1
|
Wang H, Zeng R. Aberrant protein aggregation in amyotrophic lateral sclerosis. J Neurol 2024:10.1007/s00415-024-12485-z. [PMID: 38869826 DOI: 10.1007/s00415-024-12485-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 05/27/2024] [Accepted: 05/28/2024] [Indexed: 06/14/2024]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal disease. As its pathological mechanisms are not well understood, there are no efficient therapeutics for it at present. While it is highly heterogenous both etiologically and clinically, it has a common salient hallmark, i.e., aberrant protein aggregation (APA). The upstream pathogenesis and the downstream effects of APA in ALS are sophisticated and the investigation of this pathology would be of consequence for understanding ALS. In this paper, the pathomechanism of APA in ALS and the candidate treatment strategies for it are discussed.
Collapse
Affiliation(s)
- Huaixiu Wang
- Department Neurology, Shanxi Provincial Peoples Hospital: Fifth Hospital of Shanxi Medical University, Taiyuan, 030012, China.
- Beijing Ai-Si-Kang Medical Technology Co. Ltd., No. 18 11th St Economical & Technological Development Zone, Beijing, 100176, China.
| | - Rong Zeng
- Department Neurology, Shanxi Provincial Peoples Hospital: Fifth Hospital of Shanxi Medical University, Taiyuan, 030012, China
| |
Collapse
|
2
|
Xu X, Li M, Su Y, Wang Q, Qin P, Huang H, Zhang Y, Zhou Y, Yan J. Cdk5 phosphorylation-dependent C9orf72 degradation promotes neuronal death in Parkinson's disease models. CNS Neurosci Ther 2023; 29:3952-3966. [PMID: 37353944 PMCID: PMC10651984 DOI: 10.1111/cns.14319] [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: 09/02/2022] [Revised: 04/08/2023] [Accepted: 05/22/2023] [Indexed: 06/25/2023] Open
Abstract
AIMS Chromosome 9 open reading frame 72 (C9orf72) is one of the most dazzling molecules in neurodegenerative diseases, albeit that its role in Parkinson's disease (PD) remains unknown. This article aimed to explore the potential mechanism of C9orf72 involved in the pathogenesis of PD. METHODS The expression and phosphorylation levels of C9orf72 were examined by Western blotting, RT-PCR, and immunoprecipitation using PD models. Multiple bioinformatics software was used to predict the potential phosphorylation sites of C9orf72 by Cdk5, followed by verification of whether Cdk5-inhibitor ROSCOVITINE could reverse the degradation of C9orf72 in PD. By constructing the sh-C9orf72-knockdown adenovirus and overexpressing the FLAG-C9orf72 plasmid, the effects of C9orf72 knockdown and overexpression, respectively, were determined. A short peptide termed Myr-C9orf72 was used to verify whether interfering with Cdk5 phosphorylation at the Ser9 site of the C9orf72 protein could alleviate autophagy disorder, neuronal death, and movement disorder in PD models. RESULTS The expression level of the C9orf72 protein was significantly reduced, albeit the mRNA expression was not changed in the PD models. Moreover, the phosphorylation level was enhanced, and its reduction was mainly degraded by the ubiquitin-proteasome pathway. The key nervous system kinase Cdk5 directly phosphorylated the S9 site of the C9orf72 protein, which promoted the degradation of the C9orf72 protein. The knockdown of C9orf72 aggravated autophagy dysfunction and increased neuronal loss and motor dysfunction in substantia nigra neurons of PD mice. The overexpression of C9orf72 alleviated autophagy dysfunction in PD neurons. Specifically, interference with Cdk5 phosphorylation at the S9 site of C9orf72 alleviated autophagy dysfunction, neuronal death, and motor dysfunction mediated by C9orf72 protein degradation during PD. CONCLUSIONS Cumulatively, our findings illustrate the importance of the role of C9orf72 in the regulation of neuronal death during PD progression via the Cdk5-dependent degradation.
Collapse
Affiliation(s)
- Xingfeng Xu
- Department of PhysiologyGuilin Medical UniversityGuilinGuangxiChina
- Guangxi Key Laboratory of Brain and Cognitive NeuroscienceGuilin Medical UniversityGuilinGuangxiChina
| | - Mao Li
- Department of PhysiologyGuilin Medical UniversityGuilinGuangxiChina
- Guangxi Key Laboratory of Brain and Cognitive NeuroscienceGuilin Medical UniversityGuilinGuangxiChina
| | - Yan Su
- Department of PhysiologyGuilin Medical UniversityGuilinGuangxiChina
- Guangxi Key Laboratory of Brain and Cognitive NeuroscienceGuilin Medical UniversityGuilinGuangxiChina
| | - Qi Wang
- Department of PhysiologyGuilin Medical UniversityGuilinGuangxiChina
- Guangxi Key Laboratory of Brain and Cognitive NeuroscienceGuilin Medical UniversityGuilinGuangxiChina
| | - Peifang Qin
- Department of MicrobiologyGuilin Medical UniversityGuilinGuangxiChina
| | - Haitao Huang
- Department of MicrobiologyGuilin Medical UniversityGuilinGuangxiChina
| | - Yuting Zhang
- Department of MicrobiologyGuilin Medical UniversityGuilinGuangxiChina
| | - Yali Zhou
- Department of MicrobiologyGuilin Medical UniversityGuilinGuangxiChina
| | - Jianguo Yan
- Department of PhysiologyGuilin Medical UniversityGuilinGuangxiChina
- Guangxi Key Laboratory of Brain and Cognitive NeuroscienceGuilin Medical UniversityGuilinGuangxiChina
| |
Collapse
|
3
|
Cui Z, Joiner AMN, Jansen RM, Hurley JH. Amino acid sensing and lysosomal signaling complexes. Curr Opin Struct Biol 2023; 79:102544. [PMID: 36804703 DOI: 10.1016/j.sbi.2023.102544] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 01/05/2023] [Accepted: 01/11/2023] [Indexed: 02/18/2023]
Abstract
Amino acid pools in the cell are monitored by dedicated sensors, whose structures are now coming into view. The lysosomal Rag GTPases are central to this pathway, and the regulation of their GAP complexes, FLCN-FNIP and GATOR1, have been worked out in detail. For FLCN-FNIP, the entire chain of events from the arginine transporter SLC38A9 to substrate-specific mTORC1 activation has been visualized. The structure GATOR2 has been determined, hinting at an ordering of amino acid signaling across a larger size scale than anticipated. The centerpiece of lysosomal signaling, mTORC1, has been revealed to recognize its substrates by more nuanced and substrate-specific mechanisms than previous appreciated. Beyond the well-studied Rag GTPase and mTORC1 machinery, another lysosomal amino acid sensor/effector system, that of PQLC2 and the C9orf72-containing CSW complex, is coming into structural view. These developments hold promise for further insights into lysosomal physiology and lysosome-centric therapeutics.
Collapse
Affiliation(s)
- Zhicheng Cui
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley CA 94720, USA; California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA
| | - Aaron M N Joiner
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley CA 94720, USA; California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA
| | - Rachel M Jansen
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley CA 94720, USA; California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA
| | - James H Hurley
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley CA 94720, USA; California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, CA 94720, USA.
| |
Collapse
|
4
|
Diab R, Pilotto F, Saxena S. Autophagy and neurodegeneration: Unraveling the role of C9ORF72 in the regulation of autophagy and its relationship to ALS-FTD pathology. Front Cell Neurosci 2023; 17:1086895. [PMID: 37006471 PMCID: PMC10060823 DOI: 10.3389/fncel.2023.1086895] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 03/01/2023] [Indexed: 03/18/2023] Open
Abstract
The proper functioning of the cell clearance machinery is critical for neuronal health within the central nervous system (CNS). In normal physiological conditions, the cell clearance machinery is actively involved in the elimination of misfolded and toxic proteins throughout the lifetime of an organism. The highly conserved and regulated pathway of autophagy is one of the important processes involved in preventing and neutralizing pathogenic buildup of toxic proteins that could eventually lead to the development of neurodegenerative diseases (NDs) such as Alzheimer’s disease or Amyotrophic lateral sclerosis (ALS). The most common genetic cause of ALS and frontotemporal dementia (FTD) is a hexanucleotide expansion consisting of GGGGCC (G4C2) repeats in the chromosome 9 open reading frame 72 gene (C9ORF72). These abnormally expanded repeats have been implicated in leading to three main modes of disease pathology: loss of function of the C9ORF72 protein, the generation of RNA foci, and the production of dipeptide repeat proteins (DPRs). In this review, we discuss the normal physiological role of C9ORF72 in the autophagy-lysosome pathway (ALP), and present recent research deciphering how dysfunction of the ALP synergizes with C9ORF72 haploinsufficiency, which together with the gain of toxic mechanisms involving hexanucleotide repeat expansions and DPRs, drive the disease process. This review delves further into the interactions of C9ORF72 with RAB proteins involved in endosomal/lysosomal trafficking, and their role in regulating various steps in autophagy and lysosomal pathways. Lastly, the review aims to provide a framework for further investigations of neuronal autophagy in C9ORF72-linked ALS-FTD as well as other neurodegenerative diseases.
Collapse
Affiliation(s)
- Rim Diab
- Department of Neurology, Center for Experimental Neurology, Inselspital University Hospital, Bern, Switzerland
- Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - Federica Pilotto
- Department of Neurology, Center for Experimental Neurology, Inselspital University Hospital, Bern, Switzerland
- Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - Smita Saxena
- Department of Neurology, Center for Experimental Neurology, Inselspital University Hospital, Bern, Switzerland
- Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
- *Correspondence: Smita Saxena,
| |
Collapse
|
5
|
Lopez-Herdoiza MB, Bauché S, Wilmet B, Le Duigou C, Roussel D, Frah M, Béal J, Devely G, Boluda S, Frick P, Bouteiller D, Dussaud S, Guillabert P, Dalle C, Dumont M, Camuzat A, Saracino D, Barbier M, Bruneteau G, Ravassard P, Neumann M, Nicole S, Le Ber I, Brice A, Latouche M. C9ORF72 knockdown triggers FTD-like symptoms and cell pathology in mice. Front Cell Neurosci 2023; 17:1155929. [PMID: 37138765 PMCID: PMC10149765 DOI: 10.3389/fncel.2023.1155929] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 03/27/2023] [Indexed: 05/05/2023] Open
Abstract
The GGGGCC intronic repeat expansion within C9ORF72 is the most common genetic cause of ALS and FTD. This mutation results in toxic gain of function through accumulation of expanded RNA foci and aggregation of abnormally translated dipeptide repeat proteins, as well as loss of function due to impaired transcription of C9ORF72. A number of in vivo and in vitro models of gain and loss of function effects have suggested that both mechanisms synergize to cause the disease. However, the contribution of the loss of function mechanism remains poorly understood. We have generated C9ORF72 knockdown mice to mimic C9-FTD/ALS patients haploinsufficiency and investigate the role of this loss of function in the pathogenesis. We found that decreasing C9ORF72 leads to anomalies of the autophagy/lysosomal pathway, cytoplasmic accumulation of TDP-43 and decreased synaptic density in the cortex. Knockdown mice also developed FTD-like behavioral deficits and mild motor phenotypes at a later stage. These findings show that C9ORF72 partial loss of function contributes to the damaging events leading to C9-FTD/ALS.
Collapse
Affiliation(s)
| | - Stephanie Bauché
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Baptiste Wilmet
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Caroline Le Duigou
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Delphine Roussel
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Magali Frah
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Jonas Béal
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Gabin Devely
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Susana Boluda
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Petra Frick
- German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | | | - Sébastien Dussaud
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Pierre Guillabert
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Carine Dalle
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Magali Dumont
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Agnes Camuzat
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Dario Saracino
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Mathieu Barbier
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Gaelle Bruneteau
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | | | - Manuela Neumann
- German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
- Department of Neuropathology, Tübingen University Hospital, Tübingen, Germany
| | - Sophie Nicole
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Isabelle Le Ber
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Alexis Brice
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Morwena Latouche
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
- EPHE, Neurogenetics Team, PSL Research University, Paris, France
- *Correspondence: Morwena Latouche,
| |
Collapse
|
6
|
Strohm L, Hu Z, Suk Y, Rühmkorf A, Sternburg E, Gattringer V, Riemenschneider H, Berutti R, Graf E, Weishaupt JH, Brill MS, Harbauer AB, Dormann D, Dengjel J, Edbauer D, Behrends C. Multi-omics profiling identifies a deregulated FUS-MAP1B axis in ALS/FTD-associated UBQLN2 mutants. Life Sci Alliance 2022; 5:5/11/e202101327. [PMID: 35777956 PMCID: PMC9258132 DOI: 10.26508/lsa.202101327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 06/10/2022] [Accepted: 06/14/2022] [Indexed: 11/24/2022] Open
Abstract
Analysis of ALS patient-derived and engineered cells revealed that mutant UBQLN2 increases mRNA and protein of MAP1B which is mediated by dephosphorylation of FUS within its RNA-binding domain. Ubiquilin-2 (UBQLN2) is a ubiquitin-binding protein that shuttles ubiquitinated proteins to proteasomal and autophagic degradation. UBQLN2 mutations are genetically linked to the neurodegenerative disorders amyotrophic lateral sclerosis and frontotemporal dementia (ALS/FTD). However, it remains elusive how UBQLN2 mutations cause ALS/FTD. Here, we systematically examined proteomic and transcriptomic changes in patient-derived lymphoblasts and CRISPR/Cas9–engineered HeLa cells carrying ALS/FTD UBQLN2 mutations. This analysis revealed a strong up-regulation of the microtubule-associated protein 1B (MAP1B) which was also observed in UBQLN2 knockout cells and primary rodent neurons depleted of UBQLN2, suggesting that a UBQLN2 loss-of-function mechanism is responsible for the elevated MAP1B levels. Consistent with MAP1B’s role in microtubule binding, we detected an increase in total and acetylated tubulin. Furthermore, we uncovered that UBQLN2 mutations result in decreased phosphorylation of MAP1B and of the ALS/FTD–linked fused in sarcoma (FUS) protein at S439 which is critical for regulating FUS-RNA binding and MAP1B protein abundance. Together, our findings point to a deregulated UBQLN2-FUS-MAP1B axis that may link protein homeostasis, RNA metabolism, and cytoskeleton dynamics, three molecular pathomechanisms of ALS/FTD.
