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Buchan JR. Stress granule and P-body clearance: Seeking coherence in acts of disappearance. Semin Cell Dev Biol 2024; 159-160:10-26. [PMID: 38278052 PMCID: PMC10939798 DOI: 10.1016/j.semcdb.2024.01.002] [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: 01/04/2024] [Accepted: 01/07/2024] [Indexed: 01/28/2024]
Abstract
Stress granules and P-bodies are conserved cytoplasmic biomolecular condensates whose assembly and composition are well documented, but whose clearance mechanisms remain controversial or poorly described. Such understanding could provide new insight into how cells regulate biomolecular condensate formation and function, and identify therapeutic strategies in disease states where aberrant persistence of stress granules in particular is implicated. Here, I review and compare the contributions of chaperones, the cytoskeleton, post-translational modifications, RNA helicases, granulophagy and the proteasome to stress granule and P-body clearance. Additionally, I highlight the potentially vital role of RNA regulation, cellular energy, and changes in the interaction networks of stress granules and P-bodies as means of eliciting clearance. Finally, I discuss evidence for interplay of distinct clearance mechanisms, suggest future experimental directions, and suggest a simple working model of stress granule clearance.
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Affiliation(s)
- J Ross Buchan
- Department of Molecular and Cellular Biology, University of Arizona, Tucson 85716, United States.
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2
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Zhao H, Zhao S, Zhu Q, Chen J, Quan Z, Yue X, Cao X. Label-free-based proteomic analysis reveals differential whey proteins of porcine milk during lactation. Food Chem X 2024; 21:101112. [PMID: 38268845 PMCID: PMC10805765 DOI: 10.1016/j.fochx.2023.101112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 12/19/2023] [Accepted: 12/30/2023] [Indexed: 01/26/2024] Open
Abstract
In this study, label-free proteomic technology was applied to analyze and compare the whey proteomes of porcine colostrum and mature milk. In total, 2993 and 2906 whey proteins were detected in porcine colostrum and mature milk, respectively. A total of 2745 common proteins were identified in the two milk samples, and 280 proteins were found to be significantly differentially expressed whey proteins in porcine milk. Gene Ontology analysis demonstrated that the differentially expressed whey proteins were primarily enriched in lipid homeostasis, oxidoreductase activity, and the collagen trimer. Kyoto Encyclopedia of Genes and Genomes analysis suggested that the phagosome and endocytosis were the crucial pathways. This study provides systematic and in-depth insight into the compositions and functional properties of whey proteins in porcine milk during different periods of lactation, which may be beneficial for the development of porcine whey proteins in the future.
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Affiliation(s)
- Huiwen Zhao
- College of Food Science, Shenyang Agricultural University, Shenyang 110866, China
| | - Shanshan Zhao
- College of Food Science, Shenyang Agricultural University, Shenyang 110866, China
| | - Qing Zhu
- College of Food Science, Shenyang Agricultural University, Shenyang 110866, China
| | - Jiali Chen
- College of Food Science, Shenyang Agricultural University, Shenyang 110866, China
| | - Zhizhong Quan
- Liaoning Complete Biotechnology Co., Ltd., Tieling 112600, China
| | - Xiqing Yue
- College of Food Science, Shenyang Agricultural University, Shenyang 110866, China
| | - Xueyan Cao
- College of Food Science, Shenyang Agricultural University, Shenyang 110866, China
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3
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Ryan L, Rubinsztein DC. The autophagy of stress granules. FEBS Lett 2024; 598:59-72. [PMID: 38101818 DOI: 10.1002/1873-3468.14787] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 10/20/2023] [Accepted: 11/10/2023] [Indexed: 12/17/2023]
Abstract
Our understanding of stress granule (SG) biology has deepened considerably in recent years, and with this, increased understanding of links has been made between SGs and numerous neurodegenerative diseases. One of the proposed mechanisms by which SGs and any associated protein aggregates may become pathological is based upon defects in their autophagic clearance, and so the precise processes governing the degradation of SGs are important to understand. Mutations and disease-associated variants implicated in amyotrophic lateral sclerosis, Huntington's disease, Parkinson's disease and frontotemporal lobar dementia compromise autophagy, whilst autophagy-inhibiting drugs or knockdown of essential autophagy proteins result in the persistence of SGs. In this review, we will consider the current knowledge regarding the autophagy of SG.
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Affiliation(s)
- Laura Ryan
- Department of Medical Genetics, Cambridge Institute for Medical Research (CIMR), University of Cambridge, UK
- UK Dementia Research Institute, Cambridge Institute for Medical Research (CIMR), University of Cambridge, UK
| | - David C Rubinsztein
- Department of Medical Genetics, Cambridge Institute for Medical Research (CIMR), University of Cambridge, UK
- UK Dementia Research Institute, Cambridge Institute for Medical Research (CIMR), University of Cambridge, UK
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4
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Xing F, Qin Y, Xu J, Wang W, Zhang B. Stress granules dynamics and promising functions in pancreatic cancer. Biochim Biophys Acta Rev Cancer 2023; 1878:188885. [PMID: 36990249 DOI: 10.1016/j.bbcan.2023.188885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 02/14/2023] [Accepted: 02/23/2023] [Indexed: 03/30/2023]
Abstract
Stress granules (SGs), non-membrane subcellular organelles made up of non-translational messenger ribonucleoproteins (mRNPs), assemble in response to various environmental stimuli in cancer cells, including pancreatic cancer, particularly pancreatic ductal adenocarcinoma (PDAC) which has a low 5-year survival rate of 10%. The pertinent research on SGs and pancreatic cancer has not, however, been compiled. In this review, we talk about the dynamics of SGs and their positive effects on pancreatic cancer such as SGs promote PDAC viability and repress apoptosis, meanwhile emphasizing the connection between SGs in pancreatic cancer and signature mutations such KRAS, P53, and SMAD4 as well as the functions of SGs in antitumor drug resistance. This novel stress management technique may open the door to better treatment options in the future.
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Yao H, Sun J, Zhang T, Wang L, Song L. Syk regulates the haemocyte autophagy through inducing the mRNA expressions of autophagy-related genes and the cleavage of CgLC3 in oyster antibacterial immunity. FISH AND SHELLFISH IMMUNOLOGY REPORTS 2023; 4:100085. [PMID: 37065179 PMCID: PMC10102855 DOI: 10.1016/j.fsirep.2023.100085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/07/2023] [Accepted: 01/16/2023] [Indexed: 01/18/2023] Open
Abstract
Spleen tyrosine kinase (Syk) is reported to be involved in activating the autophagy. Recently, a homologue of Syk was identified from Pacific oyster Crassostrea gigas (defined as CgSyk). In the present study, the molecular characteristics of CgSyk and its regulation mechanism in autophagy were investigated in oyster C. gigas. The full-length cDNA of CgSyk was of 4566 bp with an open reading frame (ORF) of 1989 bp. CgSyk encoded a polypeptide of 662 amino acids, containing two Src homology 2 (SH2) domains and one tyrosine kinase catalytic (TyrKc) domain. The deduced amino acid sequence of CgSyk shared low similarity with the previously identified Syks from other species. In the phylogenetic tree, CgSyk was first clustered with Crassostrea virginica CvSyk, and then classified into a branch of invertebrate Syks. In CgSyk-RNAi oysters, the mRNA expressions of CgLC3, CgP62, CgBeclin-1 and CgATG5 in haemocytes decreased significantly at 12 h after Vibrio splendidus stimulation. At the same time, the abundance of CgLC3Ⅱ in haemocytes, and the autophagy rate of haemocytes in CgSyk-RNAi oysters decreased significantly at 12 h after V. splendidus stimulation. All the results collectively suggested that CgSyk regulated the autophagy through inducing the mRNA expressions of autophagy-related genes and the cleavage of CgLC3 to defend against bacterial invasion in oysters.
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Affiliation(s)
- Hongsheng Yao
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, 52 Heishijiao Street, Dalian 116023, China
- Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian 116023, China
| | - Jiejie Sun
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, 52 Heishijiao Street, Dalian 116023, China
- Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian 116023, China
- Corresponding author at: Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, 52 Heishijiao Street, Dalian 116023, China.
| | - Tong Zhang
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, 52 Heishijiao Street, Dalian 116023, China
- Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian 116023, China
| | - Lingling Wang
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, 52 Heishijiao Street, Dalian 116023, China
- Laboratory of Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266235, China
- Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian 116023, China
- Dalian Key Laboratory of Aquatic Animal Disease Prevention and Control, Dalian Ocean University, Dalian 116023, China
| | - Linsheng Song
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, 52 Heishijiao Street, Dalian 116023, China
- Laboratory of Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266235, China
- Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian 116023, China
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Hu R, Qian B, Li A, Fang Y. Role of Proteostasis Regulation in the Turnover of Stress Granules. Int J Mol Sci 2022; 23:ijms232314565. [PMID: 36498892 PMCID: PMC9741362 DOI: 10.3390/ijms232314565] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/16/2022] [Accepted: 11/20/2022] [Indexed: 11/24/2022] Open
Abstract
RNA-binding proteins (RBPs) and RNAs can form dynamic, liquid droplet-like cytoplasmic condensates, known as stress granules (SGs), in response to a variety of cellular stresses. This process is driven by liquid-liquid phase separation, mediated by multivalent interactions between RBPs and RNAs. The formation of SGs allows a temporary suspension of certain cellular activities such as translation of unnecessary proteins. Meanwhile, non-translating mRNAs may also be sequestered and stalled. Upon stress removal, SGs are disassembled to resume the suspended biological processes and restore the normal cell functions. Prolonged stress and disease-causal mutations in SG-associated RBPs can cause the formation of aberrant SGs and/or impair SG disassembly, consequently raising the risk of pathological protein aggregation. The machinery maintaining protein homeostasis (proteostasis) includes molecular chaperones and co-chaperones, the ubiquitin-proteasome system, autophagy, and other components, and participates in the regulation of SG metabolism. Recently, proteostasis has been identified as a major regulator of SG turnover. Here, we summarize new findings on the specific functions of the proteostasis machinery in regulating SG disassembly and clearance, discuss the pathological and clinical implications of SG turnover in neurodegenerative disorders, and point to the unresolved issues that warrant future exploration.
