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Alao JP, Legon L, Dabrowska A, Tricolici AM, Kumar J, Rallis C. Interplays of AMPK and TOR in Autophagy Regulation in Yeast. Cells 2023; 12:cells12040519. [PMID: 36831186 PMCID: PMC9953913 DOI: 10.3390/cells12040519] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 02/01/2023] [Accepted: 02/03/2023] [Indexed: 02/08/2023] Open
Abstract
Cells survey their environment and need to balance growth and anabolism with stress programmes and catabolism towards maximum cellular bioenergetics economy and survival. Nutrient-responsive pathways, such as the mechanistic target of rapamycin (mTOR) interact and cross-talk, continuously, with stress-responsive hubs such as the AMP-activated protein kinase (AMPK) to regulate fundamental cellular processes such as transcription, protein translation, lipid and carbohydrate homeostasis. Especially in nutrient stresses or deprivations, cells tune their metabolism accordingly and, crucially, recycle materials through autophagy mechanisms. It has now become apparent that autophagy is pivotal in lifespan, health and cell survival as it is a gatekeeper of clearing damaged macromolecules and organelles and serving as quality assurance mechanism within cells. Autophagy is hard-wired with energy and nutrient levels as well as with damage-response, and yeasts have been instrumental in elucidating such connectivities. In this review, we briefly outline cross-talks and feedback loops that link growth and stress, mainly, in the fission yeast Schizosaccharomyces pombe, a favourite model in cell and molecular biology.
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Li YD, Si MR, Jiang SG, Yang QB, Jiang S, Yang LS, Huang JH, Chen X, Zhou FL, Li E. Transcriptome and molecular regulatory mechanisms analysis of gills in the black tiger shrimp Penaeus monodon under chronic low-salinity stress. Front Physiol 2023; 14:1118341. [PMID: 36935747 PMCID: PMC10014708 DOI: 10.3389/fphys.2023.1118341] [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: 12/07/2022] [Accepted: 02/14/2023] [Indexed: 03/05/2023] Open
Abstract
Background: Salinity is one of the main influencing factors in the culture environment and is extremely important for the survival, growth, development and reproduction of aquatic animals. Methods: In this study, a comparative transcriptome analysis (maintained for 45 days in three different salinities, 30 psu (HC group), 18 psu (MC group) and 3 psu (LC group)) was performed by high-throughput sequencing of economically cultured Penaeus monodon. P. monodon gill tissues from each treatment were collected for RNA-seq analysis to identify potential genes and pathways in response to low salinity stress. Results: A total of 64,475 unigenes were annotated in this study. There were 1,140 upregulated genes and 1,531 downregulated genes observed in the LC vs. HC group and 1,000 upregulated genes and 1,062 downregulated genes observed in the MC vs. HC group. In the LC vs. HC group, 583 DEGs significantly mapped to 37 signaling pathways, such as the NOD-like receptor signaling pathway, Toll-like receptor signaling pathway, and PI3K-Akt signaling pathway; in the MC vs. HC group, 444 DEGs significantly mapped to 28 signaling pathways, such as the MAPK signaling pathway, Hippo signaling pathway and calcium signaling pathway. These pathways were significantly associated mainly with signal transduction, immunity and metabolism. Conclusions: These results suggest that low salinity stress may affect regulatory mechanisms such as metabolism, immunity, and signal transduction in addition to osmolarity in P. monodon. The greater the difference in salinity, the more significant the difference in genes. This study provides some guidance for understanding the low-salt domestication culture of P. monodon.