Collapse
Affiliation(s)
- Laura Strohm
- Munich Cluster for Systems Neurology, Medical Faculty, Ludwig-Maximilians-University München, Munich, Germany
| | - Zehan Hu
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Yongwon Suk
- Institute for Molecular Physiology, Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Alina Rühmkorf
- Max Planck Institute of Neurobiology, Martinsried, Germany
| | - Erin Sternburg
- Institute for Molecular Physiology, Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Vanessa Gattringer
- Munich Cluster for Systems Neurology, Medical Faculty, Ludwig-Maximilians-University München, Munich, Germany
| | - Henrick Riemenschneider
- Munich Cluster for Systems Neurology, Medical Faculty, Ludwig-Maximilians-University München, Munich, Germany.,German Center for Neurodegenerative Diseases Munich, Munich, Germany
| | - Riccardo Berutti
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Elisabeth Graf
- Institut für Humangenetik, Klinikum Rechts der Isar der Technischen Universität München, Munich, Germany
| | - Jochen H Weishaupt
- Division of Neurodegenerative Disorders, Department of Neurology, Medical Faculty Mannheim, Mannheim Center for Translational Neurosciences, Heidelberg University, Mannheim, Germany
| | | | - Angelika B Harbauer
- Institute of Neuronal Cell Biology, Technical University of Munich, Munich, Germany.,Max Planck Institute of Neurobiology, Martinsried, Germany.,Munich Cluster for Systems Neurology, Munich, Germany
| | - Dorothee Dormann
- Institute for Molecular Physiology, Johannes Gutenberg-University Mainz, Mainz, Germany.,Institute of Molecule Biology, Mainz, Germany
| | - Jörn Dengjel
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Dieter Edbauer
- Munich Cluster for Systems Neurology, Medical Faculty, Ludwig-Maximilians-University München, Munich, Germany.,German Center for Neurodegenerative Diseases Munich, Munich, Germany
| | - Christian Behrends
- Munich Cluster for Systems Neurology, Medical Faculty, Ludwig-Maximilians-University München, Munich, Germany
| |
Collapse
|
7
|
Xue B, Li R, Ma H, Rahaman A, Kumar V. Comprehensive mapping of mutations in the C9ORF72 that affect folding and binding to SMCR8 protein. Process Biochem 2022. [DOI: 10.1016/j.procbio.2022.07.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
8
|
Function and regulation of ULK1: From physiology to pathology. Gene 2022; 840:146772. [PMID: 35905845 DOI: 10.1016/j.gene.2022.146772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/03/2022] [Accepted: 07/24/2022] [Indexed: 11/21/2022]
Abstract
The expression of ULK1, a core protein of autophagy, is closely related to autophagic activity. Numerous studies have shown that pathological abnormal expression of ULK1 is associated with various human diseases such as neurological disorders, infections, cardiovascular diseases, liver diseases and cancers. In addition, new advances in the regulation of ULK1 have been identified. Furthermore, targeting ULK1 as a therapeutic strategy for diseases is gaining attention as new corresponding activators or inhibitors are being developed. In this review, we describe the structure and regulation of ULK1 as well as the current targeted activators and inhibitors. Moreover, we highlight the pathological disorders of ULK1 expression and its critical role in human diseases.
Collapse
|
9
|
Zou L, Liao M, Zhen Y, Zhu S, Chen X, Zhang J, Hao Y, Liu B. Autophagy and beyond: Unraveling the complexity of UNC-51-like kinase 1 (ULK1) from biological functions to therapeutic implications. Acta Pharm Sin B 2022; 12:3743-3782. [PMID: 36213540 PMCID: PMC9532564 DOI: 10.1016/j.apsb.2022.06.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 05/27/2022] [Accepted: 06/02/2022] [Indexed: 12/13/2022] Open
Abstract
UNC-51-like kinase 1 (ULK1), as a serine/threonine kinase, is an autophagic initiator in mammals and a homologous protein of autophagy related protein (Atg) 1 in yeast and of UNC-51 in Caenorhabditis elegans. ULK1 is well-known for autophagy activation, which is evolutionarily conserved in protein transport and indispensable to maintain cell homeostasis. As the direct target of energy and nutrition-sensing kinase, ULK1 may contribute to the distribution and utilization of cellular resources in response to metabolism and is closely associated with multiple pathophysiological processes. Moreover, ULK1 has been widely reported to play a crucial role in human diseases, including cancer, neurodegenerative diseases, cardiovascular disease, and infections, and subsequently targeted small-molecule inhibitors or activators are also demonstrated. Interestingly, the non-autophagy function of ULK1 has been emerging, indicating that non-autophagy-relevant ULK1 signaling network is also linked with diseases under some specific contexts. Therefore, in this review, we summarized the structure and functions of ULK1 as an autophagic initiator, with a focus on some new approaches, and further elucidated the key roles of ULK1 in autophagy and non-autophagy. Additionally, we also discussed the relationships between ULK1 and human diseases, as well as illustrated a rapid progress for better understanding of the discovery of more candidate small-molecule drugs targeting ULK1, which will provide a clue on novel ULK1-targeted therapeutics in the future.
Collapse
Affiliation(s)
- Ling Zou
- School of Pharmaceutical Sciences, Health Science Center, Shenzhen University, Shenzhen 518060, China
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Minru Liao
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Yongqi Zhen
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Shiou Zhu
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Xiya Chen
- School of Pharmaceutical Sciences, Health Science Center, Shenzhen University, Shenzhen 518060, China
| | - Jin Zhang
- School of Pharmaceutical Sciences, Health Science Center, Shenzhen University, Shenzhen 518060, China
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, China
- Corresponding authors. Tel./fax: +86 28 85503817.
| | - Yue Hao
- School of Pharmaceutical Sciences, Health Science Center, Shenzhen University, Shenzhen 518060, China
- Corresponding authors. Tel./fax: +86 28 85503817.
| | - Bo Liu
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, China
- Corresponding authors. Tel./fax: +86 28 85503817.
| |
Collapse
|
10
|
Jiang L, Zhang T, Lu K, Qi S. The progress in C9orf72 research: ALS/FTD pathogenesis, functions and structure. Small GTPases 2022; 13:56-76. [PMID: 33663328 PMCID: PMC9707547 DOI: 10.1080/21541248.2021.1892443] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The hexanucleotide repeat (GGGGCC) expansion in C9orf72 is accounted for a large proportion of the genetic amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The hypotheses of how the massive G4C2 repeats in C9orf72 destroy the neurons and lead to ALS/FTD are raised and improving. As a multirole player, C9orf72 exerts critical roles in many cellular processes, including autophagy, membrane trafficking, immune response, and so on. Notably, the partners of C9orf72, through which C9orf72 participates in the cell activities, have been identified. Notably, the structures of the C9orf72-SMCR8-WDR41 complex shed light on its activity as GTPase activating proteins (GAP). In this manuscript, we reviewed the latest research progress in the C9orf72-mediated ALS/FTD, the physiological functions of C9orf72, and the putative function models of C9orf72/C9orf72-containing complex.
Collapse
Affiliation(s)
- Lan Jiang
- Department of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, Chengdu, China
| | - Tizhong Zhang
- Department of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, Chengdu, China
| | - Kefeng Lu
- Department of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, Chengdu, China
| | - Shiqian Qi
- Department of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, Chengdu, China,CONTACT Shiqian Qi Department of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, Chengdu, China.
These authors contributed equally to this work.
| |
Collapse
|
11
|
Nörpel J, Cavadini S, Schenk AD, Graff-Meyer A, Hess D, Seebacher J, Chao JA, Bhaskar V. Structure of the human C9orf72-SMCR8 complex reveals a multivalent protein interaction architecture. PLoS Biol 2021; 19:e3001344. [PMID: 34297726 PMCID: PMC8336837 DOI: 10.1371/journal.pbio.3001344] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 08/04/2021] [Accepted: 07/01/2021] [Indexed: 12/30/2022] Open
Abstract
A major cause of familial amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) spectrum disorder is the hexanucleotide G4C2 repeat expansion in the first intron of the C9orf72 gene. Many underlying mechanisms lead to manifestation of disease that include toxic gain-of-function by repeat G4C2 RNAs, dipeptide repeat proteins, and a reduction of the C9orf72 gene product. The C9orf72 protein interacts with SMCR8 and WDR41 to form a trimeric complex and regulates multiple cellular pathways including autophagy. Here, we report the structure of the C9orf72-SMCR8 complex at 3.8 Å resolution using single-particle cryo-electron microscopy (cryo-EM). The structure reveals 2 distinct dimerization interfaces between C9orf72 and SMCR8 that involves an extensive network of interactions. Homology between C9orf72-SMCR8 and Folliculin-Folliculin Interacting Protein 2 (FLCN-FNIP2), a GTPase activating protein (GAP) complex, enabled identification of a key residue within the active site of SMCR8. Further structural analysis suggested that a coiled-coil region within the uDenn domain of SMCR8 could act as an interaction platform for other coiled-coil proteins, and its deletion reduced the interaction of the C9orf72-SMCR8 complex with FIP200 upon starvation. In summary, this study contributes toward our understanding of the biological function of the C9orf72-SMCR8 complex. Structural and biochemical characterisation of the C9orf72-SMCR8 complex sheds light on its overall architecture and highlights its role as a multi-functional scaffold for coordinating autophagy.
Collapse
Affiliation(s)
- Julia Nörpel
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Simone Cavadini
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Andreas D. Schenk
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | | | - Daniel Hess
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Jan Seebacher
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Jeffrey A. Chao
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- * E-mail: (JAC); (VB)
| | - Varun Bhaskar
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- * E-mail: (JAC); (VB)
| |
Collapse
|
12
|
Abstract
Autophagy is an important intracellular lysosomal degradation process in cells, which is highly conserved from yeast to mammals. The process of autophagy is roughly divided into the following key steps: the formation of a membrane structure called ISM (isolated membrane) after stimulation, the biogenesis and maturation of autophagosomes, and finally the degradation of autophagosomes. A number of proteins are required to function in the whole process of autophagy. Since the initial genetic screening in yeast cells, multiple genes that play pivotal roles in autophagy have been discovered. These molecules have been named ATG genes (AuTophaGy related genes). The screening for new key molecules involved in autophagy has greatly promoted the characterization of the mechanism of the autophagy machinery and provides multiple targets for the development of autophagy-based regulatory drugs.
Collapse
|
13
|
Root J, Merino P, Nuckols A, Johnson M, Kukar T. Lysosome dysfunction as a cause of neurodegenerative diseases: Lessons from frontotemporal dementia and amyotrophic lateral sclerosis. Neurobiol Dis 2021; 154:105360. [PMID: 33812000 PMCID: PMC8113138 DOI: 10.1016/j.nbd.2021.105360] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 03/16/2021] [Accepted: 03/29/2021] [Indexed: 12/11/2022] Open
Abstract
Frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) are fatal neurodegenerative disorders that are thought to exist on a clinical and pathological spectrum. FTD and ALS are linked by shared genetic causes (e.g. C9orf72 hexanucleotide repeat expansions) and neuropathology, such as inclusions of ubiquitinated, misfolded proteins (e.g. TAR DNA-binding protein 43; TDP-43) in the CNS. Furthermore, some genes that cause FTD or ALS when mutated encode proteins that localize to the lysosome or modulate endosome-lysosome function, including lysosomal fusion, cargo trafficking, lysosomal acidification, autophagy, or TFEB activity. In this review, we summarize evidence that lysosomal dysfunction, caused by genetic mutations (e.g. C9orf72, GRN, MAPT, TMEM106B) or toxic-gain of function (e.g. aggregation of TDP-43 or tau), is an important pathogenic disease mechanism in FTD and ALS. Further studies into the normal function of many of these proteins are required and will help uncover the mechanisms that cause lysosomal dysfunction in FTD and ALS. Mutations or polymorphisms in genes that encode proteins important for endosome-lysosome function also occur in other age-dependent neurodegenerative diseases, including Alzheimer's (e.g. APOE, PSEN1, APP) and Parkinson's (e.g. GBA, LRRK2, ATP13A2) disease. A more complete understanding of the common and unique features of lysosome dysfunction across the spectrum of neurodegeneration will help guide the development of therapies for these devastating diseases.
