1
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van der Graaf K, Srivastav S, Nishad R, Stern M, McNew JA. The Drosophila Nesprin-1 homolog MSP300 is required for muscle autophagy and proteostasis. J Cell Sci 2024; 137:jcs262096. [PMID: 38757366 PMCID: PMC11213522 DOI: 10.1242/jcs.262096] [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: 03/06/2024] [Accepted: 05/13/2024] [Indexed: 05/18/2024] Open
Abstract
Nesprin proteins, which are components of the linker of nucleoskeleton and cytoskeleton (LINC) complex, are located within the nuclear envelope and play prominent roles in nuclear architecture. For example, LINC complex proteins interact with both chromatin and the cytoskeleton. Here, we report that the Drosophila Nesprin MSP300 has an additional function in autophagy within larval body wall muscles. RNAi-mediated MSP300 knockdown in larval body wall muscles resulted in defects in the contractile apparatus, muscle degeneration and defective autophagy. In particular, MSP300 knockdown caused accumulation of cytoplasmic aggregates that contained poly-ubiquitylated cargo, as well as the autophagy receptor ref(2)P (the fly homolog of p62 or SQSTM) and Atg8a. Furthermore, MSP300 knockdown larvae expressing an mCherry-GFP-tagged Atg8a transgene exhibited aberrant persistence of the GFP signal within these aggregates, indicating failure of autophagosome maturation. These autophagy deficits were similar to those exhibited by loss of the endoplasmic reticulum (ER) fusion protein Atlastin (Atl), raising the possibility that Atl and MSP300 might function in the same pathway. In support of this possibility, we found that a GFP-tagged MSP300 protein trap exhibited extensive localization to the ER. Alteration of ER-directed MSP300 might abrogate important cytoskeletal contacts necessary for autophagosome completion.
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Affiliation(s)
| | | | - Rajkishor Nishad
- Department of BioSciences, Rice University, Houston, TX 77005, USA
| | - Michael Stern
- Department of BioSciences, Rice University, Houston, TX 77005, USA
| | - James A. McNew
- Department of BioSciences, Rice University, Houston, TX 77005, USA
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2
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Naeimzadeh Y, Tajbakhsh A, Fallahi J. Understanding the prion-like behavior of mutant p53 proteins in triple-negative breast cancer pathogenesis: The current therapeutic strategies and future directions. Heliyon 2024; 10:e26260. [PMID: 38390040 PMCID: PMC10881377 DOI: 10.1016/j.heliyon.2024.e26260] [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: 10/23/2023] [Revised: 01/20/2024] [Accepted: 02/09/2024] [Indexed: 02/24/2024] Open
Abstract
Breast cancer (BC) is viewed as a significant public health issue and is the primary cause of cancer-related deaths among women worldwide. Triple-negative breast cancer (TNBC) is a particularly aggressive subtype that predominantly affects young premenopausal women. The tumor suppressor p53 playsa vital role in the cellular response to DNA damage, and its loss or mutations are commonly present in many cancers, including BC. Recent evidence suggests that mutant p53 proteins can aggregate and form prion-like structures, which may contribute to the pathogenesis of different types of malignancies, such as BC. This review provides an overview of BC molecular subtypes, the epidemiology of TNBC, and the role of p53 in BC development. We also discuss the potential implications of prion-like aggregation in BC and highlight future research directions. Moreover, a comprehensive analysis of the current therapeutic approaches targeting p53 aggregates in BC treatment is presented. Strategies including small molecules, chaperone inhibitors, immunotherapy, CRISPR-Cas9, and siRNA are discussed, along with their potential benefits and drawbacks. The use of these approaches to inhibit p53 aggregation and degradation represents a promising target for cancer therapy. Future investigations into the efficacy of these approaches against various p53 mutations or binding to non-p53 proteins should be conducted to develop more effective and personalized therapies for BC treatment.
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Affiliation(s)
- Yasaman Naeimzadeh
- Department of Molecular Medicine, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences, Shiraz, 7133654361, Iran
| | - Amir Tajbakhsh
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Jafar Fallahi
- Department of Molecular Medicine, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences, Shiraz, 7133654361, Iran
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3
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Srivastav S, van der Graaf K, Singh P, Utama AB, Meyer MD, McNew JA, Stern M. Atl (atlastin) regulates mTor signaling and autophagy in Drosophila muscle through alteration of the lysosomal network. Autophagy 2024; 20:131-150. [PMID: 37649246 PMCID: PMC10761077 DOI: 10.1080/15548627.2023.2249794] [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: 03/06/2023] [Revised: 08/08/2023] [Accepted: 08/11/2023] [Indexed: 09/01/2023] Open
Abstract
ABBREVIATIONS atl atlastin; ALR autophagic lysosome reformation; ER endoplasmic reticulum; GFP green fluorescent protein; HSP hereditary spastic paraplegia; Lamp1 lysosomal associated membrane protein 1 PolyUB polyubiquitin; RFP red fluorescent protein; spin spinster; mTor mechanistic Target of rapamycin; VCP valosin containing protein.
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Affiliation(s)
| | | | - Pratibha Singh
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, USA
| | | | - Matthew D. Meyer
- Shared Equipment Authority, Rice University, Houston, Texas, USA
| | - James A. McNew
- Department of BioSciences, Rice University, Houston, Texas, USA
| | - Michael Stern
- Department of BioSciences, Rice University, Houston, Texas, USA
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4
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Wu X, Liu XQ, Liu ZN, Xia GQ, Zhu H, Zhang MD, Wu BM, Lv XW. CD73 aggravates alcohol-related liver fibrosis by promoting autophagy mediated activation of hepatic stellate cells through AMPK/AKT/mTOR signaling pathway. Int Immunopharmacol 2022; 113:109229. [DOI: 10.1016/j.intimp.2022.109229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/30/2022] [Accepted: 09/01/2022] [Indexed: 11/05/2022]
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5
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Anticancer Therapeutic Strategies Targeting p53 Aggregation. Int J Mol Sci 2022; 23:ijms231911023. [PMID: 36232329 PMCID: PMC9569952 DOI: 10.3390/ijms231911023] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 09/10/2022] [Accepted: 09/13/2022] [Indexed: 11/17/2022] Open
Abstract
p53 is a tumor suppressor protein that is mutated in more than 50% of cancer cases. When mutated, it frequently results in p53 oncogenic gain of function (GOF), resulting in a greater tendency to aggregate in the phase separation and phase transition pathway. GOFs related to p53 aggregation include chemoresistance, which makes therapy even more difficult. The therapies available for the treatment of cancer are still quite limited, so the study of new molecules and therapeutic targets focusing on p53 aggregates is a promising strategy against cancer. In this review, we classify anticancer molecules with antiaggregation properties into four categories: thiol alkylating agents, designed peptides, agents with chaperone-based mechanisms that inhibit p53 aggregation, and miscellaneous compounds with anti-protein aggregation properties that have been studied in neurodegenerative diseases. Furthermore, we highlight autophagy as a possible degradation pathway for aggregated p53. Here, considering cancer as a protein aggregation disease, we review strategies that have been used to disrupt p53 aggregates, leading to cancer regression.
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6
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Ye H, Han Y, Li P, Su Z, Huang Y. The Role of Post-Translational Modifications on the Structure and Function of Tau Protein. J Mol Neurosci 2022; 72:1557-1571. [PMID: 35325356 DOI: 10.1007/s12031-022-02002-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 03/14/2022] [Indexed: 12/14/2022]
Abstract
Involving addition of chemical groups or protein units to specific residues of the target protein, post-translational modifications (PTMs) alter the charge, hydrophobicity, and conformation of a protein, which in tune influences protein function, protein - protein interaction, and protein aggregation. While the occurrence of PTMs is dynamic and subject to regulations, conformational disorder of the target protein facilitates PTMs. The microtubule-associated protein tau is a typical intrinsically disordered protein that undergoes a variety of PTMs including phosphorylation, acetylation, ubiquitination, methylation, and oxidation. Accumulated evidence shows that these PTMs play a critical role in regulating tau-microtubule interaction, tau localization, tau degradation and aggregation, and reinforces the correlation between tau PTMs and pathogenesis of neurodegenerative disease. Here, we review tau PTMs with an emphasis on their influence on tau structure. With available biophysical characterization results, we describe how PTMs induce conformational changes in tau monomer and regulate tau aggregation. Compared to functional analysis of tau PTMs, biophysical characterization of tau PTMs is lagging. While it is challenging, characterizing the specific effects of PTMs on tau conformation and interaction is indispensable to unravel the tau PTM code.
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Affiliation(s)
- Haiqiong Ye
- Key Laboratory of Industrial Fermentation (Ministry of Education), Hubei University of Technology, Wuhan, 430068, China.,Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan, 430068, China.,Department of Biological Engineering, Hubei University of Technology, Wuhan, 430068, China
| | - Yue Han
- Key Laboratory of Industrial Fermentation (Ministry of Education), Hubei University of Technology, Wuhan, 430068, China.,Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan, 430068, China.,Department of Biological Engineering, Hubei University of Technology, Wuhan, 430068, China
| | - Ping Li
- Key Laboratory of Industrial Fermentation (Ministry of Education), Hubei University of Technology, Wuhan, 430068, China.,Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan, 430068, China.,Department of Biological Engineering, Hubei University of Technology, Wuhan, 430068, China
| | - Zhengding Su
- Key Laboratory of Industrial Fermentation (Ministry of Education), Hubei University of Technology, Wuhan, 430068, China.,Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan, 430068, China.,Department of Biological Engineering, Hubei University of Technology, Wuhan, 430068, China
| | - Yongqi Huang
- Key Laboratory of Industrial Fermentation (Ministry of Education), Hubei University of Technology, Wuhan, 430068, China. .,Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan, 430068, China. .,Department of Biological Engineering, Hubei University of Technology, Wuhan, 430068, China.
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7
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Pellegrini P, Hervera A, Varea O, Brewer MK, López-Soldado I, Guitart A, Aguilera M, Prats N, del Río JA, Guinovart JJ, Duran J. Lack of p62 Impairs Glycogen Aggregation and Exacerbates Pathology in a Mouse Model of Myoclonic Epilepsy of Lafora. Mol Neurobiol 2021; 59:1214-1229. [PMID: 34962634 PMCID: PMC8857170 DOI: 10.1007/s12035-021-02682-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 12/04/2021] [Indexed: 01/06/2023]
Abstract
Lafora disease (LD) is a fatal childhood-onset dementia characterized by the extensive accumulation of glycogen aggregates—the so-called Lafora Bodies (LBs)—in several organs. The accumulation of LBs in the brain underlies the neurological phenotype of the disease. LBs are composed of abnormal glycogen and various associated proteins, including p62, an autophagy adaptor that participates in the aggregation and clearance of misfolded proteins. To study the role of p62 in the formation of LBs and its participation in the pathology of LD, we generated a mouse model of the disease (malinKO) lacking p62. Deletion of p62 prevented LB accumulation in skeletal muscle and cardiac tissue. In the brain, the absence of p62 altered LB morphology and increased susceptibility to epilepsy. These results demonstrate that p62 participates in the formation of LBs and suggest that the sequestration of abnormal glycogen into LBs is a protective mechanism through which it reduces the deleterious consequences of its accumulation in the brain.
