651
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Mazor KM, Dong L, Mao Y, Swanda RV, Qian SB, Stipanuk MH. Effects of single amino acid deficiency on mRNA translation are markedly different for methionine versus leucine. Sci Rep 2018; 8:8076. [PMID: 29795412 PMCID: PMC5967319 DOI: 10.1038/s41598-018-26254-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 05/04/2018] [Indexed: 11/09/2022] Open
Abstract
Although amino acids are known regulators of translation, the unique contributions of specific amino acids are not well understood. We compared effects of culturing HEK293T cells in medium lacking either leucine, methionine, histidine, or arginine on eIF2 and 4EBP1 phosphorylation and measures of mRNA translation. Methionine starvation caused the most drastic decrease in translation as assessed by polysome formation, ribosome profiling, and a measure of protein synthesis (puromycin-labeled polypeptides) but had no significant effect on eIF2 phosphorylation, 4EBP1 hyperphosphorylation or 4EBP1 binding to eIF4E. Leucine starvation suppressed polysome formation and was the only tested condition that caused a significant decrease in 4EBP1 phosphorylation or increase in 4EBP1 binding to eIF4E, but effects of leucine starvation were not replicated by overexpressing nonphosphorylatable 4EBP1. This suggests the binding of 4EBP1 to eIF4E may not by itself explain the suppression of mRNA translation under conditions of leucine starvation. Ribosome profiling suggested that leucine deprivation may primarily inhibit ribosome loading, whereas methionine deprivation may primarily impair start site recognition. These data underscore our lack of a full understanding of how mRNA translation is regulated and point to a unique regulatory role of methionine status on translation initiation that is not dependent upon eIF2 phosphorylation.
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Affiliation(s)
- Kevin M Mazor
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, 14853, USA
| | - Leiming Dong
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, 14853, USA
| | - Yuanhui Mao
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, 14853, USA
| | - Robert V Swanda
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, 14853, USA
| | - Shu-Bing Qian
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, 14853, USA
| | - Martha H Stipanuk
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, 14853, USA.
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652
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Guo L, Liang Z, Zheng C, Liu B, Yin Q, Cao Y, Yao J. Leucine Affects α-Amylase Synthesis through PI3K/Akt-mTOR Signaling Pathways in Pancreatic Acinar Cells of Dairy Calves. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:5149-5156. [PMID: 29733580 DOI: 10.1021/acs.jafc.8b01111] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Dietary nutrient utilization, particularly starch, is potentially limited by digestion in dairy cow small intestine because of shortage of α-amylase. Leucine acts as an effective signal molecular in the mTOR signaling pathway, which regulates a series of biological processes, especially protein synthesis. It has been reported that leucine could affect α-amylase synthesis and secretion in ruminant pancreas, but mechanisms have not been elaborated. In this study, pancreatic acinar (PA) cells were used as a model to determine the cellular signal of leucine influence on α-amylase synthesis. PA cells were isolated from newborn Holstein dairy bull calves and cultured in Dulbecco's modifed Eagle's medium/nutrient mixture F12 liquid media containing four leucine treatments (0, 0.23, 0.45, and 0.90 mM, respectively), following α-amylase activity, zymogen granule, and signal pathway factor expression detection. Rapamycin, a specific inhibitor of mTOR, was also applied to PA cells. Results showed that leucine increased ( p < 0.05) synthesis of α-amylase as well as phosphorylation of PI3K, Akt, mTOR, and S6K1 while reduced ( p < 0.05) GCN2 expression. Inhibition of mTOR signaling downregulated the α-amylase synthesis. In addition, the extracellular leucine dosage significantly influenced intracellular metabolism of isoleucine ( p < 0.05). Overall, leucine regulates α-amylase synthesis through promoting the PI3K/Akt-mTOR pathway and reducing the GCN2 pathway in PA cells of dairy calves. These pathways form the signaling network that controls the protein synthesis and metabolism. It would be of great interest in future studies to explore the function of leucine in ruminant nutrition.
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Affiliation(s)
- Long Guo
- College of Animal Science and Technology , Northwest A&F University , Yangling , Shaanxi 712100 , People's Republic of China
| | - Ziqi Liang
- College of Animal Science and Technology , Northwest A&F University , Yangling , Shaanxi 712100 , People's Republic of China
| | - Chen Zheng
- College of Animal Science and Technology , Northwest A&F University , Yangling , Shaanxi 712100 , People's Republic of China
| | - Baolong Liu
- College of Animal Science and Technology , Northwest A&F University , Yangling , Shaanxi 712100 , People's Republic of China
| | - Qingyan Yin
- College of Animal Science and Technology , Northwest A&F University , Yangling , Shaanxi 712100 , People's Republic of China
| | - Yangchun Cao
- College of Animal Science and Technology , Northwest A&F University , Yangling , Shaanxi 712100 , People's Republic of China
| | - Junhu Yao
- College of Animal Science and Technology , Northwest A&F University , Yangling , Shaanxi 712100 , People's Republic of China
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653
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RagD regulates amino acid mediated-casein synthesis and cell proliferation via mTOR signalling in cow mammary epithelial cells. J DAIRY RES 2018; 85:204-211. [DOI: 10.1017/s0022029918000146] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
This research paper addresses the hypothesis that RagD is a key signalling factor that regulates amino acid (AA) mediated-casein synthesis and cell proliferation in cow mammary epithelial cells (CMECs). The expression of RagD was analysed at different times during pregnancy and lactation in bovine mammary tissue from dairy cows. We showed that expression of RagD at lactation period was higher (P < 0·05) than that at pregnancy period. When CMECs were treated with methionine (Met) or lysine (Lys), expression of RagD, β-casein (CSN2), mTOR and p-mTOR, and cell proliferation were increased. Further, when CMECs were treated to overexpress RagD, expression of CSN2, mTOR and p-mTOR, and cell proliferation were up-regulated. Furthermore, the increase in expression of CSN2, mTOR and p-mTOR, and cell proliferation in response to Met or Lys supply was inhibited by inhibiting RagD, and those effects were reversed in the overexpression model. When CMECs were treated with RagD overexpression together with mTOR inhibition or conversely with RagD inhibition together with mTOR overexpression, results showed that the increase in expression of CSN2 and cell proliferation in response to RagD overexpression was prevented by inhibiting mTOR, and those effects were reversed by overexpressing mTOR. The interaction of RagD with subunit proteins of mTORC1 was analysed, and the result showed that RagD interacted with Raptor. CMECs were treated with Raptor inhibition, and the result showed that the increase in expression of mTOR and p-mTOR in response to RagD overexpression was inhibited by inhibiting Raptor.In conclusion, our study showed that RagD is an important activation factor of mTORC1 in CMECs, activating AA-mediated casein synthesis and cell proliferation, potentially acting via Raptor.
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654
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Coordination of the leucine-sensing Rag GTPase cycle by leucyl-tRNA synthetase in the mTORC1 signaling pathway. Proc Natl Acad Sci U S A 2018; 115:E5279-E5288. [PMID: 29784813 DOI: 10.1073/pnas.1801287115] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
A protein synthesis enzyme, leucyl-tRNA synthetase (LRS), serves as a leucine sensor for the mechanistic target of rapamycin complex 1 (mTORC1), which is a central effector for protein synthesis, metabolism, autophagy, and cell growth. However, its significance in mTORC1 signaling and cancer growth and its functional relationship with other suggested leucine signal mediators are not well-understood. Here we show the kinetics of the Rag GTPase cycle during leucine signaling and that LRS serves as an initiating "ON" switch via GTP hydrolysis of RagD that drives the entire Rag GTPase cycle, whereas Sestrin2 functions as an "OFF" switch by controlling GTP hydrolysis of RagB in the Rag GTPase-mTORC1 axis. The LRS-RagD axis showed a positive correlation with mTORC1 activity in cancer tissues and cells. The GTP-GDP cycle of the RagD-RagB pair, rather than the RagC-RagA pair, is critical for leucine-induced mTORC1 activation. The active RagD-RagB pair can overcome the absence of the RagC-RagA pair, but the opposite is not the case. This work suggests that the GTPase cycle of RagD-RagB coordinated by LRS and Sestrin2 is critical for controlling mTORC1 activation, and thus will extend the current understanding of the amino acid-sensing mechanism.
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655
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656
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Abstract
Musculoskeletal injuries account for more than 70% of time away from sports. One of the reasons for the high number of injuries and long return to play is that we have only a very basic understanding of how our training alters tendon and ligament (sinew) structure and function. Sinews are highly dense tissues that are difficult to characterize both in vivo and in vitro. Recently, engineered ligaments have been developed in vitro using cells from human anterior cruciate ligaments or hamstring tendons. These three-dimensional tissues can be grown in a laboratory, treated with agents thought to affect sinew physiology, and then mechanically tested to determine their function. Using these tissues, we have learned that sinews, like bone, quickly become refractory to an exercise stimulus, suggesting that short (<10 min) periods of activity with relatively long (6 h) periods of rest are best to train these tissues. The engineered sinews have also shown how estrogen decreases sinew function and that a factor released following intense exercise increases sinew collagen synthesis and function. Last, engineered sinews are being used to screen possible nutritional interventions that may benefit tendon or ligament function. Using the data derived from these tissue-engineered sinews, new nutritional and training regimes are being designed and tested with the goal of minimizing injury and accelerating return to play.
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Affiliation(s)
- Keith Baar
- Department of Neurobiology, Physiology and Behavior, University of California Davis, One Shields Ave, Davis, CA, 95616, USA.
- Department of Physiology and Membrane Biology, University of California Davis, One Shields Ave, Davis, CA, 95616, USA.