Collapse
Affiliation(s)
- Jessica Root
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta 30322, Georgia; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta 30322, Georgia
| | - Paola Merino
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta 30322, Georgia; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta 30322, Georgia
| | - Austin Nuckols
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta 30322, Georgia; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta 30322, Georgia
| | - Michelle Johnson
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta 30322, Georgia; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta 30322, Georgia
| | - Thomas Kukar
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta 30322, Georgia; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta 30322, Georgia; Department of Neurology, Emory University, School of Medicine, Atlanta 30322, Georgia.
| |
Collapse
|
14
|
Chua JP, De Calbiac H, Kabashi E, Barmada SJ. Autophagy and ALS: mechanistic insights and therapeutic implications. Autophagy 2021; 18:254-282. [PMID: 34057020 PMCID: PMC8942428 DOI: 10.1080/15548627.2021.1926656] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mechanisms of protein homeostasis are crucial for overseeing the clearance of misfolded and toxic proteins over the lifetime of an organism, thereby ensuring the health of neurons and other cells of the central nervous system. The highly conserved pathway of autophagy is particularly necessary for preventing and counteracting pathogenic insults that may lead to neurodegeneration. In line with this, mutations in genes that encode essential autophagy factors result in impaired autophagy and lead to neurodegenerative conditions such as amyotrophic lateral sclerosis (ALS). However, the mechanistic details underlying the neuroprotective role of autophagy, neuronal resistance to autophagy induction, and the neuron-specific effects of autophagy-impairing mutations remain incompletely defined. Further, the manner and extent to which non-cell autonomous effects of autophagy dysfunction contribute to ALS pathogenesis are not fully understood. Here, we review the current understanding of the interplay between autophagy and ALS pathogenesis by providing an overview of critical steps in the autophagy pathway, with special focus on pivotal factors impaired by ALS-causing mutations, their physiologic effects on autophagy in disease models, and the cell type-specific mechanisms regulating autophagy in non-neuronal cells which, when impaired, can contribute to neurodegeneration. This review thereby provides a framework not only to guide further investigations of neuronal autophagy but also to refine therapeutic strategies for ALS and related neurodegenerative diseases.Abbreviations: ALS: amyotrophic lateral sclerosis; Atg: autophagy-related; CHMP2B: charged multivesicular body protein 2B; DPR: dipeptide repeat; FTD: frontotemporal dementia; iPSC: induced pluripotent stem cell; LIR: LC3-interacting region; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MTOR: mechanistic target of rapamycin kinase; PINK1: PTEN induced kinase 1; RNP: ribonuclear protein; sALS: sporadic ALS; SPHK1: sphingosine kinase 1; TARDBP/TDP-43: TAR DNA binding protein; TBK1: TANK-binding kinase 1; TFEB: transcription factor EB; ULK: unc-51 like autophagy activating kinase; UPR: unfolded protein response; UPS: ubiquitin-proteasome system; VCP: valosin containing protein.
Collapse
Affiliation(s)
- Jason P Chua
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| | - Hortense De Calbiac
- Recherche translationnelle sur les maladies neurologiques, Institut Imagine, UMR-1163 INSERM et Université Paris Descartes, Hôpital Universitaire Necker-Enfants Malades, Paris, France
| | - Edor Kabashi
- Recherche translationnelle sur les maladies neurologiques, Institut Imagine, UMR-1163 INSERM et Université Paris Descartes, Hôpital Universitaire Necker-Enfants Malades, Paris, France
| | - Sami J Barmada
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| |
Collapse
|
15
|
Mimura K, Sakamaki JI, Morishita H, Kawazu M, Mano H, Mizushima N. Genome-wide CRISPR screening reveals nucleotide synthesis negatively regulates autophagy. J Biol Chem 2021; 296:100780. [PMID: 34000301 PMCID: PMC8191307 DOI: 10.1016/j.jbc.2021.100780] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 04/12/2021] [Accepted: 05/12/2021] [Indexed: 02/06/2023] Open
Abstract
Macroautophagy (hereafter, autophagy) is a process that directs the degradation of cytoplasmic material in lysosomes. In addition to its homeostatic roles, autophagy undergoes dynamic positive and negative regulation in response to multiple forms of cellular stress, thus enabling the survival of cells. However, the precise mechanisms of autophagy regulation are not fully understood. To identify potential negative regulators of autophagy, we performed a genome-wide CRISPR screen using the quantitative autophagic flux reporter GFP-LC3-RFP. We identified phosphoribosylformylglycinamidine synthase, a component of the de novo purine synthesis pathway, as one such negative regulator of autophagy. Autophagy was activated in cells lacking phosphoribosylformylglycinamidine synthase or phosphoribosyl pyrophosphate amidotransferase, another de novo purine synthesis enzyme, or treated with methotrexate when exogenous levels of purines were insufficient. Purine starvation-induced autophagy activation was concomitant with mammalian target of rapamycin complex 1 (mTORC1) suppression and was profoundly suppressed in cells deficient for tuberous sclerosis complex 2, which negatively regulates mTORC1 through inhibition of Ras homolog enriched in brain, suggesting that purines regulate autophagy through the tuberous sclerosis complex-Ras homolog enriched in brain-mTORC1 signaling axis. Moreover, depletion of the pyrimidine synthesis enzymes carbamoyl-phosphate synthetase 2, aspartate transcarbamylase, and dihydroorotase and dihydroorotate dehydrogenase activated autophagy as well, although mTORC1 activity was not altered by pyrimidine shortage. These results suggest a different mechanism of autophagy induction between purine and pyrimidine starvation. These findings provide novel insights into the regulation of autophagy by nucleotides and possibly the role of autophagy in nucleotide metabolism, leading to further developing anticancer strategies involving nucleotide synthesis and autophagy.
Collapse
Affiliation(s)
- Kaito Mimura
- Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Jun-Ichi Sakamaki
- Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Hideaki Morishita
- Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Masahito Kawazu
- Division of Cellular Signaling, National Cancer Center Research Institute, Tokyo, Japan
| | - Hiroyuki Mano
- Division of Cellular Signaling, National Cancer Center Research Institute, Tokyo, Japan
| | - Noboru Mizushima
- Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, Tokyo, Japan.
| |
Collapse
|
16
|
Creekmore BC, Chang YW, Lee EB. The Cryo-EM Effect: Structural Biology of Neurodegenerative Disease Proteostasis Factors. J Neuropathol Exp Neurol 2021; 80:494-513. [PMID: 33860329 DOI: 10.1093/jnen/nlab029] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Neurodegenerative diseases are characterized by the accumulation of misfolded proteins. This protein aggregation suggests that abnormal proteostasis contributes to aging-related neurodegeneration. A better fundamental understanding of proteins that regulate proteostasis may provide insight into the pathophysiology of neurodegenerative disease and may perhaps reveal novel therapeutic opportunities. The 26S proteasome is the key effector of the ubiquitin-proteasome system responsible for degrading polyubiquitinated proteins. However, additional factors, such as valosin-containing protein (VCP/p97/Cdc48) and C9orf72, play a role in regulation and trafficking of substrates through the normal proteostasis systems of a cell. Nonhuman AAA+ ATPases, such as the disaggregase Hsp104, also provide insights into the biochemical processes that regulate protein aggregation. X-ray crystallography and cryo-electron microscopy (cryo-EM) structures not bound to substrate have provided meaningful information about the 26S proteasome, VCP, and Hsp104. However, recent cryo-EM structures bound to substrate have provided new information about the function and mechanism of these proteostasis factors. Cryo-EM and cryo-electron tomography data combined with biochemical data have also increased the understanding of C9orf72 and its role in maintaining proteostasis. These structural insights provide a foundation for understanding proteostasis mechanisms with near-atomic resolution upon which insights can be gleaned regarding the pathophysiology of neurodegenerative diseases.
Collapse
Affiliation(s)
- Benjamin C Creekmore
- From the Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Graduate Program in Biochemistry and Molecular Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Translational Neuropathology Research Laboratory, Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yi-Wei Chang
- From the Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Edward B Lee
- Translational Neuropathology Research Laboratory, Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| |
Collapse
|
17
|
Beckers J, Tharkeshwar AK, Van Damme P. C9orf72 ALS-FTD: recent evidence for dysregulation of the autophagy-lysosome pathway at multiple levels. Autophagy 2021; 17:3306-3322. [PMID: 33632058 PMCID: PMC8632097 DOI: 10.1080/15548627.2021.1872189] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are two clinically distinct classes of neurodegenerative disorders. Yet, they share a range of genetic, cellular, and molecular features. Hexanucleotide repeat expansions (HREs) in the C9orf72 gene and the accumulation of toxic protein aggregates in the nervous systems of the affected individuals are among such common features. Though the mechanisms by which HREs cause toxicity is not clear, the toxic gain of function due to transcribed HRE RNA or dipeptide repeat proteins (DPRs) produced by repeat-associated non-AUG translation together with a reduction in C9orf72 expression are proposed as the contributing factors for disease pathogenesis in ALS and FTD. In addition, several recent studies point toward alterations in protein homeostasis as one of the root causes of the disease pathogenesis. In this review, we discuss the effects of the C9orf72 HRE in the autophagy-lysosome pathway based on various recent findings. We suggest that dysfunction of the autophagy-lysosome pathway synergizes with toxicity from C9orf72 repeat RNA and DPRs to drive disease pathogenesis. Abbreviation: ALP: autophagy-lysosome pathway; ALS: amyotrophic lateral sclerosis; AMPK: AMP-activated protein kinase; ATG: autophagy-related; ASO: antisense oligonucleotide; C9orf72: C9orf72-SMCR8 complex subunit; DENN: differentially expressed in normal and neoplastic cells; DPR: dipeptide repeat protein; EIF2A/eIF2α: eukaryotic translation initiation factor 2A; ER: endoplasmic reticulum; FTD: frontotemporal dementia; GAP: GTPase-activating protein; GEF: guanine nucleotide exchange factor; HRE: hexanucleotide repeat expansion; iPSC: induced pluripotent stem cell; ISR: integrated stress response; M6PR: mannose-6-phosphate receptor, cation dependent; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MN: motor neuron; MTORC1: mechanistic target of rapamycin kinase complex 1; ND: neurodegenerative disorder; RAN: repeat-associated non-ATG; RB1CC1/FIP200: RB1 inducible coiled-coil 1; SLC66A1/PQLC2: solute carrier family 66 member 1; SMCR8: SMCR8-C9orf72 complex subunit; SQSTM1/p62: sequestosome 1; STX17: syntaxin 17; TARDBP/TDP-43: TAR DNA binding protein; TBK1: TANK binding kinase 1; TFEB: transcription factor EB; ULK1: unc-51 like autophagy activating kinase 1; UPS: ubiquitin-proteasome system; WDR41: WD repeat domain 41.
Collapse
Affiliation(s)
- Jimmy Beckers
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven-University of Leuven, Leuven, Belgium.,VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - Arun Kumar Tharkeshwar
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven-University of Leuven, Leuven, Belgium.,VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - Philip Van Damme
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven-University of Leuven, Leuven, Belgium.,VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium.,University Hospitals Leuven, Department of Neurology, Leuven, Belgium
| |
Collapse
|
18
|
Lu Q, Wang PS, Yang L. Golgi-associated Rab GTPases implicated in autophagy. Cell Biosci 2021; 11:35. [PMID: 33557950 PMCID: PMC7869216 DOI: 10.1186/s13578-021-00543-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 01/18/2021] [Indexed: 12/24/2022] Open
Abstract
Autophagy is a conserved cellular degradation process in eukaryotes that facilitates the recycling and reutilization of damaged organelles and compartments. It plays a pivotal role in cellular homeostasis, pathophysiological processes, and diverse diseases in humans. Autophagy involves dynamic crosstalk between different stages associated with intracellular vesicle trafficking. Golgi apparatus is the central organelle involved in intracellular vesicle trafficking where Golgi-associated Rab GTPases function as important mediators. This review focuses on the recent findings that highlight Golgi-associated Rab GTPases as master regulators of autophagic flux. The scope for future research in elucidating the role and mechanism of Golgi-associated Rab GTPases in autophagy and autophagy-related diseases is discussed further.