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Affiliation(s)
- Pasquale Pellegrini
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
| | - Arnau Hervera
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain
- Department of Cell Biology, Physiology and Immunology, Universitat de Barcelona, 08028 Barcelona, Spain
- Institute of Neurosciences, University of Barcelona, 08028 Barcelona, Spain
| | - Olga Varea
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
| | - M. Kathryn Brewer
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
| | - Iliana López-Soldado
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28029 Madrid, Spain
| | - Anna Guitart
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
| | - Mònica Aguilera
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
| | - Neus Prats
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
| | - José Antonio del Río
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain
- Department of Cell Biology, Physiology and Immunology, Universitat de Barcelona, 08028 Barcelona, Spain
- Institute of Neurosciences, University of Barcelona, 08028 Barcelona, Spain
| | - Joan J. Guinovart
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28029 Madrid, Spain
- Department of Biochemistry and Molecular Biomedicine, University of Barcelona, 08028 Barcelona, Spain
| | - Jordi Duran
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28029 Madrid, Spain
- Institut Químic de Sarrià, University Ramon Llull, 08017 Barcelona, Spain
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8
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Kim KY, Yun UJ, Yeom SH, Kim SC, Lee HJ, Ahn SC, Park KI, Kim YW. Inhibition of Autophagy Promotes Hemistepsin A-Induced Apoptosis via Reactive Oxygen Species-Mediated AMPK-Dependent Signaling in Human Prostate Cancer Cells. Biomolecules 2021; 11:biom11121806. [PMID: 34944451 PMCID: PMC8699411 DOI: 10.3390/biom11121806] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 11/29/2021] [Accepted: 11/29/2021] [Indexed: 12/09/2022] Open
Abstract
Chemotherapy is an essential strategy for cancer treatment. On the other hand, consistent exposure to chemotherapeutic drugs induces chemo-resistance in cancer cells through a variety of mechanisms. Therefore, it is important to develop a new drug inhibiting chemo-resistance. Although hemistepsin A (HsA) is known to have anti-tumor effects, the molecular mechanisms of HsA-mediated cell death are unclear. Accordingly, this study examined whether HsA could induce apoptosis in aggressive prostate cancer cells, along with its underlying mechanism. Using HsA on two prostate cancer cell lines, PC-3 and LNCaP cells, the cell analysis and in vivo xenograft model were assayed. In this study, HsA induced apoptosis and autophagy in PC-3 cells. HsA-mediated ROS production attenuated HsA-induced apoptosis and autophagy after treatment with N-acetyl-L-cysteine (NAC), a ROS scavenger. Moreover, autophagy inhibition by 3-MA or CQ is involved in accelerating the apoptosis induced by HsA. Furthermore, we showed the anti-tumor effects of HsA in mice, as assessed by the reduced growth of the xenografted tumors. In conclusion, HsA induced apoptosis and ROS generation, which were blocked by protective autophagy signaling.
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Affiliation(s)
- Kwang-Youn Kim
- Korean Medicine (KM) Application Center, Korea Institute of Oriental Medicine, 70 Cheomdan-ro, Dong-gu, Daegu 41062, Korea;
| | - Un-Jung Yun
- School of Korean Medicine, Dongguk University, Gyeongju 38066, Korea; (U.-J.Y.); (S.-H.Y.)
| | - Seung-Hee Yeom
- School of Korean Medicine, Dongguk University, Gyeongju 38066, Korea; (U.-J.Y.); (S.-H.Y.)
- Medical Research Center, College of Oriental Medicine, Daegu Haany University, Gyeongsan 38610, Korea;
| | - Sang-Chan Kim
- Medical Research Center, College of Oriental Medicine, Daegu Haany University, Gyeongsan 38610, Korea;
| | - Hu-Jang Lee
- College of Veterinary Medicine, Gyeongsang National University, Jinju 52828, Korea;
| | - Soon-Cheol Ahn
- Department of Microbiology & Immunology, Pusan National University School of Medicine, Yangsan 50612, Korea
- Correspondence: (S.-C.A.); (K.-I.P.); (Y.-W.K.)
| | - Kwang-Il Park
- College of Veterinary Medicine, Gyeongsang National University, Jinju 52828, Korea;
- Correspondence: (S.-C.A.); (K.-I.P.); (Y.-W.K.)
| | - Young-Woo Kim
- School of Korean Medicine, Dongguk University, Gyeongju 38066, Korea; (U.-J.Y.); (S.-H.Y.)
- Correspondence: (S.-C.A.); (K.-I.P.); (Y.-W.K.)
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9
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Chen HY, Hsu CL, Lin HY, Lin YF, Tsai SF, Ho YJ, Li YR, Tsai JW, Teng SC, Lin CH. Clinical and functional characterization of a novel STUB1 frameshift mutation in autosomal dominant spinocerebellar ataxia type 48 (SCA48). J Biomed Sci 2021; 28:65. [PMID: 34565360 PMCID: PMC8466936 DOI: 10.1186/s12929-021-00763-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Accepted: 09/23/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Heterozygous pathogenic variants in STUB1 are implicated in autosomal dominant spinocerebellar ataxia type 48 (SCA48), which is a rare familial ataxia disorder. We investigated the clinical, genetic and functional characteristics of STUB1 mutations identified from a Taiwanese ataxia cohort. METHODS We performed whole genome sequencing in a genetically undiagnosed family with an autosomal dominant ataxia syndrome. Further Sanger sequencing of all exons and intron-exon boundary junctions of STUB1 in 249 unrelated patients with cerebellar ataxia was performed. The pathogenicity of the identified novel STUB1 variant was investigated. RESULTS We identified a novel heterozygous frameshift variant, c.832del (p.Glu278fs), in STUB1 in two patients from the same family. This rare mutation is located in the U-box of the carboxyl terminus of the Hsc70-interacting protein (CHIP) protein, which is encoded by STUB1. Further in vitro experiments demonstrated that this novel heterozygous STUB1 frameshift variant impairs the CHIP protein's activity and its interaction with the E2 ubiquitin ligase, UbE2D1, leading to neuronal accumulation of tau and α-synuclein, caspase-3 activation, and promoting cellular apoptosis through a dominant-negative pathogenic effect. The in vivo study revealed the influence of the CHIP expression level on the differentiation and migration of cerebellar granule neuron progenitors during cerebellar development. CONCLUSIONS Our findings provide clinical, genetic, and a mechanistic insight linking the novel heterozygous STUB1 frameshift mutation at the highly conserved U-box domain of CHIP as the cause of autosomal dominant SCA48. Our results further stress the importance of CHIP activity in neuronal protein homeostasis and cerebellar functions.
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Affiliation(s)
- Huan-Yun Chen
- Department of Microbiology, College of Medicine, National Taiwan University, No. 1, Section 1, Jen-Ai Road, Taipei, 10051, Taiwan
| | - Chia-Lang Hsu
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan
| | - Han-Yi Lin
- Department of Neurology, National Taiwan University Hospital, Number 7, Chung-Shan South Road, Taipei, 10051, Taiwan
| | - Yung-Feng Lin
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan.,Institute of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan, Taiwan
| | - Shih-Feng Tsai
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan.,Institute of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan, Taiwan
| | - Yu-Jung Ho
- Institute of Brain Science, College of Medicine, National Yang Ming Chiao Tung University, Taipei, 112, Taiwan
| | - Ye-Ru Li
- Institute of Brain Science, College of Medicine, National Yang Ming Chiao Tung University, Taipei, 112, Taiwan
| | - Jin-Wu Tsai
- Institute of Brain Science, College of Medicine, National Yang Ming Chiao Tung University, Taipei, 112, Taiwan.,Brain Research Center, National Yang Ming Chiao Tung University, Taipei, 112, Taiwan
| | - Shu-Chun Teng
- Department of Microbiology, College of Medicine, National Taiwan University, No. 1, Section 1, Jen-Ai Road, Taipei, 10051, Taiwan. .,Center of Precision Medicine, National Taiwan University, Taipei, Taiwan.
| | - Chin-Hsien Lin
- Department of Neurology, National Taiwan University Hospital, Number 7, Chung-Shan South Road, Taipei, 10051, Taiwan.
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10
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Muscolino E, Luoto LM, Brune W. Viral Induced Protein Aggregation: A Mechanism of Immune Evasion. Int J Mol Sci 2021; 22:ijms22179624. [PMID: 34502533 PMCID: PMC8431809 DOI: 10.3390/ijms22179624] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 08/31/2021] [Accepted: 09/04/2021] [Indexed: 12/20/2022] Open
Abstract
Various intrinsic and extrinsic factors can interfere with the process of protein folding, resulting in protein aggregates. Usually, cells prevent the formation of aggregates or degrade them to prevent the cytotoxic effects they may cause. However, during viral infection, the formation of aggregates may serve as a cellular defense mechanism. On the other hand, some viruses are able to exploit the process of aggregate formation and removal to promote their replication or evade the immune response. This review article summarizes the process of cellular protein aggregation and gives examples of how different viruses exploit it. Particular emphasis is placed on the ribonucleotide reductases of herpesviruses and how their additional non-canonical functions in viral immune evasion are closely linked to protein aggregation.
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Affiliation(s)
- Elena Muscolino
- Leibniz Institute for Experimental Virology (HPI), 20251 Hamburg, Germany; (E.M.); (L.-M.L.)
- Molecular Virology Group, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - Laura-Marie Luoto
- Leibniz Institute for Experimental Virology (HPI), 20251 Hamburg, Germany; (E.M.); (L.-M.L.)
| | - Wolfram Brune
- Leibniz Institute for Experimental Virology (HPI), 20251 Hamburg, Germany; (E.M.); (L.-M.L.)
- Correspondence: ; Tel.: +49-40-48051351
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11
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Raj K, Akundi RS. Mutant Ataxin-3-Containing Aggregates (MATAGGs) in Spinocerebellar Ataxia Type 3: Dynamics of the Disorder. Mol Neurobiol 2021; 58:3095-3118. [PMID: 33629274 DOI: 10.1007/s12035-021-02314-z] [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: 10/11/2020] [Accepted: 01/25/2021] [Indexed: 11/25/2022]
Abstract
Spinocerebellar ataxia type 3 (SCA3) is the most common type of SCA worldwide caused by abnormal polyglutamine expansion in the coding region of the ataxin-3 gene. Ataxin-3 is a multi-faceted protein involved in various cellular processes such as deubiquitination, cytoskeletal organisation, and transcriptional regulation. The presence of an expanded poly(Q) stretch leads to altered processing and misfolding of the protein culminating in the production of insoluble protein aggregates in the cell. Various post-translational modifications affect ataxin-3 fibrillation and aggregation. This review provides an exhaustive assessment of the various pathogenic mechanisms undertaken by the mutant ataxin-3-containing aggregates (MATAGGs) for disease induction and neurodegeneration. This includes in-depth discussion on MATAGG dynamics including their formation, role in neuronal pathogenesis, and the debate over the toxic v/s protective nature of the MATAGGs in disease progression. Additionally, the currently available therapeutic strategies against SCA3 have been reviewed. The shift in the focus of such strategies, from targeting the steps that lead to or reduce aggregate formation to targeting the expression of mutant ataxin-3 itself via RNA-based therapeutics, has also been presented. We also discuss the intriguing promise that various growth and neurotrophic factors, especially the insulin pathway, hold in the modulation of SCA3 progression. These emerging areas show the newer directions through which SCA3 can be targeted including various preclinical and clinical trials. All these advances made in the last three decades since the discovery of the ataxin-3 gene have been critically reviewed here.
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Affiliation(s)
- Kritika Raj
- Neuroinflammation Research Lab, Faculty of Life Sciences and Biotechnology, South Asian University, Chanakyapuri, New Delhi, 110021, India
| | - Ravi Shankar Akundi
- Neuroinflammation Research Lab, Faculty of Life Sciences and Biotechnology, South Asian University, Chanakyapuri, New Delhi, 110021, India.
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12
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Schuster S, Heuten E, Velic A, Admard J, Synofzik M, Ossowski S, Macek B, Hauser S, Schöls L. CHIP mutations affect the heat shock response differently in human fibroblasts and iPSC-derived neurons. Dis Model Mech 2020; 13:13/10/dmm045096. [PMID: 33097556 PMCID: PMC7578354 DOI: 10.1242/dmm.045096] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 08/10/2020] [Indexed: 01/09/2023] Open
Abstract
C-terminus of HSC70-interacting protein (CHIP) encoded by the gene STUB1 is a co-chaperone and E3 ligase that acts as a key regulator of cellular protein homeostasis. Mutations in STUB1 cause autosomal recessive spinocerebellar ataxia type 16 (SCAR16) with widespread neurodegeneration manifesting as spastic-ataxic gait disorder, dementia and epilepsy. CHIP-/- mice display severe cerebellar atrophy, show high perinatal lethality and impaired heat stress tolerance. To decipher the pathomechanism underlying SCAR16, we investigated the heat shock response (HSR) in primary fibroblasts of three SCAR16 patients. We found impaired HSR induction and recovery compared to healthy controls. HSPA1A/B transcript levels (coding for HSP70) were reduced upon heat shock but HSP70 remained higher upon recovery in patient- compared to control-fibroblasts. As SCAR16 primarily affects the central nervous system we next investigated the HSR in cortical neurons (CNs) derived from induced pluripotent stem cells of SCAR16 patients. We found CNs of patients and controls to be surprisingly resistant to heat stress with high basal levels of HSP70 compared to fibroblasts. Although heat stress resulted in strong transcript level increases of many HSPs, this did not translate into higher HSP70 protein levels upon heat shock, independent of STUB1 mutations. Furthermore, STUB1(-/-) neurons generated by CRISPR/Cas9-mediated genome editing from an isogenic healthy control line showed a similar HSR to patients. Proteomic analysis of CNs showed dysfunctional protein (re)folding and higher basal oxidative stress levels in patients. Our results question the role of impaired HSR in SCAR16 neuropathology and highlight the need for careful selection of proper cell types for modeling human diseases.