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Affiliation(s)
- Rirong Hu
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201203, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Beituo Qian
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201203, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ang Li
- Guangdong-Hong Kong-Macau Institute of CNS Regeneration, Key Laboratory of CNS Regeneration of Ministry of Education, Jinan University, Guangzhou 510632, China
- Correspondence: (A.L.); (Y.F.); Tel.: +86-21-6858-2510 (Y.F.)
| | - Yanshan Fang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201203, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Correspondence: (A.L.); (Y.F.); Tel.: +86-21-6858-2510 (Y.F.)
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Xu C, Li T, Lei J, Zhang Y, Zhou J, Hu B. The Autophagy Cargo Receptor SQSTM1 Inhibits Infectious Bursal Disease Virus Infection through Selective Autophagic Degradation of Double-Stranded Viral RNA. Viruses 2021; 13:v13122494. [PMID: 34960763 PMCID: PMC8704251 DOI: 10.3390/v13122494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 12/02/2021] [Accepted: 12/08/2021] [Indexed: 11/16/2022] Open
Abstract
Selective autophagy mediates the degradation of cytoplasmic cargos, such as damaged organelles, invading pathogens, and protein aggregates. However, whether it targets double-stranded RNA (dsRNA) of intracellular pathogens is still largely unknown. Here, we show that selective autophagy regulates the degradation of the infectious bursal disease virus (IBDV) dsRNA genome. The amount of dsRNA decreased greatly in cells that overexpressed the autophagy-required protein VPS34 or autophagy cargo receptor SQSTM1, while it increased significantly in SQSTM1 or VPS34 knockout cells or by treating wild-type cells with the autophagy inhibitor chloroquine or wortmannin. Confocal microscopy and structured illumination microscopy showed SQSTM1 colocalized with dsRNA during IBDV infection. A pull-down assay further confirmed the direct binding of SQSTM1 to dsRNA through amino acid sites R139 and K141. Overexpression of SQSTM1 inhibited the replication of IBDV, while knockout of SQSTM1 promoted IBDV replication. Therefore, our findings reveal the role of SQSTM1 in clearing viral dsRNA through selective autophagy, highlighting the antiviral role of autophagy in the removal of the viral genome.
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Affiliation(s)
- Chenyang Xu
- MOE International Joint Collaborative Research Laboratory for Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; (C.X.); (T.L.); (J.L.)
| | - Tongtong Li
- MOE International Joint Collaborative Research Laboratory for Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; (C.X.); (T.L.); (J.L.)
| | - Jing Lei
- MOE International Joint Collaborative Research Laboratory for Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; (C.X.); (T.L.); (J.L.)
| | - Yina Zhang
- MOA Key Laboratory of Animal Virology, Center for Veterinary Sciences, Zhejiang University, Hangzhou 310058, China; (Y.Z.); (J.Z.)
| | - Jiyong Zhou
- MOA Key Laboratory of Animal Virology, Center for Veterinary Sciences, Zhejiang University, Hangzhou 310058, China; (Y.Z.); (J.Z.)
| | - Boli Hu
- MOE International Joint Collaborative Research Laboratory for Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; (C.X.); (T.L.); (J.L.)
- MOA Key Laboratory of Animal Virology, Center for Veterinary Sciences, Zhejiang University, Hangzhou 310058, China; (Y.Z.); (J.Z.)
- Correspondence:
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8
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Asadi MR, Rahmanpour D, Moslehian MS, Sabaie H, Hassani M, Ghafouri-Fard S, Taheri M, Rezazadeh M. Stress Granules Involved in Formation, Progression and Metastasis of Cancer: A Scoping Review. Front Cell Dev Biol 2021; 9:745394. [PMID: 34604242 PMCID: PMC8485071 DOI: 10.3389/fcell.2021.745394] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 08/25/2021] [Indexed: 12/15/2022] Open
Abstract
The assembly of stress granules (SGs) is a well-known cellular strategy for reducing stress-related damage and promoting cell survival. SGs have become important players in human health, in addition to their fundamental role in the stress response. The critical role of SGs in cancer cells in formation, progression, and metastasis makes sense. Recent researchers have found that several SG components play a role in tumorigenesis and cancer metastasis via tumor-associated signaling pathways and other mechanisms. Gene-ontology analysis revealed the role of these protein components in the structure of SGs. Involvement in the translation process, regulation of mRNA stability, and action in both the cytoplasm and nucleus are among the main features of SG proteins. The present scoping review aimed to consider all studies on the effect of SGs on cancer formation, proliferation, and metastasis and performed based on a six-stage methodology structure and the PRISMA guideline. A systematic search of seven databases for qualified articles was conducted before July 2021. Publications were screened, and quantitative and qualitative analysis was performed on the extracted data. Go analysis was performed on seventy-one SGs protein components. Remarkably G3BP1, TIA1, TIAR, and YB1 have the largest share among the proteins considered in the studies. Altogether, this scoping review tries to demonstrate and provide a comprehensive summary of the role of SGs in the formation, progression, and metastasis of cancer by reviewing all studies.
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Affiliation(s)
- Mohammad Reza Asadi
- Molecular Medicine Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
- Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Dara Rahmanpour
- Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Hani Sabaie
- Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
- Department of Medical Genetics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mehdi Hassani
- Student Research Committee, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Soudeh Ghafouri-Fard
- Department of Medical Genetics, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Taheri
- Skull Base Research Center, Loghman Hakim Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Maryam Rezazadeh
- Molecular Medicine Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
- Department of Medical Genetics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
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Xiao Q, Huang Z, Shen Y, Gan Y, Wang Y, Gong S, Lu Y, Luo X, You W, Ke C. Transcriptome analysis reveals the molecular mechanisms of heterosis on thermal resistance in hybrid abalone. BMC Genomics 2021; 22:650. [PMID: 34496767 PMCID: PMC8428104 DOI: 10.1186/s12864-021-07954-y] [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: 04/19/2021] [Accepted: 08/23/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Heterosis has been exploited for decades in different animals and crops due to it resulting in dramatic increases in yield and adaptability. Hybridization is a classical breeding method that can effectively improve the genetic characteristics of organisms through heterosis. Abalone has become an increasingly economically important aquaculture resource with high commercial value. However, due to changing climate, abalone is now facing serious threats of high temperature in summer. Interspecific hybrid abalone (Haliotis gigantea ♀ × H. discus hannai ♂, SD) has been cultured at large scale in southern China and has been shown high survival rates under heat stress in summer. Therefore, SD has become a good model material for heterosis research, but the molecular basis of heterosis remains elusive. RESULTS Heterosis in thermal tolerance of SD was verified through Arrhenius break temperatures (ABT) of cardiac performance in this study. Then RNA-Sequencing was conducted to obtain gene expression patterns and alternative splicing events at control temperature (20 °C) and heat stress temperature (30 °C). A total of 356 (317 genes), 476 (435genes), and 876 (726 genes) significantly diverged alternative splicing events were identified in H. discus hannai (DD), H. gigantea (SS), and SD in response to heat stress, respectively. In the heat stress groups, 93.37% (20,512 of 21,969) of the expressed genes showed non-additive expression patterns, and over-dominance expression patterns of genes account for the highest proportion (40.15%). KEGG pathway enrichment analysis showed that the overlapping genes among common DEGs and NAGs were significantly enriched in protein processing in the endoplasmic reticulum, mitophagy, and NF-κB signaling pathway. In addition, we found that among these overlap genes, 39 genes had undergone alternative splicing events in SD. These pathways and genes may play an important role in the thermal resistance of hybrid abalone. CONCLUSION More alternative splicing events and non-additive expressed genes were detected in hybrid under heat stress and this may contribute to its thermal heterosis. These results might provide clues as to how hybrid abalone has a better physiological regulation ability than its parents under heat stress, to increase our understanding of heterosis in abalone.
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Affiliation(s)
- Qizhen Xiao
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, People's Republic of China
- Fujian Key Laboratory of Genetics and Breeding of Marine Organisms, Xiamen University, Xiamen, 361102, People's Republic of China
| | - Zekun Huang
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, People's Republic of China
- Fujian Key Laboratory of Genetics and Breeding of Marine Organisms, Xiamen University, Xiamen, 361102, People's Republic of China
| | - Yawei Shen
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, People's Republic of China
- Fujian Key Laboratory of Genetics and Breeding of Marine Organisms, Xiamen University, Xiamen, 361102, People's Republic of China
| | - Yang Gan
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, People's Republic of China
- Fujian Key Laboratory of Genetics and Breeding of Marine Organisms, Xiamen University, Xiamen, 361102, People's Republic of China
| | - Yi Wang
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, People's Republic of China
- Fujian Key Laboratory of Genetics and Breeding of Marine Organisms, Xiamen University, Xiamen, 361102, People's Republic of China
| | - Shihai Gong
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, People's Republic of China
- Fujian Key Laboratory of Genetics and Breeding of Marine Organisms, Xiamen University, Xiamen, 361102, People's Republic of China
| | - Yisha Lu
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, People's Republic of China
- Fujian Key Laboratory of Genetics and Breeding of Marine Organisms, Xiamen University, Xiamen, 361102, People's Republic of China
| | - Xuan Luo
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, People's Republic of China
- Fujian Key Laboratory of Genetics and Breeding of Marine Organisms, Xiamen University, Xiamen, 361102, People's Republic of China
| | - Weiwei You
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, People's Republic of China.
- Fujian Key Laboratory of Genetics and Breeding of Marine Organisms, Xiamen University, Xiamen, 361102, People's Republic of China.
| | - Caihuan Ke
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, People's Republic of China.
- Fujian Key Laboratory of Genetics and Breeding of Marine Organisms, Xiamen University, Xiamen, 361102, People's Republic of China.
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10
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Gwon Y, Maxwell BA, Kolaitis RM, Zhang P, Kim HJ, Taylor JP. Ubiquitination of G3BP1 mediates stress granule disassembly in a context-specific manner. Science 2021; 372:eabf6548. [PMID: 34739333 PMCID: PMC8574224 DOI: 10.1126/science.abf6548] [Citation(s) in RCA: 136] [Impact Index Per Article: 45.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Stress granules are dynamic, reversible condensates composed of RNA and protein that assemble in eukaryotic cells in response to a variety of stressors and are normally disassembled after stress is removed. The composition and assembly of stress granules is well understood, but little is known about the mechanisms that govern disassembly. Impaired disassembly has been implicated in some diseases including amyotrophic lateral sclerosis, frontotemporal dementia, and multisystem proteinopathy. Using cultured human cells, we found that stress granule disassembly was context-dependent: Specifically in the setting of heat shock, disassembly required ubiquitination of G3BP1, the central protein within the stress granule RNA-protein network. We found that ubiquitinated G3BP1 interacted with the endoplasmic reticulum–associated protein FAF2, which engaged the ubiquitin-dependent segregase p97/VCP (valosin-containing protein). Thus, targeting of G3BP1 weakened the stress granule–specific interaction network, resulting in granule disassembly.
