1
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Lee Y, Kim H, Barker D, Vijayvargia R, Atwal RS, Specht H, Keshishian H, Carr SA, Lee R, Kwak S, Hyun KG, Loupe J, MacDonald ME, Song JJ, Seong IS. Huntingtin turnover: modulation of huntingtin degradation by cAMP-dependent protein kinase A (PKA) phosphorylation of C-HEAT domain Ser2550. Hum Mol Genet 2023; 32:30-45. [PMID: 35908190 DOI: 10.1093/hmg/ddac165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/07/2022] [Accepted: 07/12/2022] [Indexed: 01/25/2023] Open
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by an inherited unstable HTT CAG repeat that expands further, thereby eliciting a disease process that may be initiated by polyglutamine-expanded huntingtin or a short polyglutamine-product. Phosphorylation of selected candidate residues is reported to mediate polyglutamine-fragment degradation and toxicity. Here to support the discovery of phosphosites involved in the life-cycle of (full-length) huntingtin, we employed mass spectrometry-based phosphoproteomics to systematically identify sites in purified huntingtin and in the endogenous protein by proteomic and phosphoproteomic analyses of members of an HD neuronal progenitor cell panel. Our results bring total huntingtin phosphosites to 95, with more located in the N-HEAT domain relative to numbers in the Bridge and C-HEAT domains. Moreover, phosphorylation of C-HEAT Ser2550 by cAMP-dependent protein kinase (PKA), the top hit in kinase activity screens, was found to hasten huntingtin degradation, such that levels of the catalytic subunit (PRKACA) were inversely related to huntingtin levels. Taken together, these findings highlight categories of phosphosites that merit further study and provide a phosphosite kinase pair (pSer2550-PKA) with which to investigate the biological processes that regulate huntingtin degradation and thereby influence the steady state levels of huntingtin in HD cells.
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Affiliation(s)
- Yejin Lee
- Department of Biological Sciences, KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.,Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Hyeongju Kim
- Department of Biological Sciences, KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Douglas Barker
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Ravi Vijayvargia
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Ranjit Singh Atwal
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Harrison Specht
- Broad Institute of MIT and Harvard, 7 Cambridge Center, Cambridge, MA 02142, USA
| | - Hasmik Keshishian
- Broad Institute of MIT and Harvard, 7 Cambridge Center, Cambridge, MA 02142, USA
| | - Steven A Carr
- Broad Institute of MIT and Harvard, 7 Cambridge Center, Cambridge, MA 02142, USA
| | - Ramee Lee
- CHDI Management/CHDI Foundation, Princeton, NJ 08540, USA
| | - Seung Kwak
- CHDI Management/CHDI Foundation, Princeton, NJ 08540, USA
| | - Kyung-Gi Hyun
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Jacob Loupe
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Marcy E MacDonald
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Ji-Joon Song
- Department of Biological Sciences, KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Ihn Sik Seong
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
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2
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Seefelder M, Klein FAC, Landwehrmeyer B, Fernández-Busnadiego R, Kochanek S. Huntingtin and Its Partner Huntingtin-Associated Protein 40: Structural and Functional Considerations in Health and Disease. J Huntingtons Dis 2022; 11:227-242. [PMID: 35871360 PMCID: PMC9484127 DOI: 10.3233/jhd-220543] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Since the discovery of the mutation causing Huntington’s disease (HD) in 1993, it has been debated whether an expanded polyglutamine (polyQ) stretch affects the properties of the huntingtin (HTT) protein and thus contributes to the pathological mechanisms responsible for HD. Here we review the current knowledge about the structure of HTT, alone (apo-HTT) or in a complex with Huntingtin-Associated Protein 40 (HAP40), the influence of polyQ-length variation on apo-HTT and the HTT-HAP40 complex, and the biology of HAP40. Phylogenetic analyses suggest that HAP40 performs essential functions. Highlighting the relevance of its interaction with HTT, HAP40 is one of the most abundant partners copurifying with HTT and is rapidly degraded, when HTT levels are reduced. As the levels of both proteins decrease during disease progression, HAP40 could also be a biomarker for HD. Whether declining HAP40 levels contribute to disease etiology is an open question. Structural studies have shown that the conformation of apo-HTT is less constrained but resembles that adopted in the HTT-HAP40 complex, which is exceptionally stable because of extensive interactions between HAP40 and the three domains of HTT. The complex— and to some extent apo-HTT— resists fragmentation after limited proteolysis. Unresolved regions of apo-HTT, constituting about 25% of the protein, are the main sites of post-translational modifications and likely have major regulatory functions. PolyQ elongation does not substantially alter the structure of HTT, alone or when associated with HAP40. Particularly, polyQ above the disease length threshold does not induce drastic conformational changes in full-length HTT. Therefore, models of HD pathogenesis stating that polyQ expansion drastically alters HTT properties should be reconsidered.