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657
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Xia Z, Cholewa JM, Zhao Y, Yang Y, Shang H, Jiang H, Su Q, Zanchi NE. A potential strategy for counteracting age-related sarcopenia: preliminary evidence of combined exercise training and leucine supplementation. Food Funct 2018; 8:4528-4538. [PMID: 29099523 DOI: 10.1039/c7fo01181d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Previous research has demonstrated the positive effects of concurrent/combined aerobic and resistance exercise or leucine supplementation on skeletal muscle protein synthesis (MPS) and hypertrophy in aging organisms. However, the effects of a multimodal intervention which combines both aerobic and resistance exercise and leucine supplementation has not been fully elucidated. Eighteen month old and 2 month old C57BL/6 mice were assigned to aging control (AC, n = 8), aging and multimodal intervention (AMI, n = 8) and young control (YC, n = 8). Mice in the YC and AC groups were fed an alanine-rich diet (3.4%), and mice in the AMI group received an isonitrogenous leucine-supplemented (5%) diet in combination with combined aerobic (30 minutes swimming) and resistance exercise training (incremental jumping submersed in water with overload corresponding to 40%-50% body weight) for a total of 4 weeks. The gastrocnemius muscles were dissected for western blotting detection (signaling proteins involved in MPS) and the ex vivo determination of protein synthesis and protein content. The muscle strength of the hind limbs was measured pre-experiment and repeated once per week on Sunday for 4 weeks. Mice in the AC and AMI groups showed lower ex vivo protein synthesis, protein content, expression of signaling proteins involved in MPS, maximal grip strength but higher plasma cortisol compared with the YC group post intervention. When compared to AC mice, the multimodal treatment led to lower activity of Sestrin2, higher expression of PI3K III and the phosphorylation of mTOR, p70S6K and 4E-BP1, as well as higher plasma leucine, wet gastrocnemius muscle weight and muscle weight to body weight ratio. Furthermore, the multimodal intervention induced more pronounced anabolic response such as higher ex vivo protein synthesis rate, total protein content, and myofibrillar fractions in gastrocnemius muscle, and greater maximum grip strength. The present research shows that a multimodal intervention including combined both aerobic and resistance exercise training and 5% leucine supplementation has the potential to maintain skeletal muscle protein synthesis and attenuate losses in muscular strength during the aging process.
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Affiliation(s)
- Z Xia
- Exercise Physiology and Biochemistry Laboratory, College of Physical Education, Jinggangshan University, Ji'an, China
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658
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Kumar V. T cells and their immunometabolism: A novel way to understanding sepsis immunopathogenesis and future therapeutics. Eur J Cell Biol 2018; 97:379-392. [PMID: 29773345 DOI: 10.1016/j.ejcb.2018.05.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 03/03/2018] [Accepted: 05/03/2018] [Indexed: 02/08/2023] Open
Abstract
Sepsis has always been considered as a big challenge for pharmaceutical companies in terms of discovering and designing new therapeutics. The pathogenesis of sepsis involves aberrant activation of innate immune cells (i.e. macrophages, neutrophils etc.) at early stages. However, a stage of immunosuppression is also observed during sepsis even in the patients who have recovered from it. This stage of immunosuppression is observed due to the loss of conventional (i.e. CD4+, CD8+) T cells, Th17 cells and an upregulation of regulatory T cells (Tregs). This process also impacts metabolic processes controlling immune cell metabolism called immunometabolism. The present review is focused on the T cell-mediated immune response, their immunometabolism and targeting T cell immunometabolism during sepsis as future therapeutic approach. The first part of the manuscripts describes an impact of sepsis on conventional T cells, Th17 cells and Tregs along with their impact on sepsis. The subsequent section further describes the immunometabolism of these cells (CD4+, CD8+, Th17, and Tregs) under normal conditions and during sepsis-induced immunosuppression. The article ends with the therapeutic targeting of T cell immunometabolism (both conventional T cells and Tregs) during sepsis as a future immunomodulatory approach for its management.
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Affiliation(s)
- V Kumar
- Children's Health Queensland Clinical Unit, School of Clinical Medicine, Mater Research, Faculty of Medicine, University of Queensland, St. Lucia, Brisbane, Queensland 4078, Australia; School of Biomedical Sciences, Faculty of Medicine, University of Queensland, St. Lucia, Brisbane, Queensland 4078, Australia.
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659
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Traylor DA, Gorissen SHM, Phillips SM. Perspective: Protein Requirements and Optimal Intakes in Aging: Are We Ready to Recommend More Than the Recommended Daily Allowance? Adv Nutr 2018; 9:171-182. [PMID: 29635313 PMCID: PMC5952928 DOI: 10.1093/advances/nmy003] [Citation(s) in RCA: 129] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 01/08/2018] [Indexed: 12/17/2022] Open
Abstract
The Dietary Reference Intakes set the protein RDA for persons >19 y of age at 0.8 g protein ⋅ kg body weight-1 ⋅ d-1. A growing body of evidence suggests, however, that the protein RDA may be inadequate for older individuals. The evidence for recommending a protein intake greater than the RDA comes from a variety of metabolic approaches. Methodologies centered on skeletal muscle are of paramount importance given the age-related decline in skeletal muscle mass and function (sarcopenia) and the degree to which dietary protein could mitigate these declines. In addition to evidence from short-term experimental trials, observational data show that higher protein intakes are associated with greater muscle mass and, more importantly, better muscle function with aging. We are in dire need of more evidence from longer-term intervention trials showing the efficacy of protein intakes that are higher than the RDA in older persons to support skeletal muscle health. We propose that it should be recommended that older individuals consume ≥1.2 g protein · kg-1 · d-1 and that there should be an emphasis on the intake of the amino acid leucine, which plays a central role in stimulating skeletal muscle anabolism. Critically, the often-cited potential negative effects of consuming higher protein intakes on renal and bone health are without a scientific foundation in humans.
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Affiliation(s)
- Daniel A Traylor
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Stefan H M Gorissen
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Stuart M Phillips
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada,Address correspondence to SMP (e-mail: )
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660
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Ukai H, Araki Y, Kira S, Oikawa Y, May AI, Noda T. Gtr/Ego-independent TORC1 activation is achieved through a glutamine-sensitive interaction with Pib2 on the vacuolar membrane. PLoS Genet 2018; 14:e1007334. [PMID: 29698392 PMCID: PMC5919408 DOI: 10.1371/journal.pgen.1007334] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 03/15/2018] [Indexed: 12/18/2022] Open
Abstract
TORC1 is a central regulator of cell growth in response to amino acids. The role of the evolutionarily conserved Gtr/Rag pathway in the regulation of TORC1 is well-established. Recent genetic studies suggest that an additional regulatory pathway, depending on the activity of Pib2, plays a role in TORC1 activation independently of the Gtr/Rag pathway. However, the interplay between the Pib2 pathway and the Gtr/Rag pathway remains unclear. In this study, we show that Pib2 and Gtr/Ego form distinct complexes with TORC1 in a mutually exclusive manner, implying dedicated functional relationships between TORC1 and Pib2 or Gtr/Rag in response to specific amino acids. Furthermore, simultaneous depletion of Pib2 and the Gtr/Ego system abolishes TORC1 activity and completely compromises the vacuolar localization of TORC1. Thus, the amino acid-dependent activation of TORC1 is achieved through the Pib2 and Gtr/Ego pathways alone. Finally, we show that glutamine induces a dose-dependent increase in Pib2-TORC1 complex formation, and that glutamine binds directly to the Pib2 complex. These data provide strong preliminary evidence for Pib2 functioning as a putative glutamine sensor in the regulation of TORC1. TORC1 is a central regulator of cell growth in response to amino acids. The evolutionarily conserved Gtr/Rag pathway is a well-established TORC1 regulatory pathway. In this study, we show that two molecular machineries, Pib2 and Gtr/Ego, form distinct complexes with TORC1 in a mutually exclusive manner, implying an exclusive functional relationship between TORC1 and Pib2 or Gtr/Rag in response to various amino acids. We also show that the amino acid-dependent activation of TORC1 is achieved through the Pib2 and Gtr/Ego pathways by anchoring them to the vacuolar membrane. Finally, we show that glutamine binds directly to the Pib2 complex and that glutamine enhances Pib2-TORC1 complex formation. Collectively we provide evidence supporting a role for Pib2 as an element of a putative glutamine sensor.
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Affiliation(s)
- Hirofumi Ukai
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Yasuhiro Araki
- Graduate School of Dentistry, Osaka University, Osaka, Japan
- * E-mail: (TN); (YA)
| | - Shintaro Kira
- Graduate School of Dentistry, Osaka University, Osaka, Japan
| | - Yu Oikawa
- Research Center of Cell Biology, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Alexander I. May
- Research Center of Cell Biology, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Takeshi Noda
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
- Graduate School of Dentistry, Osaka University, Osaka, Japan
- * E-mail: (TN); (YA)
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661
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van Leeuwen W, van der Krift F, Rabouille C. Modulation of the secretory pathway by amino-acid starvation. J Cell Biol 2018; 217:2261-2271. [PMID: 29669743 PMCID: PMC6028531 DOI: 10.1083/jcb.201802003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 03/28/2018] [Accepted: 03/29/2018] [Indexed: 12/30/2022] Open
Abstract
As a major anabolic pathway, the secretory pathway needs to adapt to the demands of the surrounding environment and responds to different exogenous signals and stimuli. In this context, the transport in the early secretory pathway from the endoplasmic reticulum (ER) to the Golgi apparatus appears particularly regulated. For instance, protein export from the ER is critically stimulated by growth factors. Conversely, nutrient starvation also modulates functions of the early secretory pathway in multiple ways. In this review, we focus on amino-acid starvation and how the function of the early secretory pathway is redirected to fuel autophagy, how the ER exit sites are remodeled into novel cytoprotective stress assemblies, and how secretion is modulated in vivo in starving organisms. With the increasingly exciting knowledge on mechanistic target of rapamycin complex 1 (mTORC1), the major nutrient sensor, it is also a good moment to establish how the modulation of the secretory pathway by amino-acid restriction intersects with this major signaling hub.