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Affiliation(s)
- Youngdae Gwon
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Brian A. Maxwell
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Regina-Maria Kolaitis
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Peipei Zhang
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Hong Joo Kim
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - J. Paul Taylor
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
- Howard Hughes Medical Institute, Chevy Chase, MD 20815
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11
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Marcelo A, Koppenol R, de Almeida LP, Matos CA, Nóbrega C. Stress granules, RNA-binding proteins and polyglutamine diseases: too much aggregation? Cell Death Dis 2021; 12:592. [PMID: 34103467 PMCID: PMC8187637 DOI: 10.1038/s41419-021-03873-8] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 05/25/2021] [Accepted: 05/25/2021] [Indexed: 02/05/2023]
Abstract
Stress granules (SGs) are membraneless cell compartments formed in response to different stress stimuli, wherein translation factors, mRNAs, RNA-binding proteins (RBPs) and other proteins coalesce together. SGs assembly is crucial for cell survival, since SGs are implicated in the regulation of translation, mRNA storage and stabilization and cell signalling, during stress. One defining feature of SGs is their dynamism, as they are quickly assembled upon stress and then rapidly dispersed after the stress source is no longer present. Recently, SGs dynamics, their components and their functions have begun to be studied in the context of human diseases. Interestingly, the regulated protein self-assembly that mediates SG formation contrasts with the pathological protein aggregation that is a feature of several neurodegenerative diseases. In particular, aberrant protein coalescence is a key feature of polyglutamine (PolyQ) diseases, a group of nine disorders that are caused by an abnormal expansion of PolyQ tract-bearing proteins, which increases the propensity of those proteins to aggregate. Available data concerning the abnormal properties of the mutant PolyQ disease-causing proteins and their involvement in stress response dysregulation strongly suggests an important role for SGs in the pathogenesis of PolyQ disorders. This review aims at discussing the evidence supporting the existence of a link between SGs functionality and PolyQ disorders, by focusing on the biology of SGs and on the way it can be altered in a PolyQ disease context.
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Affiliation(s)
- Adriana Marcelo
- Algarve Biomedical Center Research Institute (ABC-RI), Faro, Portugal
- PhD Program in Biomedial Sciences, Faculty of Medicine and Biomedical Sciences, University of Algarve, Faro, Portugal
- Centre for Biomedical Research (CBMR), Universidade do Algarve, Faro, Portugal
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal
- Faculty of Medicine and Biomedical Sciences, University of Algarve, Faro, Portugal
| | - Rebekah Koppenol
- Algarve Biomedical Center Research Institute (ABC-RI), Faro, Portugal
- PhD Program in Biomedial Sciences, Faculty of Medicine and Biomedical Sciences, University of Algarve, Faro, Portugal
- Centre for Biomedical Research (CBMR), Universidade do Algarve, Faro, Portugal
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal
- Faculty of Medicine and Biomedical Sciences, University of Algarve, Faro, Portugal
| | - Luís Pereira de Almeida
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - Carlos A Matos
- Algarve Biomedical Center Research Institute (ABC-RI), Faro, Portugal
- Centre for Biomedical Research (CBMR), Universidade do Algarve, Faro, Portugal
- Faculty of Medicine and Biomedical Sciences, University of Algarve, Faro, Portugal
| | - Clévio Nóbrega
- Algarve Biomedical Center Research Institute (ABC-RI), Faro, Portugal.
- Centre for Biomedical Research (CBMR), Universidade do Algarve, Faro, Portugal.
- Faculty of Medicine and Biomedical Sciences, University of Algarve, Faro, Portugal.
- Champalimaud Research Program, Champalimaud Center for the Unknown, Lisbon, Portugal.
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12
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Formicola N, Heim M, Dufourt J, Lancelot AS, Nakamura A, Lagha M, Besse F. Tyramine induces dynamic RNP granule remodeling and translation activation in the Drosophila brain. eLife 2021; 10:65742. [PMID: 33890854 PMCID: PMC8064753 DOI: 10.7554/elife.65742] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 04/04/2021] [Indexed: 02/06/2023] Open
Abstract
Ribonucleoprotein (RNP) granules are dynamic condensates enriched in regulatory RNA binding proteins (RBPs) and RNAs under tight spatiotemporal control. Extensive recent work has investigated the molecular principles underlying RNP granule assembly, unraveling that they form through the self-association of RNP components into dynamic networks of interactions. How endogenous RNP granules respond to external stimuli to regulate RNA fate is still largely unknown. Here, we demonstrate through high-resolution imaging of intact Drosophila brains that Tyramine induces a reversible remodeling of somatic RNP granules characterized by the decondensation of granule-enriched RBPs (e.g. Imp/ZBP1/IGF2BP) and helicases (e.g. Me31B/DDX-6/Rck). Furthermore, our functional analysis reveals that Tyramine signals both through its receptor TyrR and through the calcium-activated kinase CamkII to trigger RNP component decondensation. Finally, we uncover that RNP granule remodeling is accompanied by the rapid and specific translational activation of associated mRNAs. Thus, this work sheds new light on the mechanisms controlling cue-induced rearrangement of physiological RNP condensates.
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Affiliation(s)
- Nadia Formicola
- Université Côte d'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
| | - Marjorie Heim
- Université Côte d'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
| | - Jérémy Dufourt
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, Montpellier, France
| | - Anne-Sophie Lancelot
- Université Côte d'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
| | - Akira Nakamura
- Department of Germline Development, Institute of Molecular Embryology and Genetics, and Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Mounia Lagha
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, Montpellier, France
| | - Florence Besse
- Université Côte d'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
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13
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Akkoc Y, Peker N, Akcay A, Gozuacik D. Autophagy and Cancer Dormancy. Front Oncol 2021; 11:627023. [PMID: 33816262 PMCID: PMC8017298 DOI: 10.3389/fonc.2021.627023] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Accepted: 01/22/2021] [Indexed: 12/13/2022] Open
Abstract
Metastasis and relapse account for the great majority of cancer-related deaths. Most metastatic lesions are micro metastases that have the capacity to remain in a non-dividing state called “dormancy” for months or even years. Commonly used anticancer drugs generally target actively dividing cancer cells. Therefore, cancer cells that remain in a dormant state evade conventional therapies and contribute to cancer recurrence. Cellular and molecular mechanisms of cancer dormancy are not fully understood. Recent studies indicate that a major cellular stress response mechanism, autophagy, plays an important role in the adaptation, survival and reactivation of dormant cells. In this review article, we will summarize accumulating knowledge about cellular and molecular mechanisms of cancer dormancy, and discuss the role and importance of autophagy in this context.
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Affiliation(s)
- Yunus Akkoc
- Koç University Research Center for Translational Medicine (KUTTAM), Istanbul, Turkey
| | - Nesibe Peker
- Koç University Research Center for Translational Medicine (KUTTAM), Istanbul, Turkey
| | - Arzu Akcay
- Yeni Yüzyıl University, School of Medicine, Private Gaziosmanpaşa Hospital, Department of Pathology, Istanbul, Turkey
| | - Devrim Gozuacik
- Koç University Research Center for Translational Medicine (KUTTAM), Istanbul, Turkey.,Koç University School of Medicine, Istanbul, Turkey.,Sabancı University Nanotechnology Research and Application Center (SUNUM), Istanbul, Turkey
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14
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Legrand N, Dixon DA, Sobolewski C. Stress granules in colorectal cancer: Current knowledge and potential therapeutic applications. World J Gastroenterol 2020; 26:5223-5247. [PMID: 32994684 PMCID: PMC7504244 DOI: 10.3748/wjg.v26.i35.5223] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/12/2020] [Accepted: 09/03/2020] [Indexed: 02/06/2023] Open
Abstract
Stress granules (SGs) represent important non-membrane cytoplasmic compartments, involved in cellular adaptation to various stressful conditions (e.g., hypoxia, nutrient deprivation, oxidative stress). These granules contain several scaffold proteins and RNA-binding proteins, which bind to mRNAs and keep them translationally silent while protecting them from harmful conditions. Although the role of SGs in cancer development is still poorly known and vary between cancer types, increasing evidence indicate that the expression and/or the activity of several key SGs components are deregulated in colorectal tumors but also in pre-neoplastic conditions (e.g., inflammatory bowel disease), thus suggesting a potential role in the onset of colorectal cancer (CRC). It is therefore believed that SGs formation importantly contributes to various steps of colorectal tumorigenesis but also in chemoresistance. As CRC is the third most frequent cancer and one of the leading causes of cancer mortality worldwide, development of new therapeutic targets is needed to offset the development of chemoresistance and formation of metastasis. Abolishing SGs assembly may therefore represent an appealing therapeutic strategy to re-sensitize colon cancer cells to anti-cancer chemotherapies. In this review, we summarize the current knowledge on SGs in colorectal cancer and the potential therapeutic strategies that could be employed to target them.
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Affiliation(s)
- Noémie Legrand
- Department of Medicine, Faculty of Medicine, University of Geneva, Geneva CH-1211, Switzerland
| | - Dan A Dixon
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, and University of Kansas Cancer Center, Lawrence, KS 66045, United States
| | - Cyril Sobolewski
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva CH-1211, Switzerland
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15
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Eiermann N, Haneke K, Sun Z, Stoecklin G, Ruggieri A. Dance with the Devil: Stress Granules and Signaling in Antiviral Responses. Viruses 2020; 12:v12090984. [PMID: 32899736 PMCID: PMC7552005 DOI: 10.3390/v12090984] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/31/2020] [Accepted: 08/31/2020] [Indexed: 02/07/2023] Open
Abstract
Cells have evolved highly specialized sentinels that detect viral infection and elicit an antiviral response. Among these, the stress-sensing protein kinase R, which is activated by double-stranded RNA, mediates suppression of the host translation machinery as a strategy to limit viral replication. Non-translating mRNAs rapidly condensate by phase separation into cytosolic stress granules, together with numerous RNA-binding proteins and components of signal transduction pathways. Growing evidence suggests that the integrated stress response, and stress granules in particular, contribute to antiviral defense. This review summarizes the current understanding of how stress and innate immune signaling act in concert to mount an effective response against virus infection, with a particular focus on the potential role of stress granules in the coordination of antiviral signaling cascades.