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Affiliation(s)
- Yun-Dong Li
- Key Laboratory of Tropical Hydrobiology and Biotechnology of Hainan Province, Hainan Aquaculture Breeding Engineering Research Center, College of Marine Sciences, Hainan University, Haikou, China
- Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China
- Key Laboratory of Efficient Utilization and Processing of Marine Fishery Resources of Hainan Province, Sanya Tropical Fisheries Research Institute, Sanya, China
- Hainan Yazhou Bay Seed Laboratory, Sanya, China
| | - Meng-Ru Si
- Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China
| | - Shi-Gui Jiang
- Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China
| | - Qi-Bin Yang
- Key Laboratory of Efficient Utilization and Processing of Marine Fishery Resources of Hainan Province, Sanya Tropical Fisheries Research Institute, Sanya, China
| | - Song Jiang
- Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China
| | - Li-Shi Yang
- Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China
| | - Jian-Hua Huang
- Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China
| | - Xu Chen
- Key Laboratory of Efficient Utilization and Processing of Marine Fishery Resources of Hainan Province, Sanya Tropical Fisheries Research Institute, Sanya, China
| | - Fa-Lin Zhou
- Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China
- Key Laboratory of Efficient Utilization and Processing of Marine Fishery Resources of Hainan Province, Sanya Tropical Fisheries Research Institute, Sanya, China
- Hainan Yazhou Bay Seed Laboratory, Sanya, China
- *Correspondence: Fa-Lin Zhou, ; ErChao Li,
| | - ErChao Li
- Key Laboratory of Tropical Hydrobiology and Biotechnology of Hainan Province, Hainan Aquaculture Breeding Engineering Research Center, College of Marine Sciences, Hainan University, Haikou, China
- Hainan Yazhou Bay Seed Laboratory, Sanya, China
- *Correspondence: Fa-Lin Zhou, ; ErChao Li,
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Sun J, Chen M, Fu Z, Yu G, Ma Z, Xing Y. Transcriptome analysis of the mantle tissue of Pinctada fucata with red and black shells under salinity stress. Gene 2022; 823:146367. [PMID: 35202732 DOI: 10.1016/j.gene.2022.146367] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 02/14/2022] [Accepted: 02/18/2022] [Indexed: 11/16/2022]
Abstract
To understand the molecular responses of Pinctada fucata with different shell colors to salinity stress, we used transcriptome sequencing on the mantle of P. fucata with a black shell and red shell color under the salinity of 20, 35, and 50. The 414 and 2371 differentially expressed genes (DEGs) in P. fucata with a black shell under low- or high-salt stress, while there were 588 and 3009 DEGs in P. fucata with a red shell. KEGG pathway enrichment analysis showed that, under low salt stress, the DEGs of P. fucata with the black shell were significantly enriched in pathways MAPK signaling pathway, protein processing in endoplasmic reticulum, vitamin B6 metabolism, longevity regulating pathway-multiple species, estrogen signaling pathway and antigen processing and presentation, the DEGs of P. fucata with a red shell were significantly enriched in pathways vitamin B6 metabolism. Under high salt stress, the DEGs of P. fucata with a red shell were significantly enriched in pathways arginine biosynthesis. 11 DEGs were randomly selected for quantitative real-time PCR, and the results were consistent with the RNA-seq. In addition, under high salt stress, DEGs were enriched into some pathways related to osmotic regulation and immune defense of P. fucata with black shell and red shell, such as Glycolysis / Gluconeogenesis, AMPK signaling pathway, Beta-Alanine metabolism, Glycine, serine and threonine metabolism, MAPK signaling pathway and Phagosome. The study showed that high salt stress had a greater influence on P. fucata with two shell colors, and P. fucata with a black shell made a positive immune defense response. Our results will improve to further understand the salt tolerance mechanism of P. fucata with different shell colors.
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Affiliation(s)
- Jing Sun
- Tropical Aquaculture Research and Development Center, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Sanya 572018, PR China; Sanya Fisheries Research Institute, Sanya 572018, PR China; Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture, Guangzhou 510300, PR China; College of Fisheries, Tianjin Agricultural University, Tianjin 300384, PR China
| | - Mingqiang Chen
- Tropical Aquaculture Research and Development Center, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Sanya 572018, PR China; Sanya Fisheries Research Institute, Sanya 572018, PR China; Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture, Guangzhou 510300, PR China
| | - Zhengyi Fu
- Tropical Aquaculture Research and Development Center, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Sanya 572018, PR China; Sanya Fisheries Research Institute, Sanya 572018, PR China; Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture, Guangzhou 510300, PR China
| | - Gang Yu
- Tropical Aquaculture Research and Development Center, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Sanya 572018, PR China; Sanya Fisheries Research Institute, Sanya 572018, PR China; Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture, Guangzhou 510300, PR China
| | - Zhenhua Ma
- Tropical Aquaculture Research and Development Center, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Sanya 572018, PR China; Sanya Fisheries Research Institute, Sanya 572018, PR China; Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture, Guangzhou 510300, PR China; College of Fisheries, Tianjin Agricultural University, Tianjin 300384, PR China.
| | - Yingchun Xing
- Resource and Environmental Research Center, Chinese Academy of Fishery Sciences, Beijing 100141, PR China.