Collapse
Affiliation(s)
- Qingchun Lu
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, 3440 N Broad St, Kresge Hall, Rm. 624, Philadelphia, PA19140, USA
| | - Po-Shun Wang
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, 3440 N Broad St, Kresge Hall, Rm. 624, Philadelphia, PA19140, USA
| | - Ling Yang
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, 3440 N Broad St, Kresge Hall, Rm. 624, Philadelphia, PA19140, USA.
| |
Collapse
|
19
|
Zmat3 Is a Key Splicing Regulator in the p53 Tumor Suppression Program. Mol Cell 2021; 80:452-469.e9. [PMID: 33157015 PMCID: PMC7654708 DOI: 10.1016/j.molcel.2020.10.022] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 08/19/2020] [Accepted: 10/14/2020] [Indexed: 12/22/2022]
Abstract
Although TP53 is the most commonly mutated gene in human cancers, the p53-dependent transcriptional programs mediating tumor suppression remain incompletely understood. Here, to uncover critical components downstream of p53 in tumor suppression, we perform unbiased RNAi and CRISPR-Cas9-based genetic screens in vivo. These screens converge upon the p53-inducible gene Zmat3, encoding an RNA-binding protein, and we demonstrate that ZMAT3 is an important tumor suppressor downstream of p53 in mouse KrasG12D-driven lung and liver cancers and human carcinomas. Integrative analysis of the ZMAT3 RNA-binding landscape and transcriptomic profiling reveals that ZMAT3 directly modulates exon inclusion in transcripts encoding proteins of diverse functions, including the p53 inhibitors MDM4 and MDM2, splicing regulators, and components of varied cellular processes. Interestingly, these exons are enriched in NMD signals, and, accordingly, ZMAT3 broadly affects target transcript stability. Collectively, these studies reveal ZMAT3 as a novel RNA-splicing and homeostasis regulator and a key component of p53-mediated tumor suppression.
Collapse
|
20
|
Ihenacho UK, Meacham KA, Harwig MC, Widlansky ME, Hill RB. Mitochondrial Fission Protein 1: Emerging Roles in Organellar Form and Function in Health and Disease. Front Endocrinol (Lausanne) 2021; 12:660095. [PMID: 33841340 PMCID: PMC8027123 DOI: 10.3389/fendo.2021.660095] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 03/05/2021] [Indexed: 12/13/2022] Open
Abstract
Mitochondrial fission protein 1 (Fis1) was identified in yeast as being essential for mitochondrial division or fission and subsequently determined to mediate human mitochondrial and peroxisomal fission. Yet, its exact functions in humans, especially in regard to mitochondrial fission, remains an enigma as genetic deletion of Fis1 elongates mitochondria in some cell types, but not others. Fis1 has also been identified as an important component of apoptotic and mitophagic pathways suggesting the protein may have multiple, essential roles. This review presents current perspectives on the emerging functions of Fis1 and their implications in human health and diseases, with an emphasis on Fis1's role in both endocrine and neurological disorders.
Collapse
Affiliation(s)
| | - Kelsey A. Meacham
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Megan Cleland Harwig
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Michael E. Widlansky
- Department of Medicine, Division of Cardiovascular Medicine, Medical College of Wisconsin, Milwaukee, WI, United States
| | - R. Blake Hill
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, United States
- *Correspondence: R. Blake Hill,
| |
Collapse
|
21
|
Pang W, Hu F. Cellular and physiological functions of C9ORF72 and implications for ALS/FTD. J Neurochem 2020; 157:334-350. [PMID: 33259633 DOI: 10.1111/jnc.15255] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 10/27/2020] [Accepted: 11/26/2020] [Indexed: 12/12/2022]
Abstract
The hexanucleotide repeat expansion (HRE) in the C9ORF72 gene is the main cause of two tightly linked neurodegenerative diseases, amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). HRE leads to not only a gain of toxicity from RNA repeats and dipeptide repeats but also reduced levels of C9ORF72 protein. However, the cellular and physiological functions of C9ORF72 were unknown until recently. Through proteomic analysis, Smith-Magenis chromosome regions 8 (SMCR8) and WD repeat-containing protein (WDR41) were identified as binding partners of C9ORF72. These three proteins have been shown to form a tight complex, but the exact functions of this complex remain to be characterized. Both C9ORF72 and SMCR8 contain a DENN domain, which has been shown to regulate the activities of small GTPases. The C9ORF72 complex has been implicated in many cellular processes, including vesicle trafficking, lysosome homeostasis, mTORC1 signaling , and autophagy. C9ORF72 deficiency in mice results in exaggerated inflammatory responses and human patients with C9ORF72 mutations have neuroinflammation phenotype. Recent studies indicate that C9ORF72 regulates trafficking and lysosomal degradation of inflammatory mediators, including toll-like receptors (TLRs) and STING, to affect inflammatory outputs. Further exploration of cellular and physiological functions of C9ORF72 will help dissect the pathological mechanism of ALS/FTD caused by C9ORF72 mutations.
Collapse
Affiliation(s)
- Weilun Pang
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
| | - Fenghua Hu
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
| |
Collapse
|
22
|
Gagliardi D, Costamagna G, Taiana M, Andreoli L, Biella F, Bersani M, Bresolin N, Comi GP, Corti S. Insights into disease mechanisms and potential therapeutics for C9orf72-related amyotrophic lateral sclerosis/frontotemporal dementia. Ageing Res Rev 2020; 64:101172. [PMID: 32971256 DOI: 10.1016/j.arr.2020.101172] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 08/31/2020] [Indexed: 12/12/2022]
Abstract
In 2011, a hexanucleotide repeat expansion (HRE) in the noncoding region of C9orf72 was associated with the most frequent genetic cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). The main pathogenic mechanisms in C9-ALS/FTD are haploinsufficiency of the C9orf72 protein and gain of function toxicity from bidirectionally-transcribed repeat-containing RNAs and dipeptide repeat proteins (DPRs) resulting from non-canonical RNA translation. Additionally, abnormalities in different downstream cellular mechanisms, such as nucleocytoplasmic transport and autophagy, play a role in pathogenesis. Substantial research efforts using in vitro and in vivo models have provided valuable insights into the contribution of each mechanism in disease pathogenesis. However, conflicting evidence exists, and a unifying theory still lacks. Here, we provide an overview of the recently published literature on clinical, neuropathological and molecular features of C9-ALS/FTD. We highlight the supposed neuronal role of C9orf72 and the HRE pathogenic cascade, mainly focusing on the contribution of RNA foci and DPRs to neurodegeneration and discussing the several downstream mechanisms. We summarize the emerging biochemical and neuroimaging biomarkers, as well as the potential therapeutic approaches. Despite promising results, a specific disease-modifying treatment is still not available to date and greater insights into disease mechanisms may help in this direction.
Collapse
Affiliation(s)
- Delia Gagliardi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Gianluca Costamagna
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Michela Taiana
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Luca Andreoli
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Fabio Biella
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Margherita Bersani
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Nereo Bresolin
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy; Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Giacomo Pietro Comi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy; Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Stefania Corti
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy; Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy.
| |
Collapse
|
23
|
Phosphoproteomics of Acute Cell Stressors Targeting Exercise Signaling Networks Reveal Drug Interactions Regulating Protein Secretion. Cell Rep 2020; 29:1524-1538.e6. [PMID: 31693893 DOI: 10.1016/j.celrep.2019.10.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 09/09/2019] [Accepted: 09/30/2019] [Indexed: 01/25/2023] Open
Abstract
Exercise engages signaling networks to control the release of circulating factors beneficial to health. However, the nature of these networks remains undefined. Using high-throughput phosphoproteomics, we quantify 20,249 phosphorylation sites in skeletal muscle-like myotube cells and monitor their responses to a panel of cell stressors targeting aspects of exercise signaling in vivo. Integrating these in-depth phosphoproteomes with the phosphoproteome of acute aerobic exercise in human skeletal muscle suggests that co-administration of β-adrenergic and calcium agonists would activate complementary signaling relevant to this exercise context. The phosphoproteome of cells treated with this combination reveals a surprising divergence in signaling from the individual treatments. Remarkably, only the combination treatment promotes multisite phosphorylation of SERBP1, a regulator of Serpine1 mRNA stability, a pro-fibrotic secreted protein. Secretome analysis reveals that the combined treatments decrease secretion of SERPINE1 and other deleterious factors. This study provides a framework for dissecting phosphorylation-based signaling relevant to acute exercise.
Collapse
|
24
|
Ho WY, Navakkode S, Liu F, Soong TW, Ling SC. Deregulated expression of a longevity gene, Klotho, in the C9orf72 deletion mice with impaired synaptic plasticity and adult hippocampal neurogenesis. Acta Neuropathol Commun 2020; 8:155. [PMID: 32887666 PMCID: PMC7473815 DOI: 10.1186/s40478-020-01030-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 08/29/2020] [Indexed: 01/17/2023] Open
Abstract
Hexanucleotide repeat expansion of C9ORF72 is the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia. Synergies between loss of C9ORF72 functions and gain of toxicities from the repeat expansions contribute to C9ORF72-mediated pathogenesis. However, how loss of C9orf72 impacts neuronal and synaptic functions remains undetermined. Here, we showed that long-term potentiation at the dentate granule cells and long-term depression at the Schaffer collateral/commissural synapses at the area CA1 were reduced in the hippocampus of C9orf72 knockout mice. Using unbiased transcriptomic analysis, we identified that Klotho, a longevity gene, was selectively dysregulated in an age-dependent manner. Specifically, Klotho protein expression in the hippocampus of C9orf72 knockout mice was incorrectly enriched in the dendritic regions of CA1 with concomitant reduction in granule cell layer of dentate gyrus at 3-month of age followed by an accelerating decline during aging. Furthermore, adult hippocampal neurogenesis was reduced in C9orf72 knockout mice. Taken together, our data suggest that C9ORF72 is required for synaptic plasticity and adult neurogenesis in the hippocampus and Klotho deregulations may be part of C9ORF72-mediated toxicity.
Collapse
|
25
|
Antonicka H, Lin ZY, Janer A, Aaltonen MJ, Weraarpachai W, Gingras AC, Shoubridge EA. A High-Density Human Mitochondrial Proximity Interaction Network. Cell Metab 2020; 32:479-497.e9. [PMID: 32877691 DOI: 10.1016/j.cmet.2020.07.017] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/24/2020] [Accepted: 07/28/2020] [Indexed: 12/17/2022]
Abstract
We used BioID, a proximity-dependent biotinylation assay with 100 mitochondrial baits from all mitochondrial sub-compartments, to create a high-resolution human mitochondrial proximity interaction network. We identified 1,465 proteins, producing 15,626 unique high-confidence proximity interactions. Of these, 528 proteins were previously annotated as mitochondrial, nearly half of the mitochondrial proteome defined by Mitocarta 2.0. Bait-bait analysis showed a clear separation of mitochondrial compartments, and correlation analysis among preys across all baits allowed us to identify functional clusters involved in diverse mitochondrial functions and to assign uncharacterized proteins to specific modules. We demonstrate that this analysis can assign isoforms of the same mitochondrial protein to different mitochondrial sub-compartments and show that some proteins may have multiple cellular locations. Outer membrane baits showed specific proximity interactions with cytosolic proteins and proteins in other organellar membranes, suggesting specialization of proteins responsible for contact site formation between mitochondria and individual organelles.
Collapse
Affiliation(s)
- Hana Antonicka
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada; Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Zhen-Yuan Lin
- Lunenfeld-Tanenbaum Research Institute, Toronto, ON, Canada
| | - Alexandre Janer
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada; Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Mari J Aaltonen
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada; Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Woranontee Weraarpachai
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada; Department of Biochemistry, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Toronto, ON, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.
| | - Eric A Shoubridge
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada; Department of Human Genetics, McGill University, Montreal, QC, Canada.
| |
Collapse
|
26
|
Su MY, Fromm SA, Zoncu R, Hurley JH. Structure of the C9orf72 ARF GAP complex that is haploinsufficient in ALS and FTD. Nature 2020; 585:251-255. [PMID: 32848248 PMCID: PMC8054479 DOI: 10.1038/s41586-020-2633-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 05/20/2020] [Indexed: 12/17/2022]
Abstract
Mutation of C9orf72 is the most prevalent defect associated with amyotrophic lateral sclerosis and frontotemporal degeneration1. Together with hexanucleotide-repeat expansion2,3, haploinsufficiency of C9orf72 contributes to neuronal dysfunction4-6. Here we determine the structure of the C9orf72-SMCR8-WDR41 complex by cryo-electron microscopy. C9orf72 and SMCR8 both contain longin and DENN (differentially expressed in normal and neoplastic cells) domains7, and WDR41 is a β-propeller protein that binds to SMCR8 such that the whole structure resembles an eye slip hook. Contacts between WDR41 and the DENN domain of SMCR8 drive the lysosomal localization of the complex in conditions of amino acid starvation. The structure suggested that C9orf72-SMCR8 is a GTPase-activating protein (GAP), and we found that C9orf72-SMCR8-WDR41 acts as a GAP for the ARF family of small GTPases. These data shed light on the function of C9orf72 in normal physiology, and in amyotrophic lateral sclerosis and frontotemporal degeneration.