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Affiliation(s)
- Nina Eiermann
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; (N.E.); (K.H.); (G.S.)
| | - Katharina Haneke
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; (N.E.); (K.H.); (G.S.)
| | - Zhaozhi Sun
- Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Disease Research (CIID), University of Heidelberg, 69120 Heidelberg, Germany;
| | - Georg Stoecklin
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; (N.E.); (K.H.); (G.S.)
| | - Alessia Ruggieri
- Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Disease Research (CIID), University of Heidelberg, 69120 Heidelberg, Germany;
- Correspondence:
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16
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Zhan Y, Wang H, Ning Y, Zheng H, Liu S, Yang Y, Zhou M, Fan S. Understanding the roles of stress granule during chemotherapy for patients with malignant tumors. Am J Cancer Res 2020; 10:2226-2241. [PMID: 32905441 PMCID: PMC7471355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 07/19/2020] [Indexed: 06/11/2023] Open
Abstract
The assembly of stress granules (SGs) is a conserved mechanism to regulate protein synthesis under cell stress, where the translation of global protein is silenced and selective protein synthesis for survival maintains. SG formation confers survival advantages and chemotherapeutic resistance to malignant cells. Targeting SG assembly may represent a potential treatment strategy to overcome the primary and acquired chemotherapeutic resistance and enhance curative effect. We conduct a comprehensive review of the published literatures focusing on the drugs that potentially induce SGs and the related mechanism, retrospect the relationship between SGs and drug resistance related proteins, illuminate the regulated pathways and potential targets for SG assembly, and discuss future directions of overcoming the resistance to chemotherapy.
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Affiliation(s)
- Yuting Zhan
- Department of Pathology, The Second Xiangya Hospital, Central South UniversityChangsha 410011, Hunan, China
| | - Haihua Wang
- Department of Pathology, The Second Xiangya Hospital, Central South UniversityChangsha 410011, Hunan, China
| | - Yue Ning
- Department of Pathology, The Second Xiangya Hospital, Central South UniversityChangsha 410011, Hunan, China
| | - Hongmei Zheng
- Department of Pathology, The Second Xiangya Hospital, Central South UniversityChangsha 410011, Hunan, China
| | - Sile Liu
- Department of Pathology, The Second Xiangya Hospital, Central South UniversityChangsha 410011, Hunan, China
| | - Yang Yang
- Department of Pathology, The Second Xiangya Hospital, Central South UniversityChangsha 410011, Hunan, China
| | - Ming Zhou
- Cancer Research Institute Xiangya School of Medicine, Central South UniversityChangsha 410078, Hunan, China
| | - Songqing Fan
- Department of Pathology, The Second Xiangya Hospital, Central South UniversityChangsha 410011, Hunan, China
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17
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Frydrýšková K, Mašek T, Pospíšek M. Changing faces of stress: Impact of heat and arsenite treatment on the composition of stress granules. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 11:e1596. [PMID: 32362075 DOI: 10.1002/wrna.1596] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Revised: 03/19/2020] [Accepted: 03/23/2020] [Indexed: 11/07/2022]
Abstract
Stress granules (SGs), hallmarks of the cellular adaptation to stress, promote survival, conserve cellular energy, and are fully dissolved upon the cessation of stress treatment. Different stresses can initiate the assembly of SGs, but arsenite and heat are the best studied of these stresses. The composition of SGs and posttranslational modifications of SG proteins differ depending on the type and severity of the stress insult, methodology used, cell line, and presence of overexpressed and tagged proteins. A group of 18 proteins showing differential localization to SGs in heat- and arsenite-stressed mammalian cell lines is described. Upon severe and prolonged stress, physiological SGs transform into more solid protein aggregates that are no longer reversible and do not contain mRNA. Similar pathological inclusions are hallmarks of neurodegenerative diseases. SGs induced by heat stress are less dynamic than SGs induced by arsenite and contain a set of unique proteins and linkage-specific polyubiquitinated proteins. The same types of ubiquitin linkages have been found to contribute to the development of neurodegenerative disorders such as Parkinson disease, Alzheimer disease, and amyotrophic lateral sclerosis (ALS). We propose heat stress-induced SGs as a possible model of an intermediate stage along the transition from dynamic, fully reversible arsenite stress-induced SGs toward aberrant SGs, the hallmark of neurodegenerative diseases. Stress- and methodology-specific differences in the compositions of SGs and the transition of SGs to aberrant protein aggregates are discussed. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes RNA Export and Localization > RNA Localization.
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Affiliation(s)
| | | | - Martin Pospíšek
- Department of Genetics and Microbiology, Faculty of Science, Charles University, Prague, Czechia
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18
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Autophagy in motor neuron diseases. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 172:157-202. [PMID: 32620242 DOI: 10.1016/bs.pmbts.2020.03.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Motor neuron diseases (MNDs) are a wide group of neurodegenerative disorders characterized by the degeneration of a specific neuronal type located in the central nervous system, the motor neuron (MN). There are two main types of MNs, spinal and cortical MNs and depending on the type of MND, one or both types are affected. Cortical MNs innervate spinal MNs and these control a variety of cellular targets, being skeletal muscle their main one which is also affected in MNDs. A correct functionality of autophagy is necessary for the survival of all cellular types and it is particularly crucial for neurons, given their postmitotic and highly specialized nature. Numerous studies have identified alterations of autophagy activity in multiple MNDs. The scientific community has been particularly prolific in reporting the role that autophagy plays in the most common adult MND, amyotrophic lateral sclerosis, although many studies have started to identify physiological and pathological functions of this catabolic system in other MNDs, such as spinal muscular atrophy and spinal and bulbar muscular atrophy. The degradation of selective cargo by autophagy and how this process is altered upon the presence of MND-causing mutations is currently also a matter of intense investigation, particularly regarding the selective autophagic clearance of mitochondria. Thorough reviews on this field have been recently published. This chapter will cover the current knowledge on the functionality of autophagy and lysosomal homeostasis in the main MNDs and other autophagy-related topics in the MND field that have risen special interest in the research community.
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19
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Bradford AM, Koirala R, Park CK, Lyons BA. Characterization of the full-length human Grb7 protein and a phosphorylation representative mutant. J Mol Recognit 2019; 32:e2803. [PMID: 31353673 DOI: 10.1002/jmr.2803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
It is well known the dimerization state of receptor tyrosine kinases (RTKs), in conjunction with binding partners such as the growth factor receptor bound protein 7 (Grb7) protein, plays an important role in cell signaling regulation. Previously, we proposed, downstream of RTKs, that the phosphorylation state of Grb7SH2 domain tyrosine residues could control Grb7 dimerization, and dimerization may be an important regulatory step in Grb7 binding to RTKs. In this manner, additional dimerization-dependent regulation could occur downstream of the membrane-bound kinase in RTK-mediated signaling pathways. Extrapolation to the full-length (FL) Grb7 protein, and the ability to test this hypothesis further, has been hampered by the availability of large quantities of pure and stable FL protein. Here, we report the biophysical characterization of the FL Grb7 protein and also a mutant representing a tyrosine-phosphorylated Grb7 protein form. Through size exclusion chromatography and analytical ultracentrifugation, we show the phosphorylated-tyrosine-mimic Y492E-FL-Grb7 protein (Y492E-FL-Grb7) is essentially monomeric at expected physiological concentrations. It has been shown previously the wild-type FL Grb7(WT-FLGrb7) protein is dimeric with a dissociation constant (Kd) of approximately 11μM. Our studies here measure a FL protein dimerization Kd of WT-FL-Grb7 within one order of magnitude at approximately 1μM. The approximate size and shape of the WT-FL-Grb7 in comparison the tyrosine-phosphorylation mimic Y492E-FL-Grb7 protein was determined by dynamic light scattering methods. In vitro phosphorylation of the Grb7SH2 domain indicates only one of the available tyrosine residues is phosphorylated, suggesting the same phosphorylation pattern could be relevant in the FL protein. The biophysical characterization studies in total are interpreted with a view towards understanding the functionally active Grb7 protein conformation.
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Affiliation(s)
| | - Rajan Koirala
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM, USA
| | - Chad K Park
- Analytical Biophysics Core, Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
| | - Barbara A Lyons
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM, USA
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20
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Schweig JE, Yao H, Coppola K, Jin C, Crawford F, Mullan M, Paris D. Spleen tyrosine kinase (SYK) blocks autophagic Tau degradation in vitro and in vivo. J Biol Chem 2019; 294:13378-13395. [PMID: 31324720 DOI: 10.1074/jbc.ra119.008033] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 07/12/2019] [Indexed: 12/29/2022] Open
Abstract
Spleen tyrosine kinase (SYK) plays a major role in inflammation and in adaptive immune responses and could therefore contribute to the neuroinflammation observed in various neurodegenerative diseases. Indeed, previously we have reported that SYK also regulates β-amyloid (Aβ) production and hyperphosphorylation of Tau protein involved in these diseases. Moreover, SYK hyperactivation occurs in a subset of activated microglia, in dystrophic neurites surrounding Aβ deposits, and in neurons affected by Tau pathology both in individuals with Alzheimer's disease (AD) and in AD mouse models. SYK activation increases Tau phosphorylation and accumulation, suggesting that SYK could be an attractive target for treating AD. However, the mechanism by which SYK affects Tau pathology is not clear. In this study, using cell biology and biochemical approaches, along with immunoprecipitation and immunoblotting, quantitative RT-PCR, and ELISAs, we found that SYK inhibition increases autophagic Tau degradation without impacting Tau production. Using neuron-like SH-SY5Y cells, we demonstrate that SYK acts upstream of the mammalian target of rapamycin (mTOR) pathway and that pharmacological inhibition or knockdown of SYK decreases mTOR pathway activation and increases autophagic Tau degradation. Interestingly, chronic SYK inhibition in a tauopathy mouse model profoundly reduced Tau accumulation, neuroinflammation, neuronal and synaptic loss, and also reversed defective autophagy. Our results further suggest that the SYK up-regulation observed in the brains of individuals with AD contributes to defective autophagic clearance leading to the accumulation of pathogenic Tau species. These findings further highlight SYK as a therapeutic target for the treatment of tauopathies and other neurodegenerative proteinopathies associated with defective autophagic clearance.