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4
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Magliozzi JO, Moseley JB. Pak1 kinase controls cell shape through ribonucleoprotein granules. eLife 2021; 10:67648. [PMID: 34282727 PMCID: PMC8318594 DOI: 10.7554/elife.67648] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 07/19/2021] [Indexed: 11/29/2022] Open
Abstract
Fission yeast cells maintain a rod shape due to conserved signaling pathways that organize the cytoskeleton for polarized growth. We discovered a mechanism linking the conserved protein kinase Pak1 with cell shape through the RNA-binding protein Sts5. Pak1 (also called Shk1 and Orb2) prevents Sts5 association with P bodies by directly phosphorylating its intrinsically disordered region (IDR). Pak1 and the cell polarity kinase Orb6 both phosphorylate the Sts5 IDR but at distinct residues. Mutations preventing phosphorylation in the Sts5 IDR cause increased P body formation and defects in cell shape and polarity. Unexpectedly, when cells encounter glucose starvation, PKA signaling triggers Pak1 recruitment to stress granules with Sts5. Through retargeting experiments, we reveal that Pak1 localizes to stress granules to promote rapid dissolution of Sts5 upon glucose addition. Our work reveals a new role for Pak1 in regulating cell shape through ribonucleoprotein granules during normal and stressed growth conditions.
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Affiliation(s)
- Joseph O Magliozzi
- Department of Biochemistry and Cell Biology, The Geisel School of Medicine at Dartmouth, Hanover, United States
| | - James B Moseley
- Department of Biochemistry and Cell Biology, The Geisel School of Medicine at Dartmouth, Hanover, United States
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Saldaña C, Villava C, Ramírez-Villarreal J, Morales-Tlalpan V, Campos-Guillen J, Chávez-Servín J, García-Gasca T. Rapid and reversible cell volume changes in response to osmotic stress in yeast. Braz J Microbiol 2021; 52:895-903. [PMID: 33476034 DOI: 10.1007/s42770-021-00427-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Accepted: 01/06/2021] [Indexed: 01/26/2023] Open
Abstract
Saccharomyces cerevisiae has evolved diverse mechanisms to osmotic changes: the cell wall, ion and water transport systems, and signaling cascades. At the present time, little is known about the mechanisms involved in short-term responses of osmotic stress in yeast or their physiological state during this process. We conducted studies of flow cytometry, wet weight measurements, and electron microscopy to evaluate the modifications in cell volume and the cell wall induced by osmotic stress. In response to osmotic challenges, we show very fast and drastic changes in cell volume (up to 60%), which were completed in less than eight seconds. This dramatic change was completely reversible approximately 16 s after returning to an isosmotic solution. Cell volume changes were also accompanied by adaptations in yeast metabolism observed as a reduction by 50% in the respiratory rate, measured as oxygen consumption. This effect was also fully reversible upon returning to an isosmotic solution. It is noteworthy that we observed a significant recovery in oxygen consumption during the first 10 min of the osmotic shock. The rapid adjustment of the cellular volume may represent an evolutionary advantage, allowing greater flexibility for survival.
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Affiliation(s)
- Carlos Saldaña
- Laboratorio de Biofísica de Membranas, Unidad de Microbiología Básica y Aplicada, Facultad de Ciencias Naturales, Querétaro, Mexico. .,Facultad de Ciencias Naturales-Campus Aeropuerto, Universidad Autónoma de Querétaro, Querétaro, Mexico.