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Affiliation(s)
- S Schuster
- Department of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany.,Department of Neurodegenerative Diseases, German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen, Germany.,Graduate School of Cellular and Molecular Neuroscience, University of Tübingen, 72076 Tübingen, Germany
| | - E Heuten
- Department of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany
| | - A Velic
- Proteome Center Tübingen, University of Tübingen, 72076 Tübingen, Germany
| | - J Admard
- Institute for Medical Genetics and Applied Genomics, University of Tübingen, 72076 Tübingen, Germany
| | - M Synofzik
- Department of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany
| | - S Ossowski
- Institute for Medical Genetics and Applied Genomics, University of Tübingen, 72076 Tübingen, Germany
| | - B Macek
- Proteome Center Tübingen, University of Tübingen, 72076 Tübingen, Germany
| | - S Hauser
- Department of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany .,Department of Neurodegenerative Diseases, German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen, Germany
| | - L Schöls
- Department of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany .,Department of Neurodegenerative Diseases, German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen, Germany
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13
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Abstract
Neurodegenerative diseases are, at present, major socio-economic burdens without effective treatments and their increasing prevalence means that these diseases will be a challenge for future generations. Neurodegenerative diseases may differ in etiology and pathology but are often caused by the accumulation of dysfunctional and aggregation-prone proteins. Autophagy, a conserved cellular mechanism, deals with cellular stress and waste product build-up and has been shown to reduce the accumulation of dysfunctional proteins in animal models of neurodegenerative diseases. Historically, progress in understanding the precise function of lipids has traditionally been far behind other biological molecules (like proteins) but emerging works demonstrate the importance of lipids in the autophagy pathway and how the disturbance of lipid metabolism is connected to neurodegeneration. Here we review how altered autophagy and the disturbance of lipid metabolism, particularly of phosphoinositols and sphingolipids, feature in neurodegenerative diseases and address work from the field that suggests that these potentially offer an opportunity of therapeutic intervention.
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Affiliation(s)
- Sergio Hernandez-Diaz
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, 33000, Bordeaux, France.,CNRS, Institut des Maladies Neurodégénératives, UMR 5293, 33000, Bordeaux, France
| | - Sandra-Fausia Soukup
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, 33000, Bordeaux, France.,CNRS, Institut des Maladies Neurodégénératives, UMR 5293, 33000, Bordeaux, France
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14
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Thomas JM, Wang X, Guo G, Li T, Dai B, Nucifora LG, Nucifora FC, Liu Z, Xue F, Liu C, Ross CA, Smith WW. GTP-binding inhibitors increase LRRK2-linked ubiquitination and Lewy body-like inclusions. J Cell Physiol 2020; 235:7309-7320. [PMID: 32180220 DOI: 10.1002/jcp.29632] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 01/30/2020] [Indexed: 01/05/2023]
Abstract
Parkinson's disease (PD) is one of the most common movement disorders with loss of dopaminergic neurons and the presence of Lewy bodies in certain brain areas. However, it is not clear how Lewy body (inclusion with protein aggregation) formation occurs. Mutations in leucine-rich repeat kinase 2 (LRRK2) can cause a genetic form of PD and contribute to sporadic PD with the typical Lewy body pathology. Here, we used our recently identified LRRK2 GTP-binding inhibitors as pharmacological probes to study the LRRK2-linked ubiquitination and protein aggregation. Pharmacological inhibition of GTP-binding by GTP-binding inhibitors (68 and Fx2149) increased LRRK2-linked ubiquitination predominantly via K27 linkage. Compound 68- or Fx2149 increased G2019S-LRRK2-linked ubiquitinated aggregates, which occurred through the atypical linkage types K27 and K63. Coexpression of K27R and K63R, which prevented ubiquitination via K27 and K63 linkages, reversed the effects of 68 and Fx2149. Moreover, 68 and Fx2149 also promoted G2019S-LRRK2-linked aggresome (Lewy body-like inclusion) formation via K27 and K63 linkages. These findings demonstrate that LRRK2 GTP-binding activity is critical in LRRK2-linked ubiquitination and aggregation formation. These studies provide novel insight into the LRRK2-linked Lewy body-like inclusion formation underlying PD pathogenesis.
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Affiliation(s)
- Joseph M Thomas
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland.,Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland
| | - Xiaobo Wang
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland.,Institute of Neuroscience, Soochow University School of Medicine, Suzhou, China
| | - Gongbo Guo
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Tianxia Li
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Bingling Dai
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Leslie G Nucifora
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Frederick C Nucifora
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Zhaohui Liu
- Institute of Neuroscience, Soochow University School of Medicine, Suzhou, China
| | - Fengtian Xue
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland
| | - Chunfeng Liu
- Institute of Neuroscience, Soochow University School of Medicine, Suzhou, China
| | - Christopher A Ross
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland.,Department of Neurology and Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland.,Department of Pharmacology and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Wanli W Smith
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
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15
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Suresh SN, Chakravorty A, Giridharan M, Garimella L, Manjithaya R. Pharmacological Tools to Modulate Autophagy in Neurodegenerative Diseases. J Mol Biol 2020; 432:2822-2842. [PMID: 32105729 DOI: 10.1016/j.jmb.2020.02.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 02/03/2020] [Accepted: 02/12/2020] [Indexed: 12/11/2022]
Abstract
Considerable evidences suggest a link between autophagy dysfunction, protein aggregation, and neurodegenerative diseases. Given that autophagy is a conserved intracellular housekeeping process, modulation of autophagy flux in various model organisms have highlighted its importance for maintaining proteostasis. In postmitotic cells such as neurons, compromised autophagy is sufficient to cause accumulation of ubiquitinated aggregates, neuronal dysfunction, degeneration, and loss of motor coordination-all hallmarks of neurodegenerative diseases. Reciprocally, enhanced autophagy flux augments cellular and organismal health, in addition to extending life span. These genetic studies not-withstanding a plethora of small molecule modulators of autophagy flux have been reported that alleviate disease symptoms in models of neurodegenerative diseases. This review summarizes the potential of such molecules to be, perhaps, one of the first autophagy drugs for treating these currently incurable diseases.
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Affiliation(s)
- S N Suresh
- Centre for Brain Research, Indian Institute of Science, Bangalore, 560012, Karnataka, India
| | - Anushka Chakravorty
- Autophagy Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, Karnataka, India
| | - Mridhula Giridharan
- Autophagy Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, Karnataka, India
| | - Lakshmi Garimella
- Autophagy Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, Karnataka, India
| | - Ravi Manjithaya
- Autophagy Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, Karnataka, India; Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, Karnataka, India.
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16
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Kumar D, Kumar P. Aβ, Tau, and α-Synuclein aggregation and integrated role of PARK2 in the regulation and clearance of toxic peptides. Neuropeptides 2019; 78:101971. [PMID: 31540705 DOI: 10.1016/j.npep.2019.101971] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 09/09/2019] [Accepted: 09/11/2019] [Indexed: 12/20/2022]
Abstract
Alzheimer's and Parkinson's diseases are one of the world's leading causes of death. >50 million people throughout the world are suffering with these diseases. They are two distinct progressive neurodegenerative disorders affecting different regions of the brain with diverse symptoms, including memory and motor loss respectively, but with the advancement of diseases, both affect the whole brain and exhibit some common biological symptoms. For instance, >50% PD patients develop dementia in their later stages, though it is a hallmark of Alzheimer's disease. In fact, latest research has suggested the involvement of some common pathophysiological and genetic links between these diseases, including the deposition of pathological Aβ, Tau, and α-synuclein in both the cases. Therefore, it is pertinent to diagnose the shared biomarkers, their aggregation mechanism, their intricate relationships in the pathophysiology of disease and therapeutic markers to target them. This would enable us to identify novel markers for the early detection of disease and targets for the future therapies. Herein, we investigated molecular aspects of Aβ, Tau, and α-Synuclein aggregation, and characterized their functional partners involved in the pathology of AD and PD. Moreover, we identified the molecular-crosstalk between AD and PD associated with their pathogenic proteins- Aβ, Tau, and α-Synuclein. Furthermore, we characterized their ubiquitinational enzymes and associated interaction network regulating the proteasomal clearance of these pathological proteins.
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Affiliation(s)
- Dhiraj Kumar
- Molecular Neuroscience and Functional Genomics Laboratory, Delhi Technological University, Shahbad Daulatpur, Bawana Road, Delhi 110042, India
| | - Pravir Kumar
- Molecular Neuroscience and Functional Genomics Laboratory, Delhi Technological University, Shahbad Daulatpur, Bawana Road, Delhi 110042, India.
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17
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He X, Zhu Y, Zhang Y, Geng Y, Gong J, Geng J, Zhang P, Zhang X, Liu N, Peng Y, Wang C, Wang Y, Liu X, Wan L, Gong F, Wei C, Zhong H. RNF34 functions in immunity and selective mitophagy by targeting MAVS for autophagic degradation. EMBO J 2019; 38:e100978. [PMID: 31304625 PMCID: PMC6627233 DOI: 10.15252/embj.2018100978] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 05/06/2019] [Accepted: 05/13/2019] [Indexed: 12/13/2022] Open
Abstract
Viral infection triggers the formation of mitochondrial antiviral signaling protein (MAVS) aggregates, which potently promote immune signaling. Autophagy plays an important role in controlling MAVS-mediated antiviral signaling; however, the exact molecular mechanism underlying the targeted autophagic degradation of MAVS remains unclear. Here, we investigated the mechanism by which RNF34 regulates immunity and mitophagy by targeting MAVS. RNF34 binds to MAVS in the mitochondrial compartment after viral infection and negatively regulates RIG-I-like receptor (RLR)-mediated antiviral immunity. Moreover, RNF34 catalyzes the K27-/K29-linked ubiquitination of MAVS at Lys 297, 311, 348, and 362 Arg, which serves as a recognition signal for NDP52-dependent autophagic degradation. Specifically, RNF34 initiates the K63- to K27-linked ubiquitination transition on MAVS primarily at Lys 311, which facilitates the autophagic degradation of MAVS upon RIG-I stimulation. Notably, RNF34 is required for the clearance of damaged mitochondria upon viral infection. Thus, we elucidated the mechanism by which RNF34-mediated autophagic degradation of MAVS regulates the innate immune response, mitochondrial homeostasis, and infection.
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Affiliation(s)
- Xiang He
- Beijing Institute of BiotechnologyBeijingChina
| | - Yongjie Zhu
- Beijing Institute of BiotechnologyBeijingChina
| | | | - Yunqi Geng
- Beijing Institute of BiotechnologyBeijingChina
- Institute of Physical Science and Information TechnologyAnhui UniversityHefeiChina
| | - Jing Gong
- Beijing Institute of BiotechnologyBeijingChina
- Institute of Physical Science and Information TechnologyAnhui UniversityHefeiChina
| | - Jin Geng
- Beijing Institute of BiotechnologyBeijingChina
- Institute of Physical Science and Information TechnologyAnhui UniversityHefeiChina
| | | | | | - Ning Liu
- Beijing Institute of BiotechnologyBeijingChina
| | - Yumeng Peng
- Beijing Institute of BiotechnologyBeijingChina
| | | | - Yujie Wang
- Beijing Institute of BiotechnologyBeijingChina
- Institute of Physical Science and Information TechnologyAnhui UniversityHefeiChina
| | - Xin Liu
- Beijing Institute of BiotechnologyBeijingChina
| | - Luming Wan
- Stem Cell and Regenerative Medicine LabInstitute of Health Service and Transfusion MedicineAcademy of Military Medical SciencesBeijingChina
| | - Feng Gong
- Stem Cell and Regenerative Medicine LabInstitute of Health Service and Transfusion MedicineAcademy of Military Medical SciencesBeijingChina
| | - Congwen Wei
- Beijing Institute of BiotechnologyBeijingChina
| | - Hui Zhong
- Beijing Institute of BiotechnologyBeijingChina
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18
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IGFBPrP1 accelerates autophagy and activation of hepatic stellate cells via mutual regulation between H19 and PI3K/AKT/mTOR pathway. Biomed Pharmacother 2019; 116:109034. [PMID: 31152924 DOI: 10.1016/j.biopha.2019.109034] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 05/04/2019] [Accepted: 05/22/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Our previous study found that insulin-like growth factor binding protein-associated protein (IGFBPrP1) drives hepatic stellate cells (HSCs) activation, and IGFBPrP1 and transforming growth factor β1 (TGFβ1) likely interact with each other to promote HSCs activation. TGFβ1 reportedly promotes autophagy and contributes to HSCs activation; however, the mechanism between IGFBPrP1 and autophagy in liver fibrogenesis is yet unknown. Moreover, long noncoding RNA (lncRNA) H19 participates in autophagy regulation and plays a crucial function in liver fibrosis. AIMS To define the relationship between IGFBPrP1 and autophagy and the role of H19 in IGFBPrP1-induced hepatic fibrosis. METHODS IGFBPrP1 and autophagy were detected in bile duct ligation (BDL)-induced hepatic fibrosis. Adenovirus-mediated IGFBPrP1 was transfected into mouse liver and JS-1 cells with or without LY294002 or rapamycin to examine the effects of IGFBPrP1 on HSCs activation and autophagy as well as the PI3K/AKT/mTOR pathway. lncRNA H19 in liver fibrosis tissues and JS-1 cells induced by IGFBPrP1 were detected, then autophagy and HSCs activation level were detected in JS-1 cells by IGFBPrP1 with H19 overexpression or knowdown. RESULTS IGFBPrP1 expression and autophagy level were concomitantly increased in liver tissue with BDL-induced hepatic fibrosis. Furthermore, we found that IGFBPrP1 stimulated autophagy and HSCs activation in vivo and in vitro, and PI3K/AKT/mTOR signaling pathway was involved in the regulation of autophagy by IGFBPrP1. In addition, H19 promoted autophagy by interacting with the PI3K/AKT/mTOR pathway in IGFBPrP1-induced HSCs activation. CONCLUSIONS IGFBPrP1 promoted autophagy and contributed to HSCs activation via mutual regulation between H19 and the PI3K/AKT/mTOR pathway.