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Affiliation(s)
| | | | | | - Rubén Fernández-Busnadiego
- Institute of Neuropathology, University Medical Center Göttingen, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
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3
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Jarosińska OD, Rüdiger SGD. Molecular Strategies to Target Protein Aggregation in Huntington's Disease. Front Mol Biosci 2021; 8:769184. [PMID: 34869596 PMCID: PMC8636123 DOI: 10.3389/fmolb.2021.769184] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 10/18/2021] [Indexed: 11/30/2022] Open
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by the aggregation of the mutant huntingtin (mHTT) protein in nerve cells. mHTT self-aggregates to form soluble oligomers and insoluble fibrils, which interfere in a number of key cellular functions. This leads to cell quiescence and ultimately cell death. There are currently still no treatments available for HD, but approaches targeting the HTT levels offer systematic, mechanism-driven routes towards curing HD and other neurodegenerative diseases. This review summarizes the current state of knowledge of the mRNA targeting approaches such as antisense oligonucleotides and RNAi system; and the novel methods targeting mHTT and aggregates for degradation via the ubiquitin proteasome or the autophagy-lysosomal systems. These methods include the proteolysis-targeting chimera, Trim-Away, autophagosome-tethering compound, autophagy-targeting chimera, lysosome-targeting chimera and approach targeting mHTT for chaperone-mediated autophagy. These molecular strategies provide a knowledge-based approach to target HD and other neurodegenerative diseases at the origin.
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Affiliation(s)
- Olga D. Jarosińska
- Cellular Protein Chemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, Utrecht, Netherlands
- Science for Life, Utrecht University, Utrecht, Netherlands
| | - Stefan G. D. Rüdiger
- Cellular Protein Chemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, Utrecht, Netherlands
- Science for Life, Utrecht University, Utrecht, Netherlands
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4
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Huang B, Seefelder M, Buck E, Engler T, Lindenberg KS, Klein F, Landwehrmeyer GB, Kochanek S. HAP40 protein levels are huntingtin-dependent and decrease in Huntington disease. Neurobiol Dis 2021; 158:105476. [PMID: 34390835 DOI: 10.1016/j.nbd.2021.105476] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 07/08/2021] [Accepted: 08/09/2021] [Indexed: 12/01/2022] Open
Abstract
The huntingtin-associated protein 40 (HAP40) is an abundant interactor of huntingtin (HTT). In complexes of these proteins, HAP40 tightly binds to HTT in a cleft formed by two larger domains rich in HEAT repeats, and a smaller bridge domain connecting the two. We show that HAP40 steady-state protein levels are directly dependent on HTT (both normal and mutant HTT) and that HAP40 is strongly stabilized by the interaction with HTT resulting in an at least 5-fold increase in HAP40's half-life when bound to HTT. Cellular HAP40 protein levels were reduced in primary fibroblasts and lymphoblasts of Huntington Disease (HD) patients and in brain tissue of a full-length HTT mouse model of HD, concomitant with decreased soluble HTT levels in these cell types. This data and our previous demonstration of coevolution between HTT and HAP40 and evolutionary conservation of their interaction suggest that HAP40 is an obligate interaction partner of HTT. Our observation of reduced HAP40 levels in HD invites further studies, whether HAP40 loss-of-function contributes to the pathophysiology of HD.
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Affiliation(s)
- Bin Huang
- Department of Gene Therapy, Ulm University, 89081 Ulm, Germany
| | | | - Eva Buck
- Department of Neurology, Ulm University, 89081 Ulm, Germany
| | - Tatjana Engler
- Department of Gene Therapy, Ulm University, 89081 Ulm, Germany
| | | | - Fabrice Klein
- Department of Neurology, Ulm University, 89081 Ulm, Germany
| | | | - Stefan Kochanek
- Department of Gene Therapy, Ulm University, 89081 Ulm, Germany.