| | - Casandra Villava
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México. Cd, México, Mexico
| | - Jimena Ramírez-Villarreal
- Laboratorio de Biofísica de Membranas, Unidad de Microbiología Básica y Aplicada, Facultad de Ciencias Naturales, Querétaro, Mexico.,Facultad de Ciencias Naturales-Campus Aeropuerto, Universidad Autónoma de Querétaro, Querétaro, Mexico
| | - Verónica Morales-Tlalpan
- Laboratorio de Biofísica de Membranas, Unidad de Microbiología Básica y Aplicada, Facultad de Ciencias Naturales, Querétaro, Mexico.,Facultad de Ciencias Naturales-Campus Aeropuerto, Universidad Autónoma de Querétaro, Querétaro, Mexico
| | | | - Jorge Chávez-Servín
- Facultad de Ciencias Naturales. Campus Juriquilla, Universidad Autónoma de Querétaro, Querétaro, Mexico
| | - Teresa García-Gasca
- Facultad de Ciencias Naturales. Campus Juriquilla, Universidad Autónoma de Querétaro, Querétaro, Mexico
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Wang Y, Xian H, Qi J, Wei F, Cheng X, Li S, Wang Q, Liu Z, Yu Y, Zhou J, Sun X, Liu H, Wei Y. Inhibition of glycolysis ameliorate arthritis in adjuvant arthritis rats by inhibiting synoviocyte activation through AMPK/NF-кB pathway. Inflamm Res 2020; 69:569-578. [PMID: 32303781 DOI: 10.1007/s00011-020-01332-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/19/2020] [Accepted: 02/25/2020] [Indexed: 01/01/2023] Open
Abstract
OBJECTIVE This study aimed to evaluate glycolysis inhibitor which can effectively ameliorate arthritis by inhibiting synoviocyte activation through AMPK/NF-кB pathway in AA rats. METHODS Adjuvant arthritis (AA) rats were treated with 2-deoxyglucose (2-DG), glycolysis inhibitor. HE staining and radiological Examination were used for histopathology analysis and evaluation of joint destruction. HKII expression was quantified by immunostaining. Proliferation and migration of synoviocytes were assessed by synovicyte scores of joint, CCK8 and transwell assay. Inflammatory factors and levels of AMPK, p65 and IκBα were quantified by ELISA analysis and WB. RESULTS We observed that HKII expression was positively correlated with synovial hyperplasia, inflammatory cell infiltration, and cartilage destruction, and glycolysis inhibitor reduces the joint swelling degree, alleviates bone destruction, inhibits the proliferation and migration of synoviocyte, and reduces secretory function of synoviocytes in AA rats. In addition, we investigated that glycolysis inhibitor may inhibit activation of the NF-κB signaling pathway by activating the AMPK pathway. CONCLUSION This study suggests the involvement of energy metabolism in the pathological inflammation process in RA joints. Glycolysis inhibitors might, therefore, provide an opportunity for therapeutic intervention.
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Affiliation(s)
- Ying Wang
- School of Pharmacy, Bengbu Medical College, No. 2600 Donghai Avenue, Bengbu, 233000, Anhui, China.,Anhui BBCA Pharmaceuticals Co., Ltd., No. 6288, Donghai Avenue, Bengbu, 233000, Anhui, China
| | - Hao Xian
- Anhui BBCA Pharmaceuticals Co., Ltd., No. 6288, Donghai Avenue, Bengbu, 233000, Anhui, China
| | - Jiajia Qi
- Anhui BBCA Pharmaceuticals Co., Ltd., No. 6288, Donghai Avenue, Bengbu, 233000, Anhui, China
| | - Fang Wei
- School of Pharmacy, Bengbu Medical College, No. 2600 Donghai Avenue, Bengbu, 233000, Anhui, China.,Anhui BBCA Pharmaceuticals Co., Ltd., No. 6288, Donghai Avenue, Bengbu, 233000, Anhui, China
| | - Xiu Cheng
- Anhui BBCA Pharmaceuticals Co., Ltd., No. 6288, Donghai Avenue, Bengbu, 233000, Anhui, China
| | - Sha Li
- Anhui BBCA Pharmaceuticals Co., Ltd., No. 6288, Donghai Avenue, Bengbu, 233000, Anhui, China