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19
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Upadhyay A. Structure of proteins: Evolution with unsolved mysteries. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 149:160-172. [PMID: 31014967 DOI: 10.1016/j.pbiomolbio.2019.04.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 04/16/2019] [Accepted: 04/19/2019] [Indexed: 02/07/2023]
Abstract
Evolution of macromolecules could be considered as a milestone in the history of life. Nucleic acids are the long stretches of nucleotides that contain all the possible codes and information of life. On the other hand, proteins are their actual translated outcomes, or reflections of modifications in their structure that have occurred at a slow, but steady rate over a very long period of evolution. Over the years of research, biophysicists, biochemists, molecular and structural biologists have unfurled several layers of the structural convolutions in these chemical molecules; however evolutionists look over their structures through a different prism, which may or may not coincide with others. There remains a need to outline several well-known, but less discussed features of protein structures, like intrinsically disordered states, degron signals and different types of ubiquitin chains providing degradation signals, which help the cellular proteolytic machinery to identify and target the proteins towards degradation pathways. There are several important factors, which are critical for folding of proteins into their native three-dimensional conformations by the cytoplasmic chaperones; but in real time how the chaperones fold the newly synthesized polypeptide sequences into a particular three-dimensional shape within a fraction of second is still a mystery for biologists as well as mathematicians. Multiple similar unsolved or unaddressed questions need to be addressed in detail so that future line of research can dig deeper into the finer details of these structures of the proteins.
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Affiliation(s)
- Arun Upadhyay
- Department of Biochemistry, Central University of Rajasthan, Ajmer, 305817, India.
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20
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Autophagy as a Homeostatic Mechanism in Response to Stress Conditions in the Central Nervous System. Mol Neurobiol 2019; 56:6594-6608. [DOI: 10.1007/s12035-019-1546-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 03/12/2019] [Indexed: 12/11/2022]
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21
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Cao Y, Banks DA, Mattei AM, Riddick AT, Reed KM, Zhang AM, Pickering ES, Hinton SD. Pseudophosphatase MK-STYX Alters Histone Deacetylase 6 Cytoplasmic Localization, Decreases Its Phosphorylation, and Increases Detyrosination of Tubulin. Int J Mol Sci 2019; 20:ijms20061455. [PMID: 30909412 PMCID: PMC6470616 DOI: 10.3390/ijms20061455] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 03/14/2019] [Accepted: 03/19/2019] [Indexed: 12/14/2022] Open
Abstract
The catalytically inactive mitogen-activated protein (MAP) kinase phosphatase, MK-STYX (MAPK (mitogen-activated protein kinase) phosphoserine/threonine/tyrosine-binding protein) interacts with the stress granule nucleator G3BP-1 (Ras-GAP (GTPase-activating protein) SH3 (Src homology 3) domain-binding protein-1), and decreases stress granule (stalled mRNA) formation. Histone deacetylase isoform 6 (HDAC6) also binds G3BP-1 and serves as a major component of stress granules. The discovery that MK-STYX and HDAC6 both interact with G3BP-1 led us to investigate the effects of MK-STYX on HDAC6 dynamics. In control HEK/293 cells, HDAC6 was cytosolic, as expected, and formed aggregates under conditions of stress. In contrast, in cells overexpressing MK-STYX, HDAC6 was both nuclear and cytosolic and the number of stress-induced aggregates significantly decreased. Immunoblots showed that MK-STYX decreases HDAC6 serine phosphorylation, protein tyrosine phosphorylation, and lysine acetylation. HDAC6 is known to regulate microtubule dynamics to form aggregates. MK-STYX did not affect the organization of microtubules, but did affect their post-translational modification. Tubulin acetylation was increased in the presence of MK-STYX. In addition, the detyrosination of tubulin was significantly increased in the presence of MK-STYX. These findings show that MK-STYX decreases the number of HDAC6-containing aggregates and alters their localization, sustains microtubule acetylation, and increases detyrosination of microtubules, implicating MK-STYX as a signaling molecule in HDAC6 activity.
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Affiliation(s)
- Yuming Cao
- Department of Biology, Integrated Science Center, College of William and Mary, Williamsburg, VA 23185, USA.
| | - Dallas A Banks
- Department of Biology, Integrated Science Center, College of William and Mary, Williamsburg, VA 23185, USA.
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA.
| | - Andrew M Mattei
- Department of Biology, Integrated Science Center, College of William and Mary, Williamsburg, VA 23185, USA.
| | - Alexys T Riddick
- Department of Biology, Integrated Science Center, College of William and Mary, Williamsburg, VA 23185, USA.
| | - Kirstin M Reed
- Department of Biology, Integrated Science Center, College of William and Mary, Williamsburg, VA 23185, USA.
| | - Ashley M Zhang
- Department of Biology, Integrated Science Center, College of William and Mary, Williamsburg, VA 23185, USA.
| | - Emily S Pickering
- Department of Biology, Integrated Science Center, College of William and Mary, Williamsburg, VA 23185, USA.
| | - Shantá D Hinton
- Department of Biology, Integrated Science Center, College of William and Mary, Williamsburg, VA 23185, USA.
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22
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Transglutaminase 2: The Maestro of the Oncogenic Mediators in Renal Cell Carcinoma. Med Sci (Basel) 2019; 7:medsci7020024. [PMID: 30736384 PMCID: PMC6409915 DOI: 10.3390/medsci7020024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 02/01/2019] [Accepted: 02/01/2019] [Indexed: 12/13/2022] Open
Abstract
Transglutaminase 2 (TG2) is a multifunctional crosslinking enzyme that displays transamidation, protein disulfide isomerase, protein kinase, as well as GTPase and ATPase activities. TG2 can also act as an adhesion molecule involved in the syndecan and integrin receptor signaling. In recent years, TG2 was implicated in cancer progression, survival, invasion, migration, and stemness of many cancer types, including renal cell carcinoma (RCC). Von Hippel-Lindau mutations leading to the subsequent activation of Hypoxia Inducible Factor (HIF)-1-mediated signaling pathways, survival signaling via the PI3K/Akt pathway resulting in Epithelial Mesenchymal Transition (EMT) metastasis and angiogenesis are the main factors in RCC progression. A number of studies have shown that TG2 was important in HIF-1- and PI3K-mediated signaling, VHL and p53 stabilization, glycolytic metabolism and migratory phenotype in RCC. This review focuses on the role of TG2 in the regulation of molecular pathways nurturing not only the development and propagation of RCC, but also drug-resistance and metastatic potential.
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23
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Tapia-Rojas C, Cabezas-Opazo F, Deaton CA, Vergara EH, Johnson GVW, Quintanilla RA. It's all about tau. Prog Neurobiol 2018; 175:54-76. [PMID: 30605723 DOI: 10.1016/j.pneurobio.2018.12.005] [Citation(s) in RCA: 111] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 12/07/2018] [Accepted: 12/28/2018] [Indexed: 12/21/2022]
Abstract
Tau is a protein that is highly enriched in neurons and was originally defined by its ability to bind and stabilize microtubules. However, it is now becoming evident that the functions of tau extend beyond its ability to modulate microtubule dynamics. Tau plays a role in mediating axonal transport, synaptic structure and function, and neuronal signaling pathways. Although tau plays important physiological roles in neurons, its involvement in neurodegenerative diseases, and most prominently in the pathogenesis of Alzheimer disease (AD), has directed the majority of tau studies. However, a thorough knowledge of the physiological functions of tau and its post-translational modifications under normal conditions are necessary to provide the foundation for understanding its role in pathological settings. In this review, we will focus on human tau, summarizing tau structure and organization, as well as its posttranslational modifications associated with physiological processes. We will highlight possible mechanisms involved in mediating the turnover of tau and finally discuss newly elucidated tau functions in a physiological context.
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Affiliation(s)
- Cheril Tapia-Rojas
- Laboratory of Neurobiology of Aging, Centro de Biología Celular y Biomedicina (CEBICEM), Universidad San Sebastián, Santiago, Chile
| | - Fabian Cabezas-Opazo
- Laboratory of Neurodegenerative Diseases, Centro de Investigación Biomédica, Universidad Autónoma de Chile, Santiago, Chile
| | - Carol A Deaton
- Department of Anesthesiology and Perioperative Medicine, University of Rochester Medical Center, NY, USA
| | - Erick H Vergara
- Laboratory of Neurodegenerative Diseases, Centro de Investigación Biomédica, Universidad Autónoma de Chile, Santiago, Chile
| | - Gail V W Johnson
- Department of Anesthesiology and Perioperative Medicine, University of Rochester Medical Center, NY, USA
| | - Rodrigo A Quintanilla
- Laboratory of Neurodegenerative Diseases, Centro de Investigación Biomédica, Universidad Autónoma de Chile, Santiago, Chile; Centro de Investigación y Estudio del Consumo de Alcohol en Adolescentes (CIIA), Santiago, Chile.
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24
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Kaliszczak M, van Hechanova E, Li Y, Alsadah H, Parzych K, Auner HW, Aboagye EO. The HDAC6 inhibitor C1A modulates autophagy substrates in diverse cancer cells and induces cell death. Br J Cancer 2018; 119:1278-1287. [PMID: 30318510 PMCID: PMC6251030 DOI: 10.1038/s41416-018-0232-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 07/18/2018] [Accepted: 07/25/2018] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Cytosolic deacetylase histone deacetylase 6 (HDAC6) is involved in the autophagy degradation pathway of malformed proteins, an important survival mechanism in cancer cells. We evaluated modulation of autophagy-related proteins and cell death by the HDAC6-selective inhibitor C1A. METHODS Autophagy substrates (light chain-3 (LC-3) and p62 proteins) and endoplasmic reticulum (ER) stress phenotype were determined. Caspase-3/7 activation and cellular proliferation assays were used to assess consequences of autophagy modulation. RESULTS C1A potently resolved autophagy substrates induced by 3-methyladenine and chloroquine. The mechanism of autophagy inhibition by HDAC6 genetic knockout or C1A treatment was consistent with abrogation of autophagosome-lysosome fusion, and decrease of Myc protein. C1A alone or combined with the proteasome inhibitor, bortezomib, enhanced cell death in malignant cells, demonstrating the complementary roles of the proteasome and autophagy pathways for clearing malformed proteins. Myc-positive neuroblastoma, KRAS-positive colorectal cancer and multiple myeloma cells showed marked cell growth inhibition in response to HDAC6 inhibitors. Finally, growth of neuroblastoma xenografts was arrested in vivo by single agent C1A, while combination with bortezomib slowed the growth of colorectal cancer xenografts. CONCLUSIONS C1A resolves autophagy substrates in malignant cells and induces cell death, warranting its use for in vivo pre-clinical autophagy research.
