ko KY, Kwon JH, Lee SR, Kim IY. Selenoprotein S-dependent Selenoprotein K Binding to p97(VCP) Protein Is Essential for Endoplasmic Reticulum-associated Degradation. J Biol Chem 2015; 290:29941-52. [PMID: 26504085 DOI: 10.1074/jbc.m115.680215] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Indexed: 01/24/2023] Open
Abstract
Cytosolic valosin-containing protein (p97(VCP)) is translocated to the ER membrane by binding to selenoprotein S (SelS), which is an ER membrane protein, during endoplasmic reticulum-associated degradation (ERAD). Selenoprotein K (SelK) is another known p97(VCP)-binding selenoprotein, and the expression of both SelS and SelK is increased under ER stress. To understand the regulatory mechanisms of SelS, SelK, and p97(VCP) during ERAD, the interaction of the selenoproteins with p97(VCP) was investigated using N2a cells and HEK293 cells. Both SelS and SelK co-precipitated with p97(VCP). However, the association between SelS and SelK did not occur in the absence of p97(VCP). SelS had the ability to recruit p97(VCP) to the ER membrane but SelK did not. The interaction between SelK and p97(VCP) did not occur in SelS knockdown cells, whereas SelS interacted with p97(VCP) in the presence or absence of SelK. These results suggest that p97(VCP) is first translocated to the ER membrane via its interaction with SelS, and then SelK associates with the complex on the ER membrane. Therefore, the interaction between SelK and p97(VCP) is SelS-dependent, and the resulting ERAD complex (SelS-p97(VCP)-SelK) plays an important role in ERAD and ER stress.
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Affiliation(s)
- Jea Hwang Lee
- From the Laboratory of Cellular and Molecular Biochemistry, Division of Life Sciences, Korea University, 1, 5-Ka, Anam-Dong, Sungbuk-Ku, Seoul 136-713, Republic of Korea and
| | - Ki Jun Park
- From the Laboratory of Cellular and Molecular Biochemistry, Division of Life Sciences, Korea University, 1, 5-Ka, Anam-Dong, Sungbuk-Ku, Seoul 136-713, Republic of Korea and
| | - Jun Ki Jang
- From the Laboratory of Cellular and Molecular Biochemistry, Division of Life Sciences, Korea University, 1, 5-Ka, Anam-Dong, Sungbuk-Ku, Seoul 136-713, Republic of Korea and
| | - Yeong Ha Jeon
- From the Laboratory of Cellular and Molecular Biochemistry, Division of Life Sciences, Korea University, 1, 5-Ka, Anam-Dong, Sungbuk-Ku, Seoul 136-713, Republic of Korea and
| | - Kwan Young Ko
- From the Laboratory of Cellular and Molecular Biochemistry, Division of Life Sciences, Korea University, 1, 5-Ka, Anam-Dong, Sungbuk-Ku, Seoul 136-713, Republic of Korea and
| | - Joon Hyun Kwon
- From the Laboratory of Cellular and Molecular Biochemistry, Division of Life Sciences, Korea University, 1, 5-Ka, Anam-Dong, Sungbuk-Ku, Seoul 136-713, Republic of Korea and
| | - Seung-Rock Lee
- the Departments of Biochemistry and Biomedical Science, Research Center for Aging and Geriatrics, Research Institute of Medical Science, Chonnam National University Medical School, Gwangju 501-190, Republic of Korea
| | - Ick Young Kim
- From the Laboratory of Cellular and Molecular Biochemistry, Division of Life Sciences, Korea University, 1, 5-Ka, Anam-Dong, Sungbuk-Ku, Seoul 136-713, Republic of Korea and
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38
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Control of p97 function by cofactor binding. FEBS Lett 2015; 589:2578-89. [PMID: 26320413 DOI: 10.1016/j.febslet.2015.08.028] [Citation(s) in RCA: 164] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 08/18/2015] [Accepted: 08/18/2015] [Indexed: 12/14/2022]
Abstract
p97 (also known as Cdc48, Ter94, and VCP) is an essential, abundant and highly conserved ATPase driving the turnover of ubiquitylated proteins in eukaryotes. Even though p97 is involved in highly diverse cellular pathways and processes, it exhibits hardly any substrate specificity on its own. Instead, it relies on a large number of regulatory cofactors controlling substrate specificity and turnover. The complexity as well as temporal and spatial regulation of the interactions between p97 and its cofactors is only beginning to be understood at the molecular level. Here, we give an overview on the structural framework of p97 interactions with its cofactors, the emerging principles underlying the assembly of complexes with different cofactors, and the pathogenic effects of disease-associated p97 mutations on cofactor binding.
