1
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Chen C, Xie Y, Qian S. Multifaceted role of GCN2 in tumor adaptation and therapeutic targeting. Transl Oncol 2024; 49:102096. [PMID: 39178574 PMCID: PMC11388189 DOI: 10.1016/j.tranon.2024.102096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 07/26/2024] [Accepted: 08/11/2024] [Indexed: 08/26/2024] Open
Abstract
Tumor cells voraciously consume nutrients from their environment to facilitate rapid proliferation, necessitating effective strategies to manage nutrient scarcity during tumor growth and progression. A pivotal regulatory mechanism in this context is the Integrated Stress Response (ISR), which ensures cellular homeostasis under conditions such as endoplasmic reticulum stress, the unfolded protein response, and nutrient deprivation. Within the ISR framework, the kinase GCN2 is critical, orchestrating a myriad of cellular processes including the inhibition of protein synthesis, the enhancement of amino acid transport, autophagy initiation, and angiogenesis. These processes collectively enable tumor survival and adaptation under nutrient-limited conditions. Furthermore, GCN2-mediated pathways may induce apoptosis, a property exploited by specific therapeutic agents. Leveraging extensive datasets from TCGA, GEO, and GTEx projects, we conducted a pan-cancer analysis to investigate the prognostic significance of GCN2 expression across diverse cancer types. Our analysis indicates that GCN2 expression significantly varies and correlates with both adverse and favorable prognoses depending on the type of cancer, illustrating its complex role in tumorigenesis. Importantly, GCN2 also modulates the tumor immune microenvironment, influencing immune checkpoint expression and the functionality of immune cells, thereby affecting immunotherapy outcomes. This study highlights the potential of targeting GCN2 with specific inhibitors, as evidenced by their efficacy in preclinical models to augment treatment responses and combat resistance in oncology. These findings advocate for a deeper exploration of GCN2's multifaceted roles, which could pave the way for novel targeted therapies in cancer treatment, aiming to improve clinical outcomes.
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Affiliation(s)
- Can Chen
- Department of Hematology, Affiliated Hangzhou First People's Hospital, Westlake University, School of Medicine, Hangzhou, China; Zhejiang University, School of Medicine, Hangzhou, China
| | - Yaping Xie
- Department of Hematology, Affiliated Hangzhou First People's Hospital, Westlake University, School of Medicine, Hangzhou, China; Zhejiang University, School of Medicine, Hangzhou, China.
| | - Shenxian Qian
- Department of Hematology, Affiliated Hangzhou First People's Hospital, Westlake University, School of Medicine, Hangzhou, China; Zhejiang University, School of Medicine, Hangzhou, China.
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2
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Gibbs VJ, Lin YH, Ghuge AA, Anderson RA, Schiemann AH, Conaglen L, Sansom BJM, da Silva RC, Sattlegger E. GCN2 in Viral Defence and the Subversive Tactics Employed by Viruses. J Mol Biol 2024; 436:168594. [PMID: 38724002 DOI: 10.1016/j.jmb.2024.168594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 05/01/2024] [Accepted: 05/01/2024] [Indexed: 06/10/2024]
Abstract
The recent SARS-CoV-2 pandemic and associated COVID19 disease illustrates the important role of viral defence mechanisms in ensuring survival and recovery of the host or patient. Viruses absolutely depend on the host's protein synthesis machinery to replicate, meaning that impeding translation is a powerful way to counteract viruses. One major approach used by cells to obstruct protein synthesis is to phosphorylate the alpha subunit of eukaryotic translation initiation factor 2 (eIF2α). Mammals possess four different eIF2α-kinases: PKR, HRI, PEK/PERK, and GCN2. While PKR is currently considered the principal eIF2α-kinase involved in viral defence, the other eIF2α-kinases have also been found to play significant roles. Unsurprisingly, viruses have developed mechanisms to counteract the actions of eIF2α-kinases, or even to exploit them to their benefit. While some of these virulence factors are specific to one eIF2α-kinase, such as GCN2, others target all eIF2α-kinases. This review critically evaluates the current knowledge of viral mechanisms targeting the eIF2α-kinase GCN2. A detailed and in-depth understanding of the molecular mechanisms by which viruses evade host defence mechanisms will help to inform the development of powerful anti-viral measures.