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Affiliation(s)
- Jonas Elias Schweig
- Roskamp Institute, Sarasota, Florida 34243; The Open University, Milton Keynes MK7 6AA, United Kingdom; James A. Haley Veterans Hospital, Tampa, Florida 33612.
| | - Hailan Yao
- Roskamp Institute, Sarasota, Florida 34243; James A. Haley Veterans Hospital, Tampa, Florida 33612
| | - Kyle Coppola
- Roskamp Institute, Sarasota, Florida 34243; James A. Haley Veterans Hospital, Tampa, Florida 33612
| | - Chao Jin
- Roskamp Institute, Sarasota, Florida 34243
| | - Fiona Crawford
- Roskamp Institute, Sarasota, Florida 34243; The Open University, Milton Keynes MK7 6AA, United Kingdom; James A. Haley Veterans Hospital, Tampa, Florida 33612
| | - Michael Mullan
- Roskamp Institute, Sarasota, Florida 34243; The Open University, Milton Keynes MK7 6AA, United Kingdom
| | - Daniel Paris
- Roskamp Institute, Sarasota, Florida 34243; The Open University, Milton Keynes MK7 6AA, United Kingdom; James A. Haley Veterans Hospital, Tampa, Florida 33612
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21
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Chu PY, Tai YL, Shen TL. Grb7, a Critical Mediator of EGFR/ErbB Signaling, in Cancer Development and as a Potential Therapeutic Target. Cells 2019; 8:cells8050435. [PMID: 31083325 PMCID: PMC6562560 DOI: 10.3390/cells8050435] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 05/02/2019] [Accepted: 05/09/2019] [Indexed: 12/20/2022] Open
Abstract
The partner of activated epidermal growth factor receptor (EGFR), growth factor receptor bound protein-7 (Grb7), a functionally multidomain adaptor protein, has been demonstrated to be a pivotal regulator for varied physiological and pathological processes by interacting with phospho-tyrosine-related signaling molecules to affect the transmission through a number of signaling pathways. In particular, critical roles of Grb7 in erythroblastic leukemia viral oncogene homolog (ERBB) family-mediated cancer development and malignancy have been intensively evaluated. The overexpression of Grb7 or the coamplification/cooverexpression of Grb7 and members of the ERBB family play essential roles in advanced human cancers and are associated with decreased survival and recurrence of cancers, emphasizing Grb7's value as a prognostic marker and a therapeutic target. Peptide inhibitors of Grb7 are being tested in preclinical trials for their possible therapeutic effects. Here, we review the molecular, functional, and clinical aspects of Grb7 in ERBB family-mediated cancer development and malignancy with the aim to reveal alternative and effective therapeutic strategies.
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Affiliation(s)
- Pei-Yu Chu
- Department of Plant Pathology and Microbiology, National Taiwan University, Taipei 10617, Taiwan.
| | - Yu-Ling Tai
- Department of Plant Pathology and Microbiology, National Taiwan University, Taipei 10617, Taiwan.
- Department of Urology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Tang-Long Shen
- Department of Plant Pathology and Microbiology, National Taiwan University, Taipei 10617, Taiwan.
- Center for Biotechnology, National Taiwan University, Taipei 10617, Taiwan.
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22
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Shinde A, Hardy SD, Kim D, Akhand SS, Jolly MK, Wang WH, Anderson JC, Khodadadi RB, Brown WS, George JT, Liu S, Wan J, Levine H, Willey CD, Krusemark CJ, Geahlen RL, Wendt MK. Spleen Tyrosine Kinase-Mediated Autophagy Is Required for Epithelial-Mesenchymal Plasticity and Metastasis in Breast Cancer. Cancer Res 2019; 79:1831-1843. [PMID: 30733195 PMCID: PMC6467765 DOI: 10.1158/0008-5472.can-18-2636] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 12/19/2018] [Accepted: 02/04/2019] [Indexed: 12/19/2022]
Abstract
The ability of breast cancer cells to transiently transition between epithelial and mesenchymal states contributes to their metastatic potential. Therefore, driving tumor cells into a stable mesenchymal state, as opposed to complete tumor cell eradication, presents an opportunity to pharmacologically limit disease progression by promoting an asymptomatic state of dormancy. Here, we compare a reversible model of epithelial-mesenchymal transition (EMT) induced by TGFβ to a stable mesenchymal phenotype induced by chronic exposure to the ErbB kinase inhibitor lapatinib. Only cells capable of returning to an epithelial phenotype resulted in skeletal metastasis. Gene expression analyses of the two mesenchymal states indicated similar transition expression profiles. A potently downregulated gene in both datasets was spleen tyrosine kinase (SYK). In contrast to this similar diminution in mRNA, kinome analyses using a peptide array and DNA-conjugated peptide substrates showed a robust increase in SYK activity upon TGFβ-induced EMT only. SYK was present in cytoplasmic RNA processing depots known as P-bodies formed during the onset of EMT, and SYK activity was required for autophagy-mediated clearance of P-bodies during mesenchymal-epithelial transition (MET). Genetic knockout of autophagy-related 7 (ATG7) or pharmacologic inhibition of SYK activity with fostamatinib, a clinically approved inhibitor of SYK, prevented P-body clearance and MET, inhibiting metastatic tumor outgrowth. Overall, this study suggests assessment of SYK activity as a biomarker for metastatic disease and the use of fostamatinib as a means to stabilize the latency of disseminated tumor cells. SIGNIFICANCE: These findings present inhibition of spleen tyrosine kinase as a therapeutic option to limit breast cancer metastasis by promoting systemic tumor dormancy.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/79/8/1831/F1.large.jpg.See related commentary by Farrington and Narla, p. 1756.
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Affiliation(s)
- Aparna Shinde
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
- Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana
| | - Shana D Hardy
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
- Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana
| | - Dongwook Kim
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
- Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana
| | - Saeed Salehin Akhand
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
- Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana
| | - Mohit Kumar Jolly
- Centre for BioSystems Science and Engineering, Indian Institute of Science, Bangalore, India
| | - Wen-Hung Wang
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
- Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana
| | - Joshua C Anderson
- Department of Radiation Oncology, University of Alabama, Birmingham, Alabama
| | - Ryan B Khodadadi
- Department of Graduate Medical Education, Mayo Clinic, Rochester. Minnesota
| | - Wells S Brown
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
- Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana
| | - Jason T George
- Center for Theoretical Biological Physics, Rice University, Houston, Texas
- Medical Science Training Program, Baylor College of Medicine, Houston, Texas
| | - Sheng Liu
- Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana
| | - Jun Wan
- Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana
| | - Herbert Levine
- Center for Theoretical Biological Physics, Rice University, Houston, Texas
| | | | - Casey J Krusemark
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
- Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana
| | - Robert L Geahlen
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
- Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana
| | - Michael K Wendt
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana.
- Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana
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23
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Ibañez-Vega J, Del Valle Batalla F, Saez JJ, Soza A, Yuseff MI. Proteasome Dependent Actin Remodeling Facilitates Antigen Extraction at the Immune Synapse of B Cells. Front Immunol 2019; 10:225. [PMID: 30873155 PMCID: PMC6401660 DOI: 10.3389/fimmu.2019.00225] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 01/28/2019] [Indexed: 12/24/2022] Open
Abstract
Engagement of the B cell receptor (BCR) with surface-tethered antigens leads to the formation of an immune synapse (IS), where cell signaling and antigen uptake are tightly coordinated. Centrosome re-orientation to the immune synapse has emerged as a critical regulatory step to guide the local recruitment and secretion of lysosomes, which can facilitate the extraction of immobilized antigens. This process is coupled to actin remodeling at the centrosome and at the immune synapse, which is crucial to promote cell polarity. How B cells balance both pools of actin cytoskeleton to achieve a polarized phenotype during the formation of an immune synapse is not fully understood. Here, we reveal that B cells rely on proteasome activity to achieve this task. The proteasome is a multi-catalytic protease that degrades cytosolic and nuclear proteins and its dysfunction is associated with diseases, such as cancer and autoimmunity. Our results show that resting B cells contain an active proteasome pool at the centrosome, which is required for efficient actin clearance at this level. As a result of proteasome inhibition, activated B cells do not deplete actin at the centrosome and are unable to separate the centrosome from the nucleus and thus display impaired polarity. Consequently, lysosome recruitment to the immune synapse, antigen extraction and presentation are severely compromised in B cells with diminished proteasome activity. Additionally, we found that proteasome inhibition leads to impaired actin remodeling at the immune synapse, where B cells display defective spreading responses and distribution of key signaling molecules at the synaptic membrane. Overall, our results reveal a new role for the proteasome in regulating the immune synapse of B cells, where the intracellular compartmentalization of proteasome activity controls cytoskeleton remodeling between the centrosome and synapse, with functional repercussions in antigen extraction and presentation.
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Affiliation(s)
- Jorge Ibañez-Vega
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Felipe Del Valle Batalla
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan José Saez
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Andrea Soza
- Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Facultad de Ciencias, Universidad San Sebastián, Santiago, Chile
- Centro de Envejecimiento y Regeneración (CARE), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Maria-Isabel Yuseff
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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RNA Granules and Their Role in Neurodegenerative Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1203:195-245. [DOI: 10.1007/978-3-030-31434-7_8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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25
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Hofweber M, Dormann D. Friend or foe-Post-translational modifications as regulators of phase separation and RNP granule dynamics. J Biol Chem 2018; 294:7137-7150. [PMID: 30587571 DOI: 10.1074/jbc.tm118.001189] [Citation(s) in RCA: 227] [Impact Index Per Article: 37.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Ribonucleoprotein (RNP) granules are membrane-less organelles consisting of RNA-binding proteins (RBPs) and RNA. RNA granules form through liquid-liquid phase separation (LLPS), whereby weak promiscuous interactions among RBPs and/or RNAs create a dense network of interacting macromolecules and drive the phase separation. Post-translational modifications (PTMs) of RBPs have emerged as important regulators of LLPS and RNP granule dynamics, as they can directly weaken or enhance the multivalent interactions between phase-separating macromolecules or can recruit or exclude certain macromolecules into or from condensates. Here, we review recent insights into how PTMs regulate phase separation and RNP granule dynamics, in particular arginine (Arg)-methylation and phosphorylation. We discuss how these PTMs regulate the phase behavior of prototypical RBPs and how, as "friend or foe," they might influence the assembly, disassembly, or material properties of cellular RNP granules, such as stress granules or amyloid-like condensates. We particularly highlight how PTMs control the phase separation and aggregation behavior of disease-linked RBPs. We also review how disruptions of PTMs might be involved in aberrant phase transitions and the formation of amyloid-like protein aggregates as observed in neurodegenerative diseases.
