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Riehl J, Rijal R, Nitz L, Clemen CS, Hofmann A, Eichinger L. Domain Organization of the UBX Domain Containing Protein 9 and Analysis of Its Interactions With the Homohexameric AAA + ATPase p97 (Valosin-Containing Protein). Front Cell Dev Biol 2021; 9:748860. [PMID: 34631722 PMCID: PMC8495200 DOI: 10.3389/fcell.2021.748860] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 08/31/2021] [Indexed: 11/13/2022] Open
Abstract
The abundant homohexameric AAA + ATPase p97 (also known as valosin-containing protein, VCP) is highly conserved from Dictyostelium discoideum to human and a pivotal factor of cellular protein homeostasis as it catalyzes the unfolding of proteins. Owing to its fundamental function in protein quality control pathways, it is regulated by more than 30 cofactors, including the UBXD protein family, whose members all carry an Ubiquitin Regulatory X (UBX) domain that enables binding to p97. One member of this latter protein family is the largely uncharacterized UBX domain containing protein 9 (UBXD9). Here, we analyzed protein-protein interactions of D. discoideum UBXD9 with p97 using a series of N- and C-terminal truncation constructs and probed the UBXD9 interactome in D. discoideum. Pull-down assays revealed that the UBX domain (amino acids 384-466) is necessary and sufficient for p97 interactions and that the N-terminal extension of the UBX domain, which folds into a β0-α- 1-α0 lariat structure, is required for the dissociation of p97 hexamers. Functionally, this finding is reflected by strongly reduced ATPase activity of p97 upon addition of full length UBXD9 or UBXD9261-573. Results from Blue Native PAGE as well as structural model prediction suggest that hexamers of UBXD9 or UBXD9261-573 interact with p97 hexamers and disrupt the p97 subunit interactions via insertion of a helical lariat structure, presumably by destabilizing the p97 D1:D1' intermolecular interface. We thus propose that UBXD9 regulates p97 activity in vivo by shifting the quaternary structure equilibrium from hexamers to monomers. Using three independent approaches, we further identified novel interaction partners of UBXD9, including glutamine synthetase type III as well as several actin-binding proteins. These findings suggest a role of UBXD9 in the organization of the actin cytoskeleton, and are in line with the hypothesized oligomerization-dependent mechanism of p97 regulation.
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Affiliation(s)
- Jana Riehl
- Medical Faculty, Center for Biochemistry, Institute of Biochemistry I, University of Cologne, Cologne, Germany
| | - Ramesh Rijal
- Department of Biology, College Station, Texas A&M University, Texas, TX, United States
| | - Leonie Nitz
- Medical Faculty, Center for Biochemistry, Institute of Biochemistry I, University of Cologne, Cologne, Germany
| | - Christoph S. Clemen
- Medical Faculty, Center for Biochemistry, Institute of Biochemistry I, University of Cologne, Cologne, Germany
- German Aerospace Center, Institute of Aerospace Medicine, Cologne, Germany
- Medical Faculty, Center for Physiology and Pathophysiology, Institute of Vegetative Physiology, University of Cologne, Cologne, Germany
| | - Andreas Hofmann
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, VIC, Australia
| | - Ludwig Eichinger
- Medical Faculty, Center for Biochemistry, Institute of Biochemistry I, University of Cologne, Cologne, Germany
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Clemen CS, Winter L, Strucksberg KH, Berwanger C, Türk M, Kornblum C, Florin A, Aguilar-Pimentel JA, Amarie OV, Becker L, Garrett L, Hans W, Moreth K, Neff F, Pingen L, Rathkolb B, Rácz I, Rozman J, Treise I, Fuchs H, Gailus-Durner V, de Angelis MH, Vorgerd M, Eichinger L, Schröder R. The heterozygous R155C VCP mutation: Toxic in humans! Harmless in mice? Biochem Biophys Res Commun 2018; 503:2770-2777. [PMID: 30100055 DOI: 10.1016/j.bbrc.2018.08.038] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 08/04/2018] [Indexed: 12/12/2022]
Abstract
Heterozygous missense mutations in the human VCP gene cause inclusion body myopathy associated with Paget disease of bone and fronto-temporal dementia (IBMPFD) and amyotrophic lateral sclerosis (ALS). The exact molecular mechanisms by which VCP mutations cause disease manifestation in different tissues are incompletely understood. In the present study, we report the comprehensive analysis of a newly generated R155C VCP knock-in mouse model, which expresses the ortholog of the second most frequently occurring human pathogenic VCP mutation. Heterozygous R155C VCP knock-in mice showed decreased plasma lactate, serum albumin and total protein concentrations, platelet numbers, and liver to body weight ratios, and increased oxygen consumption and CD8+/Ly6C + T-cell fractions, but none of the typical human IBMPFD or ALS pathologies. Breeding of heterozygous mice did not yield in the generation of homozygous R155C VCP knock-in animals. Immunoblotting showed identical total VCP protein levels in human IBMPFD and murine R155C VCP knock-in tissues as compared to wild-type controls. However, while in human IBMPFD skeletal muscle tissue 70% of the total VCP mRNA was derived from the mutant allele, in R155C VCP knock-in mice only 5% and 7% mutant mRNA were detected in skeletal muscle and brain tissue, respectively. The lack of any obvious IBMPFD or ALS pathology could thus be a consequence of the very low expression of mutant VCP. We conclude that the increased and decreased fractions of the R155C mutant VCP mRNA in man and mice, respectively, are due to missense mutation-induced, divergent alterations in the biological half-life of the human and murine mutant mRNAs. Furthermore, our work suggests that therapy approaches lowering the expression of the mutant VCP mRNA below a critical threshold may ameliorate the intrinsic disease pathology.