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Affiliation(s)
- Maciej Kaliszczak
- Department of Surgery and Cancer, Cancer Imaging Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK
- Pre-clinical Imaging and Pharmacology, Biogen, 125 Broadway Street, Cambridge, MA, 02142, USA
| | - Erich van Hechanova
- Department of Surgery and Cancer, Cancer Imaging Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK
- Developmental Biology of Birth Defects Section, UCL Great Ormond Street Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK
| | - Yunqing Li
- Department of Surgery and Cancer, Cancer Imaging Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK
| | - Hibah Alsadah
- Cancer Cell Protein Metabolism Group, Department of Medicine, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK
| | - Katarzyna Parzych
- Cancer Cell Protein Metabolism Group, Department of Medicine, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK
| | - Holger W Auner
- Cancer Cell Protein Metabolism Group, Department of Medicine, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK
| | - Eric O Aboagye
- Department of Surgery and Cancer, Cancer Imaging Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK.
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25
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Ghosh S, Shang P, Terasaki H, Stepicheva N, Hose S, Yazdankhah M, Weiss J, Sakamoto T, Bhutto IA, Xia S, Zigler JS, Kannan R, Qian J, Handa JT, Sinha D. A Role for βA3/A1-Crystallin in Type 2 EMT of RPE Cells Occurring in Dry Age-Related Macular Degeneration. Invest Ophthalmol Vis Sci 2018; 59:AMD104-AMD113. [PMID: 30098172 PMCID: PMC6058694 DOI: 10.1167/iovs.18-24132] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Purpose The RPE cells have a major role in the development of dry age-related macular degeneration (AMD). We present novel evidence that βA3/A1-crystallin, encoded by the Cryba1 gene, a protein known to be important for lysosomal clearance in the RPE, also has a role in epithelial-to-mesenchymal transition (EMT) of RPE cells. Methods RPE from dry AMD globes, genetically engineered mice lacking Cryba1 globally or specifically in the RPE, spontaneous mutant rats (Nuc1) with a loss-of-function mutation in Cryba1, and the melanoma OCM3 cell line were used. Spatial localization of proteins was demonstrated with immunofluorescence, gene expression levels were determined by quantitative PCR (qPCR), and protein levels by Western blotting. Cell movement was evaluated using wound healing and cell migration assays. Co-immunoprecipitation was used to identify binding partners of βA3/A1-crystallin. Results βA3/A1-crystallin is upregulated in polarized RPE cells compared to undifferentiated cells. Loss of βA3/A1-crystallin in murine and human RPE cells resulted in upregulation of Snail and vimentin, downregulation of E-cadherin, and increased cell migration. βA3/A1-crystallin binds to cortactin, and loss of βA3/A1-crystallin resulted in increased P-cortactinY421. The RPE from AMD samples had increased Snail and vimentin, and decreased E-cadherin, compared to age-matched controls. Conclusions We introduced a novel concept of dry AMD initiation induced by lysosomal clearance defects in the RPE and subsequent attempts by RPE cells to avoid the resulting stress by undergoing EMT. We demonstrate that βA3/A1-crystallin is a potential therapeutic target for AMD through rejuvenation of lysosomal dysfunction and potentially, reversal of EMT.
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Affiliation(s)
- Sayan Ghosh
- Glia Research Laboratory, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Peng Shang
- Glia Research Laboratory, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Hiroto Terasaki
- Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Los Angeles, California, United States.,Department of Ophthalmology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Nadezda Stepicheva
- Glia Research Laboratory, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Stacey Hose
- Glia Research Laboratory, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Meysam Yazdankhah
- Glia Research Laboratory, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Joseph Weiss
- Glia Research Laboratory, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Taiji Sakamoto
- Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Los Angeles, California, United States.,Department of Ophthalmology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Imran A Bhutto
- Glia Research Laboratory, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Shuli Xia
- Hugo W. Moser Research Institute at Kennedy Krieger and Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - J Samuel Zigler
- The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Ram Kannan
- Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Los Angeles, California, United States
| | - Jiang Qian
- The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - James T Handa
- The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Debasish Sinha
- Glia Research Laboratory, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States.,The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
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26
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Jena KK, Kolapalli SP, Mehto S, Nath P, Das B, Sahoo PK, Ahad A, Syed GH, Raghav SK, Senapati S, Chauhan S, Chauhan S. TRIM16 controls assembly and degradation of protein aggregates by modulating the p62-NRF2 axis and autophagy. EMBO J 2018; 37:embj.201798358. [PMID: 30143514 PMCID: PMC6138442 DOI: 10.15252/embj.201798358] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 07/18/2018] [Accepted: 07/26/2018] [Indexed: 12/20/2022] Open
Abstract
Sequestration of protein aggregates in inclusion bodies and their subsequent degradation prevents proteostasis imbalance, cytotoxicity, and proteinopathies. The underlying molecular mechanisms controlling the turnover of protein aggregates are mostly uncharacterized. Herein, we show that a TRIM family protein, TRIM16, governs the process of stress-induced biogenesis and degradation of protein aggregates. TRIM16 facilitates protein aggregate formation by positively regulating the p62-NRF2 axis. We show that TRIM16 is an integral part of the p62-KEAP1-NRF2 complex and utilizes multiple mechanisms for stabilizing NRF2. Under oxidative and proteotoxic stress conditions, TRIM16 activates ubiquitin pathway genes and p62 via NRF2, leading to ubiquitination of misfolded proteins and formation of protein aggregates. We further show that TRIM16 acts as a scaffold protein and, by interacting with p62, ULK1, ATG16L1, and LC3B, facilitates autophagic degradation of protein aggregates. Thus, TRIM16 streamlines the process of stress-induced aggregate clearance and protects cells against oxidative/proteotoxic stress-induced toxicity in vitro and in vivo Taken together, this work identifies a new mechanism of protein aggregate turnover, which could be relevant in protein aggregation-associated diseases such as neurodegeneration.
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Affiliation(s)
- Kautilya Kumar Jena
- Cell Biology and Infectious Diseases Unit, Institute of Life Sciences, Bhubaneswar, India.,School of Biotechnology, KIIT University, Bhubaneswar, India
| | | | - Subhash Mehto
- Cell Biology and Infectious Diseases Unit, Institute of Life Sciences, Bhubaneswar, India
| | - Parej Nath
- Cell Biology and Infectious Diseases Unit, Institute of Life Sciences, Bhubaneswar, India.,School of Biotechnology, KIIT University, Bhubaneswar, India
| | - Biswajit Das
- Tumor Microenvironment and Animal Models, Institute of Life Sciences, Bhubaneswar, India.,Manipal University, Manipal, India
| | - Pradyumna Kumar Sahoo
- Cell Biology and Infectious Diseases Unit, Institute of Life Sciences, Bhubaneswar, India
| | - Abdul Ahad
- Immuno-Genomics and Systems Biology, Institute of Life Sciences, Bhubaneswar, India
| | - Gulam Hussain Syed
- Molecular Virology and Infectious Diseases, Institute of Life Sciences, Bhubaneswar, India
| | - Sunil K Raghav
- Immuno-Genomics and Systems Biology, Institute of Life Sciences, Bhubaneswar, India
| | - Shantibhusan Senapati
- Tumor Microenvironment and Animal Models, Institute of Life Sciences, Bhubaneswar, India
| | - Swati Chauhan
- Translational Research, Institute of Life Sciences, Bhubaneswar, India
| | - Santosh Chauhan
- Cell Biology and Infectious Diseases Unit, Institute of Life Sciences, Bhubaneswar, India
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27
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Maan M, Pati U. CHIP promotes autophagy-mediated degradation of aggregating mutant p53 in hypoxic conditions. FEBS J 2018; 285:3197-3214. [PMID: 29953728 DOI: 10.1111/febs.14602] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 05/05/2018] [Accepted: 06/26/2018] [Indexed: 12/18/2022]
Abstract
Tumor suppressor protein p53 aggregates in the hypoxic core of solid tumors. C terminus of Hsc70-interacting protein (CHIP) displays chaperone as well as E3 ligase activities in both stabilizing and degrading wild-type and mutant p53. In this study, we have discovered that CHIP selectively degrades aggregating mutant p53 under both normal and hypoxic conditions. Silencing of CHIP alleviates degradation of aggregating mutant p53 in both normoxia and hypoxia, but has no significant effect on the level of nonaggregating mutant p53. Although both U-box and TPR domains of CHIP are responsible for p53 degradation, the U-box domain selectively binds to aggregating mutant p53, whereas the TPR domain interacts with nonaggregating mutant p53. The degradation of mutant p53 by CHIP is shown to be via autophagy through K63-linked polyubiquitination. Both in normoxia and under physiological hypoxia, the level of aggregating mutant p53 in the presence of CHIP was reduced threefold, whereas under serum starvation, it was reduced fivefold. Interestingly, both wild-type and mutant p53 interact with and stabilize CHIP at the post-translational level, suggesting a chaperone synergy between p53 and CHIP. This finding may have strong therapeutic significance via selective degradation of oncogenic mutant p53 in regressing hypoxic tumors.
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Affiliation(s)
- Meenu Maan
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Uttam Pati
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
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28
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Designing an effective drug combination for ER stress loading in cancer therapy using a real-time monitoring system. Biochem Biophys Res Commun 2018; 501:286-292. [PMID: 29729272 DOI: 10.1016/j.bbrc.2018.05.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Accepted: 05/01/2018] [Indexed: 12/20/2022]
Abstract
Excess stress caused by accumulation of misfolded proteins inside the endoplasmic reticulum (ER) lumen can cause cells to undergo apoptosis. Misfolded proteins exported from ER to cytoplasm are ubiquitinated and mostly degraded by the proteasome, but can also be destroyed by autophagy mediated by the docking proteins p62 and NBR1. When misfolded proteins accumulate beyond the capacity of these clearance systems, they are transported to the microtubule organization center to form aggresomes, which are also degraded by autophagy. Together, these phenomena suggest the existence of a coordinated intracellular network for coping with the accumulation of misfolded proteins. Thus, rational inhibition of this network system might enhance killing of cancer cells subjected to pronounced ER stress loading. Based on this rationale, we sought to establish a quantitative assay for monitoring ER stress loading. MDA-MB231 cells stably transfected with the ERAI-Venus vector exhibited a strong XBP1 splicing signal in response to ER stress. Using the IncuCyte cell imaging system, we monitored the fluorescence intensity of XBP1-Venus, normalized against cell density, as an ER stress indicator. This parameter correlated closely with other reporters of unfolded protein responses. Assessment of the XBP1-Venus signal during exposure to various drug combinations revealed that simultaneous inhibition of the proteasome, autophagy, and aggresome formation led to more effective ER stress loading and higher cytotoxicity than inhibition of only two components. Our data suggest that this monitoring system is a useful tool for designing effective drug combinations for ER stress loading in cancer therapy.
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29
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CNOT2 promotes degradation of p62/SQSTM1 as a negative regulator in ATG5 dependent autophagy. Oncotarget 2018; 8:46034-46046. [PMID: 28537904 PMCID: PMC5542246 DOI: 10.18632/oncotarget.17682] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 04/20/2017] [Indexed: 12/19/2022] Open
Abstract
Though CNOT2 is involved in regulation of adipogenic differentiation, apoptotic cell death and metastasis, the underlying autophagic mechanism of CNOT2 was unknown until now. Thus, in the present study, the critical role of CNOT2 in autophagy was elucidated in association with p62/SQSTM1 signaling. CNOT2 depletion induced p62/SQSTM1 accumulation and LC3B-II conversion, and also increased the number of puncta with impaired autophagic flux. In contrast, CNOT2 overexpression induced downregulation and ubiquitination of p62/SQSTM1 in HEK293 QBI. Furthermore, ubiquitination of p62/SQSTM1 was blocked by autophagy inhibition. Interestingly, CNOT2 was correlated with p62/SQSTM1 in HEK293 QBI cells and also was colocalized with p62/SQSTM1 in H1299 cells. Additionally, ATG5 was upregulated in CNOT2-depleted H1299 cells, while degradation of p62/SQSTM1 by CNOT2 was detected in ATG5+/+ MEF cells but not in ATG5−/− MEF cells. Of note, CNOT2 induced degradation of p62/SQSTM1 in HEK293 QBI cells co-transfected with Myc-ΔLIR/KIR or Myc-ΔUBA, but not with Myc-ΔPB1. Sub G1 population was increased in CNOT2-depleted H1299 cells by late autophagy inhibitors, ammonium chloride and chloroquine compared to 3-methyladenine. Overall, these findings provide novel insight into the critical role of CNOT2 as a negative regulator in ATG5 dependent autophagy.