Collapse
Affiliation(s)
- Ming-Yuan Su
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.,California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA, USA
| | - Simon A Fromm
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.,California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA, USA
| | - Roberto Zoncu
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.,California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA, USA
| | - James H Hurley
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA. .,California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA, USA. .,Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| |
Collapse
|
27
|
McEachin ZT, Parameswaran J, Raj N, Bassell GJ, Jiang J. RNA-mediated toxicity in C9orf72 ALS and FTD. Neurobiol Dis 2020; 145:105055. [PMID: 32829028 DOI: 10.1016/j.nbd.2020.105055] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 07/27/2020] [Accepted: 08/18/2020] [Indexed: 12/13/2022] Open
Abstract
A GGGGCC hexanucleotide repeat expansion in the first intron of C9orf72 is the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia. Compelling evidence suggests that gain of toxicity from the bidirectionally transcribed repeat expanded RNAs plays a central role in disease pathogenesis. Two potential mechanisms have been proposed including RNA-mediated toxicity and/or the production of toxic dipeptide repeat proteins. In this review, we focus on the role of RNA mediated toxicity in ALS/FTD caused by the C9orf72 mutation and discuss arguments for and against this mechanism. In addition, we summarize how G4C2 repeat RNAs can elicit toxicity and potential therapeutic strategies to mitigate RNA-mediated toxicity.
Collapse
Affiliation(s)
- Zachary T McEachin
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; Laboratory for Translational Cell Biology, Emory University, Atlanta, GA 30322, USA.
| | | | - Nisha Raj
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; Laboratory for Translational Cell Biology, Emory University, Atlanta, GA 30322, USA
| | - Gary J Bassell
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; Laboratory for Translational Cell Biology, Emory University, Atlanta, GA 30322, USA; Department of Neurology, Emory University, Atlanta, GA 30322, USA
| | - Jie Jiang
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA.
| |
Collapse
|
28
|
Amick J, Tharkeshwar AK, Talaia G, Ferguson SM. PQLC2 recruits the C9orf72 complex to lysosomes in response to cationic amino acid starvation. J Cell Biol 2020; 219:132798. [PMID: 31851326 PMCID: PMC7039192 DOI: 10.1083/jcb.201906076] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 10/07/2019] [Accepted: 10/25/2019] [Indexed: 12/13/2022] Open
Abstract
This study reveals that PQLC2, a lysosomal transporter of cationic amino acids, coordinates cellular responses to cationic amino acid availability via the regulated recruitment of a heterotrimeric protein complex containing C9orf72, SMCR8, and WDR41 to the surface of lysosomes. The C9orf72 protein is required for normal lysosome function. In support of such functions, C9orf72 forms a heterotrimeric complex with SMCR8 and WDR41 that is recruited to lysosomes when amino acids are scarce. These properties raise questions about the identity of the lysosomal binding partner of the C9orf72 complex and the amino acid–sensing mechanism that regulates C9orf72 complex abundance on lysosomes. We now demonstrate that an interaction with the lysosomal cationic amino acid transporter PQLC2 mediates C9orf72 complex recruitment to lysosomes. This is achieved through an interaction between PQLC2 and WDR41. The interaction between PQLC2 and the C9orf72 complex is negatively regulated by arginine, lysine, and histidine, the amino acids that PQLC2 transports across the membrane of lysosomes. These results define a new role for PQLC2 in the regulated recruitment of the C9orf72 complex to lysosomes and reveal a novel mechanism that allows cells to sense and respond to changes in the availability of cationic amino acids within lysosomes.
Collapse
Affiliation(s)
- Joseph Amick
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT.,Department of Neuroscience, Yale University School of Medicine, New Haven, CT.,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT
| | - Arun Kumar Tharkeshwar
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT.,Department of Neuroscience, Yale University School of Medicine, New Haven, CT.,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT
| | - Gabriel Talaia
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT.,Department of Neuroscience, Yale University School of Medicine, New Haven, CT.,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT
| | - Shawn M Ferguson
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT.,Department of Neuroscience, Yale University School of Medicine, New Haven, CT.,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT
| |
Collapse
|
29
|
Goodier JL, Soares AO, Pereira GC, DeVine LR, Sanchez L, Cole RN, García-Pérez JL. C9orf72-associated SMCR8 protein binds in the ubiquitin pathway and with proteins linked with neurological disease. Acta Neuropathol Commun 2020; 8:110. [PMID: 32678027 PMCID: PMC7364817 DOI: 10.1186/s40478-020-00982-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 06/26/2020] [Indexed: 02/08/2023] Open
Abstract
A pathogenic GGGCCC hexanucleotide expansion in the first intron/promoter region of the C9orf72 gene is the most common mutation associated with amyotrophic lateral sclerosis (ALS). The C9orf72 gene product forms a complex with SMCR8 (Smith-Magenis Syndrome Chromosome Region, Candidate 8) and WDR41 (WD Repeat domain 41) proteins. Recent studies have indicated roles for the complex in autophagy regulation, vesicle trafficking, and immune response in transgenic mice, however a direct connection with ALS etiology remains unclear. With the aim of increasing understanding of the multi-functional C9orf72-SMCR8-WDR41 complex, we determined by mass spectrometry analysis the proteins that directly associate with SMCR8. SMCR8 protein binds many components of the ubiquitin-proteasome system, and we demonstrate its poly-ubiquitination without obvious degradation. Evidence is also presented for localization of endogenous SMCR8 protein to cytoplasmic stress granules. However, in several cell lines we failed to reproduce previous observations that C9orf72 protein enters these granules. SMCR8 protein associates with many products of genes associated with various Mendelian neurological disorders in addition to ALS, implicating SMCR8-containing complexes in a range of neuropathologies. We reinforce previous observations that SMCR8 and C9orf72 protein levels are positively linked, and now show in vivo that SMCR8 protein levels are greatly reduced in brain tissues of C9orf72 gene expansion carrier individuals. While further study is required, these data suggest that SMCR8 protein level might prove a useful biomarker for the C9orf72 expansion in ALS.
Collapse
Affiliation(s)
- John L. Goodier
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Alisha O. Soares
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Gavin C. Pereira
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Lauren R. DeVine
- Mass Spectrometry and Proteomics Facility, Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Laura Sanchez
- GENYO. Centre for Genomics and Oncological Research: Pfizer, University of Granada, Andalusian Regional Government, Granada, Spain
| | - Robert N. Cole
- Mass Spectrometry and Proteomics Facility, Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Jose Luis García-Pérez
- GENYO. Centre for Genomics and Oncological Research: Pfizer, University of Granada, Andalusian Regional Government, Granada, Spain
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine (IGMM), University of Edinburgh, Western General Hospital, Edinburgh, UK
| |
Collapse
|
30
|
Demeter A, Romero-Mulero MC, Csabai L, Ölbei M, Sudhakar P, Haerty W, Korcsmáros T. ULK1 and ULK2 are less redundant than previously thought: computational analysis uncovers distinct regulation and functions of these autophagy induction proteins. Sci Rep 2020; 10:10940. [PMID: 32616830 PMCID: PMC7331686 DOI: 10.1038/s41598-020-67780-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 06/15/2020] [Indexed: 01/17/2023] Open
Abstract
Macroautophagy, the degradation of cytoplasmic content by lysosomal fusion, is an evolutionary conserved process promoting homeostasis and intracellular defence. Macroautophagy is initiated primarily by a complex containing ULK1 or ULK2 (two paralogs of the yeast Atg1 protein). To understand the differences between ULK1 and ULK2, we compared the human ULK1 and ULK2 proteins and their regulation. Despite the similarity in their enzymatic domain, we found that ULK1 and ULK2 have major differences in their autophagy-related interactors and their post-translational and transcriptional regulators. We identified 18 ULK1-specific and 7 ULK2-specific protein motifs serving as different interaction interfaces. We found that interactors of ULK1 and ULK2 all have different tissue-specific expressions partially contributing to diverse and ULK-specific interaction networks in various tissues. We identified three ULK1-specific and one ULK2-specific transcription factor binding sites, and eight sites shared by the regulatory region of both genes. Importantly, we found that both their post-translational and transcriptional regulators are involved in distinct biological processes-suggesting separate functions for ULK1 and ULK2. Unravelling differences between ULK1 and ULK2 could lead to a better understanding of how ULK-type specific dysregulation affects autophagy and other cellular processes that have been implicated in diseases such as inflammatory bowel disease and cancer.
Collapse
Affiliation(s)
- Amanda Demeter
- Earlham Institute, Norwich Research Park, Norwich, NR4 7UZ, UK
- Quadram Institute Bioscience, Norwich Research Park, Norwich, NR4 7UQ, UK
| | - Mari Carmen Romero-Mulero
- Earlham Institute, Norwich Research Park, Norwich, NR4 7UZ, UK
- Faculty of Biology, University of Seville, 41012, Seville, Spain
| | - Luca Csabai
- Earlham Institute, Norwich Research Park, Norwich, NR4 7UZ, UK
- Eötvös Loránd University, Budapest, 1117, Hungary
| | - Márton Ölbei
- Earlham Institute, Norwich Research Park, Norwich, NR4 7UZ, UK
- Quadram Institute Bioscience, Norwich Research Park, Norwich, NR4 7UQ, UK
| | - Padhmanand Sudhakar
- Earlham Institute, Norwich Research Park, Norwich, NR4 7UZ, UK
- Quadram Institute Bioscience, Norwich Research Park, Norwich, NR4 7UQ, UK
| | - Wilfried Haerty
- Earlham Institute, Norwich Research Park, Norwich, NR4 7UZ, UK
| | - Tamás Korcsmáros
- Earlham Institute, Norwich Research Park, Norwich, NR4 7UZ, UK.
- Quadram Institute Bioscience, Norwich Research Park, Norwich, NR4 7UQ, UK.
| |
Collapse
|
31
|
Liang C, Shao Q, Zhang W, Yang M, Chang Q, Chen R, Chen JF. Smcr8 deficiency disrupts axonal transport-dependent lysosomal function and promotes axonal swellings and gain of toxicity in C9ALS/FTD mouse models. Hum Mol Genet 2020; 28:3940-3953. [PMID: 31625563 DOI: 10.1093/hmg/ddz230] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 08/28/2019] [Accepted: 09/23/2019] [Indexed: 02/06/2023] Open
Abstract
G4C2 repeat expansions in an intron of C9ORF72 cause the most common familial amyotrophic lateral sclerosis and frontotemporal dementia (collectively, C9ALS/FTD). Mechanisms and mediators of C9ALS/FTD pathogenesis remain poorly understood. C9orf72 and Smcr8 form a protein complex. Here, we show that expression of Smcr8, like C9orf72, is reduced in C9ALS/FTD mouse models and patient tissues. Since Smcr8 is highly conserved between human and mouse, we evaluated the effects of Smcr8 downregulation in mice. Smcr8 knockout (KO) mice exhibited motor behavior deficits, which resemble those of C9ALS/FTD mouse models, and displayed axonal swellings in their spinal cords and neuromuscular junctions. These deficits are caused by impaired autophagy-lysosomal functions due to disrupted axonal transport in mutant motor neurons. Consistent with its interaction with C9orf72 and their downregulation in patient tissues, Smcr8 deficiency exacerbated autophagy-lysosomal impairment in C9orf72 KO mice. The disease relevance of Smcr8 downregulation was reflected by exacerbated axonal swellings and gain of toxicity pathology arising from Smcr8 haploinsufficiency in a mouse model of C9ALS/FTD. Thus, our in vivo studies suggested that Smcr8 deficiency impairs axonal transport dependent autophagy-lysosomal function and exacerbates axonal degeneration and gain of toxicity in C9ALS/FTD mouse models.