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Affiliation(s)
- Mario Hofweber
- From the BioMedical Center, Cell Biology, Ludwig-Maximilians-University Munich, Grosshaderner Strasse 9, 82152 Planegg-Martinsried.,the Graduate School of Systemic Neurosciences, Ludwig-Maximilians-University Munich, Grosshaderner Strasse 2, 82152 Planegg-Martinsried, and
| | - Dorothee Dormann
- From the BioMedical Center, Cell Biology, Ludwig-Maximilians-University Munich, Grosshaderner Strasse 9, 82152 Planegg-Martinsried, .,the Graduate School of Systemic Neurosciences, Ludwig-Maximilians-University Munich, Grosshaderner Strasse 2, 82152 Planegg-Martinsried, and.,the Munich Cluster for Systems Neurology (SyNergy), Feodor-Lynen-Strasse 17, 81377 Munich, Germany
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26
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Gao D, Wang L, Zhang H, Yan X, Yang J, Zhou R, Chang X, Sun Y, Tian S, Yao Z, Zhang K, Liu Z, Ma Z. Spleen tyrosine kinase
SYK
(L) interacts with
YY
1 and coordinately suppresses
SNAI
2
transcription in lung cancer cells. FEBS J 2018; 285:4229-4245. [DOI: 10.1111/febs.14665] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 07/26/2018] [Accepted: 09/21/2018] [Indexed: 12/23/2022]
Affiliation(s)
- Dan Gao
- Department of Biochemistry and Molecular Biology, Immunology School of Basic Medical Sciences Tianjin Key Laboratory of Medical Epigenetics Tianjin Medical University China
| | - Lingling Wang
- Department of Biochemistry and Molecular Biology, Immunology School of Basic Medical Sciences Tianjin Key Laboratory of Medical Epigenetics Tianjin Medical University China
| | - Hua Zhang
- Department of Biochemistry and Molecular Biology, Immunology School of Basic Medical Sciences Tianjin Key Laboratory of Medical Epigenetics Tianjin Medical University China
| | - Xiaojie Yan
- Department of Biochemistry and Molecular Biology, Immunology School of Basic Medical Sciences Tianjin Key Laboratory of Medical Epigenetics Tianjin Medical University China
- State Key Laboratory of Medicinal Chemical Biology Nankai University Tianjin China
| | - Jie Yang
- Department of Biochemistry and Molecular Biology, Immunology School of Basic Medical Sciences Tianjin Key Laboratory of Medical Epigenetics Tianjin Medical University China
| | - Ruimin Zhou
- Department of Biochemistry and Molecular Biology, Immunology School of Basic Medical Sciences Tianjin Key Laboratory of Medical Epigenetics Tianjin Medical University China
| | - Xinzhong Chang
- Department of Breast Cancer Breast Cancer Center Tianjin Medical University Cancer Institute and Hospital China
| | - Yanan Sun
- Department of Biochemistry and Molecular Biology, Immunology School of Basic Medical Sciences Tianjin Key Laboratory of Medical Epigenetics Tianjin Medical University China
| | - Shanshan Tian
- Department of Biochemistry and Molecular Biology, Immunology School of Basic Medical Sciences Tianjin Key Laboratory of Medical Epigenetics Tianjin Medical University China
| | - Zhi Yao
- Department of Biochemistry and Molecular Biology, Immunology School of Basic Medical Sciences Tianjin Key Laboratory of Medical Epigenetics Tianjin Medical University China
- Key Laboratory of Immune Microenvironment and Disease of the Ministry of Education Tianjin Medical University China
| | - Kai Zhang
- Department of Biochemistry and Molecular Biology, Immunology School of Basic Medical Sciences Tianjin Key Laboratory of Medical Epigenetics Tianjin Medical University China
| | - Zhe Liu
- Department of Biochemistry and Molecular Biology, Immunology School of Basic Medical Sciences Tianjin Key Laboratory of Medical Epigenetics Tianjin Medical University China
- Key Laboratory of Immune Microenvironment and Disease of the Ministry of Education Tianjin Medical University China
| | - Zhenyi Ma
- Department of Biochemistry and Molecular Biology, Immunology School of Basic Medical Sciences Tianjin Key Laboratory of Medical Epigenetics Tianjin Medical University China
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27
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Feng C, Roy A, Post CB. Entropic allostery dominates the phosphorylation-dependent regulation of Syk tyrosine kinase release from immunoreceptor tyrosine-based activation motifs. Protein Sci 2018; 27:1780-1796. [PMID: 30051939 PMCID: PMC6225982 DOI: 10.1002/pro.3489] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 07/05/2018] [Accepted: 07/05/2018] [Indexed: 01/15/2023]
Abstract
Spleen tyrosine kinase (Syk) is an essential player in immune signaling through its ability to couple multiple classes of membrane immunoreceptors to intracellular signaling pathways. Ligand binding leads to the recruitment of Syk to a phosphorylated cytoplasmic region of the receptors called ITAM. Syk binds to ITAM with high-affinity (nanomolar Kd ) via its tandem pair of SH2 domains. The affinity between Syk and ITAM is allosterically regulated by phosphorylation at Y130 in a linker connecting the tandem SH2 domains; when Y130 is phosphorylated, the binding affinity decreases (micromolar Kd ). Previous equilibrium binding studies attribute the increase in the binding free energy to an intra-molecular binding (isomerization) step of the tandem SH2 and ITAM, but a physical basis for the increased free energy is unknown. Here, we provide evidence that Y130 phosphorylation imposes an entropy penalty to isomerization, but surprisingly, has negligible effect on the SH2 binding interactions with ITAM and thus on the binding enthalpy. An analysis of NMR chemical shift differences characterized conformational effects of ITAM binding, and binding thermodynamics were measured from isothermal titration calorimetry. Together the data support a previously unknown mechanism for the basis of regulating protein-protein interactions through protein phosphorylation. The decreased affinity for Syk association with immune receptor ITAMs by Y130 phosphorylation is an allosteric mechanism driven by an increased entropy penalty, likely contributed by conformational disorder in the SH2-SH2 inter-domain structure, while SH2-ITAM binding contacts are not affected, and binding enthalpy is unchanged.
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Affiliation(s)
- Chao Feng
- Department of Medicinal Chemistry and Molecular PharmacologyMarkey Center for Structural Biology, and Purdue Center for Cancer Research, Purdue UniversityWest Lafayette, Indiana, 47907
| | - Amitava Roy
- Bioinformatics and Computational Biosciences Branch, Rocky Mountain Laboratories, NIAIDNational Institutes of HealthHamilton, Montana, 59840
| | - Carol Beth Post
- Department of Medicinal Chemistry and Molecular PharmacologyMarkey Center for Structural Biology, and Purdue Center for Cancer Research, Purdue UniversityWest Lafayette, Indiana, 47907
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28
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Glass L, Wente SR. Gle1 mediates stress granule-dependent survival during chemotoxic stress. Adv Biol Regul 2018; 71:156-171. [PMID: 30262214 DOI: 10.1016/j.jbior.2018.09.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 09/12/2018] [Accepted: 09/13/2018] [Indexed: 12/12/2022]
Abstract
Stress granules (SGs) are non-membrane bound organelles that form in response to multiple different stress stimuli, including exposure to sodium arsenite. SGs are postulated to support cells during periods of stress and provide a protective effect, allowing survival. Gle1 is a highly conserved, essential modulator of RNA-dependent DEAD-box proteins that exists as at least two distinct isoforms in human cells. Gle1A is required for proper SG formation, whereas Gle1B functions in mRNA export at the nuclear pore complex. Since Gle1A is required for SG function, we hypothesized that SG-dependent survival responses would also be Gle1-dependent. We describe here an experimental system for quantifying and testing the SG-associated survival response to sodium arsenite stress in HeLa cells. Gle1A was required for the sodium arsenite survival response, and overexpression of Gle1A supported the survival response. Overexpression of the SG-component G3BP also enabled the response. Next, we analyzed whether cells undergoing multiple rounds of stress yield a subpopulation with a higher propensity for SG formation and an increased resistance to undergoing apoptosis. After ten doses of sodium arsenite treatment, cells became resistant to sodium arsenite and to diclofenac sodium (another SG-inducing drug). The sodium arsenite-resistant cells exhibited changes in SG biology and had an increased survival response that was conferred in a paracrine manner. Changes in secreted factors occurred including a significantly lower level of MCP-1, a known regulator of stress granules and stress-induced apoptosis. This study supports models wherein SGs play a role in cell evasion of apoptosis and further reveal Gle1A and SG functions as targets for clinical approaches directed at chemoresistant/refractory cells.
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Affiliation(s)
- Laura Glass
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, 37240, USA
| | - Susan R Wente
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, 37240, USA.