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30
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Cytoprotective role of ubiquitin against toxicity induced by polyglutamine-expanded aggregates. Biochem Biophys Res Commun 2018; 500:344-350. [PMID: 29654755 DOI: 10.1016/j.bbrc.2018.04.072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 04/10/2018] [Indexed: 11/21/2022]
Abstract
Ubiquitin (Ub) homeostasis is important for cellular function and survival, especially under stress conditions. Recently, we have demonstrated that Ubc-/- (Ub-deficient) mouse embryonic fibroblasts (MEFs) exhibited reduced viability under oxidative stress induced by arsenite, which was not due to dysregulation of the antioxidant response pathway, but rather due to the potential toxicity caused by the misfolded protein aggregates. However, it is still not clear whether Ub deficiency is directly related to the accumulation of toxic protein aggregates, as arsenite itself triggers protein aggregation and renders cells into aberrant conditions such as reduced proteasome function and inhibition of autophagic flux. Therefore, under arsenite treatment, the outcome could be derived from the combination of multiple defective pathways. Furthermore, it has also been suggested that ubiquitination status of misfolded proteins may not be important for the formation of inclusion bodies composed of misfolded protein aggregates. We therefore wondered whether Ub deficiency is sufficient to trigger the accumulation of toxic protein aggregates inside the cells. In this study, we ectopically expressed polyQ-expanded aggregates (Q103) in MEFs and observed inclusion body formation at the juxtanuclear region, which was independent of cellular Ub levels. In contrast to arsenite treatment, polyQ expression did not affect proteasome function. However, we observed an increased accumulation of Q103 aggregates in Ubc-/- MEFs, which was due to impaired autophagic clearance. Finally, we demonstrated that the increased accumulation of Q103 aggregates under Ub deficiency dramatically reduced the viability of cells. Therefore, our results suggest that the maintenance of proper levels of cellular Ub is important to protect cells against the toxicity induced by the accumulation of protein aggregates.
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31
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Molecular responses to therapeutic proteasome inhibitors in multiple myeloma patients are donor-, cell type- and drug-dependent. Oncotarget 2018; 9:17797-17809. [PMID: 29707147 PMCID: PMC5915155 DOI: 10.18632/oncotarget.24882] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 03/06/2018] [Indexed: 02/04/2023] Open
Abstract
Proteasome is central to proteostasis network functionality and its over-activation represents a hallmark of advanced tumors; thus, its selective inhibition provides a strategy for the development of novel antitumor therapies. In support, proteasome inhibitors, e.g. Bortezomib or Carfilzomib have demonstrated clinical efficacy against hematological cancers. Herein, we studied proteasome regulation in peripheral blood mononuclear cells and erythrocytes isolated from healthy donors or from Multiple Myeloma patients treated with Bortezomib or Carfilzomib. In healthy donors we found that peripheral blood mononuclear cells express higher, as compared to erythrocytes, basal proteasome activities, as well as that proteasome activities decline during aging. Studies in cells isolated from Multiple Myeloma patients treated with proteasome inhibitors revealed that in most (but, interestingly enough, not all) patients, proteasome activities decline in both cell types during therapy. In peripheral blood mononuclear cells, most proteostatic genes expression patterns showed a positive correlation during therapy indicating that proteostasis network modules likely respond to proteasome inhibition as a functional unit. Finally, the expression levels of antioxidant, chaperone and aggresomes removal/autophagy genes were found to inversely associate with patients' survival. Our studies will support a more personalized therapeutic approach in hematological malignancies treated with proteasome inhibitors.
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32
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Zhou L, Hao Z, Wang G, Xu G. Cereblon suppresses the formation of pathogenic protein aggregates in a p62-dependent manner. Hum Mol Genet 2017; 27:667-678. [DOI: 10.1093/hmg/ddx433] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 12/15/2017] [Indexed: 01/27/2023] Open
Affiliation(s)
- Liang Zhou
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Department of Pharmacology, College of Pharmaceutical Sciences, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Soochow University, Suzhou, Jiangsu 215123, China
| | - Zongbing Hao
- Laboratory of Molecular Neuropathology, Jiangsu Key Laboratory of Neuropsychiatric Diseases, Department of Pharmacology, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu 215123, China
| | - Guanghui Wang
- Laboratory of Molecular Neuropathology, Jiangsu Key Laboratory of Neuropsychiatric Diseases, Department of Pharmacology, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu 215123, China
| | - Guoqiang Xu
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Department of Pharmacology, College of Pharmaceutical Sciences, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Soochow University, Suzhou, Jiangsu 215123, China
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33
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Abstract
The efficient production, folding, and secretion of proteins is critical for cancer cell survival. However, cancer cells thrive under stress conditions that damage proteins, so many cancer cells overexpress molecular chaperones that facilitate protein folding and target misfolded proteins for degradation via the ubiquitin-proteasome or autophagy pathway. Stress response pathway induction is also important for cancer cell survival. Indeed, validated targets for anti-cancer treatments include molecular chaperones, components of the unfolded protein response, the ubiquitin-proteasome system, and autophagy. We will focus on links between breast cancer and these processes, as well as the development of drug resistance, relapse, and treatment.
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Affiliation(s)
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, A320 Langley Hall, 4249 Fifth Ave, Pittsburgh, PA, 15260, USA.
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34
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Guha P, Kaptan E, Gade P, Kalvakolanu DV, Ahmed H. Tunicamycin induced endoplasmic reticulum stress promotes apoptosis of prostate cancer cells by activating mTORC1. Oncotarget 2017; 8:68191-68207. [PMID: 28978108 PMCID: PMC5620248 DOI: 10.18632/oncotarget.19277] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 06/10/2017] [Indexed: 01/11/2023] Open
Abstract
Studies suggest that tunicamycin may work as a therapeutic drug to cancer cells by inducing stress in the endoplasmic reticulum (ER) through unfolded protein response (UPR) and thereby promoting apoptosis. However, mechanisms of the prolonged activation of the UPR under sustained ER stress in the regulation of cell apoptosis are largely unknown. To delineate the role of candidate genes in the apoptotic process under ER stress and to search for new therapeutic strategies to treat metastatic castration resistant prostate cancer, we performed whole genome expression microarray analysis in tunicamycin treated metastatic androgen-insensitive prostate cancer cells, PC-3. Among several induced genes, the expression of eNOS (NOS3) gene was remarkably high. The increased expression of eNOS activates mTORC1 through RagC. This results into an accumulation of p62 (SQSTM1) which facilitates aggregation of ubiquitinated protein thus compromising clearance of misfolded toxic protein aggregates. Lastly, association of p62 proteins and misfolded proteins promote reactive oxygen species (ROS) mediated mitochondrial apoptosis. Overall, our data demonstrate that tunicamycin induced ER stress promotes prostate cancer cell death by activating mTORC1 through eNOS-RagC pathway.
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Affiliation(s)
- Prasun Guha
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine and Institute of Marine and Environmental Technology, Baltimore, Maryland, USA
- Current address: The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Engin Kaptan
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine and Institute of Marine and Environmental Technology, Baltimore, Maryland, USA
- Current address: Department of Biology, Istanbul University, Vezneciler, Istanbul, Turkey
| | - Padmaja Gade
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Dhananjaya V. Kalvakolanu
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
- University of Maryland Greenebaum Cancer Center, Baltimore, Maryland, USA
| | - Hafiz Ahmed
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine and Institute of Marine and Environmental Technology, Baltimore, Maryland, USA
- University of Maryland Greenebaum Cancer Center, Baltimore, Maryland, USA
- Current address: GlycoMantra Inc., Baltimore, Maryland, USA
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35
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Tundo GR, Sbardella D, Ciaccio C, Grasso G, Gioia M, Coletta A, Polticelli F, Di Pierro D, Milardi D, Van Endert P, Marini S, Coletta M. Multiple functions of insulin-degrading enzyme: a metabolic crosslight? Crit Rev Biochem Mol Biol 2017. [PMID: 28635330 DOI: 10.1080/10409238.2017.1337707] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Insulin-degrading enzyme (IDE) is a ubiquitous zinc peptidase of the inverzincin family, which has been initially discovered as the enzyme responsible for insulin catabolism; therefore, its involvement in the onset of diabetes has been largely investigated. However, further studies on IDE unraveled its ability to degrade several other polypeptides, such as β-amyloid, amylin, and glucagon, envisaging the possible implication of IDE dys-regulation in the "aggregopathies" and, in particular, in neurodegenerative diseases. Over the last decade, a novel scenario on IDE biology has emerged, pointing out a multi-functional role of this enzyme in several basic cellular processes. In particular, latest advances indicate that IDE behaves as a heat shock protein and modulates the ubiquitin-proteasome system, suggesting a major implication in proteins turnover and cell homeostasis. In addition, recent observations have highlighted that the regulation of glucose metabolism by IDE is not merely based on its largely proposed role in the degradation of insulin in vivo. There is increasing evidence that improper IDE function, regulation, or trafficking might contribute to the etiology of metabolic diseases. In addition, the enzymatic activity of IDE is affected by metals levels, thus suggesting a role also in the metal homeostasis (metallostasis), which is thought to be tightly linked to the malfunction of the "quality control" machinery of the cell. Focusing on the physiological role of IDE, we will address a comprehensive vision of the very complex scenario in which IDE takes part, outlining its crucial role in interconnecting several relevant cellular processes.
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Affiliation(s)
- Grazia R Tundo
- a Department of Clinical Sciences and Translation Medicine , University of Roma Tor Vergata , Roma , Italy.,b CIRCMSB , Bari , Italy
| | - Diego Sbardella
- a Department of Clinical Sciences and Translation Medicine , University of Roma Tor Vergata , Roma , Italy.,b CIRCMSB , Bari , Italy.,c Center for TeleInfrastructures, University of Roma Tor Vergata , Roma , Italy
| | - Chiara Ciaccio
- a Department of Clinical Sciences and Translation Medicine , University of Roma Tor Vergata , Roma , Italy.,b CIRCMSB , Bari , Italy
| | - Giuseppe Grasso
- d Department of Chemistry , University of Catania , Catania , Italy.,e CNR IBB , Catania , Italy
| | - Magda Gioia
- a Department of Clinical Sciences and Translation Medicine , University of Roma Tor Vergata , Roma , Italy.,b CIRCMSB , Bari , Italy
| | - Andrea Coletta
- f Department of Chemistry , University of Aarhus , Aarhus , Denmark
| | | | - Donato Di Pierro
- a Department of Clinical Sciences and Translation Medicine , University of Roma Tor Vergata , Roma , Italy.,b CIRCMSB , Bari , Italy
| | | | - Peter Van Endert
- h Université Paris Descartes, INSERM, U1151, CNRS , Paris , France
| | - Stefano Marini
- a Department of Clinical Sciences and Translation Medicine , University of Roma Tor Vergata , Roma , Italy.,b CIRCMSB , Bari , Italy.,c Center for TeleInfrastructures, University of Roma Tor Vergata , Roma , Italy
| | - Massimo Coletta
- a Department of Clinical Sciences and Translation Medicine , University of Roma Tor Vergata , Roma , Italy.,b CIRCMSB , Bari , Italy.,c Center for TeleInfrastructures, University of Roma Tor Vergata , Roma , Italy
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36
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Abstract
A healthy proteome is essential for cell survival. Protein misfolding is linked to a rapidly expanding list of human diseases, ranging from neurodegenerative diseases to aging and cancer. Many of these diseases are characterized by the accumulation of misfolded proteins in intra- and extracellular inclusions, such as amyloid plaques. The clear link between protein misfolding and disease highlights the need to better understand the elaborate machinery that manages proteome homeostasis, or proteostasis, in the cell. Proteostasis depends on a network of molecular chaperones and clearance pathways involved in the recognition, refolding, and/or clearance of aberrant proteins. Recent studies reveal that an integral part of the cellular management of misfolded proteins is their spatial sequestration into several defined compartments. Here, we review the properties, function, and formation of these compartments. Spatial sequestration plays a central role in protein quality control and cellular fitness and represents a critical link to the pathogenesis of protein aggregation-linked diseases.