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Affiliation(s)
- Christoph S Clemen
- Department of Neurology, Heimer Institute for Muscle Research, University Hospital Bergmannsheil, Ruhr-University Bochum, 44789, Bochum, Germany; Center for Biochemistry, Institute of Biochemistry I, Medical Faculty, University of Cologne, 50931, Cologne, Germany.
| | - Lilli Winter
- Institute of Neuropathology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, 91054, Erlangen, Germany; Neuromuscular Research Department, Center for Anatomy and Cell Biology, Medical University of Vienna, 1090, Vienna, Austria
| | - Karl-Heinz Strucksberg
- Center for Biochemistry, Institute of Biochemistry I, Medical Faculty, University of Cologne, 50931, Cologne, Germany
| | - Carolin Berwanger
- Department of Neurology, Heimer Institute for Muscle Research, University Hospital Bergmannsheil, Ruhr-University Bochum, 44789, Bochum, Germany; Center for Biochemistry, Institute of Biochemistry I, Medical Faculty, University of Cologne, 50931, Cologne, Germany
| | - Matthias Türk
- Department of Neurology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, 91054, Erlangen, Germany
| | - Cornelia Kornblum
- Department of Neurology, University Hospital Bonn, 53125, Bonn, Germany; Center for Rare Diseases Bonn, University Hospital Bonn, 53127, Bonn, Germany
| | - Alexandra Florin
- Institute for Pathology, University Hospital Cologne, 50937, Cologne, Germany
| | - Juan Antonio Aguilar-Pimentel
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany
| | - Oana Veronica Amarie
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany; Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany
| | - Lore Becker
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany
| | - Lillian Garrett
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany; Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany
| | - Wolfgang Hans
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany
| | - Kristin Moreth
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany
| | - Frauke Neff
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany; Institute of Pathology, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany
| | - Laura Pingen
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany
| | - Birgit Rathkolb
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany; Institute of Molecular Animal Breeding and Biotechnology, Gene Center, Ludwig-Maximilians-University München, 81377, Munich, Germany; German Center for Diabetes Research (DZD), 85764, Neuherberg, Germany
| | - Ildikó Rácz
- Institute of Molecular Psychiatry, Medical Faculty, University of Bonn, 53127, Bonn, Germany; Clinic of Neurodegenerative Diseases and Gerontopsychiatry, University of Bonn Medical Center, 53127, Bonn, Germany
| | - Jan Rozman
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764, Neuherberg, Germany
| | - Irina Treise
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany
| | - Helmut Fuchs
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany
| | - Valerie Gailus-Durner
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany
| | - Martin Hrabe de Angelis
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764, Neuherberg, Germany; Chair of Experimental Genetics, School of Life Science Weihenstephan, Technische Universität München, 85354, Freising, Germany
| | - Matthias Vorgerd
- Department of Neurology, Heimer Institute for Muscle Research, University Hospital Bergmannsheil, Ruhr-University Bochum, 44789, Bochum, Germany
| | - Ludwig Eichinger
- Center for Biochemistry, Institute of Biochemistry I, Medical Faculty, University of Cologne, 50931, Cologne, Germany
| | - Rolf Schröder
- Institute of Neuropathology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, 91054, Erlangen, Germany.
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