| | - Qing Wang
- School of Pharmacy, Bengbu Medical College, No. 2600 Donghai Avenue, Bengbu, 233000, Anhui, China.,Anhui BBCA Pharmaceuticals Co., Ltd., No. 6288, Donghai Avenue, Bengbu, 233000, Anhui, China
| | - Zhaoyang Liu
- Anhui BBCA Pharmaceuticals Co., Ltd., No. 6288, Donghai Avenue, Bengbu, 233000, Anhui, China
| | - Yun Yu
- Anhui BBCA Pharmaceuticals Co., Ltd., No. 6288, Donghai Avenue, Bengbu, 233000, Anhui, China
| | - Jing Zhou
- Anhui BBCA Pharmaceuticals Co., Ltd., No. 6288, Donghai Avenue, Bengbu, 233000, Anhui, China
| | - Xiaojin Sun
- School of Pharmacy, Bengbu Medical College, No. 2600 Donghai Avenue, Bengbu, 233000, Anhui, China.,Anhui BBCA Pharmaceuticals Co., Ltd., No. 6288, Donghai Avenue, Bengbu, 233000, Anhui, China
| | - Hao Liu
- School of Pharmacy, Bengbu Medical College, No. 2600 Donghai Avenue, Bengbu, 233000, Anhui, China.,Anhui BBCA Pharmaceuticals Co., Ltd., No. 6288, Donghai Avenue, Bengbu, 233000, Anhui, China
| | - Yingmei Wei
- School of Pharmacy, Bengbu Medical College, No. 2600 Donghai Avenue, Bengbu, 233000, Anhui, China. .,Anhui BBCA Pharmaceuticals Co., Ltd., No. 6288, Donghai Avenue, Bengbu, 233000, Anhui, China.
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7
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Sml1 Inhibits the DNA Repair Activity of Rev1 in Saccharomyces cerevisiae during Oxidative Stress. Appl Environ Microbiol 2020; 86:AEM.02838-19. [PMID: 32005731 DOI: 10.1128/aem.02838-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 01/13/2020] [Indexed: 12/25/2022] Open
Abstract
In Saccharomyces cerevisiae, Y family DNA polymerase Rev1 is involved in the repair of DNA damage by translesion DNA synthesis (TLS). In the current study, to elucidate the role of Rev1 in oxidative stress-induced DNA damage in S. cerevisiae, REV1 was deleted and overexpressed; transcriptome analysis of these mutants along with the wild-type strain was performed to screen potential genes that could be associated with REV1 during response to DNA damage. When the yeast cells were treated with 2 mM H2O2, the deletion of REV1 resulted in a 1.5- and 2.8-fold decrease in the survival rate and mutation frequency, respectively, whereas overexpression of REV1 increased the survival rate and mutation frequency by 1.1- and 2.9-fold, respectively, compared to the survival rate and mutation frequency of the wild-type strain. Transcriptome and phenotypic analyses identified that Sml1 aggravated oxidative stress in the yeast cells by inhibiting the activity of Rev1. This inhibition was due to the physical interaction between the BRCA1 C terminus (BRCT) domain of Rev1 and amino acid residues 36 to 70 of Sml1; the cell survival rate and mutation frequency increased by 1.8- and 3.1-fold, respectively, when this interaction was blocked. We also found that Sml1 inhibited Rev1 phosphorylation under oxidative stress and that deletion of SML1 increased the phosphorylation of Rev1 by 46%, whereas overexpression of SML1 reduced phosphorylation of Rev1. Overall, these findings demonstrate that Sml1 could be a novel regulator that mediates Rev1 dephosphorylation to inhibit its activity during oxidative stress.IMPORTANCE Rev1 was critical for cell growth in S. cerevisiae, and the deletion of REV1 caused a severe growth defect in cells exposed to oxidative stress (2 mM H2O2). Furthermore, we found that Sml1 physically interacted with Rev1 and inhibited Rev1 phosphorylation, thereby inhibiting Rev1 DNA antioxidant activity. These findings indicate that Sml1 could be a novel regulator for Rev1 in response to DNA damage by oxidative stress.