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5
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Lv S, Song Q, Chen G, Cheng E, Chen W, Cole R, Wu Z, Pascal LE, Wang K, Wipf P, Nelson JB, Wei Q, Huang W, Wang Z. Regulation and targeting of androgen receptor nuclear localization in castration-resistant prostate cancer. J Clin Invest 2021; 131:141335. [PMID: 33332287 DOI: 10.1172/jci141335] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 12/09/2020] [Indexed: 12/14/2022] Open
Abstract
Nuclear localization of the androgen receptor (AR) is necessary for its activation as a transcription factor. Defining the mechanisms regulating AR nuclear localization in androgen-sensitive cells and how these mechanisms are dysregulated in castration-resistant prostate cancer (CRPC) cells is fundamentally important and clinically relevant. According to the classical model of AR intracellular trafficking, androgens induce AR nuclear import and androgen withdrawal causes AR nuclear export. The present study has led to an updated model that AR could be imported in the absence of androgens, ubiquitinated, and degraded in the nucleus. Androgen withdrawal caused nuclear AR degradation, but not export. In comparison with their parental androgen-sensitive LNCaP prostate cancer cells, castration-resistant C4-2 cells exhibited reduced nuclear AR polyubiquitination and increased nuclear AR level. We previously identified 3-(4-chlorophenyl)-6,7-dihydro-5H-pyrrolo[1,2-a]imidazole (CPPI) in a high-throughput screen for its inhibition of androgen-independent AR nuclear localization in CRPC cells. The current study shows that CPPI is a competitive AR antagonist capable of enhancing AR interaction with its E3 ligase MDM2 and degradation of AR in the nuclei of CRPC cells. Also, CPPI blocked androgen-independent AR nuclear import. Overall, these findings suggest the feasibility of targeting androgen-independent AR nuclear import and stabilization, two necessary steps leading to AR nuclear localization and activation in CRPC cells, with small molecule inhibitors.
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Affiliation(s)
- Shidong Lv
- Department of Urology, Nanfang Hospital, Southern Medical University, and.,National Key Discipline of Human Anatomy, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong, China.,Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Qiong Song
- Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,Key Laboratory of Longevity and Ageing Related Disease of Chinese Ministry of Education, Center for Translational Medicine and School of Preclinical Medicine, Guangxi Medical University, Nanning, Guangxi, China
| | - Guang Chen
- Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,Department of Urology, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Erdong Cheng
- Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Wei Chen
- Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Ryan Cole
- Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Zeyu Wu
- Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Laura E Pascal
- Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Ke Wang
- Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,Department of Urology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shanxi, China
| | - Peter Wipf
- UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Joel B Nelson
- Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Qiang Wei
- Department of Urology, Nanfang Hospital, Southern Medical University, and
| | - Wenhua Huang
- National Key Discipline of Human Anatomy, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong, China
| | - Zhou Wang
- Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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6
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Jung R, Lee Y, Barker D, Correia K, Shin B, Loupe J, Collins RL, Lucente D, Ruliera J, Gillis T, Mysore JS, Rodan L, Picker J, Lee JM, Howland D, Lee R, Kwak S, MacDonald ME, Gusella JF, Seong IS. Mutations causing Lopes-Maciel-Rodan syndrome are huntingtin hypomorphs. Hum Mol Genet 2021; 30:135-148. [PMID: 33432339 DOI: 10.1093/hmg/ddaa283] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 11/18/2020] [Accepted: 12/24/2020] [Indexed: 12/31/2022] Open
Abstract
Huntington's disease pathogenesis involves a genetic gain-of-function toxicity mechanism triggered by the expanded HTT CAG repeat. Current therapeutic efforts aim to suppress expression of total or mutant huntingtin, though the relationship of huntingtin's normal activities to the gain-of-function mechanism and what the effects of huntingtin-lowering might be are unclear. Here, we have re-investigated a rare family segregating two presumed HTT loss-of-function (LoF) variants associated with the developmental disorder, Lopes-Maciel-Rodan syndrome (LOMARS), using whole-genome sequencing of DNA from cell lines, in conjunction with analysis of mRNA and protein expression. Our findings correct the muddled annotation of these HTT variants, reaffirm they are the genetic cause of the LOMARS phenotype and demonstrate that each variant is a huntingtin hypomorphic mutation. The NM_002111.8: c.4469+1G>A splice donor variant results in aberrant (exon 34) splicing and severely reduced mRNA, whereas, surprisingly, the NM_002111.8: c.8157T>A NP_002102.4: Phe2719Leu missense variant results in abnormally rapid turnover of the Leu2719 huntingtin protein. Thus, although rare and subject to an as yet unknown LoF intolerance at the population level, bona fide HTT LoF variants can be transmitted by normal individuals leading to severe consequences in compound heterozygotes due to huntingtin deficiency.