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29
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APOBEC3G-Regulated Host Factors Interfere with Measles Virus Replication: Role of REDD1 and Mammalian TORC1 Inhibition. J Virol 2018; 92:JVI.00835-18. [PMID: 29925665 DOI: 10.1128/jvi.00835-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 06/14/2018] [Indexed: 01/23/2023] Open
Abstract
We found earlier that ectopic expression of the cytidine deaminase APOBEC3G (A3G) in Vero cells inhibits measles virus (MV), respiratory syncytial virus, and mumps virus, while the mechanism of inhibition remained unclear. A microarray analysis revealed that in A3G-transduced Vero cells, several cellular transcripts were differentially expressed, suggesting that A3G regulates the expression of host factors. One of the most upregulated host cell factors, REDD1 (regulated in development and DNA damage response-1, also called DDIT4), reduced MV replication ∼10-fold upon overexpression in Vero cells. REDD1 is an endogenous inhibitor of mTORC1 (mammalian target of rapamycin complex-1), the central regulator of cellular metabolism. Interestingly, rapamycin reduced the MV replication similarly to REDD1 overexpression, while the combination of both did not lead to further inhibition, suggesting that the same pathway is affected. REDD1 silencing in A3G-expressing Vero cells abolished the inhibitory effect of A3G. In addition, silencing of A3G led to reduced REDD1 expression, confirming that its expression is regulated by A3G. In primary human peripheral blood lymphocytes (PBL), expression of A3G and REDD1 was found to be stimulated by phytohemagglutinin (PHA) and interleukin-2. Small interfering RNA (siRNA)-mediated depletion of A3G in PHA-stimulated PBL reduced REDD1 expression and increased viral titers, which corroborates our findings in Vero cells. Silencing of REDD1 also increased viral titers, confirming the antiviral role of REDD1. Finally, pharmacological inhibition of mTORC1 by rapamycin in PHA-stimulated PBL reduced viral replication to the level found in unstimulated lymphocytes, indicating that mTORC1 activity supports MV replication as a proviral host factor.IMPORTANCE Knowledge about host factors supporting or restricting virus replication is required for a deeper understanding of virus-cell interactions and may eventually provide the basis for therapeutic intervention. This work was undertaken predominantly to explain the mechanism of A3G-mediated inhibition of MV, a negative-strand RNA virus that is not affected by the deaminase activity of A3G acting on single-stranded DNA. We found that A3G regulates the expression of several cellular proteins, which influences the capacity of the host cell to replicate MV. One of these, REDD1, which modulates the cellular metabolism in a central position by regulating the kinase complex mTORC1, was identified as the major cellular factor impairing MV replication. These findings show interesting aspects of the function of A3G and the dependence of the MV replication on the metabolic state of the cell. Interestingly, pharmacological inhibition of mTORC1 can be utilized to inhibit MV replication in Vero cells and primary human peripheral blood lymphocytes.
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30
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TDP-43 regulation of stress granule dynamics in neurodegenerative disease-relevant cell types. Sci Rep 2018; 8:7551. [PMID: 29765078 PMCID: PMC5953947 DOI: 10.1038/s41598-018-25767-0] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 04/27/2018] [Indexed: 12/24/2022] Open
Abstract
Stress granules (SGs) are cytoplasmic foci that form in response to various external stimuli and are essential to cell survival following stress. SGs are studied in several diseases, including ALS and FTD, which involve the degeneration of motor and cortical neurons, respectively, and are now realized to be linked pathogenically by TDP-43, originally discovered as a component of ubiquitin-positive aggregates within patients’ neurons and some glial cells. So far, studies to undercover the role of TDP-43 in SGs have used primarily transformed cell lines, and thus rely on the extrapolation of the mechanisms to cell types affected in ALS/FTD, potentially masking cell specific effects. Here, we investigate SG dynamics in primary motor and cortical neurons as well as astrocytes. Our data suggest a cell and stress specificity and demonstrate a requirement for TDP-43 for efficient SG dynamics. In addition, based on our in vitro approach, our data suggest that aging may be an important modifier of SG dynamics which could have relevance to the initiation and/or progression of age-related neurodegenerative diseases.
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31
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Dautova Y, Kapustin AN, Pappert K, Epple M, Okkenhaug H, Cook SJ, Shanahan CM, Bootman MD, Proudfoot D. Calcium phosphate particles stimulate interleukin-1β release from human vascular smooth muscle cells: A role for spleen tyrosine kinase and exosome release. J Mol Cell Cardiol 2018; 115:82-93. [PMID: 29274344 PMCID: PMC5823844 DOI: 10.1016/j.yjmcc.2017.12.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 12/18/2017] [Accepted: 12/19/2017] [Indexed: 12/16/2022]
Abstract
AIMS Calcium phosphate (CaP) particle deposits are found in several inflammatory diseases including atherosclerosis and osteoarthritis. CaP, and other forms of crystals and particles, can promote inflammasome formation in macrophages leading to caspase-1 activation and secretion of mature interleukin-1β (IL-1β). Given the close association of small CaP particles with vascular smooth muscle cells (VSMCs) in atherosclerotic fibrous caps, we aimed to determine if CaP particles affected pro-inflammatory signalling in human VSMCs. METHODS AND RESULTS Using ELISA to measure IL-1β release from VSMCs, we demonstrated that CaP particles stimulated IL-1β release from proliferating and senescent human VSMCs, but with substantially greater IL-1β release from senescent cells; this required caspase-1 activity but not LPS-priming of cells. Potential inflammasome agonists including ATP, nigericin and monosodium urate crystals did not stimulate IL-1β release from VSMCs. Western blot analysis demonstrated that CaP particles induced rapid activation of spleen tyrosine kinase (SYK) (increased phospho-Y525/526). The SYK inhibitor R406 reduced IL-1β release and caspase-1 activation in CaP particle-treated VSMCs, indicating that SYK activation occurs upstream of and is required for caspase-1 activation. In addition, IL-1β and caspase-1 colocalised in intracellular endosome-like vesicles and we detected IL-1β in exosomes isolated from VSMC media. Furthermore, CaP particle treatment stimulated exosome secretion by VSMCs in a SYK-dependent manner, while the exosome-release inhibitor spiroepoxide reduced IL-1β release. CONCLUSIONS CaP particles stimulate SYK and caspase-1 activation in VSMCs, leading to the release of IL-1β, at least in part via exosomes. These novel findings in human VSMCs highlight the pro-inflammatory and pro-calcific potential of microcalcification.
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Affiliation(s)
- Yana Dautova
- Signalling Programme, Babraham Institute, Babraham, Cambridge CB22 3AT, UK
| | - Alexander N Kapustin
- Cardiovascular Division, James Black Centre, King's College London,125 Coldharbour Lane, London SE5 9NU, UK
| | - Kevin Pappert
- Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Essen-Duisburg, Essen 45117, Germany
| | - Matthias Epple
- Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Essen-Duisburg, Essen 45117, Germany
| | - Hanneke Okkenhaug
- Signalling Programme, Babraham Institute, Babraham, Cambridge CB22 3AT, UK
| | - Simon J Cook
- Signalling Programme, Babraham Institute, Babraham, Cambridge CB22 3AT, UK
| | - Catherine M Shanahan
- Cardiovascular Division, James Black Centre, King's College London,125 Coldharbour Lane, London SE5 9NU, UK
| | - Martin D Bootman
- School of Life, Health and Chemical Sciences, The Open University, Milton Keynes MK7 6AA, UK
| | - Diane Proudfoot
- Signalling Programme, Babraham Institute, Babraham, Cambridge CB22 3AT, UK.
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32
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Fernandes N, Eshleman N, Buchan JR. Stress Granules and ALS: A Case of Causation or Correlation? ADVANCES IN NEUROBIOLOGY 2018; 20:173-212. [PMID: 29916020 DOI: 10.1007/978-3-319-89689-2_7] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease characterized by cytoplasmic protein aggregates within motor neurons. These aggregates are linked to ALS pathogenesis. Recent evidence has suggested that stress granules may aid the formation of ALS protein aggregates. Here, we summarize current understanding of stress granules, focusing on assembly and clearance. We also assess the evidence linking alterations in stress granule formation and dynamics to ALS protein aggregates and disease pathology.
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Affiliation(s)
- Nikita Fernandes
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, USA
| | - Nichole Eshleman
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, USA
| | - J Ross Buchan
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, USA.
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33
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Lin YL, Tsai HC, Liu PY, Benneyworth M, Wei LN. Receptor-interacting protein 140 as a co-repressor of Heat Shock Factor 1 regulates neuronal stress response. Cell Death Dis 2017; 8:3203. [PMID: 29233969 PMCID: PMC5870597 DOI: 10.1038/s41419-017-0008-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 09/23/2017] [Accepted: 09/29/2017] [Indexed: 12/15/2022]
Abstract
Heat shock response (HSR) is a highly conserved transcriptional program that protects organisms against various stressful conditions. However, the molecular mechanisms modulating HSR, especially the suppression of HSR, is poorly understood. Here, we found that RIP140, a wide-spectrum cofactor of nuclear hormone receptors, acts as a co-repressor of heat shock factor 1 (HSF1) to suppress HSR in healthy neurons. When neurons are stressed such as by heat shock or sodium arsenite (As), cells engage specific proteosome-mediated degradation to reduce RIP140 level, thereby relieving the suppression and activating HSR. RIP140 degradation requires specific Tyr-phosphorylation by Syk that is activated in stressful conditions. Lowering RIP140 level protects hippocampal neurons from As stress, significantly it increases neuron survival and improves spine density. Reducing hippocampal RIP140 in the mouse rescues chronic As-induced spatial learning deficits. This is the first study elucidating RIP140-mediated suppression of HSF1-activated HSR in neurons and brain. Importantly, degradation of RIP140 in stressed neurons relieves this suppression, allowing neurons to efficiently and timely engage HSR programs and recover. Therefore, stimulating RIP140 degradation to activate anti-stress program provides a potential preventive or therapeutic strategy for neurodegeneration diseases.
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Affiliation(s)
- Yu-Lung Lin
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Hong-Chieh Tsai
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA.,Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang-Gung University, Tao-Yuan, Taiwan, ROC.,Department of Neurosurgery, Chang-Gung Memorial Hospital and University, Tao-Yuan, Taiwan, ROC
| | - Pei-Yao Liu
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Michael Benneyworth
- Departments of Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Li-Na Wei
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA.
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34
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Ghosh S, Castillo E, Frias ES, Swanson RA. Bioenergetic regulation of microglia. Glia 2017; 66:1200-1212. [PMID: 29219210 DOI: 10.1002/glia.23271] [Citation(s) in RCA: 173] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 10/31/2017] [Accepted: 11/09/2017] [Indexed: 02/06/2023]
Abstract
Microglia have diverse actions, ranging from synapse pruning in development to cytotoxic effects in disease. Brain energy metabolism and substrate availability vary under normal and disease states, but how these variations influence microglial function is relatively unknown. Microglia, like most other cell types, express the full complement of gene products required for both glycolytic and oxidative metabolism. Evidence suggests that microglia increase aerobic glycolysis and decrease respiration when activated by various stimuli. Mitochondrial function, glucose availability, and glycolytic rate influence pro-inflammatory gene expression at both transcriptional and post-translational levels. These effects are mediated through CtBP, an NADH-sensitive transcriptional co-repressor; through effects on NLRP3 inflammasome assembly and caspase-1 activation; through formation of advanced glycation end-products; and by less well-defined mechanisms. In addition to these transcriptional effects, microglial glucose metabolism is also required for superoxide production by NADPH oxidase, as glucose is the obligate substrate for regenerating NADPH in the hexose monophosphate shunt. Microglia also metabolize acetoacetate and β-hydroxybutyrate, which are generated during fasting or ketogenic diet, and respond to these ketones as metabolic signals. β-Hydroxybutyrate inhibits histone de-acetylases and activates microglial GRP109A receptors. These actions suppress microglia activation after brain injury and promote neuroprotective microglia phenotypes. As our understanding of microglial activation matures, additional links between energy metabolism and microglial function are likely to be identified.