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Affiliation(s)
- Victoria J Gibbs
- School of Food Technology and Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Yu H Lin
- School of Food Technology and Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Aditi A Ghuge
- School of Food Technology and Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Reuben A Anderson
- School of Food Technology and Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Anja H Schiemann
- School of Food Technology and Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Layla Conaglen
- School of Food Technology and Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Bianca J M Sansom
- School of Natural Sciences, Massey University, Auckland, New Zealand
| | - Richard C da Silva
- School of Natural Sciences, Massey University, Auckland, New Zealand; Genome Biology and Epigenetics, Department of Biology, Utrecht University, Utrecht, the Netherlands
| | - Evelyn Sattlegger
- School of Food Technology and Natural Sciences, Massey University, Palmerston North, New Zealand; School of Natural Sciences, Massey University, Auckland, New Zealand; Maurice Wilkins Centre for Molecular BioDiscovery, Palmerston North, New Zealand.
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3
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Rainero E. Macropinocytosis at the crossroad between nutrient scavenging and metabolism in cancer. Curr Opin Cell Biol 2024; 88:102359. [PMID: 38626703 DOI: 10.1016/j.ceb.2024.102359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 03/21/2024] [Accepted: 03/25/2024] [Indexed: 04/18/2024]
Abstract
Macropinocytosis (MP), the actin-dependent bulk uptake of extracellular fluids, plays a central role in nutrient scavenging, allowing cancer cells to sustain their growth in the hypoxic and nutrient-deprived microenvironment often found in solid tumours. The lack of soluble nutrients and several oncogenic signalling pathways, with RAS being the most studied, push MP-dependent internalisation of extracellular proteins, which are then digested in the lysosomes, replenishing the intracellular nutrient pools. This review will highlight recent advances in understanding how MP is regulated in hypoxic cancers, how it impinges on chemoresistance, and how different MP cargos facilitate tumour growth. Finally, I will highlight the crosstalk between MP and extracellular matrix receptors.
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Affiliation(s)
- Elena Rainero
- School of Biosciences, University of Sheffield, Sheffield, S10 2TN, UK.
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4
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Malnassy G, Ziolkowski L, Macleod KF, Oakes SA. The Integrated Stress Response in Pancreatic Development, Tissue Homeostasis, and Cancer. Gastroenterology 2024:S0016-5085(24)04931-X. [PMID: 38768690 DOI: 10.1053/j.gastro.2024.05.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 04/06/2024] [Accepted: 05/02/2024] [Indexed: 05/22/2024]
Abstract
Present in all eukaryotic cells, the integrated stress response (ISR) is a highly coordinated signaling network that controls cellular behavior, metabolism, and survival in response to diverse stresses. The ISR is initiated when any 1 of 4 stress-sensing kinases (protein kinase R-like endoplasmic reticulum kinase [PERK], general control non-derepressible 2 [GCN2], double-stranded RNA-dependent protein kinase [PKR], heme-regulated eukaryotic translation initiation factor 2α kinase [HRI]) becomes activated to phosphorylate the protein translation initiation factor eukaryotic translation initiation factor 2α (eIF2α), shifting gene expression toward a comprehensive rewiring of cellular machinery to promote adaptation. Although the ISR has been shown to play an important role in the homeostasis of multiple tissues, evidence suggests that it is particularly crucial for the development and ongoing health of the pancreas. Among the most synthetically dynamic tissues in the body, the exocrine and endocrine pancreas relies heavily on the ISR to rapidly adjust cell function to meet the metabolic demands of the organism. The hardwiring of the ISR into normal pancreatic functions and adaptation to stress may explain why it is a commonly used pro-oncogenic and therapy-resistance mechanism in pancreatic ductal adenocarcinoma and pancreatic neuroendocrine tumors. Here, we review what is known about the key roles that the ISR plays in the development, homeostasis, and neoplasia of the pancreas.
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Affiliation(s)
- Greg Malnassy
- Department of Pathology, University of Chicago, Chicago, Illinois
| | - Leah Ziolkowski
- The Ben May Department for Cancer Research, University of Chicago, Chicago, Illinoi; Committee on Molecular Metabolism and Nutrition, University of Chicago, Chicago, Illinois
| | - Kay F Macleod
- The Ben May Department for Cancer Research, University of Chicago, Chicago, Illinoi; Committee on Molecular Metabolism and Nutrition, University of Chicago, Chicago, Illinois; Committee on Cancer Biology, University of Chicago, Chicago, Illinois.
| | - Scott A Oakes
- Department of Pathology, University of Chicago, Chicago, Illinois; Committee on Molecular Metabolism and Nutrition, University of Chicago, Chicago, Illinois; Committee on Cancer Biology, University of Chicago, Chicago, Illinois.