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Affiliation(s)
| | - Rahul S Samant
- Department of Biology, Stanford University, Stanford, California 94305; , ,
| | - Judith Frydman
- Department of Biology, Stanford University, Stanford, California 94305; , ,
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37
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Ubiquitin C-terminal hydrolase L1 (UCH-L1): structure, distribution and roles in brain function and dysfunction. Biochem J 2017; 473:2453-62. [PMID: 27515257 PMCID: PMC4980807 DOI: 10.1042/bcj20160082] [Citation(s) in RCA: 153] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Accepted: 04/29/2016] [Indexed: 12/13/2022]
Abstract
Ubiquitin C-terminal hydrolase L1 (UCH-L1) is an extremely abundant protein in the brain where, remarkably, it is estimated to make up 1–5% of total neuronal protein. Although it comprises only 223 amino acids it has one of the most complicated 3D knotted structures yet discovered. Beyond its expression in neurons UCH-L1 has only very limited expression in other healthy tissues but it is highly expressed in several forms of cancer. Although UCH-L1 is classed as a deubiquitinating enzyme (DUB) the direct functions of UCH-L1 remain enigmatic and a wide array of alternative functions has been proposed. UCH-L1 is not essential for neuronal development but it is absolutely required for the maintenance of axonal integrity and UCH-L1 dysfunction is implicated in neurodegenerative disease. Here we review the properties of UCH-L1, and how understanding its complex structure can provide new insights into its roles in neuronal function and pathology.
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38
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De Conti L, Borroni B, Baralle M. New routes in frontotemporal dementia drug discovery. Expert Opin Drug Discov 2017; 12:659-671. [DOI: 10.1080/17460441.2017.1329294] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Laura De Conti
- Biotechnology Development Group, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Barbara Borroni
- Centre for Neurodegenerative Disorders - Neurology Unit, University of Brescia, Brescia, Italy
| | - Marco Baralle
- Biotechnology Development Group, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
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39
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Stern M. Evidence that a mitochondrial death spiral underlies antagonistic pleiotropy. Aging Cell 2017; 16:435-443. [PMID: 28185435 PMCID: PMC5418193 DOI: 10.1111/acel.12579] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/12/2017] [Indexed: 01/01/2023] Open
Abstract
The antagonistic pleiotropy (AP) theory posits that aging occurs because alleles that are detrimental in older organisms are beneficial to growth early in life and thus are maintained in populations. Although genes of the insulin signaling pathway likely participate in AP, the insulin‐regulated cellular correlates of AP have not been identified. The mitochondrial quality control process called mitochondrial autophagy (mitophagy), which is inhibited by insulin signaling, might represent a cellular correlate of AP. In this view, rapidly growing cells are limited by ATP production; these cells thus actively inhibit mitophagy to maximize mitochondrial ATP production and compete successfully for scarce nutrients. This process maximizes early growth and reproduction, but by permitting the persistence of damaged mitochondria with mitochondrial DNA mutations, becomes detrimental in the longer term. I suggest that as mitochondrial ATP output drops, cells respond by further inhibiting mitophagy, leading to a further decrease in ATP output in a classic death spiral. I suggest that this increasing ATP deficit is communicated by progressive increases in mitochondrial ROS generation, which signals inhibition of mitophagy via ROS‐dependent activation of insulin signaling. This hypothesis clarifies a role for ROS in aging, explains why insulin signaling inhibits autophagy, and why cells become progressively more oxidized during aging with increased levels of insulin signaling and decreased levels of autophagy. I suggest that the mitochondrial death spiral is not an error in cell physiology but rather a rational approach to the problem of enabling successful growth and reproduction in a competitive world of scarce nutrients.
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Affiliation(s)
- Michael Stern
- Department of BioSciences, Program in Biochemistry and Cell Biology; Rice University; Houston TX USA
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UCH-L1 Inhibition Suppresses tau Aggresome Formation during Proteasomal Impairment. Mol Neurobiol 2017; 55:3812-3821. [PMID: 28540657 DOI: 10.1007/s12035-017-0558-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 04/12/2017] [Indexed: 10/19/2022]
Abstract
In conditions of proteasomal impairment, the damaged or misfolded proteins, collectively known as aggresome, can accumulate in the perinuclear space and be subsequently eliminated by autophagy. Abnormal aggregation of microtubule-associated protein tau in the cytoplasm is a common neuropathological feature of tauopathies. The deficiency in ubiquitin carboxy-terminal hydrolase L1 (UCH-L1), a proteasomal deubiquitinating enzyme, is closely related to tau aggregation; however, the associated mechanisms remain unclear. Here, we showed that UCH-L1 inhibition interrupts proteasomal impairment-induced tau aggresome formation. By reducing the production of lysine (K63)-linked ubiquitin chains, UCH-L1 inhibition decreases HDAC6 deacetylase activity and attenuates the interaction of HDAC6 and tau protein, finally leading to tau aggresome formation impairment. All these results indicated that UCH-L1 plays a key role in the process of tau aggresome formation by regulating HDAC6 deacetylase activity and implied that UCH-L1 may act as a signaling molecule to coordinate the effects of the ubiquitin-proteasome system and the autophagy-lysosome pathway, which mediate protein aggregates degradation in the cytoplasm.
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Kim KY, Park KI, Kim SH, Yu SN, Park SG, Kim YW, Seo YK, Ma JY, Ahn SC. Inhibition of Autophagy Promotes Salinomycin-Induced Apoptosis via Reactive Oxygen Species-Mediated PI3K/AKT/mTOR and ERK/p38 MAPK-Dependent Signaling in Human Prostate Cancer Cells. Int J Mol Sci 2017; 18:ijms18051088. [PMID: 28524116 PMCID: PMC5454997 DOI: 10.3390/ijms18051088] [Citation(s) in RCA: 123] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/15/2017] [Accepted: 05/16/2017] [Indexed: 01/06/2023] Open
Abstract
Recently, the interplay between autophagy and apoptosis has become an important factor in chemotherapy for cancer treatment. Inhibition of autophagy may be an effective strategy to improve the treatment of chemo-resistant cancer by consistent exposure to chemotherapeutic drugs. However, no reports have clearly elucidated the underlying mechanisms. Therefore, in this study, we assessed whether salinomycin, a promising anticancer drug, induces apoptosis and elucidated potential antitumor mechanisms in chemo-resistant prostate cancer cells. Cell viability assay, Western blot, annexin V/propidium iodide assay, acridine orange (AO) staining, caspase-3 activity assay, reactive oxygen species (ROS) production, and mitochondrial membrane potential were assayed. Our data showed that salinomycin alters the sensitivity of prostate cancer cells to autophagy. Pretreatment with 3-methyladenine (3-MA), an autophagy inhibitor, enhanced the salinomycin-induced apoptosis. Notably, salinomycin decreased phosphorylated of AKT and phosphorylated mammalian target of rapamycin (mTOR) in prostate cancer cells. Pretreatment with LY294002, an autophagy and PI3K inhibitor, enhanced the salinomycin-induced apoptosis by decreasing the AKT and mTOR activities and suppressing autophagy. However, pretreatment with PD98059 and SB203580, an extracellular signal-regulated kinases (ERK), and p38 inhibitors, suppressed the salinomycin-induced autophagy by reversing the upregulation of ERK and p38. In addition, pretreatment with N-acetyl-l-cysteine (NAC), an antioxidant, inhibited salinomycin-induced autophagy by suppressing ROS production. Our results suggested that salinomycin induces apoptosis, which was related to ROS-mediated autophagy through regulation of the PI3K/AKT/mTOR and ERK/p38 MAPK signaling pathways.
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Affiliation(s)
- Kwang-Youn Kim
- Department of Herbal Formula, Medical Research Center (MRC-GHF), College of Oriental Medicine, Daegu Haany University, Gyeongsan 38610, Korea.
- Department of Microbiology & Immunology, Pusan National University School of Medicine, Yangsan 50612, Korea.
| | - Kwang-Il Park
- Korean Medicine (KM)-Application Center, Korea Institute of Oriental Medicine (KIOM), Daegu 41062, Korea.
| | - Sang-Hun Kim
- Department of Microbiology & Immunology, Pusan National University School of Medicine, Yangsan 50612, Korea.
| | - Sun-Nyoung Yu
- Department of Microbiology & Immunology, Pusan National University School of Medicine, Yangsan 50612, Korea.
| | - Sul-Gi Park
- Department of Microbiology & Immunology, Pusan National University School of Medicine, Yangsan 50612, Korea.
| | - Young Woo Kim
- Department of Herbal Formula, Medical Research Center (MRC-GHF), College of Oriental Medicine, Daegu Haany University, Gyeongsan 38610, Korea.
| | - Young-Kyo Seo
- School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea.
| | - Jin-Yeul Ma
- Korean Medicine (KM)-Application Center, Korea Institute of Oriental Medicine (KIOM), Daegu 41062, Korea.
| | - Soon-Cheol Ahn
- Department of Microbiology & Immunology, Pusan National University School of Medicine, Yangsan 50612, Korea.
- Immunoregulatory Therapeutics Group in Brain Busan 21 Project, Pusan National University, Yangsan 50612, Korea.
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Bersuker K, Brandeis M, Kopito RR. Protein misfolding specifies recruitment to cytoplasmic inclusion bodies. J Cell Biol 2017; 213:229-41. [PMID: 27114501 DOI: 10.1083/jcb.201511024] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 03/21/2016] [Indexed: 12/17/2022] Open
Abstract
Inclusion bodies (IBs) containing aggregated disease-associated proteins and polyubiquitin (poly-Ub) conjugates are universal histopathological features of neurodegenerative diseases. Ub has been proposed to target proteins to IBs for degradation via autophagy, but the mechanisms that govern recruitment of ubiquitylated proteins to IBs are not well understood. In this paper, we use conditionally destabilized reporters that undergo misfolding and ubiquitylation upon removal of a stabilizing ligand to examine the role of Ub conjugation in targeting proteins to IBs that are composed of an N-terminal fragment of mutant huntingtin, the causative protein of Huntington's disease. We show that reporters are excluded from IBs in the presence of the stabilizing ligand but are recruited to IBs after ligand washout. However, we find that Ub conjugation is not necessary to target reporters to IBs. We also report that forced Ub conjugation by the Ub fusion degradation pathway is not sufficient for recruitment to IBs. Finally, we find that reporters and Ub conjugates are stable at IBs. These data indicate that compromised folding states, rather than conjugation to Ub, can specify recruitment to IBs.
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Affiliation(s)
- Kirill Bersuker
- Department of Biology, Stanford University, Stanford, CA 94305
| | - Michael Brandeis
- Department of Genetics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Ron R Kopito
- Department of Biology, Stanford University, Stanford, CA 94305
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Montecalvo A, Watkins SC, Orange J, Kane LP. Inducible turnover of optineurin regulates T cell activation. Mol Immunol 2017; 85:9-17. [PMID: 28192730 DOI: 10.1016/j.molimm.2017.01.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 01/13/2017] [Accepted: 01/28/2017] [Indexed: 12/28/2022]
Abstract
Optineurin (Optn) is an adaptor protein with homology to NF-κB essential modulator (NEMO), the regulatory subunit of the IκB kinase (IKK) complex. Dysregulation of Optn has been linked to neurodegenerative, autoimmune and bone diseases. Optn shares a high degree of homology with NEMO, but is not part of the same high-molecular weight complex containing IKKα and IKKβ. Despite its homology with NEMO and the fact that it has been the subject of extensive study in several cell types, there are no published studies addressing the role of Optn during T cell activation. Here we demonstrate that ectopic expression of Optn down-regulates TCR-induced NF-κB activation and TNF-α production, in a manner dependent on ubiquitin-binding. Conversely, knock-down of Optn enhances NF-κB activation and the production of TNF-α. Consistent with a negative regulatory role for this protein, we observed transient loss of Optn after TCR stimulation in both cell lines and in primary murine T cells. The acute loss of Optn appears to be due to both protein degradation and exocytosis, the latter via activation-induced exosomes. This study therefore provides novel information regarding the role of Optn during TCR activation, suggesting the possible importance of Optn during inflammation and/or autoimmune diseases.
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Affiliation(s)
- Angela Montecalvo
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, United States
| | - Simon C Watkins
- Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, United States
| | - Jordan Orange
- Texas Children's Hospital, Houston, TX 77030, United States
| | - Lawrence P Kane
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, United States.