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Affiliation(s)
- Wessel van Leeuwen
- Hubrecht Institute of the Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Utrecht, Netherlands
| | - Felix van der Krift
- Hubrecht Institute of the Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Utrecht, Netherlands
| | - Catherine Rabouille
- Hubrecht Institute of the Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Utrecht, Netherlands .,Department of Cell Biology, University Medical Center Groningen, Groningen, Netherlands
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662
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Chiu M, Taurino G, Bianchi MG, Ottaviani L, Andreoli R, Ciociola T, Lagrasta CAM, Tardito S, Bussolati O. Oligodendroglioma Cells Lack Glutamine Synthetase and Are Auxotrophic for Glutamine, but Do not Depend on Glutamine Anaplerosis for Growth. Int J Mol Sci 2018; 19:E1099. [PMID: 29642388 PMCID: PMC5979401 DOI: 10.3390/ijms19041099] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 03/29/2018] [Accepted: 04/04/2018] [Indexed: 12/31/2022] Open
Abstract
In cells derived from several types of cancer, a transcriptional program drives high consumption of glutamine (Gln), which is used for anaplerosis, leading to a metabolic addiction for the amino acid. Low or absent expression of Glutamine Synthetase (GS), the only enzyme that catalyzes de novo Gln synthesis, has been considered a marker of Gln-addicted cancers. In this study, two human cell lines derived from brain tumors with oligodendroglioma features, HOG and Hs683, have been shown to be GS-negative. Viability of both lines depends from extracellular Gln with EC50 of 0.175 ± 0.056 mM (Hs683) and 0.086 ± 0.043 mM (HOG), thus suggesting that small amounts of extracellular Gln are sufficient for OD cell growth. Gln starvation does not significantly affect the cell content of anaplerotic substrates, which, consistently, are not able to rescue cell growth, but causes hindrance of the Wnt/β-catenin pathway and protein synthesis attenuation, which is mitigated by transient GS expression. Gln transport inhibitors cause partial depletion of intracellular Gln and cell growth inhibition, but do not lower cell viability. Therefore, GS-negative human oligodendroglioma cells are Gln-auxotrophic but do not use the amino acid for anaplerosis and, hence, are not Gln addicted, exhibiting only limited Gln requirements for survival and growth.
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Affiliation(s)
- Martina Chiu
- Laboratory of General Pathology, Department of Medicine and Surgery, University of Parma, Via Volturno 39, 43125 Parma, Italy.
| | - Giuseppe Taurino
- Laboratory of General Pathology, Department of Medicine and Surgery, University of Parma, Via Volturno 39, 43125 Parma, Italy.
| | - Massimiliano G Bianchi
- Laboratory of General Pathology, Department of Medicine and Surgery, University of Parma, Via Volturno 39, 43125 Parma, Italy.
| | - Laura Ottaviani
- Laboratory of General Pathology, Department of Medicine and Surgery, University of Parma, Via Volturno 39, 43125 Parma, Italy.
| | - Roberta Andreoli
- Laboratory of Industrial Toxicology, Department of Medicine and Surgery, University of Parma, Via Gramsci 14, 43126 Parma, Italy.
| | - Tecla Ciociola
- Laboratory of Medical Microbiology and Virology, Department of Medicine and Surgery, University of Parma, Via Volturno 39, 43125 Parma, Italy.
| | - Costanza A M Lagrasta
- Laboratory of Anatomical Pathology, Department of Medicine and Surgery, University of Parma, Via Gramsci 14, 43126 Parma, Italy.
| | - Saverio Tardito
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback road, Glasgow G611BD, UK.
| | - Ovidio Bussolati
- Laboratory of General Pathology, Department of Medicine and Surgery, University of Parma, Via Volturno 39, 43125 Parma, Italy.
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663
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Byun JK, Choi YK, Kim JH, Jeong JY, Jeon HJ, Kim MK, Hwang I, Lee SY, Lee YM, Lee IK, Park KG. A Positive Feedback Loop between Sestrin2 and mTORC2 Is Required for the Survival of Glutamine-Depleted Lung Cancer Cells. Cell Rep 2018; 20:586-599. [PMID: 28723563 DOI: 10.1016/j.celrep.2017.06.066] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 05/14/2017] [Accepted: 06/22/2017] [Indexed: 01/05/2023] Open
Abstract
Proper regulation of mTORC1 and mTORC2 upon nutrient starvation is critical for cancer cell survival. Upregulation of Sestrin2 in response to glutamine deprivation rescues cell death by suppressing mTORC1. However, the contribution of mTORC2 to Sestrin2-mediated mTORC1 suppression remains unclear. Here, we report that both Sestrin2 and mTORC2 are upregulated in glutamine-depleted lung cancer cells. Moreover, glutamine depletion caused Sestrin2 to associate with mTORC2, which was required for the increase in Sestrin2 protein stability and the reduction in mTORC1 activity. Ultimately, differential regulation of mTORC1 and 2 by Sestrin2 reprogramed lipid metabolism and enabled glutamine-depleted lung cancer cells to survive by maintaining energy and redox balance. Importantly, combined inhibition of glutamine utilization and Sestrin2 induced lung cancer cell death both in vitro and in vivo. This study shows that differential Sestrin2-mediated regulation of mTORC1 and mTORC2 is necessary for the survival of glutamine-depleted lung cancer cells.
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Affiliation(s)
- Jun-Kyu Byun
- Research Institute of Pharmaceutical Science, College of Pharmacy, Kyungpook National University, Daegu 41566, Republic of Korea; Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu 41944, Republic of Korea; Leading-edge Research Center for Diabetes and Metabolic Disease, Kyungpook National University School of Medicine, Daegu 41944, Republic of Korea
| | - Yeon-Kyung Choi
- Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu 41944, Republic of Korea; Leading-edge Research Center for Diabetes and Metabolic Disease, Kyungpook National University School of Medicine, Daegu 41944, Republic of Korea
| | - Ji-Hyun Kim
- Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu 41944, Republic of Korea; Leading-edge Research Center for Diabetes and Metabolic Disease, Kyungpook National University School of Medicine, Daegu 41944, Republic of Korea; Research Institute of Aging and Metabolism, Kyungpook National University School of Medicine, Daegu 41944, Republic of Korea
| | - Ji Yun Jeong
- Department of Pathology, Kyungpook National University School of Medicine, Daegu 41944, Republic of Korea
| | - Hui-Jeon Jeon
- Leading-edge Research Center for Diabetes and Metabolic Disease, Kyungpook National University School of Medicine, Daegu 41944, Republic of Korea
| | - Mi-Kyung Kim
- Department of Internal Medicine, Keimyung University School of Medicine, Daegu 41931, Republic of Korea
| | - Ilseon Hwang
- Department of Pathology, Keimyung University School of Medicine, Daegu 41931, Republic of Korea
| | - Shin-Yup Lee
- Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu 41944, Republic of Korea
| | - You Mie Lee
- Research Institute of Pharmaceutical Science, College of Pharmacy, Kyungpook National University, Daegu 41566, Republic of Korea
| | - In-Kyu Lee
- Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu 41944, Republic of Korea; Leading-edge Research Center for Diabetes and Metabolic Disease, Kyungpook National University School of Medicine, Daegu 41944, Republic of Korea; Research Institute of Aging and Metabolism, Kyungpook National University School of Medicine, Daegu 41944, Republic of Korea.
| | - Keun-Gyu Park
- Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu 41944, Republic of Korea; Leading-edge Research Center for Diabetes and Metabolic Disease, Kyungpook National University School of Medicine, Daegu 41944, Republic of Korea; Research Institute of Aging and Metabolism, Kyungpook National University School of Medicine, Daegu 41944, Republic of Korea.
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664
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Importance of Serum Amino Acid Profile for Induction of Hepatic Steatosis under Protein Malnutrition. Sci Rep 2018; 8:5461. [PMID: 29615653 PMCID: PMC5882898 DOI: 10.1038/s41598-018-23640-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 03/15/2018] [Indexed: 12/31/2022] Open
Abstract
We previously reported that a low-protein diet caused animals to develop fatty liver containing a high level of triglycerides (TG), similar to the human nutritional disorder “kwashiorkor”. To investigate the underlying mechanisms, we cultured hepatocytes in amino acid-sufficient or deficient medium. Surprisingly, the intracellular TG level was increased by amino acid deficiency without addition of any lipids or hormones, accompanied by enhanced lipid synthesis, indicating that hepatocytes themselves monitored the extracellular amino acid concentrations to induce lipid accumulation in a cell-autonomous manner. We then confirmed that a low-amino acid diet also resulted in the development of fatty liver, and supplementation of the low-amino acid diet with glutamic acid to compensate the loss of nitrogen source did not completely suppress the hepatic TG accumulation. Only a dietary arginine or threonine deficiency was sufficient to induce hepatic TG accumulation. However, supplementation of a low-amino acid diet with arginine or threonine failed to reverse it. In silico analysis succeeded in predicting liver TG level from the serum amino acid profile. Based on these results, we conclude that dietary amino acid composition dynamically affects the serum amino acid profile, which is sensed by hepatocytes and lipid synthesis was activated cell-autonomously, leading to hepatic steatosis.