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Affiliation(s)
- Roy Jung
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Yejin Lee
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Douglas Barker
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Kevin Correia
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Baehyun Shin
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Jacob Loupe
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Ryan L Collins
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Medical and Population Genetics Program, The Broad Institute of M.I.T. and Harvard, Cambridge, MA, 02142, USA.,Program in Bioinformatics and Integrative Genomics, Division of Medical Sciences, Harvard Medical School, Boston, MA 02114, USA
| | - Diane Lucente
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Jayla Ruliera
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Tammy Gillis
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Jayalakshmi S Mysore
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Lance Rodan
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA.,Department of Neurology, Boston Children's Hospital, Harvard Medical School, MA 02115, USA
| | - Jonathan Picker
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA.,Department of Child and Adolescent Psychiatry, Boston Children's Hospital, Harvard Medical School, MA 02115, USA
| | - Jong-Min Lee
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - David Howland
- CHDI Management/CHDI Foundation Inc., Princeton, NJ 08540, USA
| | - Ramee Lee
- CHDI Management/CHDI Foundation Inc., Princeton, NJ 08540, USA
| | - Seung Kwak
- CHDI Management/CHDI Foundation Inc., Princeton, NJ 08540, USA
| | - Marcy E MacDonald
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA.,Medical and Population Genetics Program, The Broad Institute of M.I.T. and Harvard, Cambridge, MA, 02142, USA
| | - James F Gusella
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Medical and Population Genetics Program, The Broad Institute of M.I.T. and Harvard, Cambridge, MA, 02142, USA.,Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Ihn Sik Seong
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
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7
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Simard JR, Lee L, Vieux E, Improgo R, Tieu T, Phillips AJ, Fisher SL, Pollock RM, Park E. High-Throughput Quantitative Assay Technologies for Accelerating the Discovery and Optimization of Targeted Protein Degradation Therapeutics. SLAS DISCOVERY 2021; 26:503-517. [PMID: 33430712 DOI: 10.1177/2472555220985049] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The aberrant regulation of protein expression and function can drastically alter cellular physiology and lead to numerous pathophysiological conditions such as cancer, inflammatory diseases, and neurodegeneration. The steady-state expression levels of endogenous proteins are controlled by a balance of de novo synthesis rates and degradation rates. Moreover, the levels of activated proteins in signaling cascades can be further modulated by a variety of posttranslational modifications and protein-protein interactions. The field of targeted protein degradation is an emerging area for drug discovery in which small molecules are used to recruit E3 ubiquitin ligases to catalyze the ubiquitination and subsequent degradation of disease-causing target proteins by the proteasome in both a dose- and time-dependent manner. Traditional approaches for quantifying protein level changes in cells, such as Western blots, are typically low throughput with limited quantification, making it hard to drive the rapid development of therapeutics that induce selective, rapid, and sustained protein degradation. In the last decade, a number of techniques and technologies have emerged that have helped to accelerate targeted protein degradation drug discovery efforts, including the use of fluorescent protein fusions and reporter tags, flow cytometry, time-resolved fluorescence energy transfer (TR-FRET), and split luciferase systems. Here we discuss the advantages and disadvantages associated with these technologies and their application to the development and optimization of degraders as therapeutics.