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5
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Lu J, Li H, Yu Z, Cao C, Xu Z, Peng L, Zhang JH, Chen G. Cathepsin B as a key regulator of ferroptosis in microglia following intracerebral hemorrhage. Neurobiol Dis 2024; 194:106468. [PMID: 38460801 DOI: 10.1016/j.nbd.2024.106468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 03/06/2024] [Accepted: 03/06/2024] [Indexed: 03/11/2024] Open
Abstract
Intracerebral hemorrhage (ICH) is a subtype of stroke marked by elevated mortality and disability rates. Recently, mounting evidence suggests a significant role of ferroptosis in the pathogenesis of ICH. Through a combination of bioinformatics analysis and basic experiments, our goal is to identify the primary cell types and key molecules implicated in ferroptosis post-ICH. This aims to propel the advancement of ferroptosis research, offering potential therapeutic targets for ICH treatment. Our study reveals pronounced ferroptosis in microglia and identifies the target gene, cathepsin B (Ctsb), by analyzing differentially expressed genes following ICH. Ctsb, a cysteine protease primarily located in lysosomes, becomes a focal point in our investigation. Utilizing in vitro and in vivo models, we explore the correlation between Ctsb and ferroptosis in microglia post-ICH. Results demonstrate that ICH and hemin-induced ferroptosis in microglia coincide with elevated levels and activity of Ctsb protein. Effective alleviation of ferroptosis in microglia after ICH is achieved through the inhibition of Ctsb protease activity and protein levels using inhibitors and shRNA. Additionally, a notable increase in m6A methylation levels of Ctsb mRNA post-ICH is observed, suggesting a pivotal role of m6A methylation in regulating Ctsb translation. These research insights deepen our comprehension of the molecular pathways involved in ferroptosis after ICH, underscoring the potential of Ctsb as a promising target for mitigating brain damage resulting from ICH.
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Affiliation(s)
- Jinxin Lu
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Soochow University, Suzhou 215006, China; Institute of Stroke Research, Soochow University, Suzhou 215006, China
| | - Haiying Li
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Soochow University, Suzhou 215006, China; Institute of Stroke Research, Soochow University, Suzhou 215006, China
| | - Zhengquan Yu
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Soochow University, Suzhou 215006, China; Institute of Stroke Research, Soochow University, Suzhou 215006, China.
| | - Chang Cao
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Soochow University, Suzhou 215006, China; Institute of Stroke Research, Soochow University, Suzhou 215006, China
| | - Zhongmou Xu
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Soochow University, Suzhou 215006, China; Institute of Stroke Research, Soochow University, Suzhou 215006, China
| | - Lu Peng
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Soochow University, Suzhou 215006, China; Institute of Stroke Research, Soochow University, Suzhou 215006, China
| | - John H Zhang
- Departments of Neurosurgery, Anesthesiology, Physiology and Pharmacology, Pathology and Human Anatomy, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Gang Chen
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Soochow University, Suzhou 215006, China; Institute of Stroke Research, Soochow University, Suzhou 215006, China.
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6
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Todorova PK, Jackson BT, Garg V, Paras KI, Brunner JS, Bridgeman AE, Chen Y, Baksh SC, Yan J, Hadjantonakis AK, Finley LWS. Amino acid intake strategies define pluripotent cell states. Nat Metab 2024; 6:127-140. [PMID: 38172382 PMCID: PMC10842923 DOI: 10.1038/s42255-023-00940-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Accepted: 11/07/2023] [Indexed: 01/05/2024]
Abstract
Mammalian preimplantation development is associated with marked metabolic robustness, and embryos can develop under a wide variety of nutrient conditions, including even the complete absence of soluble amino acids. Here we show that mouse embryonic stem cells (ESCs) capture the unique metabolic state of preimplantation embryos and proliferate in the absence of several essential amino acids. Amino acid independence is enabled by constitutive uptake of exogenous protein through macropinocytosis, alongside a robust lysosomal digestive system. Following transition to more committed states, ESCs reduce digestion of extracellular protein and instead become reliant on exogenous amino acids. Accordingly, amino acid withdrawal selects for ESCs that mimic the preimplantation epiblast. More broadly, we find that all lineages of preimplantation blastocysts exhibit constitutive macropinocytic protein uptake and digestion. Taken together, these results highlight exogenous protein uptake and digestion as an intrinsic feature of preimplantation development and provide insight into the catabolic strategies that enable embryos to sustain viability before implantation.