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665
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Yoshida S, Pacitto R, Inoki K, Swanson J. Macropinocytosis, mTORC1 and cellular growth control. Cell Mol Life Sci 2018; 75:1227-1239. [PMID: 29119228 PMCID: PMC5843684 DOI: 10.1007/s00018-017-2710-y] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 10/31/2017] [Accepted: 11/03/2017] [Indexed: 12/15/2022]
Abstract
The growth and proliferation of metazoan cells are driven by cellular nutrient status and by extracellular growth factors. Growth factor receptors on cell surfaces initiate biochemical signals that increase anabolic metabolism and macropinocytosis, an actin-dependent endocytic process in which relatively large volumes of extracellular solutes and nutrients are internalized and delivered efficiently into lysosomes. Macropinocytosis is prominent in many kinds of cancer cells, and supports the growth of cells transformed by oncogenic K-Ras. Growth factor receptor signaling and the overall metabolic status of the cell are coordinated in the cytoplasm by the mechanistic target-of-rapamycin complex-1 (mTORC1), which positively regulates protein synthesis and negatively regulates molecular salvage pathways such as autophagy. mTORC1 is activated by two distinct Ras-related small GTPases, Rag and Rheb, which associate with lysosomal membranes inside the cell. Rag recruits mTORC1 to the lysosomal surface where Rheb directly binds to and activates mTORC1. Rag is activated by both lysosomal luminal and cytosolic amino acids; Rheb activation requires phosphoinositide 3-kinase, Akt, and the tuberous sclerosis complex-1/2. Signals for activation of Rag and Rheb converge at the lysosomal membrane, and several lines of evidence support the idea that growth factor-dependent endocytosis facilitates amino acid transfer into the lysosome leading to the activation of Rag. This review summarizes evidence that growth factor-stimulated macropinocytosis is essential for amino acid-dependent activation of mTORC1, and that increased solute accumulation by macropinocytosis in transformed cells supports unchecked cell growth.
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Affiliation(s)
- Sei Yoshida
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109-5620, USA
| | - Regina Pacitto
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109-5620, USA
| | - Ken Inoki
- Department of Integrative and Molecular Physiology and Internal Medicine, Life Sciences Institute, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Joel Swanson
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109-5620, USA.
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666
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Zeng N, D'Souza RF, Sorrenson B, Merry TL, Barnett MPG, Mitchell CJ, Cameron-Smith D. The putative leucine sensor Sestrin2 is hyperphosphorylated by acute resistance exercise but not protein ingestion in human skeletal muscle. Eur J Appl Physiol 2018; 118:1241-1253. [PMID: 29574525 DOI: 10.1007/s00421-018-3853-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 03/21/2018] [Indexed: 12/29/2022]
Abstract
PURPOSE Dietary protein and resistance exercise (RE) are both potent stimuli of the mammalian target of rapamycin complex 1 (mTORC1). Sestrins1, 2, 3 are multifunctional proteins that regulate mTORC1, stimulate autophagy and alleviate oxidative stress. Of this family, Sestrin2 is a putative leucine sensor implicated in mTORC1 and AMP-dependent protein kinase (AMPK) regulation. There is currently no data examining the responsiveness of Sestrin2 to dietary protein ingestion, with or without RE. METHODS In Study 1, 16 males ingested either 10 or 20 g of milk protein concentrate (MPC) with muscle biopsies collected pre, 90 and 210 min post-beverage consumption. In Study 2, 20 males performed a bout of RE immediately followed by the consumption of 9 g of MPC or carbohydrate placebo. Analysis of Sestrins, AMPK and antioxidant responses was examined. RESULTS Dietary protein ingestion did not result in Sestrin2 mobility shift. After RE, Sestrin2 phosphorylation state was significantly altered and was not further modified by post-exercise protein or carbohydrate ingestion. With RE, AMPK phosphorylation remained stable, while the mRNA expressions of several antioxidants were upregulated. CONCLUSIONS Dietary protein ingestion did not affect the signalling by the family of Sestrins. With RE, Sestrin2 was hyperphosphorylated, with no further evidence of a relationship to AMPK signalling.
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Affiliation(s)
- Nina Zeng
- Liggins Institute, The University of Auckland, Private Bag 92 019, Victoria Street West, Auckland, 1142, New Zealand
| | - Randall F D'Souza
- Liggins Institute, The University of Auckland, Private Bag 92 019, Victoria Street West, Auckland, 1142, New Zealand
| | - Brie Sorrenson
- Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
| | - Troy L Merry
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
- Discipline of Nutrition, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Matthew P G Barnett
- Food Nutrition and Health Team, AgResearch, Palmerston North, 4474, New Zealand
| | - Cameron J Mitchell
- Liggins Institute, The University of Auckland, Private Bag 92 019, Victoria Street West, Auckland, 1142, New Zealand
| | - David Cameron-Smith
- Liggins Institute, The University of Auckland, Private Bag 92 019, Victoria Street West, Auckland, 1142, New Zealand.
- Food and Bio-based Products Group, AgResearch, Palmerston North, 4474, New Zealand.
- Riddet Institute, Palmerston North, 4442, New Zealand.
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667
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Nie C, He T, Zhang W, Zhang G, Ma X. Branched Chain Amino Acids: Beyond Nutrition Metabolism. Int J Mol Sci 2018; 19:E954. [PMID: 29570613 PMCID: PMC5979320 DOI: 10.3390/ijms19040954] [Citation(s) in RCA: 383] [Impact Index Per Article: 63.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 03/01/2018] [Accepted: 03/14/2018] [Indexed: 12/14/2022] Open
Abstract
Branched chain amino acids (BCAAs), including leucine (Leu), isoleucine (Ile), and valine (Val), play critical roles in the regulation of energy homeostasis, nutrition metabolism, gut health, immunity and disease in humans and animals. As the most abundant of essential amino acids (EAAs), BCAAs are not only the substrates for synthesis of nitrogenous compounds, they also serve as signaling molecules regulating metabolism of glucose, lipid, and protein synthesis, intestinal health, and immunity via special signaling network, especially phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signal pathway. Current evidence supports BCAAs and their derivatives as the potential biomarkers of diseases such as insulin resistance (IR), type 2 diabetes mellitus (T2DM), cancer, and cardiovascular diseases (CVDs). These diseases are closely associated with catabolism and balance of BCAAs. Hence, optimizing dietary BCAA levels should have a positive effect on the parameters associated with health and diseases. This review focuses on recent findings of BCAAs in metabolic pathways and regulation, and underlying the relationship of BCAAs to related disease processes.
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Affiliation(s)
- Cunxi Nie
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, No. 2. Yuanmingyuan West Road, Beijing 100193, China.
- College of Animal Science and Technology, Shihezi University, No. 221. Beisi Road, Shihezi, Xinjiang 832003, China.
| | - Ting He
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, No. 2. Yuanmingyuan West Road, Beijing 100193, China.
| | - Wenju Zhang
- College of Animal Science and Technology, Shihezi University, No. 221. Beisi Road, Shihezi, Xinjiang 832003, China.
| | - Guolong Zhang
- Department of Animal Science, Oklahoma State University, Stillwater, OK 74078, USA.
| | - Xi Ma
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, No. 2. Yuanmingyuan West Road, Beijing 100193, China.
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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668
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Weng L, Han YP, Enomoto A, Kitaura Y, Nagamori S, Kanai Y, Asai N, An J, Takagishi M, Asai M, Mii S, Masuko T, Shimomura Y, Takahashi M. Negative regulation of amino acid signaling by MAPK-regulated 4F2hc/Girdin complex. PLoS Biol 2018. [PMID: 29538402 PMCID: PMC5868845 DOI: 10.1371/journal.pbio.2005090] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Amino acid signaling mediated by the activation of mechanistic target of rapamycin complex 1 (mTORC1) is fundamental to cell growth and metabolism. However, how cells negatively regulate amino acid signaling remains largely unknown. Here, we show that interaction between 4F2 heavy chain (4F2hc), a subunit of multiple amino acid transporters, and the multifunctional hub protein girders of actin filaments (Girdin) down-regulates mTORC1 activity. 4F2hc interacts with Girdin in mitogen-activated protein kinase (MAPK)- and amino acid signaling–dependent manners to translocate to the lysosome. The resultant decrease in cell surface 4F2hc leads to lowered cytoplasmic glutamine (Gln) and leucine (Leu) content, which down-regulates amino acid signaling. Consistently, Girdin depletion augments amino acid-induced mTORC1 activation and inhibits amino acid deprivation–induced autophagy. These findings uncovered the mechanism underlying negative regulation of amino acid signaling, which may play a role in tightly regulated cell growth and metabolism. The mechanistic target of rapamycin complex 1 (mTORC1) protein kinase is a master regulator of cell growth, which senses several extracellular signals, such as growth factors and nutrient levels, to coordinate cell metabolism. The activation of mTORC1 by amino acids requires many proteins such as Rag GTPase, GATOR, and Ragulator. However, how cells negatively regulate amino acid signaling remains largely unknown. In this study, we revealed that an endocytosis-related protein called Girdin negatively regulates amino acid–induced mTORC1 activation via the formation of a complex with 4F2 heavy chain (4F2hc), a subunit of multiple amino acid transporters. We show that Girdin/4F2h complex formation requires growth factor-induced Girdin phosphorylation and amino acid–induced 4F2hc ubiquitination. We also find that the complex promotes the internalization of 4F2hc from the plasma membrane to the lysosomes. The subsequent decrease of 4F2hc in the cell surface results in a lower cytoplasmic glutamine and leucine content, which then down-regulates amino acid–induced mTORC1 activation. These findings uncover the mechanism underlying negative regulation of mTORC1 signaling, which may play a role in tightly regulated cell growth and metabolism.