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Affiliation(s)
| | - Linda Lee
- C4 Therapeutics, Inc., Watertown, MA, USA
| | | | | | - Trang Tieu
- C4 Therapeutics, Inc., Watertown, MA, USA
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8
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Mideksa YG, Fottner M, Braus S, Weiß CAM, Nguyen TA, Meier S, Lang K, Feige MJ. Site-Specific Protein Labeling with Fluorophores as a Tool To Monitor Protein Turnover. Chembiochem 2020; 21:1861-1867. [PMID: 32011787 PMCID: PMC7383901 DOI: 10.1002/cbic.201900651] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 01/28/2020] [Indexed: 12/30/2022]
Abstract
Proteins that terminally fail to acquire their native structure are detected and degraded by cellular quality control systems. Insights into cellular protein quality control are key to a better understanding of how cells establish and maintain the integrity of their proteome and of how failures in these processes cause human disease. Here we have used genetic code expansion and fast bio‐orthogonal reactions to monitor protein turnover in mammalian cells through a fluorescence‐based assay. We have used immune signaling molecules (interleukins) as model substrates and shown that our approach preserves normal cellular quality control, assembly processes, and protein functionality and works for different proteins and fluorophores. We have further extended our approach to a pulse‐chase type of assay that can provide kinetic insights into cellular protein behavior. Taken together, this study establishes a minimally invasive method to investigate protein turnover in cells as a key determinant of cellular homeostasis.
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Affiliation(s)
- Yonatan G Mideksa
- Center for Integrated Protein Science Munich (CIPSM) at the Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, 85748, Garching, Germany
| | - Maximilian Fottner
- Center for Integrated Protein Science Munich (CIPSM) at the Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, 85748, Garching, Germany
| | - Sebastian Braus
- Center for Integrated Protein Science Munich (CIPSM) at the Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, 85748, Garching, Germany.,Current address: Institute of Molecular Biology and Biophysics, ETH Zürich, 8093, Zürich, Switzerland
| | - Caroline A M Weiß
- Center for Integrated Protein Science Munich (CIPSM) at the Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, 85748, Garching, Germany
| | - Tuan-Anh Nguyen
- Center for Integrated Protein Science Munich (CIPSM) at the Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, 85748, Garching, Germany
| | - Susanne Meier
- Center for Integrated Protein Science Munich (CIPSM) at the Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, 85748, Garching, Germany
| | - Kathrin Lang
- Center for Integrated Protein Science Munich (CIPSM) at the Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, 85748, Garching, Germany.,Institute for Advanced Study, Technical University of Munich, Lichtenbergstr.2a, 85748, Garching, Germany
| | - Matthias J Feige
- Center for Integrated Protein Science Munich (CIPSM) at the Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, 85748, Garching, Germany.,Institute for Advanced Study, Technical University of Munich, Lichtenbergstr.2a, 85748, Garching, Germany
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9
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Conformation Polymorphism of Polyglutamine Proteins. Trends Biochem Sci 2018; 43:424-435. [PMID: 29636213 DOI: 10.1016/j.tibs.2018.03.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 03/05/2018] [Accepted: 03/12/2018] [Indexed: 01/29/2023]
Abstract
Expanded polyglutamine (polyQ) stretches within endogenous proteins cause at least nine human diseases. The structural basis of polyQ pathogenesis is the key to understanding fundamental mechanisms of these diseases, but it remains unclear and controversial due to a lack of polyQ protein structures at the single-atom level. Various hypotheses have been proposed to explain the structure-cytotoxicity relationship of pathogenic proteins with polyQ expansion, largely based on indirect evidence. Here we review these hypotheses and their supporting evidence, along with additional insights from recent structural biology and chemical biology studies, with a focus on Huntingtin (HTT), the most extensively studied polyQ disease protein. Lastly, we propose potential novel strategies that may further clarify the conformation-cytotoxicity relationship of polyQ proteins.
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10
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Yu M, Fu Y, Liang Y, Song H, Yao Y, Wu P, Yao Y, Pan Y, Wen X, Ma L, Hexige S, Ding Y, Luo S, Lu B. Suppression of MAPK11 or HIPK3 reduces mutant Huntingtin levels in Huntington's disease models. Cell Res 2017; 27:1441-1465. [PMID: 29151587 PMCID: PMC5717400 DOI: 10.1038/cr.2017.113] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 06/14/2017] [Accepted: 08/08/2017] [Indexed: 12/13/2022] Open
Abstract
Most neurodegenerative disorders are associated with accumulation of disease-relevant proteins. Among them, Huntington disease (HD) is of particular interest because of its monogenetic nature. HD is mainly caused by cytotoxicity of the defective protein encoded by the mutant Huntingtin gene (HTT). Thus, lowering mutant HTT protein (mHTT) levels would be a promising treatment strategy for HD. Here we report two kinases HIPK3 and MAPK11 as positive modulators of mHTT levels both in cells and in vivo. Both kinases regulate mHTT via their kinase activities, suggesting that inhibiting these kinases may have therapeutic values. Interestingly, their effects on HTT levels are mHTT-dependent, providing a feedback mechanism in which mHTT enhances its own level thus contributing to mHTT accumulation and disease progression. Importantly, knockout of MAPK11 significantly rescues disease-relevant behavioral phenotypes in a knockin HD mouse model. Collectively, our data reveal new therapeutic entry points for HD and target-discovery approaches for similar diseases.