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Affiliation(s)
- Pavlina K Todorova
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Benjamin T Jackson
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Louis V. Gerstner Jr Graduate School of Biomedical Sciences, New York, NY, USA
| | - Vidur Garg
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Katrina I Paras
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, NY, USA
| | - Julia S Brunner
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Anna E Bridgeman
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Yanyang Chen
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Sanjeethan C Baksh
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jielin Yan
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Louis V. Gerstner Jr Graduate School of Biomedical Sciences, New York, NY, USA
| | | | - Lydia W S Finley
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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7
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Gauthier-Coles G, Rahimi F, Bröer A, Bröer S. Inhibition of GCN2 Reveals Synergy with Cell-Cycle Regulation and Proteostasis. Metabolites 2023; 13:1064. [PMID: 37887389 PMCID: PMC10609202 DOI: 10.3390/metabo13101064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 09/19/2023] [Accepted: 10/07/2023] [Indexed: 10/28/2023] Open
Abstract
The integrated stress response is a signaling network comprising four branches, each sensing different cellular stressors, converging on the phosphorylation of eIF2α to downregulate global translation and initiate recovery. One of these branches includes GCN2, which senses cellular amino acid insufficiency and participates in maintaining amino acid homeostasis. Previous studies have shown that GCN2 is a viable cancer target when amino acid stress is induced by inhibiting an additional target. In this light, we screened numerous drugs for their potential to synergize with the GCN2 inhibitor TAP20. The drug sensitivity of six cancer cell lines to a panel of 25 compounds was assessed. Each compound was then combined with TAP20 at concentrations below their IC50, and the impact on cell growth was evaluated. The strongly synergistic combinations were further characterized using synergy analyses and matrix-dependent invasion assays. Inhibitors of proteostasis and the MEK-ERK pathway, as well as the pan-CDK inhibitors, flavopiridol, and seliciclib, were potently synergistic with TAP20 in two cell lines. Among their common CDK targets was CDK7, which was more selectively targeted by THZ-1 and synergized with TAP20. Moreover, these combinations were partially synergistic when assessed using matrix-dependent invasion assays. However, TAP20 alone was sufficient to restrict invasion at concentrations well below its growth-inhibitory IC50. We conclude that GCN2 inhibition can be further explored in vivo as a cancer target.
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Affiliation(s)
- Gregory Gauthier-Coles
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia; (G.G.-C.); (F.R.); (A.B.)
- School of Medicine, Yale University, New Haven, CT 06504, USA
| | - Farid Rahimi
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia; (G.G.-C.); (F.R.); (A.B.)
| | - Angelika Bröer
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia; (G.G.-C.); (F.R.); (A.B.)
| | - Stefan Bröer
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia; (G.G.-C.); (F.R.); (A.B.)
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8
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Choi H, Liao YC, Yoon YJ, Grimm J, Lavis LD, Singer RH, Lippincott-Schwartz J. Lysosomal release of amino acids at ER three-way junctions regulates transmembrane and secretory protein mRNA translation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.01.551382. [PMID: 37577585 PMCID: PMC10418176 DOI: 10.1101/2023.08.01.551382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
One-third of the mammalian proteome is comprised of transmembrane and secretory proteins that are synthesized on endoplasmic reticulum (ER). Here, we investigate the spatial distribution and regulation of mRNAs encoding these membrane and secretory proteins (termed "secretome" mRNAs) through live cell, single molecule tracking to directly monitor the position and translation states of secretome mRNAs on ER and their relationship to other organelles. Notably, translation of secretome mRNAs occurred preferentially near lysosomes on ER marked by the ER junction-associated protein, Lunapark. Knockdown of Lunapark reduced the extent of secretome mRNA translation without affecting translation of other mRNAs. Less secretome mRNA translation also occurred when lysosome function was perturbed by raising lysosomal pH or inhibiting lysosomal proteases. Secretome mRNA translation near lysosomes was enhanced during amino acid deprivation. Addition of the integrated stress response inhibitor, ISRIB, reversed the translation inhibition seen in Lunapark knockdown cells, implying an eIF2 dependency. Altogether, these findings uncover a novel coordination between ER and lysosomes, in which local release of amino acids and other factors from ER-associated lysosomes patterns and regulates translation of mRNAs encoding secretory and membrane proteins.