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Affiliation(s)
- Liang Weng
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
- * E-mail: (MT); (LW); (AE)
| | - Yi-Peng Han
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Atsushi Enomoto
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
- * E-mail: (MT); (LW); (AE)
| | - Yasuyuki Kitaura
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Shushi Nagamori
- Laboratory of Biomolecular Dynamics, Department of Collaborative Research, Nara Medical University, Kashihara, Nara, Japan
| | - Yoshikatsu Kanai
- Department of Bio-System Pharmacology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Naoya Asai
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Jian An
- Department of Respiratory Medicine, Xiangya Hospital, Central South University, Kaifu District, Changsha, China
| | - Maki Takagishi
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Masato Asai
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Shinji Mii
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Takashi Masuko
- Cell Biology Laboratory, Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University, Higashiosaka, Osaka, Japan
| | - Yoshiharu Shimomura
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Masahide Takahashi
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Division of Molecular Pathology, Center for Neurological Disease and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan
- * E-mail: (MT); (LW); (AE)
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669
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Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) coordinates cellular growth and metabolism with environmental inputs to ensure that cells grow only under favourable conditions. When active, mTORC1 stimulates biosynthetic pathways including protein, lipid and nucleotide synthesis and inhibits cellular catabolism through repression of the autophagic pathway, thereby promoting cell growth and proliferation. The recruitment of mTORC1 to the lysosomal surface has been shown to be essential for its activation. This finding has significantly enhanced our knowledge of mTORC1 regulation and has focused the attention of the field on the lysosome as a signalling hub which coordinates several homeostatic pathways. The intriguing localisation of mTORC1 to the cellular organelle that plays a crucial role in catabolism enables mTORC1 to feedback to autophagy and lysosomal biogenesis, thus leading mTORC1 to enact precise spatial and temporal control of cell growth. This review will cover the signalling interactions which take place on the surface of lysosomes and the cross-talk which exists between mTORC1 activity and lysosomal function.
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Affiliation(s)
- Yoana Rabanal-Ruiz
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE4 5PL, UK.
| | - Viktor I Korolchuk
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE4 5PL, UK.
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670
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Faccio AT, Ruperez FJ, Singh NS, Angulo S, Tavares MFM, Bernier M, Barbas C, Wainer IW. Stereochemical and structural effects of (2R,6R)-hydroxynorketamine on the mitochondrial metabolome in PC-12 cells. Biochim Biophys Acta Gen Subj 2018. [PMID: 29526507 DOI: 10.1016/j.bbagen.2018.03.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND Impairment in mitochondrial biogenesis and function plays a key role in depression and anxiety, both of which being associated with changes in fatty acid and phospholipid metabolism. The antidepressant effects of (R,S)-ketamine have been linked to its conversion into (2S,6S;2R,6R)-hydroxynorketamine (HNK); however, the connection between structure and stereochemistry of ketamine and HNK in the mitochondrial homeostatic response has not yet been fully elucidated at a metabolic level. METHODS We used a multi-platform, non-targeted metabolomics approach to study the change in mitochondrial metabolome of PC-12 cells treated with ketamine and HNK enantiomers. The identified metabolites were grouped into pathways in order to assess global responses. RESULTS Treatment with (2R,6R)-HNK elicited the significant change in 49 metabolites and associated pathways implicated in fundamental mitochondrial functions such as TCA cycle, branched-chain amino acid biosynthetic pathway, glycoxylate metabolic pathway, and fatty acid β-oxidation. The affected metabolites included glycerate, citrate, leucine, N,N-dimethylglycine, 3-hexenedioic acid, and carnitine and attenuated signals associated with 9 fatty acids and elaidic acid. Important metabolites involved in the purine and pyrimidine pathways were also affected by (2R-6R)-HNK. This global metabolic profile was not as strongly impacted by treatment with (2S,6S)-HNK, (R)- and (S)-ketamine and in some instances opposite effects were observed. CONCLUSIONS The present data provide an overall view of the metabolic changes in mitochondrial function produced by (2R,6R)-HNK and related ketamine compounds and offer an insight into the source of the observed variance in antidepressant response elicited by the compounds.
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Affiliation(s)
- Andréa T Faccio
- CEMBIO (Centre for Metabolomics and Bioanalysis), Faculty of Pharmacy, Universidad San Pablo CEU, Campus Monteprincipe, Boadilla del Monte, 28668 Madrid, Spain; Institute of Chemistry, University of São Paulo (USP), 05513-970 São Paulo, SP, Brazil
| | - Francisco J Ruperez
- CEMBIO (Centre for Metabolomics and Bioanalysis), Faculty of Pharmacy, Universidad San Pablo CEU, Campus Monteprincipe, Boadilla del Monte, 28668 Madrid, Spain
| | - Nagendra S Singh
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Santiago Angulo
- CEMBIO (Centre for Metabolomics and Bioanalysis), Faculty of Pharmacy, Universidad San Pablo CEU, Campus Monteprincipe, Boadilla del Monte, 28668 Madrid, Spain
| | - Marina F M Tavares
- Institute of Chemistry, University of São Paulo (USP), 05513-970 São Paulo, SP, Brazil
| | - Michel Bernier
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Coral Barbas
- CEMBIO (Centre for Metabolomics and Bioanalysis), Faculty of Pharmacy, Universidad San Pablo CEU, Campus Monteprincipe, Boadilla del Monte, 28668 Madrid, Spain
| | - Irving W Wainer
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA; Mitchell Woods Pharmaceuticals, Shelton, CT 06484, USA.
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671
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Kumar A, Giri S, Shaha C. Sestrin2 facilitates glutamine-dependent transcription of PGC-1α and survival of liver cancer cells under glucose limitation. FEBS J 2018; 285:1326-1345. [PMID: 29436167 DOI: 10.1111/febs.14406] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 01/22/2018] [Accepted: 02/07/2018] [Indexed: 12/13/2022]
Abstract
Differential utilization of metabolites and metabolic plasticity can confer adaptation to cancer cells under metabolic stress. Glutamine is one of the vital and versatile nutrients that cancer cells consume avidly for their proliferation, and therefore mechanisms related to glutamine metabolism have been identified as targets. Recently, sestrin2 (SESN2), a stress-inducible protein, has been reported to regulate survival in glutamine-depleted cancer cells; based on this, we explored if SESN2 could regulate glutamine metabolism during glucose starvation. This report highlights the role of SESN2 in the regulation of glutamine-dependent activation of the mitochondrial biogenesis marker peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) under glucose scarcity in liver cancer cells (HepG2). We demonstrate that down-regulation of SESN2 induces a decrease in the levels of intracellular glutamine and PGC-1α under glucose deprivation, concomitant with a decline in cell survival, but no effect was observed on the invasive or migration potential of the cells. Under similar metabolic conditions, SESN2 forms a complex with c-Jun N-terminal kinase (JNK) and forkhead box protein O1 (FOXO1). Absence of SESN2 or inhibition of JNK reduces nuclear translocation of FOXO1, consequently causing transcriptional inhibition of PGC-1α. Notably, our observations demonstrate a reduction in cell viability under high glutamine and low glucose conditions during SESN2 down-regulation that could be rescued on JNK inhibition. To recover from acetaminophen-induced mitochondrial damage, SESN2 was crucial for glutamine-mediated activation of PGC-1α in HepG2 cells. Collectively, we demonstrate a novel role of SESN2 in mediating activation of PGC-1α by modulating glutamine metabolism that facilitates cancer cell survival under glucose-limited metabolic conditions.
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Affiliation(s)
- Ashish Kumar
- Cell Death and Differentiation Research Laboratory, National Institute of Immunology, New Delhi, India
| | - Sagnik Giri
- Cell Death and Differentiation Research Laboratory, National Institute of Immunology, New Delhi, India
| | - Chandrima Shaha
- Cell Death and Differentiation Research Laboratory, National Institute of Immunology, New Delhi, India
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672
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Hsu CL, Lee EX, Gordon KL, Paz EA, Shen WC, Ohnishi K, Meisenhelder J, Hunter T, La Spada AR. MAP4K3 mediates amino acid-dependent regulation of autophagy via phosphorylation of TFEB. Nat Commun 2018; 9:942. [PMID: 29507340 PMCID: PMC5838220 DOI: 10.1038/s41467-018-03340-7] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 02/05/2018] [Indexed: 12/19/2022] Open
Abstract
Autophagy is the major cellular pathway by which macromolecules are degraded, and amino acid depletion powerfully activates autophagy. MAP4K3, or germinal-center kinase-like kinase, is required for robust cell growth in response to amino acids, but the basis for MAP4K3 regulation of cellular metabolic disposition remains unknown. Here we identify MAP4K3 as an amino acid-dependent regulator of autophagy through its phosphorylation of transcription factor EB (TFEB), a transcriptional activator of autophagy, and through amino acid starvation-dependent lysosomal localization of MAP4K3. We document that MAP4K3 physically interacts with TFEB and MAP4K3 inhibition is sufficient for TFEB nuclear localization, target gene transactivation, and autophagy, even when mTORC1 is activated. Moreover, MAP4K3 serine 3 phosphorylation of TFEB is required for TFEB interaction with mTORC1-Rag GTPase-Ragulator complex and TFEB cytosolic sequestration. Our results uncover a role for MAP4K3 in the control of autophagy and reveal MAP4K3 as a central node in nutrient-sensing regulation. Amino acids stimulate cell growth and depletion in a cell activates autophagy, yet how this is regulated is unclear. Here, the authors show that MAP4K3 (also known as germinal-center kinase-like kinase) acts as an amino acid-dependent regulator of autophagy, via phosphorylation of the transcription factor EB.
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Affiliation(s)
- Cynthia L Hsu
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Elian X Lee
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Kara L Gordon
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Edwin A Paz
- Departments of Neurology, Neurobiology, and Cell Biology, Duke Center for Neurodegeneration and Neurotherapeutics, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Wen-Chuan Shen
- Departments of Neurology, Neurobiology, and Cell Biology, Duke Center for Neurodegeneration and Neurotherapeutics, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Kohta Ohnishi
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Jill Meisenhelder
- Molecular and Cellular Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Tony Hunter
- Molecular and Cellular Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Albert R La Spada
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, 92093, USA. .,Departments of Neurology, Neurobiology, and Cell Biology, Duke Center for Neurodegeneration and Neurotherapeutics, Duke University School of Medicine, Durham, NC, 27710, USA.