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Abstract
Small ubiquitin-like modifier (SUMO) modification modulates the expression of defense genes in Drosophila, activated by the Toll/nuclear factor-κB and immune-deficient/nuclear factor-κB signaling networks. We have, however, limited understanding of the SUMO-modulated regulation of the immune response and lack information on SUMO targets in the immune system. In this study, we measured the changes to the SUMO proteome in S2 cells in response to a lipopolysaccharide challenge and identified 1619 unique proteins in SUMO-enriched lysates. A confident set of 710 proteins represents the immune-induced SUMO proteome and analysis suggests that specific protein domains, cellular pathways, and protein complexes respond to immune stress. A small subset of the confident set was validated by in-bacto SUMOylation and shown to be bona-fide SUMO targets. These include components of immune signaling pathways such as Caspar, Jra, Kay, cdc42, p38b, 14-3-3ε, as well as cellular proteins with diverse functions, many being components of protein complexes, such as prosß4, Rps10b, SmD3, Tango7, and Aats-arg. Caspar, a human FAF1 ortholog that negatively regulates immune-deficient signaling, is SUMOylated at K551 and responds to treatment with lipopolysaccharide in cultured cells. Our study is one of the first to describe SUMO proteome for the Drosophila immune response. Our data and analysis provide a global framework for the understanding of SUMO modification in the host response to pathogens.
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40
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Ma X, Li X, Dong S, Xia Q, Wang F. A Fas associated factor negatively regulates anti-bacterial immunity by promoting Relish degradation in Bombyx mori. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2015; 63:144-151. [PMID: 26101847 DOI: 10.1016/j.ibmb.2015.06.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 06/15/2015] [Accepted: 06/18/2015] [Indexed: 06/04/2023]
Abstract
Negative regulation is required to keep NF-κB-dependent immune response under tight control. In previous study, we have identified a Fas associated factor (FAF) family member in Bombyx mori, BmFAF, and proposed it may act as a negative regulator in immune response. In this study, we found knock-down of BmFAF by RNAi led to a remarkable increase in transcriptional level of several antimicrobial peptide genes, including BmCecropinA1 and BmMoricin, and higher survival rate to Gram-negative bacterial infection. We also confirmed the regulatory role of BmFAF in suppressing NF-κB-dependent transcription by employing an inducible promoter in BmE cells. Consistent with these physiological phenotypes, BmFAF suppressed the activity of the essential transcription factor, Relish, in IMD signaling pathway by promoting its proteasomal degradation through direct interaction. In addition, by constructing various truncation mutants, we further demonstrated that UBA domain in BmFAF is required for the inhibitory role, and potential ubiquitination also occurs in this domain. Taken together, our results suggest that BmFAF is a negative regulator of IMD pathway by mediating degradation of Relish.
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Affiliation(s)
- Xiaojuan Ma
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China
| | - Xianyang Li
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China
| | - Shifeng Dong
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China
| | - Qingyou Xia
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China
| | - Fei Wang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China.