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9
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Sannino S, Manuel AM, Shang C, Wendell SG, Wipf P, Brodsky JL. Non-Essential Amino Acid Availability Influences Proteostasis and Breast Cancer Cell Survival During Proteotoxic Stress. Mol Cancer Res 2023; 21:675-690. [PMID: 36961392 PMCID: PMC10330057 DOI: 10.1158/1541-7786.mcr-22-0843] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 02/11/2023] [Accepted: 03/21/2023] [Indexed: 03/25/2023]
Abstract
Protein homeostasis (proteostasis) regulates tumor growth and proliferation when cells are exposed to proteotoxic stress, such as during treatment with certain chemotherapeutics. Consequently, cancer cells depend to a greater extent on stress signaling, and require the integrated stress response (ISR), amino acid metabolism, and efficient protein folding and degradation pathways to survive. To define how these interconnected pathways are wired when cancer cells are challenged with proteotoxic stress, we investigated how amino acid abundance influences cell survival when Hsp70, a master proteostasis regulator, is inhibited. We previously demonstrated that cancer cells exposed to a specific Hsp70 inhibitor induce the ISR via the action of two sensors, GCN2 and PERK, in stress-resistant and sensitive cells, respectively. In resistant cells, the induction of GCN2 and autophagy supported resistant cell survival, yet the mechanism by which these events were induced remained unclear. We now report that amino acid availability reconfigures the proteostasis network. Amino acid supplementation, and in particular arginine addition, triggered cancer cell death by blocking autophagy. Consistent with the importance of amino acid availability, which when limited activates GCN2, resistant cancer cells succumbed when challenged with a potentiator for another amino acid sensor, mTORC1, in conjunction with Hsp70 inhibition. IMPLICATIONS These data position amino acid abundance, GCN2, mTORC1, and autophagy as integrated therapeutic targets whose coordinated modulation regulates the survival of proteotoxic-resistant breast cancer cells.
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Affiliation(s)
- Sara Sannino
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Allison M. Manuel
- Health Sciences Mass Spectrometry Core, University of Pittsburgh, Pittsburgh, PA, USA
- Mass Spectrometry and Proteomics Core, The University of Utah, Salt Lake City, UT, USA
| | - Chaowei Shang
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Stacy G. Wendell
- Health Sciences Mass Spectrometry Core, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Pharmacology and Chemical Biology University of Pittsburgh, Pittsburgh, PA, USA
| | - Peter Wipf
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
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10
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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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11
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Patrick M, Gu Z, Zhang G, Wynn RM, Kaphle P, Cao H, Vu H, Cai F, Gao X, Zhang Y, Chen M, Ni M, Chuang DT, DeBerardinis RJ, Xu J. Metabolon formation regulates branched-chain amino acid oxidation and homeostasis. Nat Metab 2022; 4:1775-1791. [PMID: 36443523 DOI: 10.1038/s42255-022-00689-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 10/14/2022] [Indexed: 11/30/2022]
Abstract
The branched-chain aminotransferase isozymes BCAT1 and BCAT2, segregated into distinct subcellular compartments and tissues, initiate the catabolism of branched-chain amino acids (BCAAs). However, whether and how BCAT isozymes cooperate with downstream enzymes to control BCAA homeostasis in an intact organism remains largely unknown. Here, we analyse system-wide metabolomic changes in BCAT1- and BCAT2-deficient mouse models. Loss of BCAT2 but not BCAT1 leads to accumulation of BCAAs and branched-chain α-keto acids (BCKAs), causing morbidity and mortality that can be ameliorated by dietary BCAA restriction. Through proximity labelling, isotope tracing and enzymatic assays, we provide evidence for the formation of a mitochondrial BCAA metabolon involving BCAT2 and branched-chain α-keto acid dehydrogenase. Disabling the metabolon contributes to BCAT2 deficiency-induced phenotypes, which can be reversed by BCAT1-mediated BCKA reamination. These findings establish a role for metabolon formation in BCAA metabolism in vivo and suggest a new strategy to modulate this pathway in diseases involving dysfunctional BCAA metabolism.
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Affiliation(s)
- McKenzie Patrick
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Pediatrics, Harold C. Simmons Comprehensive Cancer Center, and Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Zhimin Gu
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Pediatrics, Harold C. Simmons Comprehensive Cancer Center, and Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Gen Zhang
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Pediatrics, Harold C. Simmons Comprehensive Cancer Center, and Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - R Max Wynn
- Departments of Biochemistry and Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Pranita Kaphle
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Pediatrics, Harold C. Simmons Comprehensive Cancer Center, and Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Hui Cao
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Pediatrics, Harold C. Simmons Comprehensive Cancer Center, and Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Hieu Vu
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Feng Cai
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Xiaofei Gao
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Yuannyu Zhang
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Pediatrics, Harold C. Simmons Comprehensive Cancer Center, and Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Mingyi Chen
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Min Ni
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - David T Chuang
- Departments of Biochemistry and Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ralph J DeBerardinis
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jian Xu
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Department of Pediatrics, Harold C. Simmons Comprehensive Cancer Center, and Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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12
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Armenta DA, Laqtom NN, Alchemy G, Dong W, Morrow D, Poltorack CD, Nathanson DA, Abu-Remalieh M, Dixon SJ. Ferroptosis inhibition by lysosome-dependent catabolism of extracellular protein. Cell Chem Biol 2022; 29:1588-1600.e7. [PMID: 36306785 PMCID: PMC9762237 DOI: 10.1016/j.chembiol.2022.10.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 09/01/2022] [Accepted: 10/05/2022] [Indexed: 01/31/2023]
Abstract
Cancer cells need a steady supply of nutrients to evade cell death and proliferate. Depriving cancer cells of the amino acid cystine can trigger the non-apoptotic cell death process of ferroptosis. Here, we report that cancer cells can evade cystine deprivation-induced ferroptosis by uptake and catabolism of the cysteine-rich extracellular protein albumin. This protective mechanism is enhanced by mTORC1 inhibition and involves albumin degradation in the lysosome, predominantly by cathepsin B (CTSB). CTSB-dependent albumin breakdown followed by export of cystine from the lysosome via the transporter cystinosin fuels the synthesis of glutathione, which suppresses lethal lipid peroxidation. When cancer cells are grown under non-adherent conditions as spheroids, mTORC1 pathway activity is reduced, and albumin supplementation alone affords considerable protection against ferroptosis. These results identify the catabolism of extracellular protein within the lysosome as a mechanism that can inhibit ferroptosis in cancer cells.