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673
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Abstract
Cell-intrinsic mechanisms of nutrient sensing are intimately linked to adaptive metabolic responses, and these pathways play critical roles in the complex and dynamic nutrient environment of a growing tumor. Nutrient-responsive transcription factors (e.g., HIF, SREBP, ATF4) and signaling pathways (e.g., mTORC1, AMPK) allow tumor cells to tune their metabolic output and strategies to fluctuations in nutrient availability, thus balancing tumor cell proliferation and survival with a combination of anabolic and adaptive responses. Coupling these nutrient-sensing mechanisms to the control of recycling and scavenging processes, such as autophagy and macropinocytosis, further enhances the adaptability to nutrients within tumors. Here, we discuss the key nutrient-sensing pathways active in cancer cells, how oncogenic events influence these pathways, and their likely contributions to tumor growth and survival. A better understanding of nutrient-sensing strategies and metabolic adaptations within the tumor microenvironment is critical to defining and targeting metabolic vulnerabilities in cancer.
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Affiliation(s)
- Margaret E. Torrence
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, USA
| | - Brendan D. Manning
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, USA
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674
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SESN2 negatively regulates cell proliferation and casein synthesis by inhibition the amino acid-mediated mTORC1 pathway in cow mammary epithelial cells. Sci Rep 2018; 8:3912. [PMID: 29500367 PMCID: PMC5834632 DOI: 10.1038/s41598-018-22208-w] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 02/09/2018] [Indexed: 01/01/2023] Open
Abstract
Amino acids (AA) are one of the key nutrients that regulate cell proliferation and casein synthesis in cow mammary epithelial cells (CMEC), but the mechanism of this regulation is not yet clear. In this study, the effect of SESN2 on AA-mediated cell proliferation and casein synthesis in CMEC was assessed. After 12 h of AA starvation, CMECs were cultured in the absence of all AA (AA-), in the presences of only essential AA (EAA+), or of all AA (AA+). Cell proliferation, casein expression, and activation of the mammalian target of rapamycin complex 1 (mTORC1) pathway were increased; but SESN2 expression was decreased in response to increased EAA or AA supply. Overexpressing or inhibiting SESN2 demonstrated that cell proliferation, casein expression, and activation of the mTORC1 pathway were all controlled by SESN2 expression. Furthermore, the increase in cell proliferation, casein expression, and activation of the mTORC1 pathway in response to AA supply was inhibited by overexpressing SESN2, and those effects were reversed by inhibiting SESN2. These results indicate that SESN2 is an important inhibitor of mTORC1 in CMEC blocking AA-mediated cell proliferation and casein synthesis.
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675
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L-Arginine regulates protein turnover in porcine mammary epithelial cells to enhance milk protein synthesis. Amino Acids 2018; 50:621-628. [PMID: 29435722 DOI: 10.1007/s00726-018-2541-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 01/29/2018] [Indexed: 10/18/2022]
Abstract
Milk is an important food for mammalian neonates, but its insufficient production is a nutritional problem for humans and other animals. Recent studies indicate that dietary supplementation with L-arginine (Arg) increases milk production in mammals, including sows, rabbits, and cows. However, the underlying molecular mechanisms remain largely unknown. The present study was conducted with porcine mammary epithelial cells (PMECs) to test the hypothesis that Arg enhances milk protein synthesis via activation of the mechanistic target of rapamycin (mTOR) cell signaling. PMECs were cultured for 4 days in Arg-free basal medium supplemented with 10, 50, 200, or 500 μmol/L Arg. Rates of protein synthesis and degradation in cells were determined with the use of L-[ring-2,4-3H]phenylalanine. Cell medium was analyzed for β-casein and α-lactalbumin, whereas cells were used for quantifying total and phosphorylated levels of mTOR, ribosomal protein S6 kinase (p70S6K), 4E-binding protein 1 (4EBP1), ubiquitin, and proteasome. Addition of 50-500 μmol/L Arg to culture medium increased (P < 0.05) the proliferation of PMECs and the synthesis of proteins (including β-casein and α-lactalbumin), while reducing the rates of proteolysis, in a dose-dependent manner. The phosphorylated levels of mTOR, p70S6K and 4EBP1 were elevated (P < 0.05), but the abundances of ubiquitin and proteasome were lower (P < 0.05), in PMECs supplemented with 200-500 μmol/L Arg, compared with 10-50 μmol/L Arg. These results provide a biochemical basis for the use of Arg to enhance milk production by sows and have important implications for improving lactation in other mammals (including humans and cows).
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676
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Sato Y, Sato Y, Suzuki R, Obeng K, Yoshizawa F. Leucyl-tRNA synthetase is required for the myogenic differentiation of C2C12 myoblasts, but not for hypertrophy or metabolic alteration of myotubes. Exp Cell Res 2018; 364:184-190. [PMID: 29425714 DOI: 10.1016/j.yexcr.2018.02.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 02/01/2018] [Accepted: 02/03/2018] [Indexed: 11/24/2022]
Abstract
Mammalian target of rapamycin (mTOR) signaling controls skeletal muscle cell differentiation, growth, and metabolism by sensing the intracellular energy status and nutrients. Recently, leucyl-tRNA synthetase (Lars) was identified as an intracellular sensor of leucine involved in the activation of mTOR signaling. However, there is still no evidence for the activation of mTOR signaling by Lars and its physiological roles in skeletal muscle cells. In this study, we determined the potential roles of Lars for the activation of mTOR signaling, skeletal muscle cell differentiation, hypertrophy, and metabolism using small interfering (si)-RNA knockdown. siRNA-mediated knockdown of Lars decreased phosphorylated p70 S6 kinase and inhibited the differentiation of C2C12 mouse myoblasts into myotubes, as evidenced by a decreased fusion index and decreased mRNA and protein expression levels of myogenic markers. Importantly, si-Lars decreased the level of Insulin-like growth factor 2 (Igf2) mRNA expression from the early stages of differentiation, indicating the possibility of an association between the mTOR-IGF2 axis and Lars. However, Lars knockdown did not decrease phosphorylated mTOR in differentiated myotubes, nor did it affect the hypertrophy of myotubes as evidenced by measuring their diameters and detecting the mRNA and protein expression of hypertrophy markers. Similarly, an extracellular flux analyzer showed that Lars knockdown did not affect the metabolism (glycolysis and mitochondrial respiration) of myotubes. These results demonstrate that Lars is required for skeletal muscle differentiation through the activation of mTOR signaling, but not for hypertrophy or metabolic alteration of myotubes.
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Affiliation(s)
- Yoriko Sato
- United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Yusuke Sato
- Department of Agrobiology and Bioresources, Utsunomiya University, 350 Minemachi, Tochigi, Japan.
| | - Reiko Suzuki
- Department of Agrobiology and Bioresources, Utsunomiya University, 350 Minemachi, Tochigi, Japan
| | - Kodwo Obeng
- United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Fumiaki Yoshizawa
- United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Tokyo, Japan; Department of Agrobiology and Bioresources, Utsunomiya University, 350 Minemachi, Tochigi, Japan
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677
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Hao F, Kondo K, Itoh T, Ikari S, Nada S, Okada M, Noda T. Rheb localized on the Golgi membrane activates lysosome-localized mTORC1 at the Golgi-lysosome contact site. J Cell Sci 2018; 131:jcs.208017. [PMID: 29222112 DOI: 10.1242/jcs.208017] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 11/26/2017] [Indexed: 12/31/2022] Open
Abstract
In response to amino acid supply, mTORC1, a master regulator of cell growth, is recruited to the lysosome and activated by the small GTPase Rheb. However, the intracellular localization of Rheb is controversial. In this study, we showed that a significant portion of Rheb is localized on the Golgi but not on the lysosome. GFP-Rheb could activate mTORC1, even when forced to exclusively localize to the Golgi. Likewise, artificial recruitment of mTORC1 to the Golgi allowed its activation. Accordingly, the Golgi was in contact with the lysosome at an newly discovered area of the cell that we term the Golgi-lysosome contact site (GLCS). The number of GLCSs increased in response to amino acid supply, whereas GLCS perturbation suppressed mTORC1 activation. These results suggest that inter-organelle communication between the Golgi and lysosome is important for mTORC1 regulation and the Golgi-localized Rheb may activate mTORC1 at GLCSs.
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Affiliation(s)
- Feike Hao
- Center for Frontier Oral Science, Graduate School of Dentistry, Osaka University, Osaka 565-0871, Japan
| | - Kazuhiko Kondo
- Graduate School of Frontier Bioscience, Osaka University, Osaka 565-0871, Japan
| | - Takashi Itoh
- Center for Frontier Oral Science, Graduate School of Dentistry, Osaka University, Osaka 565-0871, Japan
| | - Sumiko Ikari
- Graduate School of Frontier Bioscience, Osaka University, Osaka 565-0871, Japan
| | - Shigeyuki Nada
- Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Masato Okada
- Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Takeshi Noda
- Center for Frontier Oral Science, Graduate School of Dentistry, Osaka University, Osaka 565-0871, Japan .,Graduate School of Frontier Bioscience, Osaka University, Osaka 565-0871, Japan
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678
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Yoon BR, Oh YJ, Kang SW, Lee EB, Lee WW. Role of SLC7A5 in Metabolic Reprogramming of Human Monocyte/Macrophage Immune Responses. Front Immunol 2018; 9:53. [PMID: 29422900 PMCID: PMC5788887 DOI: 10.3389/fimmu.2018.00053] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/09/2018] [Indexed: 12/20/2022] Open
Abstract
Amino acids (AAs) are necessary nutrients which act not only as building blocks in protein synthesis but also in crucial anabolic cellular signaling pathways. It has been demonstrated that SLC7A5 is a critical transporter that mediates uptake of several essential amino acids in highly proliferative tumors and activated T cells. However, the dynamics and relevance of SLC7A5 activity in monocytes/macrophages is still poorly understood. We provide evidence that SLC7A5-mediated leucine influx contributes to pro-inflammatory cytokine production via mTOR complex 1 (mTORC1)-induced glycolytic reprograming in activated human monocytes/macrophages. Moreover, expression of SLC7A5 is significantly elevated in monocytes derived from patients with rheumatoid arthritis (RA), a chronic inflammatory disease, and was also markedly induced by LPS stimulation of both monocytes and macrophages from healthy individuals. Further, pharmacological blockade or silencing of SLC7A5 led to a significant reduction of IL-1β downstream of leucine-mediated mTORC1 activation. Inhibition of SLC7A5-mediated leucine influx was linked to downregulation of glycolytic metabolism as evidenced by the decreased extracellular acidification rate, suggesting a regulatory role for this molecule in glycolytic reprograming. Furthermore, the expression of SLC7A5 on circulating monocytes from RA patients positively correlated with clinical parameters, suggesting that SLC7A5-mediated AA influx is related to inflammatory conditions.