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Affiliation(s)
- Meng Yu
- State Key Laboratory of Medical Neurobiology, Huashan Hospital, School of Life Sciences, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
| | - Yuhua Fu
- State Key Laboratory of Medical Neurobiology, Huashan Hospital, School of Life Sciences, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
| | - Yijiang Liang
- State Key Laboratory of Medical Neurobiology, Huashan Hospital, School of Life Sciences, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
| | - Haikun Song
- State Key Laboratory of Medical Neurobiology, Huashan Hospital, School of Life Sciences, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
| | - Yao Yao
- State Key Laboratory of Medical Neurobiology, Huashan Hospital, School of Life Sciences, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
| | - Peng Wu
- State Key Laboratory of Medical Neurobiology, Huashan Hospital, School of Life Sciences, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
| | - Yuwei Yao
- State Key Laboratory of Medical Neurobiology, Huashan Hospital, School of Life Sciences, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
| | - Yuyin Pan
- State Key Laboratory of Medical Neurobiology, Huashan Hospital, School of Life Sciences, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
| | - Xue Wen
- State Key Laboratory of Medical Neurobiology, Huashan Hospital, School of Life Sciences, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
| | - Lixiang Ma
- Department of Anatomy and Histology & Embryology, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Saiyin Hexige
- State Key Laboratory of Medical Neurobiology, Huashan Hospital, School of Life Sciences, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
| | - Yu Ding
- State Key Laboratory of Medical Neurobiology, Huashan Hospital, School of Life Sciences, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
| | - Shouqing Luo
- Peninsula Schools of Medicine and Dentistry, Institute of Translational and Stratified Medicine, University of Plymouth, Research Way, Plymouth, PL68BU, UK
| | - Boxun Lu
- State Key Laboratory of Medical Neurobiology, Huashan Hospital, School of Life Sciences, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
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11
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Fu Y, Wu P, Pan Y, Sun X, Yang H, Difiglia M, Lu B. A toxic mutant huntingtin species is resistant to selective autophagy. Nat Chem Biol 2017; 13:1152-1154. [PMID: 28869595 DOI: 10.1038/nchembio.2461] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 07/19/2017] [Indexed: 01/24/2023]
Abstract
Protein misfolding is a common theme in neurodegenerative disorders including Huntington's disease (HD). The HD-causing mutant huntingtin protein (mHTT) has an expanded polyglutamine (polyQ) stretch that may adopt multiple conformations, and the most toxic of these is the one recognized by antibody 3B5H10. Here we show that the 3B5H10-recognized mHTT species has a slower degradation rate due to its resistance to selective autophagy in human cells and brains, revealing mechanisms of its higher toxicity.
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Affiliation(s)
- Yuhua Fu
- State Key Laboratory of Medical Neurobiology, Neurology Department at Huashan Hospital, School of Life Sciences, Fudan University, Shanghai, China
| | - Peng Wu
- State Key Laboratory of Medical Neurobiology, Neurology Department at Huashan Hospital, School of Life Sciences, Fudan University, Shanghai, China
| | - Yuyin Pan
- State Key Laboratory of Medical Neurobiology, Neurology Department at Huashan Hospital, School of Life Sciences, Fudan University, Shanghai, China
| | - Xiaoli Sun
- State Key Laboratory of Medical Neurobiology, Neurology Department at Huashan Hospital, School of Life Sciences, Fudan University, Shanghai, China.,Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Huiya Yang
- State Key Laboratory of Medical Neurobiology, Neurology Department at Huashan Hospital, School of Life Sciences, Fudan University, Shanghai, China
| | - Marian Difiglia
- MassGeneral Institute for Neurodegenerative Diseases, Massachusetts General Hospital, Boston, USA
| | - Boxun Lu
- State Key Laboratory of Medical Neurobiology, Neurology Department at Huashan Hospital, School of Life Sciences, Fudan University, Shanghai, China.,Collaborative Innovation Center of Genetics and Development, Shanghai, China
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