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Knapp BD, Odermatt P, Rojas ER, Cheng W, He X, Huang KC, Chang F. Decoupling of Rates of Protein Synthesis from Cell Expansion Leads to Supergrowth. Cell Syst 2019; 9:434-445.e6. [PMID: 31706948 PMCID: PMC6911364 DOI: 10.1016/j.cels.2019.10.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 07/02/2019] [Accepted: 09/30/2019] [Indexed: 01/02/2023]
Abstract
Cell growth is a complex process in which cells synthesize cellular components while they increase in size. It is generally assumed that the rate of biosynthesis must somehow be coordinated with the rate of growth in order to maintain intracellular concentrations. However, little is known about potential feedback mechanisms that could achieve proteome homeostasis or the consequences when this homeostasis is perturbed. Here, we identify conditions in which fission yeast cells are prevented from volume expansion but nevertheless continue to synthesize biomass, leading to general accumulation of proteins and increased cytoplasmic density. Upon removal of these perturbations, this biomass accumulation drove cells to undergo a multi-generational period of "supergrowth" wherein rapid volume growth outpaced biosynthesis, returning proteome concentrations back to normal within hours. These findings demonstrate a mechanism for global proteome homeostasis based on modulation of volume growth and dilution.
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Affiliation(s)
- Benjamin D Knapp
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143, USA; Biophysics Program, Stanford University, Stanford, CA 94305, USA
| | - Pascal Odermatt
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Enrique R Rojas
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Wenpeng Cheng
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Xiangwei He
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Kerwyn Casey Huang
- Biophysics Program, Stanford University, Stanford, CA 94305, USA; Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA; Chan Zuckerberg Biohub, San Francisco, CA 941586, USA.
| | - Fred Chang
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143, USA.
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Hyperosmotic Stress Initiates AMPK-Independent Autophagy and AMPK- and Autophagy-Independent Depletion of Thioredoxin 1 and Glyoxalase 2 in HT22 Nerve Cells. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:2715810. [PMID: 31049129 PMCID: PMC6458930 DOI: 10.1155/2019/2715810] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 12/14/2018] [Accepted: 12/24/2018] [Indexed: 02/07/2023]
Abstract
Background Hyperosmotic stress is an important pathophysiologic condition in diabetes, severe trauma, dehydration, infection, and ischemia. Furthermore, brain neuronal cells face hyperosmotic stress in ageing and Alzheimer's disease. Despite the enormous importance of knowing the homeostatic mechanisms underlying the responses of nerve cells to hyperosmotic stress, this topic has been underrepresented in the literature. Recent evidence points to autophagy induction as a hallmark of hyperosmotic stress, which has been proposed to be controlled by mTOR inhibition as a consequence of AMPK activation. We previously showed that methylglyoxal induced a decrease in the antioxidant proteins thioredoxin 1 (Trx1) and glyoxalase 2 (Glo2), which was mediated by AMPK-dependent autophagy. Thus, we hypothesized that hyperosmotic stress would have the same effect. Methods HT22 hippocampal nerve cells were treated with NaCl (37, 75, or 150 mM), and the activation of the AMPK/mTOR pathway was investigated, as well as the levels of Trx1 and Glo2. To determine if autophagy was involved, the inhibitors bafilomycin (Baf) and chloroquine (CQ), as well as ATG5 siRNA, were used. To test for AMPK involvement, AMPK-deficient mouse embryonic fibroblasts (MEFs) were used. Results Hyperosmotic stress induced a clear increase in autophagy, which was demonstrated by a decrease in p62 and an increase in LC3 lipidation. AMPK phosphorylation, linked to a decrease in mTOR and S6 ribosomal protein phosphorylation, was also observed. Deletion of AMPK in MEFs did not prevent autophagy induction by hyperosmotic stress, as detected by decreased p62 and increased LC3 II, or mTOR inhibition, inferred by decreased phosphorylation of P70 S6 kinase and S6 ribosomal protein. These data indicating that AMPK was not involved in autophagy activation by hyperosmotic stress were supported by a decrease in pS555-ULK1, an AMPK phosphorylation site. Trx1 and Glo2 levels were decreased at 6 and 18 h after treatment with 150 mM NaCl. However, this decrease in Trx1 and Glo2 in HT22 cells was not prevented by autophagy inhibition by Baf, CQ, or ATG5 siRNA. AMPK-deficient MEFs under hyperosmotic stress presented the same Trx1 and Glo2 decrease as wild-type cells. Conclusion Hyperosmotic stress induced AMPK activation, but this was not responsible for its effects on mTOR activity or autophagy induction. Moreover, the decrease in Trx1 and Glo2 induced by hyperosmotic stress was independent of both autophagy and AMPK activation.
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