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Xu S, Stern M, McNew JA. Beneficial effects of rapamycin in a Drosophila model for hereditary spastic paraplegia. J Cell Sci 2016; 130:453-465. [PMID: 27909242 DOI: 10.1242/jcs.196741] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 11/18/2016] [Indexed: 12/18/2022] Open
Abstract
The locomotor deficits in the group of diseases referred to as hereditary spastic paraplegia (HSP) reflect degeneration of upper motor neurons, but the mechanisms underlying this neurodegeneration are unknown. We established a Drosophila model for HSP, atlastin (atl), which encodes an ER fusion protein. Here, we show that neuronal atl loss causes degeneration of specific thoracic muscles that is preceded by other pathologies, including accumulation of aggregates containing polyubiquitin, increased generation of reactive oxygen species and activation of the JNK-Foxo stress response pathway. We show that inhibiting the Tor kinase, either genetically or by administering rapamycin, at least partially reversed many of these pathologies. atl loss from muscle also triggered muscle degeneration and rapamycin-sensitive locomotor deficits, as well as polyubiquitin aggregate accumulation. These results indicate that atl loss triggers muscle degeneration both cell autonomously and nonautonomously.
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Affiliation(s)
- Shiyu Xu
- Department of BioSciences, Program in Biochemistry and Cell Biology, Rice University, Houston, TX 77005, USA
| | - Michael Stern
- Department of BioSciences, Program in Biochemistry and Cell Biology, Rice University, Houston, TX 77005, USA
| | - James A McNew
- Department of BioSciences, Program in Biochemistry and Cell Biology, Rice University, Houston, TX 77005, USA
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Foggetti G, Ottaggio L, Russo D, Monti P, Degan P, Fronza G, Menichini P. Gambogic acid counteracts mutant p53 stability by inducing autophagy. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1864:382-392. [PMID: 27899303 DOI: 10.1016/j.bbamcr.2016.11.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 11/21/2016] [Accepted: 11/24/2016] [Indexed: 12/19/2022]
Abstract
Mutant p53 (mutp53) proteins are frequently present at higher levels than the wild-type (wt) protein in tumors, and some of them can acquire oncogenic properties. Consistently, knockdown of mutp53 protein in human cancer cell lines leads to reduced cell proliferation and invasion as well as to an increased sensitivity to some anticancer drugs. Therefore, the exploitation of cellular pathways and/or molecules that promote mutp53 degradation may have a therapeutic interest. Recently, autophagy is emerging as an important pathway involved in the stability of mutp53. In this paper, we explored the autophagic potential of gambogic acid (GA), a molecule that stimulates the degradation of mutp53 and increases the sensitivity of cancer cells to chemotherapeutic agents. We demonstrated that GA may induce mutp53 degradation through autophagy in cancer cells expressing the p53-R280K (MDA-MB-231) and the p53-S241F (DLD1) proteins. The inhibition of autophagy with bafilomycin A1 or chloroquine counteracted mutp53 degradation by GA. However, the autophagy induction and mutp53 degradation affected cell survival and proliferation only at low GA concentrations. At higher GA concentrations, when cells undergo massive apoptosis, autophagy is no longer detectable by immuno-fluorescence analysis. We concluded that autophagy is a relevant pathway for mutp53 degradation in cancer cells but it contributes only partially to GA-induced cell death, in a time and dose-dependent manner.
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Affiliation(s)
- Giorgia Foggetti
- U.O.C. Mutagenesi, IRCCS AOU San Martino-IST, 16132 Genova, Italy
| | - Laura Ottaggio
- U.O.C. Mutagenesi, IRCCS AOU San Martino-IST, 16132 Genova, Italy
| | - Debora Russo
- U.O.C. Mutagenesi, IRCCS AOU San Martino-IST, 16132 Genova, Italy
| | - Paola Monti
- U.O.C. Mutagenesi, IRCCS AOU San Martino-IST, 16132 Genova, Italy
| | - Paolo Degan
- U.O.C. Mutagenesi, IRCCS AOU San Martino-IST, 16132 Genova, Italy
| | - Gilberto Fronza
- U.O.C. Mutagenesi, IRCCS AOU San Martino-IST, 16132 Genova, Italy
| | - Paola Menichini
- U.O.C. Mutagenesi, IRCCS AOU San Martino-IST, 16132 Genova, Italy.
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Hubbs AF, Fluharty KL, Edwards RJ, Barnabei JL, Grantham JT, Palmer SM, Kelly F, Sargent LM, Reynolds SH, Mercer RR, Goravanahally MP, Kashon ML, Honaker JC, Jackson MC, Cumpston AM, Goldsmith WT, McKinney W, Fedan JS, Battelli LA, Munro T, Bucklew-Moyers W, McKinstry K, Schwegler-Berry D, Friend S, Knepp AK, Smith SL, Sriram K. Accumulation of Ubiquitin and Sequestosome-1 Implicate Protein Damage in Diacetyl-Induced Cytotoxicity. THE AMERICAN JOURNAL OF PATHOLOGY 2016; 186:2887-2908. [PMID: 27643531 PMCID: PMC5222965 DOI: 10.1016/j.ajpath.2016.07.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 07/09/2016] [Accepted: 07/21/2016] [Indexed: 01/12/2023]
Abstract
Inhaled diacetyl vapors are associated with flavorings-related lung disease, a potentially fatal airway disease. The reactive α-dicarbonyl group in diacetyl causes protein damage in vitro. Dicarbonyl/l-xylulose reductase (DCXR) metabolizes diacetyl into acetoin, which lacks this α-dicarbonyl group. To investigate the hypothesis that flavorings-related lung disease is caused by in vivo protein damage, we correlated diacetyl-induced airway damage in mice with immunofluorescence for markers of protein turnover and autophagy. Western immunoblots identified shifts in ubiquitin pools. Diacetyl inhalation caused dose-dependent increases in bronchial epithelial cells with puncta of both total ubiquitin and K63-ubiquitin, central mediators of protein turnover. This response was greater in Dcxr-knockout mice than in wild-type controls inhaling 200 ppm diacetyl, further implicating the α-dicarbonyl group in protein damage. Western immunoblots demonstrated decreased free ubiquitin in airway-enriched fractions. Transmission electron microscopy and colocalization of ubiquitin-positive puncta with lysosomal-associated membrane proteins 1 and 2 and with the multifunctional scaffolding protein sequestosome-1 (SQSTM1/p62) confirmed autophagy. Surprisingly, immunoreactive SQSTM1 also accumulated in the olfactory bulb of the brain. Olfactory bulb SQSTM1 often congregated in activated microglial cells that also contained olfactory marker protein, indicating neuronophagia within the olfactory bulb. This suggests the possibility that SQSTM1 or damaged proteins may be transported from the nose to the brain. Together, these findings strongly implicate widespread protein damage in the etiology of flavorings-related lung disease.
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Affiliation(s)
- Ann F Hubbs
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia.
| | - Kara L Fluharty
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Rebekah J Edwards
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia; Department of Forensic and Investigative Science, West Virginia University, Morgantown, West Virginia
| | - Jamie L Barnabei
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia; College of Veterinary Medicine, University of Georgia, Athens, Georgia
| | - John T Grantham
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia; School of Medicine, West Virginia University, Morgantown, West Virginia
| | - Scott M Palmer
- Duke University School of Medicine, Durham, North Carolina
| | - Francine Kelly
- Duke University School of Medicine, Durham, North Carolina
| | - Linda M Sargent
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Steven H Reynolds
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Robert R Mercer
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Madhusudan P Goravanahally
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia; Centers for Neuroscience, West Virginia University, Morgantown, West Virginia
| | - Michael L Kashon
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - John C Honaker
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Mark C Jackson
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Amy M Cumpston
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - William T Goldsmith
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Walter McKinney
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Jeffrey S Fedan
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Lori A Battelli
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Tiffany Munro
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Winnie Bucklew-Moyers
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Kimberly McKinstry
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Diane Schwegler-Berry
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Sherri Friend
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Alycia K Knepp
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia; Department of Forensic and Investigative Science, West Virginia University, Morgantown, West Virginia
| | - Samantha L Smith
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia; Department of Forensic and Investigative Science, West Virginia University, Morgantown, West Virginia
| | - Krishnan Sriram
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
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Inhibition of autophagy enhances heat-induced apoptosis in human non-small cell lung cancer cells through ER stress pathways. Arch Biochem Biophys 2016; 607:55-66. [DOI: 10.1016/j.abb.2016.08.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 08/17/2016] [Accepted: 08/22/2016] [Indexed: 12/11/2022]
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Lahiri P, Schmidt V, Smole C, Kufferath I, Denk H, Strnad P, Rülicke T, Fröhlich LF, Zatloukal K. p62/Sequestosome-1 Is Indispensable for Maturation and Stabilization of Mallory-Denk Bodies. PLoS One 2016; 11:e0161083. [PMID: 27526095 PMCID: PMC4985067 DOI: 10.1371/journal.pone.0161083] [Citation(s) in RCA: 30] [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: 03/09/2016] [Accepted: 07/31/2016] [Indexed: 11/19/2022] Open
Abstract
Mallory-Denk bodies (MDBs) are hepatocytic protein aggregates found in steatohepatitis and several other chronic liver diseases as well as hepatocellular carcinoma. MDBs are mainly composed of phosphorylated keratins and stress protein p62/Sequestosome-1 (p62), which is a common component of cytoplasmic aggregates in a variety of protein aggregation diseases. In contrast to the well-established role of keratins, the role of p62 in MDB pathogenesis is still elusive. We have generated total and hepatocyte-specific p62 knockout mice, fed them with 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) to induce MDBs and allowed the mice to recover from DDC intoxication on a standard diet to investigate the role of p62 in MDB formation and elimination. In the absence of p62, smaller, granular and less distinct MDBs appeared, which failed to mature to larger and compact inclusions. Moreover, p62 deficiency impaired the binding of other proteins such as NBR1 and Hsp25 to MDBs and altered the cellular defense mechanism by downregulation of Nrf2 target genes. Upon recovery from DDC intoxication on a standard diet, there was an enhanced reduction of p62-deficient MDBs, which was accompanied by a pronounced decrease in ubiquitinated proteins. Our data provide strong evidence that keratin aggregation is the initial step in MDB formation in steatohepatitis-related mouse models. Interaction of p62 with keratin aggregates then leads to maturation i.e., enlargement and stabilization of the MDBs as well as recruitment of other MDB-associated proteins.
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Affiliation(s)
- Pooja Lahiri
- Institute of Pathology, Medical University of Graz, Graz, Austria
| | - Volker Schmidt
- Institute of Laboratory Animal Science, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Claudia Smole
- Institute of Pathology, Medical University of Graz, Graz, Austria
| | - Iris Kufferath
- Institute of Pathology, Medical University of Graz, Graz, Austria
| | - Helmut Denk
- Institute of Pathology, Medical University of Graz, Graz, Austria
| | - Pavel Strnad
- IZKF and Department of Internal Medicine III, Aachen, Germany
| | - Thomas Rülicke
- Institute of Laboratory Animal Science, University of Veterinary Medicine Vienna, Vienna, Austria
| | | | - Kurt Zatloukal
- Institute of Pathology, Medical University of Graz, Graz, Austria
- * E-mail:
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Vekaria PH, Home T, Weir S, Schoenen FJ, Rao R. Targeting p97 to Disrupt Protein Homeostasis in Cancer. Front Oncol 2016; 6:181. [PMID: 27536557 PMCID: PMC4971439 DOI: 10.3389/fonc.2016.00181] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 07/22/2016] [Indexed: 12/11/2022] Open
Abstract
Cancer cells are addicted to numerous non-oncogenic traits that enable them to thrive. Proteotoxic stress is one such non-oncogenic trait that is experienced by all tumor cells owing to increased genomic abnormalities and the resulting synthesis and accumulation of non-stoichiometric amounts of cellular proteins. This imbalance in the amounts of proteins ultimately culminates in proteotoxic stress. p97, or valosin-containing protein (VCP), is an ATPase whose function is essential to restore protein homeostasis in the cells. Working in concert with the ubiquitin proteasome system, p97 promotes the retrotranslocation from cellular organelles and/or degradation of misfolded proteins. Consequently, p97 inhibition has emerged as a novel therapeutic target in cancer cells, especially those that have a highly secretory phenotype. This review summarizes our current understanding of the function of p97 in maintaining protein homeostasis and its inhibition with small molecule inhibitors as an emerging strategy to target cancer cells.
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Affiliation(s)
| | - Trisha Home
- Division of Hematologic Malignancies and Cellular Therapeutics, Kansas University Medical Center , Kansas City, KS , USA
| | - Scott Weir
- The University of Kansas Cancer Center, University of Kansas , Kansas City, KS , USA
| | - Frank J Schoenen
- Specialized Chemistry Center, University of Kansas , Lawrence, KS , USA
| | - Rekha Rao
- Division of Hematologic Malignancies and Cellular Therapeutics, Kansas University Medical Center , Kansas City, KS , USA
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