Collapse
Affiliation(s)
- Chen Liang
- Center for Craniofacial Molecular Biology, University of Southern California (USC), Los Angeles, CA 90033, USA.,Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
| | - Qiang Shao
- Center for Craniofacial Molecular Biology, University of Southern California (USC), Los Angeles, CA 90033, USA
| | - Wei Zhang
- Center for Craniofacial Molecular Biology, University of Southern California (USC), Los Angeles, CA 90033, USA
| | - Mei Yang
- Center for Craniofacial Molecular Biology, University of Southern California (USC), Los Angeles, CA 90033, USA
| | - Qing Chang
- Center for Craniofacial Molecular Biology, University of Southern California (USC), Los Angeles, CA 90033, USA
| | - Rong Chen
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, 100 N. Greene Street, Baltimore, MD 21205, USA
| | - Jian-Fu Chen
- Center for Craniofacial Molecular Biology, University of Southern California (USC), Los Angeles, CA 90033, USA
| |
Collapse
|
32
|
Autophagy in motor neuron diseases. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 172:157-202. [PMID: 32620242 DOI: 10.1016/bs.pmbts.2020.03.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Motor neuron diseases (MNDs) are a wide group of neurodegenerative disorders characterized by the degeneration of a specific neuronal type located in the central nervous system, the motor neuron (MN). There are two main types of MNs, spinal and cortical MNs and depending on the type of MND, one or both types are affected. Cortical MNs innervate spinal MNs and these control a variety of cellular targets, being skeletal muscle their main one which is also affected in MNDs. A correct functionality of autophagy is necessary for the survival of all cellular types and it is particularly crucial for neurons, given their postmitotic and highly specialized nature. Numerous studies have identified alterations of autophagy activity in multiple MNDs. The scientific community has been particularly prolific in reporting the role that autophagy plays in the most common adult MND, amyotrophic lateral sclerosis, although many studies have started to identify physiological and pathological functions of this catabolic system in other MNDs, such as spinal muscular atrophy and spinal and bulbar muscular atrophy. The degradation of selective cargo by autophagy and how this process is altered upon the presence of MND-causing mutations is currently also a matter of intense investigation, particularly regarding the selective autophagic clearance of mitochondria. Thorough reviews on this field have been recently published. This chapter will cover the current knowledge on the functionality of autophagy and lysosomal homeostasis in the main MNDs and other autophagy-related topics in the MND field that have risen special interest in the research community.
Collapse
|
33
|
Cryo-EM structure of C9ORF72-SMCR8-WDR41 reveals the role as a GAP for Rab8a and Rab11a. Proc Natl Acad Sci U S A 2020; 117:9876-9883. [PMID: 32303654 DOI: 10.1073/pnas.2002110117] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
A massive intronic hexanucleotide repeat (GGGGCC) expansion in C9ORF72 is a genetic origin of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Recently, C9ORF72, together with SMCR8 and WDR41, has been shown to regulate autophagy and function as Rab GEF. However, the precise function of C9ORF72 remains unclear. Here, we report the cryogenic electron microscopy (cryo-EM) structure of the human C9ORF72-SMCR8-WDR41 complex at a resolution of 3.2 Å. The structure reveals the dimeric assembly of a heterotrimer of C9ORF72-SMCR8-WDR41. Notably, the C-terminal tail of C9ORF72 and the DENN domain of SMCR8 play critical roles in the dimerization of the two protomers of the C9ORF72-SMCR8-WDR41 complex. In the protomer, C9ORF72 and WDR41 are joined by SMCR8 without direct interaction. WDR41 binds to the DENN domain of SMCR8 by the C-terminal helix. Interestingly, the prominent structural feature of C9ORF72-SMCR8 resembles that of the FLNC-FNIP2 complex, the GTPase activating protein (GAP) of RagC/D. Structural comparison and sequence alignment revealed that Arg147 of SMCR8 is conserved and corresponds to the arginine finger of FLCN, and biochemical analysis indicated that the Arg147 of SMCR8 is critical to the stimulatory effect of the C9ORF72-SMCR8 complex on Rab8a and Rab11a. Our study not only illustrates the basis of C9ORF72-SMCR8-WDR41 complex assembly but also reveals the GAP activity of the C9ORF72-SMCR8 complex.
Collapse
|
34
|
Ji YJ, Ugolino J, Zhang T, Lu J, Kim D, Wang J. C9orf72/ALFA-1 controls TFEB/HLH-30-dependent metabolism through dynamic regulation of Rag GTPases. PLoS Genet 2020; 16:e1008738. [PMID: 32282804 PMCID: PMC7188304 DOI: 10.1371/journal.pgen.1008738] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 04/28/2020] [Accepted: 03/25/2020] [Indexed: 12/13/2022] Open
Abstract
Nutrient utilization and energy metabolism are critical for the maintenance of cellular homeostasis. A mutation in the C9orf72 gene has been linked to the most common forms of neurodegenerative diseases that include amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Here we have identified an evolutionarily conserved function of C9orf72 in the regulation of the transcription factor EB (TFEB), a master regulator of autophagic and lysosomal genes that is negatively modulated by mTORC1. Loss of the C. elegans orthologue of C9orf72, ALFA-1, causes the nuclear translocation of HLH-30/TFEB, leading to activation of lipolysis and premature lethality during starvation-induced developmental arrest in C. elegans. A similar conserved pathway exists in human cells, in which C9orf72 regulates mTOR and TFEB signaling. C9orf72 interacts with and dynamically regulates the level of Rag GTPases, which are responsible for the recruitment of mTOR and TFEB on the lysosome upon amino acid signals. These results have revealed previously unknown functions of C9orf72 in nutrient sensing and metabolic pathways and suggest that dysregulation of C9orf72 functions could compromise cellular fitness under conditions of nutrient stress. An expansion of repeated nucleotides in the non-coding region of the C9orf72 gene has been linked to the neurodegenerative diseases amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The repeat expansion leads to a reduced expression of the C9orf72 gene and loss of function of the C9orf72 protein may contribute to the pathogenesis. In this study, we identified a new mechanism through which C9orf72 influences nutrient sensing, autophagy, and metabolism. In the multi-cellular organism Caenorhabditis elegans, the C9orf72 orthologue regulates the activity of TFEB, a crucial transcriptional regulator of autophagic and lysosomal genes, through which the lipid metabolism and survival are influenced especially under nutrient stress conditions. The regulatory effect of C9orf72 on TFEB is conserved in mammals, and this is mediated by the dynamic regulation of the Rag GTPases by C9orf72. Given the critical role of the Rag GTPases in nutrient sensing and autophagy, we propose that the C9orf72 function is important for metabolic homeostasis in the cell and its deficiency can lead to compromised fitness under stress conditions.
Collapse
Affiliation(s)
- Yon Ju Ji
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States of America
- Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD, United States of America
| | - Janet Ugolino
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States of America
- Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD, United States of America
| | - Tao Zhang
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States of America
- Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD, United States of America
| | - Jiayin Lu
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States of America
- Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD, United States of America
| | - Dohoon Kim
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States of America
| | - Jiou Wang
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States of America
- Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD, United States of America
- * E-mail:
| |
Collapse
|
35
|
Strohm L, Behrends C. Glia-specific autophagy dysfunction in ALS. Semin Cell Dev Biol 2020; 99:172-182. [DOI: 10.1016/j.semcdb.2019.05.024] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 04/30/2019] [Accepted: 05/23/2019] [Indexed: 12/12/2022]
|
36
|
Boivin M, Pfister V, Gaucherot A, Ruffenach F, Negroni L, Sellier C, Charlet-Berguerand N. Reduced autophagy upon C9ORF72 loss synergizes with dipeptide repeat protein toxicity in G4C2 repeat expansion disorders. EMBO J 2020; 39:e100574. [PMID: 31930538 PMCID: PMC7024836 DOI: 10.15252/embj.2018100574] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 11/28/2019] [Accepted: 12/03/2019] [Indexed: 12/12/2022] Open
Abstract
Expansion of G4C2 repeats within the C9ORF72 gene is the most common cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Such repeats lead to decreased expression of the autophagy regulator C9ORF72 protein. Furthermore, sense and antisense repeats are translated into toxic dipeptide repeat (DPR) proteins. It is unclear how these repeats are translated, and in which way their translation and the reduced expression of C9ORF72 modulate repeat toxicity. Here, we found that sense and antisense repeats are translated upon initiation at canonical AUG or near‐cognate start codons, resulting in polyGA‐, polyPG‐, and to a lesser degree polyGR‐DPR proteins. However, accumulation of these proteins is prevented by autophagy. Importantly, reduced C9ORF72 levels lead to suboptimal autophagy, thereby impairing clearance of DPR proteins and causing their toxic accumulation, ultimately resulting in neuronal cell death. Of clinical importance, pharmacological compounds activating autophagy can prevent neuronal cell death caused by DPR proteins accumulation. These results suggest the existence of a double‐hit pathogenic mechanism in ALS/FTD, whereby reduced expression of C9ORF72 synergizes with DPR protein accumulation and toxicity.
Collapse
Affiliation(s)
- Manon Boivin
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,Université de Strasbourg, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
| | - Véronique Pfister
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,Université de Strasbourg, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
| | - Angeline Gaucherot
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,Université de Strasbourg, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
| | - Frank Ruffenach
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,Université de Strasbourg, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
| | - Luc Negroni
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,Université de Strasbourg, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
| | - Chantal Sellier
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,Université de Strasbourg, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
| | - Nicolas Charlet-Berguerand
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,Université de Strasbourg, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
| |
Collapse
|
37
|
Shao Q, Yang M, Liang C, Ma L, Zhang W, Jiang Z, Luo J, Lee JK, Liang C, Chen JF. C9orf72 and smcr8 mutant mice reveal MTORC1 activation due to impaired lysosomal degradation and exocytosis. Autophagy 2019; 16:1635-1650. [PMID: 31847700 DOI: 10.1080/15548627.2019.1703353] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
How lysosome and MTORC1 signaling interact remains elusive in terminally differentiated cells. A G4C2 repeat expansion in C9orf72 is the most common cause of familial amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) (C9ALS-FTD). We previously identified a C9orf72-SMCR8-containing complex. Here we found that c9orf72 and smcr8 double-knockout (dKO) mice exhibit similar but more severe immune defects than the individual knockouts. In c9orf72 or smcr8 mutant macrophages, lysosomal degradation and exocytosis were impaired due to the disruption of autolysosome acidification. As a result of impaired lysosomal degradation, MTOR protein was aberrantly increased, resulting in MTORC1 signaling overactivation. Inhibition of hyperactive MTORC1 partially rescued macrophage dysfunction, splenomegaly and lymphadenopathy in c9orf72 or smcr8 mutant mice. Pharmacological inhibition of lysosomal degradation upregulated MTOR protein and MTORC1 signaling in differentiated wild-type macrophages, which resemble phenotypes in KO mice. In contrast, C9orf72 or Smcr8 depletion in proliferating macrophages decreased MTORC1 signaling. Our studies causatively link C9orf72-SMCR8's cellular functions in lysosomal degradation, exocytosis, and MTORC1 signaling with their organism-level immune regulation, suggesting cell state (proliferation vs. differentiation)-dependent regulation of MTOR signaling via lysosomes.Abbreviations: ALS: amyotrophic lateral sclerosis; ATG13: autophagy related 13; BMDMs: bone marrow-derived macrophages; BafA1: bafilomycin A1; C9orf72: C9orf72, member of C9orf72-SMCR8 complex; CD68: CD68 antigen; ConA: concanamycin A; dKO: double knockout; DENN: differentially expressed in normal and neoplastic cells; FTD: frontotemporal dementia; GEF: guanine nucleotide exchange factor; IFNB1: interferon beta 1, fibroblast; IFNG: interferon gamma; IL1B/IL-1β: interleukin 1 beta; IL6: interleukin 6; iPSCs: induced pluripotent stem cells; LAMP1: lysosomal-associated membrane protein 1; LPOs: LAMP1-positive organelles; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; LPS: lipopolysaccharide; MTORC1: mechanistic target of rapamycin kinase complex 1; MEFs: mouse embryonic fibroblasts; MNs: motor neurons; NOS2/iNOS: nitric oxide synthase 2, inducible; RAN: repeat-associated non-AUG; RB1CC1/FIP200: RB1-inducible coiled-coil 1; RPS6/S6: ribosomal protein S6; RPS6KB1/S6K1: ribosomal protein S6 kinase, polypeptide 1; SMCR8: Smith-Magenis syndrome chromosome region, candidate 8; SQSTM1/p62: sequestosome 1; TFEB: transcription factor EB; TNF: tumor necrosis factor; TSC1: TSC complex subunit 1; ULK1: unc-51 like kinase 1; v-ATPase: vacuolar-type H⁺-translocating ATPase.
Collapse
Affiliation(s)
- Qiang Shao
- Center for Craniofacial Molecular Biology, University of Southern California , Los Angeles, CA, USA
| | - Mei Yang
- Center for Craniofacial Molecular Biology, University of Southern California , Los Angeles, CA, USA.,Center for Life Sciences, School of Life Sciences, Yunnan University , Kunming, P.R. China
| | - Chen Liang
- Department of Cellular Biology, University of Georgia , Athens, GA, USA
| | - Li Ma
- Center for Craniofacial Molecular Biology, University of Southern California , Los Angeles, CA, USA
| | - Wei Zhang
- Center for Craniofacial Molecular Biology, University of Southern California , Los Angeles, CA, USA
| | - Zhiwen Jiang
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Institute of Aging Research, Guangdong Medical University , Dongguan, Guangdong, P.R. China
| | - Jun Luo
- Division of VIP Center, Stomatological Hospital of Chongqing Medical University , Chongqing, P.R. China
| | - Jae-Kyung Lee
- Department of Physiology and Pharmacology, University of Georgia , Athens, GA, USA
| | - Chengyu Liang
- Department of Molecular Microbiology and Immunology, Keck School of Medicine of the University of Southern California , Los Angeles, CA, USA
| | - Jian-Fu Chen
- Center for Craniofacial Molecular Biology, University of Southern California , Los Angeles, CA, USA
| |
Collapse
|
38
|
Jiang J, Ravits J. Pathogenic Mechanisms and Therapy Development for C9orf72 Amyotrophic Lateral Sclerosis/Frontotemporal Dementia. Neurotherapeutics 2019; 16:1115-1132. [PMID: 31667754 PMCID: PMC6985338 DOI: 10.1007/s13311-019-00797-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
In 2011, a hexanucleotide repeat expansion in the first intron of the C9orf72 gene was identified as the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The proposed disease mechanisms include loss of C9orf72 function and gain of toxicity from the bidirectionally transcribed repeat-containing RNAs. Over the last few years, substantial progress has been made to determine the contribution of loss and gain of function in disease pathogenesis. The extensive body of molecular, cellular, animal, and human neuropathological studies is conflicted, but the predominance of evidence favors gain of toxicity as the main pathogenic mechanism for C9orf72 repeat expansions. Alterations in several downstream cellular functions, such as nucleocytoplasmic transport and autophagy, are implicated. Exciting progress has also been made in therapy development targeting this mutation, such as by antisense oligonucleotide therapies targeting sense transcripts and small molecules targeting nucleocytoplasmic transport, and these are now in phase 1 clinical trials.