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Affiliation(s)
- Bo Ruem Yoon
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, South Korea
| | - Yoon-Jeong Oh
- Division of Rheumatology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, South Korea
| | - Seong Wook Kang
- Department of Internal Medicine, Chungnam National University School of Medicine, Daejeon, South Korea
| | - Eun Bong Lee
- Division of Rheumatology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, South Korea
| | - Won-Woo Lee
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, South Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, South Korea.,Cancer Research Institute, Seoul National University College of Medicine, Seoul, South Korea.,Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, South Korea.,Institute of Infectious Diseases, Seoul National University College of Medicine, Seoul, South Korea.,Seoul National University Hospital Biomedical Research Institute, Seoul, South Korea
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679
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Cuyàs E, Fernández-Arroyo S, Alarcón T, Lupu R, Joven J, Menendez JA. Germline BRCA1 mutation reprograms breast epithelial cell metabolism towards mitochondrial-dependent biosynthesis: evidence for metformin-based "starvation" strategies in BRCA1 carriers. Oncotarget 2018; 7:52974-52992. [PMID: 27259235 PMCID: PMC5288162 DOI: 10.18632/oncotarget.9732] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 05/12/2016] [Indexed: 12/17/2022] Open
Abstract
We hypothesized that women inheriting one germline mutation of the BRCA1 gene (“one-hit”) undergo cell-type-specific metabolic reprogramming that supports the high biosynthetic requirements of breast epithelial cells to progress to a fully malignant phenotype. Targeted metabolomic analysis was performed in isogenic pairs of nontumorigenic human breast epithelial cells in which the knock-in of 185delAG mutation in a single BRCA1 allele leads to genomic instability. Mutant BRCA1 one-hit epithelial cells displayed constitutively enhanced activation of biosynthetic nodes within mitochondria. This metabolic rewiring involved the increased incorporation of glutamine- and glucose-dependent carbon into tricarboxylic acid (TCA) cycle metabolite pools to ultimately generate elevated levels of acetyl-CoA and malonyl-CoA, the major building blocks for lipid biosynthesis. The significant increase of branched-chain amino acids (BCAAs) including the anabolic trigger leucine, which can not only promote protein translation via mTOR but also feed into the TCA cycle via succinyl-CoA, further underscored the anabolic reprogramming of BRCA1 haploinsufficient cells. The anti-diabetic biguanide metformin “reversed” the metabolomic signature and anabolic phenotype of BRCA1 one-hit cells by shutting down mitochondria-driven generation of precursors for lipogenic pathways and reducing the BCAA pool for protein synthesis and TCA fueling. Metformin-induced restriction of mitochondrial biosynthetic capacity was sufficient to impair the tumor-initiating capacity of BRCA1 one-hit cells in mammosphere assays. Metabolic rewiring of the breast epithelium towards increased anabolism might constitute an unanticipated and inherited form of metabolic reprogramming linked to increased risk of oncogenesis in women bearing pathogenic germline BRCA1 mutations. The ability of metformin to constrain the production of mitochondrial-dependent biosynthetic intermediates might open a new avenue for “starvation” chemopreventive strategies in BRCA1 carriers.
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Affiliation(s)
- Elisabet Cuyàs
- ProCURE (Program Against Cancer Therapeutic Resistance), Metabolism and Cancer Group, Catalan Institute of Oncology, Girona, Catalonia, Spain.,Molecular Oncology Group, Girona Biomedical Research Institute (IDIBGI), Girona, Catalonia, Spain
| | - Salvador Fernández-Arroyo
- Unitat de Recerca Biomèdica, Hospital Universitari de Sant Joan, IISPV, Universitat Rovira i Virgili, Campus of International Excellence Southern Catalonia, Reus, Spain
| | - Tomás Alarcón
- Institució Catalana d'Estudis i Recerca Avançats (ICREA), Barcelona, Spain.,Computational and Mathematical Biology Research Group, Centre de Recerca Matemàtic (CRM), Barcelona, Spain.,Departament de Matemàtiques, Universitat Autònoma de Barcelona, Barcelona, Spain.,Barcelona Graduate School of Mathematics (BGSMath), Barcelona, Spain
| | - Ruth Lupu
- Mayo Clinic, Department of Laboratory Medicine and Pathology, Division of Experimental Pathology, Rochester, MN, USA.,Mayo Clinic Cancer Center, Rochester, MN, USA
| | - Jorge Joven
- Unitat de Recerca Biomèdica, Hospital Universitari de Sant Joan, IISPV, Universitat Rovira i Virgili, Campus of International Excellence Southern Catalonia, Reus, Spain
| | - Javier A Menendez
- ProCURE (Program Against Cancer Therapeutic Resistance), Metabolism and Cancer Group, Catalan Institute of Oncology, Girona, Catalonia, Spain.,Molecular Oncology Group, Girona Biomedical Research Institute (IDIBGI), Girona, Catalonia, Spain
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680
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Profile of David M. Sabatini. Proc Natl Acad Sci U S A 2018; 115:438-440. [PMID: 29279397 DOI: 10.1073/pnas.1721196115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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681
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Otsubo Y, Matsuo T, Nishimura A, Yamamoto M, Yamashita A. tRNA production links nutrient conditions to the onset of sexual differentiation through the TORC1 pathway. EMBO Rep 2018; 19:embr.201744867. [PMID: 29330317 DOI: 10.15252/embr.201744867] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 11/30/2017] [Accepted: 12/14/2017] [Indexed: 12/14/2022] Open
Abstract
Target of rapamycin (TOR) kinase controls cell growth and metabolism in response to nutrient availability. In the fission yeast Schizosaccharomyces pombe, TOR complex 1 (TORC1) promotes vegetative growth and inhibits sexual differentiation in the presence of ample nutrients. Here, we report the isolation and characterization of mutants with similar phenotypes as TORC1 mutants, in that they initiate sexual differentiation even in nutrient-rich conditions. In most mutants identified, TORC1 activity is downregulated and the mutated genes are involved in tRNA expression or modification. Expression of tRNA precursors decreases when cells undergo sexual differentiation. Furthermore, overexpression of tRNA precursors prevents TORC1 downregulation upon nitrogen starvation and represses the initiation of sexual differentiation. Based on these observations, we propose that tRNA precursors operate in the S. pombe TORC1 pathway to switch growth mode from vegetative to reproductive.
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Affiliation(s)
- Yoko Otsubo
- Laboratory of Cell Responses, National Institute for Basic Biology, Okazaki, Aichi, Japan
| | - Tomohiko Matsuo
- Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Akiko Nishimura
- Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Masayuki Yamamoto
- Laboratory of Cell Responses, National Institute for Basic Biology, Okazaki, Aichi, Japan.,Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Tokyo, Japan.,Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi, Japan
| | - Akira Yamashita
- Laboratory of Cell Responses, National Institute for Basic Biology, Okazaki, Aichi, Japan .,Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi, Japan
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682
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Cormerais Y, Massard PA, Vucetic M, Giuliano S, Tambutté E, Durivault J, Vial V, Endou H, Wempe MF, Parks SK, Pouyssegur J. The glutamine transporter ASCT2 (SLC1A5) promotes tumor growth independently of the amino acid transporter LAT1 (SLC7A5). J Biol Chem 2018; 293:2877-2887. [PMID: 29326164 PMCID: PMC5827425 DOI: 10.1074/jbc.ra117.001342] [Citation(s) in RCA: 116] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Revised: 12/27/2017] [Indexed: 12/12/2022] Open
Abstract
The transporters for glutamine and essential amino acids, ASCT2 (solute carrier family 1 member 5, SLC1A5) and LAT1 (solute carrier family 7 member 5, SLC7A5), respectively, are overexpressed in aggressive cancers and have been identified as cancer-promoting targets. Moreover, previous work has suggested that glutamine influx via ASCT2 triggers essential amino acids entry via the LAT1 exchanger, thus activating mechanistic target of rapamycin complex 1 (mTORC1) and stimulating growth. Here, to further investigate whether these two transporters are functionally coupled, we compared the respective knockout (KO) of either LAT1 or ASCT2 in colon (LS174T) and lung (A549) adenocarcinoma cell lines. Although ASCT2KO significantly reduced glutamine import (>60% reduction), no impact on leucine uptake was observed in both cell lines. Although an in vitro growth-reduction phenotype was observed in A549-ASCT2KO cells only, we found that genetic disruption of ASCT2 strongly decreased tumor growth in both cell lines. However, in sharp contrast to LAT1KO cells, ASCT2KO cells displayed no amino acid (AA) stress response (GCN2/EIF2a/ATF4) or altered mTORC1 activity (S6K1/S6). We therefore conclude that ASCT2KO reduces tumor growth by limiting AA import, but that this effect is independent of LAT1 activity. These data were further supported by in vitro cell proliferation experiments performed in the absence of glutamine. Together these results confirm and extend ASCT2's pro-tumoral role and indicate that the proposed functional coupling model of ASCT2 and LAT1 is not universal across different cancer types.