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41
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Meng Q, Rao L, Pan Y. Enrichment and analysis of rice seedling ubiquitin-related proteins using four UBA domains (GST-qUBAs). PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2014; 229:172-180. [PMID: 25443844 DOI: 10.1016/j.plantsci.2014.09.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 07/17/2014] [Accepted: 09/03/2014] [Indexed: 06/04/2023]
Abstract
Protein ubiquitination is a common posttranslational modification that often occurs on lysine residues. It controls the half-life, interaction and trafficking of intracellular proteins and is involved in different plant development stages and responses to environment stresses. Four Ubiquitin-Associated (UBA) domains were sequentially fused with Glutathione S-transferase (GST) tag (GST-qUBA) as bait protein in this study. A two-step affinity protocol was successfully developed and the identification of ubiquitinated proteins and their interaction proteins increased almost threefold compared to methods that directly identify ubiquitinated proteins from crude samples. A total of 170 ubiquitin-related proteins were identified in GST-qUBAs enriched samples taken from rice seedlings. There were 134 ubiquitinated proteins, 5 ubiquitin-activating enzymes (E1s), 5 ubiquitin-conjugating enzymes (E2s), 19 ubiquitin ligases (E3s) and 7 deubiquitinating enzymes (DUBs), which all contained various key factors that regulated a wide range of biological processes. Moreover, a series of novel ubiquitinated proteins and E3s were identified that had not been previously reported. This study investigated a high-efficiency method for identifying novel ubiquitinated proteins involved in biological processes and a primary mapping of the ubiquitylome during rice seedling development, which could extend our understanding of how ubiquitin modification regulates plant proteins, pathways and cellular processes.
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Affiliation(s)
- Qingshi Meng
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China; The National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Science, Beijing 100081, China; Institute of Crop Science, Chinese Academy of Agricultural Science, Beijing 100081, China
| | - Liqun Rao
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China.
| | - Yinghong Pan
- The National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Science, Beijing 100081, China; Institute of Crop Science, Chinese Academy of Agricultural Science, Beijing 100081, China.
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42
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Kim SJ, Kim EE. Crystallization and preliminary X-ray crystallographic analysis of the complex between the N-D1 domain of VCP from Homo sapiens and the N domain of OTU1 from Saccharomyces cerevisiae. Acta Crystallogr F Struct Biol Commun 2014; 70:1087-9. [PMID: 25084388 PMCID: PMC4118810 DOI: 10.1107/s2053230x14013351] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 06/07/2014] [Indexed: 01/13/2023] Open
Abstract
VCP (valosin-containing protein; also known as p97) plays important roles in many biological processes including the ERAD (endoplasmic reticulum-associated degradation) pathway and its function is governed by binding partners. OTU1 (ovarian tumour domain-containing protein 1) is a recently discovered deubiquitinating enzyme that interacts directly with VCP in the ERAD pathway. In order to understand the interactions between the two proteins, the N-D1 domain of VCP and the UBXL domain of OTU1 were cloned, overexpressed, purified and crystallized. The crystals of the complex diffracted to 3.25 Å resolution and belonged to space group P21, with unit-cell parameters a = 165.45, b = 176.73, c = 165.59 Å, β = 120.095°. There are two molecules of the complex in the asymmetric unit with a Matthews coefficient of 2.62 Å(3) Da(-1) and a solvent content of 53%.
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Affiliation(s)
- Su Jin Kim
- Biomedical Research Institute, Korea Institute of Science and Technology, Seoul 136-791, Republic of Korea
| | - Eunice EunKyeong Kim
- Biomedical Research Institute, Korea Institute of Science and Technology, Seoul 136-791, Republic of Korea
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43
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Ewens CA, Panico S, Kloppsteck P, McKeown C, Ebong IO, Robinson C, Zhang X, Freemont PS. The p97-FAF1 protein complex reveals a common mode of p97 adaptor binding. J Biol Chem 2014; 289:12077-12084. [PMID: 24619421 PMCID: PMC4002113 DOI: 10.1074/jbc.m114.559591] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 03/05/2014] [Indexed: 01/07/2023] Open
Abstract
p97, also known as valosin-containing protein, is a versatile participant in the ubiquitin-proteasome system. p97 interacts with a large network of adaptor proteins to process ubiquitylated substrates in different cellular pathways, including endoplasmic reticulum-associated degradation and transcription factor activation. p97 and its adaptor Fas-associated factor-1 (FAF1) both have roles in the ubiquitin-proteasome system during NF-κB activation, although the mechanisms are unknown. FAF1 itself also has emerging roles in other cell-cycle pathways and displays altered expression levels in various cancer cell lines. We have performed a detailed study the p97-FAF1 interaction. We show that FAF1 binds p97 stably and in a stoichiometry of 3 to 6. Cryo-EM analysis of p97-FAF1 yielded a 17 Å reconstruction of the complex with FAF1 above the p97 ring. Characteristics of p97-FAF1 uncovered in this study reveal common features in the interactions of p97, providing mechanistic insight into how p97 mediates diverse functionalities.