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Affiliation(s)
- David A Armenta
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Nouf N Laqtom
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA; The Institute for Chemistry, Engineering, & Medicine for Human Health (ChEM-H), Stanford University, Stanford, CA 94305, USA
| | - Grace Alchemy
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Wentao Dong
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA; The Institute for Chemistry, Engineering, & Medicine for Human Health (ChEM-H), Stanford University, Stanford, CA 94305, USA
| | - Danielle Morrow
- Department of Molecular & Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | | | - David A Nathanson
- Department of Molecular & Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Monther Abu-Remalieh
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA; The Institute for Chemistry, Engineering, & Medicine for Human Health (ChEM-H), Stanford University, Stanford, CA 94305, USA.
| | - Scott J Dixon
- Department of Biology, Stanford University, Stanford, CA 94305, USA.
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13
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Brüggenthies JB, Fiore A, Russier M, Bitsina C, Brötzmann J, Kordes S, Menninger S, Wolf A, Conti E, Eickhoff JE, Murray PJ. A cell-based chemical-genetic screen for amino acid stress response inhibitors reveals torins reverse stress kinase GCN2 signaling. J Biol Chem 2022; 298:102629. [PMID: 36273589 PMCID: PMC9668732 DOI: 10.1016/j.jbc.2022.102629] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 10/07/2022] [Accepted: 10/10/2022] [Indexed: 11/06/2022] Open
Abstract
mTORC1 and GCN2 are serine/threonine kinases that control how cells adapt to amino acid availability. mTORC1 responds to amino acids to promote translation and cell growth while GCN2 senses limiting amino acids to hinder translation via eIF2α phosphorylation. GCN2 is an appealing target for cancer therapies because malignant cells can harness the GCN2 pathway to temper the rate of translation during rapid amino acid consumption. To isolate new GCN2 inhibitors, we created cell-based, amino acid limitation reporters via genetic manipulation of Ddit3 (encoding the transcription factor CHOP). CHOP is strongly induced by limiting amino acids and in this context, GCN2-dependent. Using leucine starvation as a model for essential amino acid sensing, we unexpectedly discovered ATP-competitive PI3 kinase-related kinase inhibitors, including ATR and mTOR inhibitors like torins, completely reversed GCN2 activation in a time-dependent way. Mechanistically, via inhibiting mTORC1-dependent translation, torins increased intracellular leucine, which was sufficient to reverse GCN2 activation and the downstream integrated stress response including stress-induced transcriptional factor ATF4 expression. Strikingly, we found that general translation inhibitors mirrored the effects of torins. Therefore, we propose that mTOR kinase inhibitors concurrently inhibit different branches of amino acid sensing by a dual mechanism involving direct inhibition of mTOR and indirect suppression of GCN2 that are connected by effects on the translation machinery. Collectively, our results highlight distinct ways of regulating GCN2 activity.