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Affiliation(s)
- Soumitra Ghosh
- Department of Neurology, University of California San Francisco, San Francisco, CA.,Department of Neurology, San Francisco Veterans Affairs Medical Center, San Francisco, CA
| | - Erika Castillo
- Department of Neurology, University of California San Francisco, San Francisco, CA.,Department of Neurology, San Francisco Veterans Affairs Medical Center, San Francisco, CA
| | - Elma S Frias
- Department of Neurology, University of California San Francisco, San Francisco, CA.,Department of Neurology, San Francisco Veterans Affairs Medical Center, San Francisco, CA
| | - Raymond A Swanson
- Department of Neurology, University of California San Francisco, San Francisco, CA.,Department of Neurology, San Francisco Veterans Affairs Medical Center, San Francisco, CA
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35
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Westbroek ML, Geahlen RL. Modulation of BCR Signaling by the Induced Dimerization of Receptor-Associated SYK. Antibodies (Basel) 2017; 6:antib6040023. [PMID: 31548538 PMCID: PMC6698873 DOI: 10.3390/antib6040023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 11/27/2017] [Accepted: 12/02/2017] [Indexed: 01/14/2023] Open
Abstract
Clustering of the B cell antigen receptor (BCR) by polyvalent antigens is transmitted through the SYK tyrosine kinase to the activation of multiple intracellular pathways that determine the physiological consequences of receptor engagement. To explore factors that modulate the quantity and quality of signals sent by the crosslinked BCR, we developed a novel chemical mediator of dimerization to induce clustering of receptor-associated SYK. To accomplish this, we fused SYK with E. coli dihydrofolate reductase (eDHFR), which binds the small molecule trimethoprim (TMP) with high affinity and selectivity and synthesized a dimer of TMP with a flexible linker. The TMP dimer is able to induce the aggregation of eDHFR-linked SYK in live cells. The induced dimerization of SYK bound to the BCR differentially regulates the activation of downstream transcription factors, promoting the activation of Nuclear Factor of Activated T cells (NFAT) without affecting the activation of NFκB. The dimerization of SYK enhances the duration but not the amplitude of calcium mobilization by enhancing the extent and duration of its interaction with the crosslinked BCR at the plasma membrane.
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Affiliation(s)
- Mark L Westbroek
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA.
| | - Robert L Geahlen
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA.
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Köhler C, Fuhr V, Dinekov M. Distribution of spleen tyrosine kinase and tau phosphorylated at tyrosine 18 in a mouse model of tauopathy and in the human hippocampus. Brain Res 2017; 1677:1-13. [DOI: 10.1016/j.brainres.2017.08.029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 08/11/2017] [Accepted: 08/25/2017] [Indexed: 12/01/2022]
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Regulation of epithelial-mesenchymal transition and metastasis by TGF-β, P-bodies, and autophagy. Oncotarget 2017; 8:103302-103314. [PMID: 29262563 PMCID: PMC5732729 DOI: 10.18632/oncotarget.21871] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 09/29/2017] [Indexed: 12/19/2022] Open
Abstract
Processing bodies (P-bodies) are ribonucleoprotein complexes involved in post-transcriptional mRNA metabolism that accumulate in cells exposed to various stress stimuli. The treatment of mammary epithelial cells with transforming growth factor-beta (TGF-β), triggers epithelial-mesenchymal transition (EMT), and induces the formation of P-bodies. Ectopic expression of the transcription factor TWIST, which stimulates EMT downstream of the TGF-β receptor, also promotes P-body formation. Removal of TGF-β from treated cells results in the clearance of P-bodies by a process that is blocked by inhibitors of autophagy. Activators of autophagy enhance P-body clearance and block EMT. Blockage of P-body formation by disruption of the gene for DDX6, a protein essential for P-body assembly, blocks EMT and prevents tumor cell metastasis in vivo. These studies suggest critical roles for P-body formation and autophagy in transitions of cancer cells between epithelial and mesenchymal phenotypes and help explain how autophagy functions to promote or suppress tumor cell growth during different stages of tumorigenesis.
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Godamudunage MP, Foster A, Warren D, Lyons BA. Grb7 protein RA domain oligomerization. J Mol Recognit 2017; 30. [PMID: 28295715 DOI: 10.1002/jmr.2620] [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: 10/07/2016] [Revised: 01/26/2017] [Accepted: 01/28/2017] [Indexed: 11/05/2022]
Abstract
The growth factor receptor bound protein 7 (Grb7) is an adaptor protein that is often coamplified with the erythroblastosis oncogene B 2 receptor in 20% to 30% of breast cancer patients. Grb7 overexpression has been linked to increased cell migration and cancer metastasis. The ras associating and pleckstrin homology domain region of Grb7 has been reported to interact with various other downstream signaling proteins such as four and half Lin11, Isl-1, Mec-3 (LIM) domains isoform 2 and filamin α. These interactions are believed to play a role in regulating Grb7-mediated cell migration function. The full-length Grb7 protein has been shown to dimerize, and the oligomeric state of the Grb7SH2 domain has been extensively studied; however, the oligomerization state of the ras associating and pleckstrin homology domains, and the importance of this oligomerization in Grb7 function, is yet to be fully known. In this study, we characterize the oligomeric state of the Grb7RA domain using size exclusion chromatography, nuclear magnetic resonance, nuclear relaxation studies, glutaraldehyde cross linking, and dynamic light scattering. We report the Grb7RA domain can exist in transient multimeric forms and, based upon modeling results, postulate the potential role of Grb7RA domain oligomerization in Grb7 function.
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Affiliation(s)
- Malika P Godamudunage
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI, USA.,Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM, 88003, USA
| | | | | | - Barbara A Lyons
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM, 88003, USA
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Abstract
Macroautophagy/autophagy is a key catabolic process, essential for maintaining cellular homeostasis and survival through the removal and recycling of unwanted cellular material. Emerging evidence has revealed intricate connections between the RNA and autophagy research fields. While a majority of studies have focused on protein, lipid and carbohydrate catabolism via autophagy, accumulating data supports the view that several types of RNA and associated ribonucleoprotein complexes are specifically recruited to phagophores (precursors to autophagosomes) and subsequently degraded in the lysosome/vacuole. Moreover, recent studies have revealed a substantial number of novel autophagy regulators with RNA-related functions, indicating roles for RNA and associated proteins not only as cargo, but also as regulators of this process. In this review, we discuss widespread evidence of RNA catabolism via autophagy in yeast, plants and animals, reviewing the molecular mechanisms and biological importance in normal physiology, stress and disease. In addition, we explore emerging evidence of core autophagy regulation mediated by RNA-binding proteins and noncoding RNAs, and point to gaps in our current knowledge of the connection between RNA and autophagy. Finally, we discuss the pathological implications of RNA-protein aggregation, primarily in the context of neurodegenerative disease.
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Affiliation(s)
- Lisa B Frankel
- a Biotech Research and Innovation Centre , University of Copenhagen , Copenhagen , Denmark
| | - Michal Lubas
- a Biotech Research and Innovation Centre , University of Copenhagen , Copenhagen , Denmark
| | - Anders H Lund
- a Biotech Research and Innovation Centre , University of Copenhagen , Copenhagen , Denmark
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Ghosh S, Geahlen RL. Stress Granules Modulate SYK to Cause Microglial Cell Dysfunction in Alzheimer's Disease. EBioMedicine 2015; 2:1785-98. [PMID: 26870803 PMCID: PMC4740304 DOI: 10.1016/j.ebiom.2015.09.053] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 09/21/2015] [Accepted: 09/30/2015] [Indexed: 12/13/2022] Open
Abstract
Microglial cells in the brains of Alzheimer's patients are known to be recruited to amyloid-beta (Aβ) plaques where they exhibit an activated phenotype, but are defective for plaque removal by phagocytosis. In this study, we show that microglia stressed by exposure to sodium arsenite or Aβ(1–42) peptides or fibrils form extensive stress granules (SGs) to which the tyrosine kinase, SYK, is recruited. SYK enhances the formation of SGs, is active within the resulting SGs and stimulates the production of reactive oxygen and nitrogen species that are toxic to neuronal cells. This sequestration of SYK inhibits the ability of microglial cells to phagocytose Escherichia coli or Aβ fibrils. We find that aged microglial cells are more susceptible to the formation of SGs; and SGs containing SYK and phosphotyrosine are prevalent in the brains of patients with severe Alzheimer's disease. Phagocytic activity can be restored to stressed microglial cells by treatment with IgG, suggesting a mechanism to explain the therapeutic efficacy of intravenous IgG. These studies describe a mechanism by which stress, including exposure to Aβ, compromises the function of microglial cells in Alzheimer's disease and suggest approaches to restore activity to dysfunctional microglial cells. Chronic stress promotes the formation of large, persistent stress granules in microglial cells. SYK is recruited to stress granules, which promotes inflammatory responses and inhibits phagocytosis. Phagocytic activity of stressed cells can be recovered by treatment with IgG.
Microglial cells in the brains of patients with Alzheimer's disease are activated, but are defective at phagocytosis of amyloid plaques. Activation and phagocytosis require the SYK tyrosine kinase. Chronic exposure to amyloid-beta promotes the formation of persistent stress granules to which active SYK binds and these are found in the brains of patients with severe Alzheimer's disease. This activation and sequestration of SYK promotes inflammation and inhibits phagocytosis. Phagocytic activity can be recovered by treatment with IgG, which causes a redistribution of SYK within the cell, suggesting potential therapeutic approaches to restoring microglial cell function to diseased or aged brains.
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Affiliation(s)
- Soumitra Ghosh
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA
| | - Robert L Geahlen
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA
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