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Affiliation(s)
- Caroline A Ewens
- Centre for Structural Biology, Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Silvia Panico
- Centre for Structural Biology, Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Patrik Kloppsteck
- Centre for Structural Biology, Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Ciaran McKeown
- Centre for Structural Biology, Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Ima-Obong Ebong
- Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3TA, United Kingdom
| | - Carol Robinson
- Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3TA, United Kingdom
| | - Xiaodong Zhang
- Centre for Structural Biology, Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Paul S Freemont
- Centre for Structural Biology, Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom.
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Lee JH, Kwon JH, Jeon YH, Ko KY, Lee SR, Kim IY. Pro178 and Pro183 of selenoprotein S are essential residues for interaction with p97(VCP) during endoplasmic reticulum-associated degradation. J Biol Chem 2014; 289:13758-68. [PMID: 24700463 DOI: 10.1074/jbc.m113.534529] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
During endoplasmic reticulum (ER)-associated degradation, p97(VCP) is recruited to the ER membrane through interactions with transmembrane proteins, such as selenoprotein S (SelS), selenoprotein K (SelK), hrd1, and gp78. SelS has a single-spanning transmembrane domain and protects cells from ER stress-induced apoptosis through interaction with p97(VCP). The cytosolic tail of SelS consists of a coiled-coil domain, a putative VCP-interacting motif (VIM), and an unpronounced glycine- and proline-rich secondary structure. To understand the regulatory mechanism of SelS during ER stress, we investigated the interaction of the protein with p97(VCP) using mouse neuroblastoma cells and human embryonic kidney 293 cells. The SelS expression level increased when ER stress was induced. In addition, the effect of ER stress was enhanced, and recruitment of p97(VCP) to the ER membrane was inhibited in SelS knockdown cells. The effect of SelS knockdown was rescued by ectopic expression of SelS U188C. p97(VCP) interacted with SelS U188C and was recruited to the ER membrane. The expression of SelS[ΔVIM], which is a VIM deletion mutant of SelS, also showed both a recovery effect and an interaction with p97(VCP) in cells. However, mutants in which the proline residue positions 178 or 183 of SelS were changed to alanine or were deleted did not interact with p97(VCP). The proline mutants did not rescue ER stress in SelS knockdown cells. These results suggest that both Pro(178) and Pro(183) of SelS play important roles in the translocation of p97(VCP) to the ER membrane and protect cells from ER stress.
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Affiliation(s)
- Jea Hwang Lee
- From the Laboratory of Cellular and Molecular Biochemistry, Division of Life Sciences, Korea University, 1, 5-Ka, Anam-Dong, Sungbuk-Ku, Seoul 136-701, Republic of Korea and
| | - Joon Hyun Kwon
- From the Laboratory of Cellular and Molecular Biochemistry, Division of Life Sciences, Korea University, 1, 5-Ka, Anam-Dong, Sungbuk-Ku, Seoul 136-701, Republic of Korea and
| | - Yeong Ha Jeon
- From the Laboratory of Cellular and Molecular Biochemistry, Division of Life Sciences, Korea University, 1, 5-Ka, Anam-Dong, Sungbuk-Ku, Seoul 136-701, Republic of Korea and
| | - Kwan Young Ko
- From the Laboratory of Cellular and Molecular Biochemistry, Division of Life Sciences, Korea University, 1, 5-Ka, Anam-Dong, Sungbuk-Ku, Seoul 136-701, Republic of Korea and
| | - Seung-Rock Lee
- the Department of Biochemistry, Department of Biomedical Science, Research Center for Aging and Geriatrics, Research Institute of Medical Science, Chonnam National University Medical School, Gwangju 501-190, Republic of Korea
| | - Ick Young Kim
- From the Laboratory of Cellular and Molecular Biochemistry, Division of Life Sciences, Korea University, 1, 5-Ka, Anam-Dong, Sungbuk-Ku, Seoul 136-701, Republic of Korea and
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45