Collapse
Affiliation(s)
- Jie Jiang
- Department of Cell Biology, Emory University, Atlanta, GA, 30322, USA.
| | - John Ravits
- Department of Neurosciences, University of California at San Diego, La Jolla, CA, 92093, USA.
| |
Collapse
|
39
|
Abstract
The discovery that repeat expansions in the C9orf72 gene are a frequent cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) has revolutionized our understanding of these diseases. Substantial headway has been made in characterizing C9orf72-mediated disease and unravelling its underlying aetiopathogenesis. Three main disease mechanisms have been proposed: loss of function of the C9orf72 protein and toxic gain of function from C9orf72 repeat RNA or from dipeptide repeat proteins produced by repeat-associated non-ATG translation. Several downstream processes across a range of cellular functions have also been implicated. In this article, we review the pathological and mechanistic features of C9orf72-associated FTD and ALS (collectively termed C9FTD/ALS), the model systems used to study these conditions, and the probable initiators of downstream disease mechanisms. We suggest that a combination of upstream mechanisms involving both loss and gain of function and downstream cellular pathways involving both cell-autonomous and non-cell-autonomous effects contributes to disease progression.
Collapse
Affiliation(s)
- Rubika Balendra
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, UK.,Department of Genetics, Evolution and Environment, Institute of Healthy Ageing, UCL, London, UK
| | - Adrian M Isaacs
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, UK. .,UK Dementia Research Institute at UCL, UCL Institute of Neurology, London, UK.
| |
Collapse
|
40
|
Ho WY, Tai YK, Chang JC, Liang J, Tyan SH, Chen S, Guan JL, Zhou H, Shen HM, Koo E, Ling SC. The ALS-FTD-linked gene product, C9orf72, regulates neuronal morphogenesis via autophagy. Autophagy 2019; 15:827-842. [PMID: 30669939 PMCID: PMC6526867 DOI: 10.1080/15548627.2019.1569441] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 10/05/2018] [Accepted: 12/18/2018] [Indexed: 12/12/2022] Open
Abstract
Mutations in C9orf72 leading to hexanucleotide expansions are the most common genetic causes for amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). A phenotype resembling ALS and FTD is seen in transgenic mice overexpressing the hexanucleotide expansions, but is absent in C9orf72-deficient mice. Thus, the exact function of C9orf72 in neurons and how loss of C9orf72 may contribute to neuronal dysfunction remains to be clearly defined. Here, we showed that primary hippocampal neurons cultured from c9orf72 knockout mice have reduced dendritic arborization and spine density. Quantitative proteomic analysis identified C9orf72 as a component of the macroautophagy/autophagy initiation complex composed of ULK1-RB1CC1-ATG13-ATG101. The association was mediated through the direct interaction with ATG13 via the isoform-specific carboxyl-terminal DENN and dDENN domain of C9orf72. Furthermore, c9orf72 knockout neurons showed reduced LC3-II puncta accompanied by reduced ULK1 levels, suggesting that loss of C9orf72 impairs basal autophagy. Conversely, wild-type neurons treated with a ULK1 kinase inhibitor showed a dose-dependent reduction of dendritic arborization and spine density. Furthermore, expression of the long isoform of human C9orf72 that interacts with the ULK1 complex, but not the short isoform, rescues autophagy and the dendritic arborization phenotypes of c9orf72 knockout neurons. Taken together, our data suggests that C9orf72 has a cell-autonomous role in neuronal and dendritic morphogenesis through promotion of ULK1-mediated autophagy.
Collapse
Affiliation(s)
- Wan Yun Ho
- Department of Physiology, National University of Singapore, Singapore, Singapore
| | - Yee Kit Tai
- Department of Physiology, National University of Singapore, Singapore, Singapore
| | - Jer-Cherng Chang
- Department of Physiology, National University of Singapore, Singapore, Singapore
| | - Jason Liang
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA, USA
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA
| | - Sheue-Houy Tyan
- Department of Medicine, National University of Singapore, Singapore, Singapore
| | - Song Chen
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Jun-Lin Guan
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Huilin Zhou
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA, USA
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA
| | - Han-Ming Shen
- Department of Physiology, National University of Singapore, Singapore, Singapore
| | - Edward Koo
- Department of Medicine, National University of Singapore, Singapore, Singapore
- Department of Neurosciences, University of California at San Diego, La Jolla, CA, USA
| | - Shuo-Chien Ling
- Department of Physiology, National University of Singapore, Singapore, Singapore
- Neurobiology/Ageing Programme, National University of Singapore, Singapore, Singapore
- Neuroscience and Behavioural Disorders Programme, Duke-NUS Medical School, Singapore, Singapore
| |
Collapse
|
41
|
Gil-Cayuela C, López A, Martínez-Dolz L, González-Juanatey JR, Lago F, Roselló-Lletí E, Rivera M, Portolés M. The altered expression of autophagy-related genes participates in heart failure: NRBP2 and CALCOCO2 are associated with left ventricular dysfunction parameters in human dilated cardiomyopathy. PLoS One 2019; 14:e0215818. [PMID: 31009519 PMCID: PMC6476534 DOI: 10.1371/journal.pone.0215818] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 04/09/2019] [Indexed: 02/02/2023] Open
Abstract
This study aimed to analyze changes in the expression of autophagy- and phagocytosis-related genes in patients with dilated cardiomyopathy (DCM), especially in relation to left ventricular (LV) dysfunction. Furthermore, transmission electron microscopy of the diseased tissue was carried out to investigate if the gene expression changes are translated into ultrastructural alterations. LV tissue samples from patients with DCM (n = 13) and from controls (CNT; n = 10) were analyzed by RNA-sequencing, whereupon the altered expression (P < 0.05) of 13 autophagy- and 3 phagocytosis-related genes was observed. The expression changes of the autophagy-related genes NRBP2 and CALCOCO2 were associated with cardiac dysfunction and remodeling (P < 0.05). The affected patients had a higher activity of these degradation processes, as evidenced by the greater number of autophagic structures in the DCM tissue (P < 0.001). Differences in the ultrastructural distribution were also found between the DCM and CNT tissues. These results show that in patients with DCM, the altered expression of NRBP2 and CALCOCO2 is related to LV dysfunction and remodeling. Clarification of the molecular mechanisms of cardiac autophagy would help in the future development of therapies to improve LV performance.
Collapse
MESH Headings
- Adaptor Proteins, Signal Transducing/genetics
- Adaptor Proteins, Signal Transducing/metabolism
- Adrenergic beta-Antagonists/therapeutic use
- Adult
- Angiotensin-Converting Enzyme Inhibitors/therapeutic use
- Autophagy/genetics
- Autophagy-Related Proteins/genetics
- Autophagy-Related Proteins/metabolism
- Cardiomyopathy, Dilated/drug therapy
- Cardiomyopathy, Dilated/genetics
- Cardiomyopathy, Dilated/metabolism
- Cardiomyopathy, Dilated/physiopathology
- Case-Control Studies
- Diuretics/therapeutic use
- Female
- Gene Expression Profiling
- Gene Expression Regulation
- Heart Ventricles/metabolism
- Heart Ventricles/pathology
- Humans
- Male
- Middle Aged
- Mineralocorticoid Receptor Antagonists/therapeutic use
- Myocardium/metabolism
- Myocardium/pathology
- Nuclear Proteins/genetics
- Nuclear Proteins/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/metabolism
- Sequence Analysis, RNA
- Ventricular Dysfunction, Left/drug therapy
- Ventricular Dysfunction, Left/genetics
- Ventricular Dysfunction, Left/metabolism
- Ventricular Dysfunction, Left/physiopathology
Collapse
Affiliation(s)
- Carolina Gil-Cayuela
- Cardiocirculatory Unit, Health Research Institute of La Fe University Hospital (IIS La Fe), Valencia, Spain
| | - Alejandro López
- Cardiocirculatory Unit, Health Research Institute of La Fe University Hospital (IIS La Fe), Valencia, Spain
| | - Luis Martínez-Dolz
- Heart Failure and Transplantation Unit, Cardiology Department, La Fe University Hospital, Valencia, Spain
| | - José Ramón González-Juanatey
- Cellular and Molecular Cardiology Research Unit, Department of Cardiology and Institute of Biomedical Research, University Clinical Hospital, Santiago de Compostela, Spain
| | - Francisca Lago
- Cellular and Molecular Cardiology Research Unit, Department of Cardiology and Institute of Biomedical Research, University Clinical Hospital, Santiago de Compostela, Spain
| | - Esther Roselló-Lletí
- Cardiocirculatory Unit, Health Research Institute of La Fe University Hospital (IIS La Fe), Valencia, Spain
- * E-mail: (MPS); (ERL)
| | - Miguel Rivera
- Cardiocirculatory Unit, Health Research Institute of La Fe University Hospital (IIS La Fe), Valencia, Spain
| | - Manuel Portolés
- Cardiocirculatory Unit, Health Research Institute of La Fe University Hospital (IIS La Fe), Valencia, Spain
- * E-mail: (MPS); (ERL)
| |
Collapse
|
42
|
Nguyen DKH, Thombre R, Wang J. Autophagy as a common pathway in amyotrophic lateral sclerosis. Neurosci Lett 2019; 697:34-48. [PMID: 29626651 PMCID: PMC6170747 DOI: 10.1016/j.neulet.2018.04.006] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 03/26/2018] [Accepted: 04/02/2018] [Indexed: 12/11/2022]
Abstract
Age-dependent neurodegenerative diseases are associated with a decline in protein quality control systems including autophagy. Amyotrophic lateral sclerosis (ALS) is a motor neuron degenerative disease of complex etiology with increasing connections to other neurodegenerative conditions such as frontotemporal dementia. Among the diverse genetic causes for ALS, a striking feature is the common connection to autophagy and its associated pathways. There is a recurring theme of protein misfolding as in other neurodegenerative diseases, but importantly there is a distinct common thread among ALS genes that connects them to the cascade of autophagy. However, the roles of autophagy in ALS remain enigmatic and it is still unclear whether activation or inhibition of autophagy would be a reliable avenue to ameliorate the disease. The main evidence that links autophagy to different genetic forms of ALS is discussed.