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Affiliation(s)
| | | | - Marion Russier
- Max Planck Institute for Biochemistry, Martinsried, Germany
| | | | | | | | | | | | - Elena Conti
- Max Planck Institute for Biochemistry, Martinsried, Germany
| | | | - Peter J. Murray
- Max Planck Institute for Biochemistry, Martinsried, Germany,For correspondence: Peter J. Murray
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14
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Toboz P, Amiri M, Tabatabaei N, Dufour CR, Kim SH, Fillebeen C, Ayemoba CE, Khoutorsky A, Nairz M, Shao L, Pajcini KV, Kim KW, Giguère V, Oliveira RL, Constante M, Santos MM, Morales CR, Pantopoulos K, Sonenberg N, Pinho S, Tahmasebi S. The amino acid sensor GCN2 controls red blood cell clearance and iron metabolism through regulation of liver macrophages. Proc Natl Acad Sci U S A 2022; 119:e2121251119. [PMID: 35994670 PMCID: PMC9436309 DOI: 10.1073/pnas.2121251119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 07/20/2022] [Indexed: 11/18/2022] Open
Abstract
GCN2 (general control nonderepressible 2) is a serine/threonine-protein kinase that controls messenger RNA translation in response to amino acid availability and ribosome stalling. Here, we show that GCN2 controls erythrocyte clearance and iron recycling during stress. Our data highlight the importance of liver macrophages as the primary cell type mediating these effects. During different stress conditions, such as hemolysis, amino acid deficiency or hypoxia, GCN2 knockout (GCN2-/-) mice displayed resistance to anemia compared with wild-type (GCN2+/+) mice. GCN2-/- liver macrophages exhibited defective erythrophagocytosis and lysosome maturation. Molecular analysis of GCN2-/- cells demonstrated that the ATF4-NRF2 pathway is a critical downstream mediator of GCN2 in regulating red blood cell clearance and iron recycling.
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Affiliation(s)
- Phoenix Toboz
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, 60612
| | - Mehdi Amiri
- Department of Biochemistry, McGill University, Montreal, QC, H3A 1A3, Canada
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC, H3A 1A3, Canada
| | - Negar Tabatabaei
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, 60612
| | - Catherine R. Dufour
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC, H3A 1A3, Canada
| | - Seung Hyeon Kim
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, 60612
| | - Carine Fillebeen
- Lady Davis Institute for Medical Research, Jewish General Hospital and Department of Medicine, McGill University, Montreal, QC, H3T 1E2, Canada
| | - Charles E. Ayemoba
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, 60612
| | - Arkady Khoutorsky
- Department of Anesthesia and Faculty of Dentistry, McGill University, Montreal, QC, H3A 0G1, Canada
| | - Manfred Nairz
- Department of Internal Medicine II, Medical University of Innsbruck, Innsbruck, 6020, Austria
| | - Lijian Shao
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, 60612
| | - Kostandin V. Pajcini
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, 60612
| | - Ki-Wook Kim
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, 60612
| | - Vincent Giguère
- Department of Biochemistry, McGill University, Montreal, QC, H3A 1A3, Canada
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC, H3A 1A3, Canada
| | - Regiana L. Oliveira
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Marco Constante
- Nutrition and Microbiome Laboratory, Centre de recherche du CHUM and Department of Medicine, Université de Montréal, Montréal, QC, H3X 0A9, Canada
| | - Manuela M. Santos
- Nutrition and Microbiome Laboratory, Centre de recherche du CHUM and Department of Medicine, Université de Montréal, Montréal, QC, H3X 0A9, Canada
| | - Carlos R. Morales
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Kostas Pantopoulos
- Lady Davis Institute for Medical Research, Jewish General Hospital and Department of Medicine, McGill University, Montreal, QC, H3T 1E2, Canada
| | - Nahum Sonenberg
- Department of Biochemistry, McGill University, Montreal, QC, H3A 1A3, Canada
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC, H3A 1A3, Canada
| | - Sandra Pinho
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, 60612
| | - Soroush Tahmasebi
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, 60612
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15
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Farooq Z, Kusuma F, Burke P, Dufour CR, Lee D, Tabatabaei N, Toboz P, Radovani E, Greenblatt J, Rehman J, Class J, Khoutorsky A, Fonseca BD, Richner JM, Mercier E, Bourque G, Giguère V, Subramaniam AR, Han J, Tahmasebi S. The amino acid sensor GCN2 suppresses Terminal Oligopyrimidine (TOP) mRNA translation via La-related Protein 1 (LARP1). J Biol Chem 2022; 298:102277. [PMID: 35863436 PMCID: PMC9396407 DOI: 10.1016/j.jbc.2022.102277] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 07/10/2022] [Accepted: 07/11/2022] [Indexed: 11/16/2022] Open
Abstract
La-related protein 1 (LARP1) has been identified as a key translational inhibitor of terminal oligopyrimidine (TOP) mRNAs downstream of the nutrient sensing protein kinase complex, mTORC1. LARP1 exerts this inhibitory effect on TOP mRNA translation by binding to the mRNA cap and the adjacent 5′TOP motif, resulting in the displacement of the cap-binding protein eIF4E from TOP mRNAs. However, the involvement of additional signaling pathway in regulating LARP1-mediated inhibition of TOP mRNA translation is largely unexplored. In the present study, we identify a second nutrient sensing kinase GCN2 that converges on LARP1 to control TOP mRNA translation. Using chromatin-immunoprecipitation followed by massive parallel sequencing (ChIP-seq) analysis of activating transcription factor 4 (ATF4), an effector of GCN2 in nutrient stress conditions, in WT and GCN2 KO mouse embryonic fibroblasts, we determined that LARP1 is a GCN2-dependent transcriptional target of ATF4. Moreover, we identified GCN1, a GCN2 activator, participates in a complex with LARP1 on stalled ribosomes, suggesting a role for GCN1 in LARP1-mediated translation inhibition in response to ribosome stalling. Therefore, our data suggest that the GCN2 pathway controls LARP1 activity via two mechanisms: ATF4-dependent transcriptional induction of LARP1 mRNA and GCN1-mediated recruitment of LARP1 to stalled ribosomes.