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Kim SJ, Cho J, Song EJ, Kim SJ, Kim HM, Lee KE, Suh SW, Kim EE. Structural basis for ovarian tumor domain-containing protein 1 (OTU1) binding to p97/valosin-containing protein (VCP). J Biol Chem 2014; 289:12264-74. [PMID: 24610782 DOI: 10.1074/jbc.m113.523936] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Valosin-containing protein (VCP), also known as p97, is an AAA(+) ATPase that plays an essential role in a broad array of cellular processes including the endoplasmic reticulum-associated degradation (ERAD) pathway. Recently, ERAD-specific deubiquitinating enzymes have been reported to be physically associated with VCP, although the exact mechanism is not yet clear. Among these enzymes is ovarian tumor domain-containing protein 1 (OTU1). Here, we report the structural basis for interaction between VCP and OTU1. The crystal structure of the ubiquitin regulatory X-like (UBXL) domain of OTU1 (UBXLOTU1) complexed to the N-terminal domain of VCP (NVCP) at 1.8-Å resolution reveals that UBXLOTU1 adopts a ubiquitin-like fold and binds at the interface of two subdomains of NVCP using the (39)GYPP(42) loop of UBXLOTU1 with the two prolines in cis- and trans-configurations, respectively. A mutagenesis study shows that this loop is not only critical for the interaction with VCP but also for its role in the ERAD pathway. Negative staining EM shows that one molecule of OTU1 binds to one VCP hexamer, and isothermal titration calorimetry suggests that the two proteins bind with a KD of 0.71 μM. Analytical size exclusion chromatography and isothermal titration calorimetry demonstrates that OTU1 can bind VCP in both the presence and absence of a heterodimer formed by ubiquitin fusion degradation protein 1 and nuclear localization protein 4.
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Affiliation(s)
- Su Jin Kim
- From the Biomedical Research Institute, Korea Institute of Science and Technology, Seoul 136-791, Republic of Korea
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Goel R, Murthy KR, Srikanth SM, Pinto SM, Bhattacharjee M, Kelkar DS, Madugundu AK, Dey G, Mohan SS, Krishna V, Prasad TK, Chakravarti S, Harsha HC, Pandey A. Characterizing the normal proteome of human ciliary body. Clin Proteomics 2013; 10:9. [PMID: 23914977 PMCID: PMC3750387 DOI: 10.1186/1559-0275-10-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 07/16/2013] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The ciliary body is the circumferential muscular tissue located just behind the iris in the anterior chamber of the eye. It plays a pivotal role in the production of aqueous humor, maintenance of the lens zonules and accommodation by changing the shape of the crystalline lens. The ciliary body is the major target of drugs against glaucoma as its inhibition leads to a drop in intraocular pressure. A molecular study of the ciliary body could provide a better understanding about the pathophysiological processes that occur in glaucoma. Thus far, no large-scale proteomic investigation has been reported for the human ciliary body. RESULTS In this study, we have carried out an in-depth LC-MS/MS-based proteomic analysis of normal human ciliary body and have identified 2,815 proteins. We identified a number of proteins that were previously not described in the ciliary body including importin 5 (IPO5), atlastin-2 (ATL2), B-cell receptor associated protein 29 (BCAP29), basigin (BSG), calpain-1 (CAPN1), copine 6 (CPNE6), fibulin 1 (FBLN1) and galectin 1 (LGALS1). We compared the plasma proteome with the ciliary body proteome and found that the large majority of proteins in the ciliary body were also detectable in the plasma while 896 proteins were unique to the ciliary body. We also classified proteins using pathway enrichment analysis and found most of proteins associated with ubiquitin pathway, EIF2 signaling, glycolysis and gluconeogenesis. CONCLUSIONS More than 95% of the identified proteins have not been previously described in the ciliary body proteome. This is the largest catalogue of proteins reported thus far in the ciliary body that should provide new insights into our understanding of the factors involved in maintaining the secretion of aqueous humor. The identification of these proteins will aid in understanding various eye diseases of the anterior segment such as glaucoma and presbyopia.