Collapse
Affiliation(s)
- Dao K H Nguyen
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, 21205, USA; Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Ravi Thombre
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, 21205, USA; Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Jiou Wang
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, 21205, USA; Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA.
| |
Collapse
|
43
|
Graab P, Bock C, Weiss K, Hirth A, Koller N, Braner M, Jung J, Loehr F, Tampé R, Behrends C, Abele R. Lysosomal targeting of the ABC transporter TAPL is determined by membrane-localized charged residues. J Biol Chem 2019; 294:7308-7323. [PMID: 30877195 DOI: 10.1074/jbc.ra118.007071] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 03/08/2019] [Indexed: 01/16/2023] Open
Abstract
The human lysosomal polypeptide ABC transporter TAPL (ABC subfamily B member 9, ABCB9) transports 6-59-amino-acid-long polypeptides from the cytosol into lysosomes. The subcellular localization of TAPL depends solely on its N-terminal transmembrane domain, TMD0, which lacks conventional targeting sequences. However, the intracellular route and the molecular mechanisms that control TAPL localization remain unclear. Here, we delineated the route of TAPL to lysosomes and investigated the determinants of single trafficking steps. By synchronizing trafficking events by a retention using selective hooks (RUSH) assay and visualizing individual intermediate steps through immunostaining and confocal microscopy, we demonstrate that TAPL takes the direct route to lysosomes. We further identified conserved charged residues within TMD0 transmembrane helices that are essential for individual steps of lysosomal targeting. Substitutions of these residues retained TAPL in the endoplasmic reticulum (ER) or Golgi. We also observed that for release from the ER, a salt bridge between Asp-17 and Arg-57 is essential. An interactome analysis revealed that Yip1-interacting factor homolog B membrane-trafficking protein (YIF1B) interacts with TAPL. We also found that YIF1B is involved in ER-to-Golgi trafficking and interacts with TMD0 of TAPL via its transmembrane domain and that this interaction strongly depends on the newly identified salt bridge within TMD0. These results expand our knowledge about lysosomal trafficking of TAPL and the general function of extra transmembrane domains of ABC transporters.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Jennifer Jung
- the Institute of Biochemistry II, Medical School, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany, and
| | - Frank Loehr
- the Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Strasse 9, 60438 Frankfurt am Main, Germany
| | - Robert Tampé
- From the Institute of Biochemistry, Biocenter, and
| | - Christian Behrends
- the Institute of Biochemistry II, Medical School, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany, and.,the Munich Cluster for Systems Neurology, Ludwig Maximilians University Munich, Feodor-Lynen-Strasse 17, 81377 Munich, Germany
| | - Rupert Abele
- From the Institute of Biochemistry, Biocenter, and
| |
Collapse
|
44
|
Lan Y, Sullivan PM, Hu F. SMCR8 negatively regulates AKT and MTORC1 signaling to modulate lysosome biogenesis and tissue homeostasis. Autophagy 2019; 15:871-885. [PMID: 30696333 PMCID: PMC6526807 DOI: 10.1080/15548627.2019.1569914] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The intronic hexanucleotide expansion in the C9orf72 gene is one of the leading causes of frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS), two devastating neurodegenerative diseases. C9orf72 forms a heterodimer with SMCR8 (Smith-Magenis syndrome chromosome region, candidate 8) protein. However, the physiological function of SMCR8 remains to be characterized. Here we report that ablation of SMCR8 in mice results in splenomegaly with autoimmune phenotypes similar to that of C9orf72 deficiency. Furthermore, SMCR8 loss leads to a drastic decrease of C9orf72 protein levels. Many proteins involved in the macroautophagy-lysosome pathways are downregulated upon SMCR8 loss due to elevated activation of MTORC1 and AKT, which also leads to increased spine density in the Smcr8 knockout neurons. In summary, our studies demonstrate a key role of SMCR8 in regulating MTORC1 and AKT signaling and tissue homeostasis. Abbreviations: ALS: amyotrophic lateral sclerosis; C9orf72: chromosome 9 open reading frame 72; FTLD: frontotemporal lobar degeneration; GEF: guanosine nucleotide exchange factor; GTPase: guanosine tri-phosphatase; KO: knockout; MTOR: mechanistic target of rapamycin kinase; SMCR8: Smith-Magenis chromosome region, candidate 8; WDR41: WD repeat domain 41; WT: wild type
Collapse
Affiliation(s)
- Yungang Lan
- a Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology , Cornell University , Ithaca , NY , USA.,b Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine , Jilin University , Changchun , China
| | - Peter M Sullivan
- a Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology , Cornell University , Ithaca , NY , USA
| | - Fenghua Hu
- a Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology , Cornell University , Ithaca , NY , USA
| |
Collapse
|
45
|
The lysosome as a cellular centre for signalling, metabolism and quality control. Nat Cell Biol 2019; 21:133-142. [DOI: 10.1038/s41556-018-0244-7] [Citation(s) in RCA: 409] [Impact Index Per Article: 81.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 10/31/2018] [Indexed: 02/06/2023]
|
46
|
Mueller AJ, Proikas-Cezanne T. Automated Detection of Autophagy Response Using Single Cell-Based Microscopy Assays. Methods Mol Biol 2019; 1880:429-445. [PMID: 30610713 DOI: 10.1007/978-1-4939-8873-0_27] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The fluorescence microscopy-based detection of intracellular LC3, p62, and/or WIPI punctate structures is a robust tool to monitor and assess macroautophagy/autophagy in single cells. This method was established for automated high-throughput/content analysis to reliably detect narrow differences in autophagy activity/capacity and to provide screening opportunities for biological and chemical libraries.
Collapse
Affiliation(s)
- Amelie J Mueller
- Interfaculty Institute of Cell Biology, Eberhard Karls University Tuebingen, Tübingen, Germany.,International Max Planck Research School "From Molecules to Organisms", Tübingen, Germany
| | - Tassula Proikas-Cezanne
- Interfaculty Institute of Cell Biology, Eberhard Karls University Tuebingen, Tübingen, Germany. .,International Max Planck Research School "From Molecules to Organisms", Tübingen, Germany.
| |
Collapse
|
47
|
Excessive endosomal TLR signaling causes inflammatory disease in mice with defective SMCR8-WDR41-C9ORF72 complex function. Proc Natl Acad Sci U S A 2018; 115:E11523-E11531. [PMID: 30442666 DOI: 10.1073/pnas.1814753115] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The SMCR8-WDR41-C9ORF72 complex is a regulator of autophagy and lysosomal function. Autoimmunity and inflammatory disease have been ascribed to loss-of-function mutations of Smcr8 or C9orf72 in mice. In humans, autoimmunity has been reported to precede amyotrophic lateral sclerosis caused by mutations of C9ORF72 However, the cellular and molecular mechanisms underlying autoimmunity and inflammation caused by C9ORF72 or SMCR8 deficiencies remain unknown. Here, we show that splenomegaly, lymphadenopathy, and activated circulating T cells observed in Smcr8 -/- mice were rescued by triple knockout of the endosomal Toll-like receptors (TLRs) TLR3, TLR7, and TLR9. Myeloid cells from Smcr8 -/- mice produced excessive inflammatory cytokines in response to endocytosed TLR3, TLR7, or TLR9 ligands administered in the growth medium and in response to TLR2 or TLR4 ligands internalized by phagocytosis. These defects likely stem from prolonged TLR signaling caused by accumulation of LysoTracker-positive vesicles and by delayed phagosome maturation, both of which were observed in Smcr8 -/- macrophages. Smcr8 -/- mice also showed elevated susceptibility to dextran sodium sulfate-induced colitis, which was not associated with increased TLR3, TLR7, or TLR9 signaling. Deficiency of WDR41 phenocopied loss of SMCR8. Our findings provide evidence that excessive endosomal TLR signaling resulting from prolonged ligand-receptor contact causes inflammatory disease in SMCR8-deficient mice.
Collapse
|
48
|
Liu Y, Wang T, Ji YJ, Johnson K, Liu H, Johnson K, Bailey S, Suk Y, Lu YN, Liu M, Wang J. A C9orf72-CARM1 axis regulates lipid metabolism under glucose starvation-induced nutrient stress. Genes Dev 2018; 32:1380-1397. [PMID: 30366907 PMCID: PMC6217731 DOI: 10.1101/gad.315564.118] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 08/27/2018] [Indexed: 12/11/2022]
Abstract
Liu et al. report here that C9orf72, which is linked to the most common forms of the neurodegenerative diseases amyotrophic lateral sclerosis and frontotemporal dementia, is a key regulator of lipid metabolism under stress. Cells undergo metabolic adaptation during environmental changes by using evolutionarily conserved stress response programs. This metabolic homeostasis is exquisitely regulated, and its imbalance could underlie human pathological conditions. We report here that C9orf72, which is linked to the most common forms of the neurodegenerative diseases amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), is a key regulator of lipid metabolism under stress. Loss of C9orf72 leads to an overactivation of starvation-induced lipid metabolism that is mediated by dysregulated autophagic digestion of lipids and increased de novo fatty acid synthesis. C9orf72 acts by promoting the lysosomal degradation of coactivator-associated arginine methyltransferase 1 (CARM1), which in turn regulates autophagy–lysosomal functions and lipid metabolism. In ALS/FTD patient-derived neurons or tissues, a reduction in C9orf72 function is associated with dysregulation in the levels of CARM1, fatty acids, and NADPH oxidase NOX2. These results reveal a C9orf72–CARM1 axis in the control of stress-induced lipid metabolism and implicates epigenetic dysregulation in relevant human diseases.
Collapse
Affiliation(s)
- Yang Liu
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA.,Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA
| | - Tao Wang
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA.,Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA
| | - Yon Ju Ji
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA.,Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA
| | - Kenji Johnson
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA.,Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA
| | - Honghe Liu
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA.,Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA
| | - Kaitlin Johnson
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA
| | - Scott Bailey
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA
| | - Yongwon Suk
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA.,Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA
| | - Yu-Ning Lu
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA.,Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA
| | - Mingming Liu
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA.,Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA
| | - Jiou Wang
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA.,Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA
| |
Collapse
|
49
|
Morita K, Hama Y, Izume T, Tamura N, Ueno T, Yamashita Y, Sakamaki Y, Mimura K, Morishita H, Shihoya W, Nureki O, Mano H, Mizushima N. Genome-wide CRISPR screen identifies TMEM41B as a gene required for autophagosome formation. J Cell Biol 2018; 217:3817-3828. [PMID: 30093494 PMCID: PMC6219718 DOI: 10.1083/jcb.201804132] [Citation(s) in RCA: 142] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 07/19/2018] [Accepted: 07/27/2018] [Indexed: 01/22/2023] Open
Abstract
Macroautophagy is an intracellular degradation process that requires multiple autophagy-related (ATG) genes. In this study, we performed a genome-wide screen using the autophagic flux reporter GFP-LC3-RFP and identified TMEM41B as a novel ATG gene. TMEM41B is a multispanning membrane protein localized in the endoplasmic reticulum (ER). It has a conserved domain also found in vacuole membrane protein 1 (VMP1), another ER multispanning membrane protein essential for autophagy, yeast Tvp38, and the bacterial DedA family of putative half-transporters. Deletion of TMEM41B blocked the formation of autophagosomes at an early step, causing accumulation of ATG proteins and small vesicles but not elongating autophagosome-like structures. Furthermore, lipid droplets accumulated in TMEM41B-knockout (KO) cells. The phenotype of TMEM41B-KO cells resembled those of VMP1-KO cells. Indeed, TMEM41B and VMP1 formed a complex in vivo and in vitro, and overexpression of VMP1 restored autophagic flux in TMEM41B-KO cells. These results suggest that TMEM41B and VMP1 function together at an early step of autophagosome formation.
Collapse
Affiliation(s)
- Keigo Morita
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yutaro Hama
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Tamaki Izume
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Norito Tamura
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Toshihide Ueno
- Department of Cellular Signaling, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yoshihiro Yamashita
- Department of Cellular Signaling, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yuriko Sakamaki
- Research Core, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kaito Mimura
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Hideaki Morishita
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Wataru Shihoya
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Hiroyuki Mano
- Department of Cellular Signaling, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Noboru Mizushima
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| |
Collapse
|
50
|
Frick P, Sellier C, Mackenzie IRA, Cheng CY, Tahraoui-Bories J, Martinat C, Pasterkamp RJ, Prudlo J, Edbauer D, Oulad-Abdelghani M, Feederle R, Charlet-Berguerand N, Neumann M. Novel antibodies reveal presynaptic localization of C9orf72 protein and reduced protein levels in C9orf72 mutation carriers. Acta Neuropathol Commun 2018; 6:72. [PMID: 30075745 PMCID: PMC6091050 DOI: 10.1186/s40478-018-0579-0] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 07/28/2018] [Indexed: 12/12/2022] Open
Abstract
Hexanucleotide repeat expansion in C9orf72 is the most common genetic cause of frontotemporal dementia and amyotrophic lateral sclerosis, but the pathogenic mechanism of this mutation remains unresolved. Haploinsufficiency has been proposed as one potential mechanism. However, insights if and how reduced C9orf72 proteins levels might contribute to disease pathogenesis are still limited because C9orf72 expression, localization and functions in the central nervous system (CNS) are uncertain, in part due to the poor specificity of currently available C9orf72 antibodies. Here, we generated and characterized novel knock-out validated monoclonal rat and mouse antibodies against C9orf72. We found that C9orf72 is a low abundant, cytoplasmic, highly soluble protein with the long 481 amino acid isoform being the predominant, if not exclusively, expressed protein isoform in mouse tissues and human brain. As consequence of the C9orf72 repeat expansion, C9orf72 protein levels in the cerebellum were reduced to 80% in our series of C9orf72 mutation carriers (n = 17) compared to controls (n = 26). However, no associations between cerebellar protein levels and clinical phenotypes were seen. Finally, by utilizing complementary immunohistochemical and biochemical approaches including analysis of human iPSC derived motor neurons, we identified C9orf72, in addition to its association to lysosomes, to be localized to the presynapses and able to interact with all members of the RAB3 protein family, suggestive of a role for C9orf72 in regulating synaptic vesicle functions by potentially acting as guanine nucleotide exchange factor for RAB3 proteins. In conclusion, our findings provide further evidence for haploinsufficiency as potential mechanism in C9orf72 pathogenesis by demonstrating reduced protein levels in C9orf72 mutation carriers and important novel insights into the physiological role of C9orf72 in the CNS. Moreover, the described novel monoclonal C9orf72 antibodies will be useful tools to further dissect the cellular and molecular functions of C9orf72.
Collapse
|