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Affiliation(s)
- Zeenat Farooq
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, USA
| | - Fedho Kusuma
- Soonchunhyang Institute of Medi-bio Science (SIMS), Soonchunhyang University, Cheonan-si, Chungcheongnam-do 31151, Korea
| | - Phillip Burke
- Basic Sciences Division and Computational Biology Section of the Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Catherine R Dufour
- Goodman Cancer Research Centre, McGill University, Montréal, QC, H3A 1A3, Canada
| | - Duckgue Lee
- Soonchunhyang Institute of Medi-bio Science (SIMS), Soonchunhyang University, Cheonan-si, Chungcheongnam-do 31151, Korea
| | - Negar Tabatabaei
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, USA
| | - Phoenix Toboz
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, USA
| | - Ernest Radovani
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Jack Greenblatt
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Jalees Rehman
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, USA
| | - Jacob Class
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, IL, USA
| | - Arkady Khoutorsky
- Department of Anesthesia and Faculty of Dentistry, McGill University, Montreal, QC H3A 0G1, Canada
| | | | - Justin M Richner
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, IL, USA
| | - Eloi Mercier
- Canadian Centre for Computational Genomics, and McGill University and Genome Québec Innovation Center, Montréal, QC H3A 0G1, Canada
| | - Guillaume Bourque
- Canadian Centre for Computational Genomics, and McGill University and Genome Québec Innovation Center, Montréal, QC H3A 0G1, Canada
| | - Vincent Giguère
- Goodman Cancer Research Centre, McGill University, Montréal, QC, H3A 1A3, Canada
| | - Arvind R Subramaniam
- Basic Sciences Division and Computational Biology Section of the Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Jaeseok Han
- Soonchunhyang Institute of Medi-bio Science (SIMS), Soonchunhyang University, Cheonan-si, Chungcheongnam-do 31151, Korea.
| | - Soroush Tahmasebi
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, USA.
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16
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The role of eIF2 phosphorylation in cell and organismal physiology: new roles for well-known actors. Biochem J 2022; 479:1059-1082. [PMID: 35604373 DOI: 10.1042/bcj20220068] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 04/21/2022] [Accepted: 04/25/2022] [Indexed: 02/06/2023]
Abstract
Control of protein synthesis (mRNA translation) plays key roles in shaping the proteome and in many physiological, including homeostatic, responses. One long-known translational control mechanism involves phosphorylation of initiation factor, eIF2, which is catalysed by any one of four protein kinases, which are generally activated in response to stresses. They form a key arm of the integrated stress response (ISR). Phosphorylated eIF2 inhibits eIF2B (the protein that promotes exchange of eIF2-bound GDP for GTP) and thus impairs general protein synthesis. However, this mechanism actually promotes translation of certain mRNAs by virtue of specific features they possess. Recent work has uncovered many previously unknown features of this regulatory system. Several studies have yielded crucial insights into the structure and control of eIF2, including that eIF2B is regulated by several metabolites. Recent studies also reveal that control of eIF2 and the ISR helps determine organismal lifespan and surprising roles in sensing mitochondrial stresses and in controlling the mammalian target of rapamycin (mTOR). The latter effect involves an unexpected role for one of the eIF2 kinases, HRI. Phosphoproteomic analysis identified new substrates for another eIF2 kinase, Gcn2, which senses the availability of amino acids. Several genetic disorders arise from mutations in genes for eIF2α kinases or eIF2B (i.e. vanishing white matter disease, VWM and microcephaly, epileptic seizures, microcephaly, hypogenitalism, diabetes and obesity, MEHMO). Furthermore, the eIF2-mediated ISR plays roles in cognitive decline associated with Alzheimer's disease. New findings suggest potential therapeutic value in interfering with the ISR in certain settings, including VWM, for example by using compounds that promote eIF2B activity.
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