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Affiliation(s)
- Renu Goel
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India.,Department of Biotechnology, Kuvempu University, Shankaraghatta, Shimoga 577 451, Karnataka, India
| | - Krishna R Murthy
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India.,Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam 690 525, Kerala, India.,Vittala International Institute Of Ophthalmology, Bangalore 560 085, Karnataka, India
| | - Srinivas M Srikanth
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India.,Centre of Excellence in Bioinformatics, Bioinformatics Centre, School of Life Sciences, Pondicherry University, Puducherry 605 014, India
| | - Sneha M Pinto
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India.,Manipal University, Madhav Nagar, Manipal 576104, Karnataka, India
| | - Mitali Bhattacharjee
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India.,Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam 690 525, Kerala, India
| | - Dhanashree S Kelkar
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India.,Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam 690 525, Kerala, India
| | - Anil K Madugundu
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India
| | - Gourav Dey
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India
| | - Sujatha S Mohan
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India.,Department of Biotechnology, Kuvempu University, Shankaraghatta, Shimoga 577 451, Karnataka, India.,Research Unit for Immunoinformatics, RIKEN Research Center for Allergy and Immunology, RIKEN Yokohama Institute, Kanagawa 230 0045, Japan
| | - Venkatarangaiah Krishna
- Department of Biotechnology, Kuvempu University, Shankaraghatta, Shimoga 577 451, Karnataka, India
| | - Ts Keshava Prasad
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India.,Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam 690 525, Kerala, India.,Manipal University, Madhav Nagar, Manipal 576104, Karnataka, India
| | - Shukti Chakravarti
- Johns Hopkins University School of Medicine, Baltimore 21205, MD, USA.,Department of Cell Biology, Johns Hopkins School of Medicine, Baltimore, MD, USA.,Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - H C Harsha
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India
| | - Akhilesh Pandey
- Johns Hopkins University School of Medicine, Baltimore 21205, MD, USA.,McKusick-Nathans Institute of Genetic Medicine, Departments of Biological Chemistry, Oncology and Pathology, Johns Hopkins University School of Medicine, Baltimore 21205, MD, USA
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Kolawa N, Sweredoski MJ, Graham RLJ, Oania R, Hess S, Deshaies RJ. Perturbations to the ubiquitin conjugate proteome in yeast δubx mutants identify Ubx2 as a regulator of membrane lipid composition. Mol Cell Proteomics 2013; 12:2791-803. [PMID: 23793018 PMCID: PMC3790291 DOI: 10.1074/mcp.m113.030163] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Yeast Cdc48 (p97/VCP in human cells) is a hexameric AAA ATPase that is thought to use ATP hydrolysis to power the segregation of ubiquitin-conjugated proteins from tightly bound partners. Current models posit that Cdc48 is linked to its substrates through adaptor proteins, including a family of seven proteins (13 in human) that contain a Cdc48-binding UBX domain. However, few substrates for specific UBX proteins are known, and hence the generality of this hypothesis remains untested. Here, we use mass spectrometry to identify ubiquitin conjugates that accumulate in cdc48 and ubx mutants. Different ubx mutants exhibit unique patterns of conjugate accumulation that point to functional specialization of individual Ubx proteins. To validate our findings, we examined in detail the endoplasmic reticulum-bound transcription factor Spt23, which we identified as a putative Ubx2 substrate. Mutant ubx2Δ cells are deficient in both cleaving the ubiquitinated 120 kDa precursor of Spt23 to form active p90 and in localizing p90 to the nucleus, resulting in reduced expression of the target gene OLE1, which encodes fatty acid desaturase. Our findings provide a resource for future investigations on Cdc48, illustrate the utility of proteomics to identify ligands for specific ubiquitin receptor pathways, and uncover Ubx2 as a key player in the regulation of membrane lipid biosynthesis.
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