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Affiliation(s)
- Yann Cormerais
- Medical Biology Department, Centre Scientifique de Monaco (CSM), MC 98000 Monaco
| | - Pierre André Massard
- Medical Biology Department, Centre Scientifique de Monaco (CSM), MC 98000 Monaco
| | - Milica Vucetic
- Medical Biology Department, Centre Scientifique de Monaco (CSM), MC 98000 Monaco
| | - Sandy Giuliano
- Medical Biology Department, Centre Scientifique de Monaco (CSM), MC 98000 Monaco
| | - Eric Tambutté
- Medical Biology Department, Centre Scientifique de Monaco (CSM), MC 98000 Monaco
| | - Jerome Durivault
- Medical Biology Department, Centre Scientifique de Monaco (CSM), MC 98000 Monaco
| | - Valérie Vial
- Medical Biology Department, Centre Scientifique de Monaco (CSM), MC 98000 Monaco
| | | | - Michael F Wempe
- School of Pharmacy, Anschutz Medical Campus, University of Colorado Denver, Aurora, Colorado 80045
| | - Scott K Parks
- Medical Biology Department, Centre Scientifique de Monaco (CSM), MC 98000 Monaco.
| | - Jacques Pouyssegur
- Medical Biology Department, Centre Scientifique de Monaco (CSM), MC 98000 Monaco; Institute for Research on Cancer and Aging (IRCAN), CNRS, INSERM, Centre A. Lacassagne, University of Nice Sophia Antipolis, 06088 Nice, France.
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683
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Panda DK, Bai X, Sabbagh Y, Zhang Y, Zaun HC, Karellis A, Koromilas AE, Lipman ML, Karaplis AC. Defective interplay between mTORC1 activity and endoplasmic reticulum stress-unfolded protein response in uremic vascular calcification. Am J Physiol Renal Physiol 2018; 314:F1046-F1061. [PMID: 29357413 DOI: 10.1152/ajprenal.00350.2017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Vascular calcification increases the risk of cardiovascular disease and death in patients with chronic kidney disease (CKD). Increased activity of mammalian target of rapamycin complex 1 (mTORC1) and endoplasmic reticulum (ER) stress-unfolded protein response (UPR) are independently reported to partake in the pathogenesis of vascular calcification in CKD. However, the association between mTORC1 activity and ER stress-UPR remains unknown. We report here that components of the uremic state [activation of the receptor for advanced glycation end products (RAGE) and hyperphosphatemia] potentiate vascular smooth muscle cell (VSMC) calcification by inducing persistent and exaggerated activity of mTORC1. This gives rise to prolonged and excessive ER stress-UPR as well as attenuated levels of sestrin 1 ( Sesn1) and Sesn3 feeding back to inhibit mTORC1 activity. Activating transcription factor 4 arising from the UPR mediates cell death via expression of CCAAT/enhancer-binding protein (c/EBP) homologous protein (CHOP), impairs the generation of pyrophosphate, a potent inhibitor of mineralization, and potentiates VSMC transdifferentiation to the osteochondrocytic phenotype. Short-term treatment of CKD mice with rapamycin, an inhibitor of mTORC1, or tauroursodeoxycholic acid, a bile acid that restores ER homeostasis, normalized mTORC1 activity, molecular markers of UPR, and calcium content of aortas. Collectively, these data highlight that increased and/or protracted mTORC1 activity arising from the uremic state leads to dysregulated ER stress-UPR and VSMC calcification. Manipulation of the mTORC1-ER stress-UPR pathway opens up new therapeutic strategies for the prevention and treatment of vascular calcification in CKD.
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Affiliation(s)
- Dibyendu K Panda
- Division of Nephrology, Department of Medicine and Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University , Montreal, Quebec , Canada
| | - Xiuying Bai
- Division of Endocrinology and Metabolism, Department of Medicine and Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University , Montreal, Quebec , Canada
| | - Yves Sabbagh
- Rare Disease, Sanofi Genzyme, Framingham, Massachusetts
| | - Yan Zhang
- Division of Nephrology, Department of Medicine and Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University , Montreal, Quebec , Canada
| | - Hans-Christian Zaun
- Division of Nephrology, Department of Medicine and Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University , Montreal, Quebec , Canada
| | - Angeliki Karellis
- Division of Endocrinology and Metabolism, Department of Medicine and Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University , Montreal, Quebec , Canada
| | - Antonis E Koromilas
- Department of Oncology and Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University , Montreal, Quebec , Canada
| | - Mark L Lipman
- Division of Nephrology, Department of Medicine and Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University , Montreal, Quebec , Canada
| | - Andrew C Karaplis
- Division of Endocrinology and Metabolism, Department of Medicine and Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University , Montreal, Quebec , Canada
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684
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He XD, Gong W, Zhang JN, Nie J, Yao CF, Guo FS, Lin Y, Wu XH, Li F, Li J, Sun WC, Wang ED, An YP, Tang HR, Yan GQ, Yang PY, Wei Y, Mao YZ, Lin PC, Zhao JY, Xu Y, Xu W, Zhao SM. Sensing and Transmitting Intracellular Amino Acid Signals through Reversible Lysine Aminoacylations. Cell Metab 2018; 27:151-166.e6. [PMID: 29198988 DOI: 10.1016/j.cmet.2017.10.015] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 08/17/2017] [Accepted: 10/26/2017] [Indexed: 02/05/2023]
Abstract
Amino acids are known regulators of cellular signaling and physiology, but how they are sensed intracellularly is not fully understood. Herein, we report that each aminoacyl-tRNA synthetase (ARS) senses its cognate amino acid sufficiency through catalyzing the formation of lysine aminoacylation (K-AA) on its specific substrate proteins. At physiologic levels, amino acids promote ARSs bound to their substrates and form K-AAs on the ɛ-amine of lysines in their substrates by producing reactive aminoacyl adenylates. The K-AA marks can be removed by deacetylases, such as SIRT1 and SIRT3, employing the same mechanism as that involved in deacetylation. These dynamically regulated K-AAs transduce signals of their respective amino acids. Reversible leucylation on ras-related GTP-binding protein A/B regulates activity of the mammalian target of rapamycin complex 1. Glutaminylation on apoptosis signal-regulating kinase 1 suppresses apoptosis. We discovered non-canonical functions of ARSs and revealed systematic and functional amino acid sensing and signal transduction networks.
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Affiliation(s)
- Xia-Di He
- Obstetrics and Gynecology Hospital of Fudan University, State Key Lab of Genetic Engineering, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PRC; Key Laboratory of Reproduction Regulation of NPFPC (SIPPR,IRD) and Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200032, PRC; State Key Laboratory of Biotherapy/ Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, PRC
| | - Wei Gong
- Obstetrics and Gynecology Hospital of Fudan University, State Key Lab of Genetic Engineering, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PRC; Fudan University Shanghai Cancer Center, Fudan University, Shanghai 200032, PRC
| | - Jia-Nong Zhang
- Obstetrics and Gynecology Hospital of Fudan University, State Key Lab of Genetic Engineering, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PRC; Key Laboratory of Reproduction Regulation of NPFPC (SIPPR,IRD) and Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200032, PRC; State Key Laboratory of Biotherapy/ Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, PRC
| | - Ji Nie
- Obstetrics and Gynecology Hospital of Fudan University, State Key Lab of Genetic Engineering, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PRC; Key Laboratory of Reproduction Regulation of NPFPC (SIPPR,IRD) and Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200032, PRC; State Key Laboratory of Biotherapy/ Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, PRC
| | - Cui-Fang Yao
- Obstetrics and Gynecology Hospital of Fudan University, State Key Lab of Genetic Engineering, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PRC; Key Laboratory of Reproduction Regulation of NPFPC (SIPPR,IRD) and Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200032, PRC; State Key Laboratory of Biotherapy/ Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, PRC
| | - Fu-Shen Guo
- Obstetrics and Gynecology Hospital of Fudan University, State Key Lab of Genetic Engineering, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PRC; Key Laboratory of Reproduction Regulation of NPFPC (SIPPR,IRD) and Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200032, PRC
| | - Yan Lin
- Obstetrics and Gynecology Hospital of Fudan University, State Key Lab of Genetic Engineering, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PRC; Key Laboratory of Reproduction Regulation of NPFPC (SIPPR,IRD) and Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200032, PRC
| | - Xiao-Hui Wu
- Obstetrics and Gynecology Hospital of Fudan University, State Key Lab of Genetic Engineering, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PRC; Institute of Developmental Biology and Molecular Medicine, Fudan University, Shanghai 200032, PRC
| | - Feng Li
- Obstetrics and Gynecology Hospital of Fudan University, State Key Lab of Genetic Engineering, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PRC; Key Laboratory of Reproduction Regulation of NPFPC (SIPPR,IRD) and Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200032, PRC; State Key Laboratory of Biotherapy/ Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, PRC
| | - Jie Li
- Obstetrics and Gynecology Hospital of Fudan University, State Key Lab of Genetic Engineering, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PRC; Fudan University Shanghai Cancer Center, Fudan University, Shanghai 200032, PRC
| | - Wei-Cheng Sun
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, PRC
| | - En-Duo Wang
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, PRC
| | - Yan-Peng An
- Obstetrics and Gynecology Hospital of Fudan University, State Key Lab of Genetic Engineering, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PRC; Key Laboratory of Reproduction Regulation of NPFPC (SIPPR,IRD) and Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200032, PRC
| | - Hui-Ru Tang
- Obstetrics and Gynecology Hospital of Fudan University, State Key Lab of Genetic Engineering, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PRC; Key Laboratory of Reproduction Regulation of NPFPC (SIPPR,IRD) and Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200032, PRC
| | - Guo-Quan Yan
- Obstetrics and Gynecology Hospital of Fudan University, State Key Lab of Genetic Engineering, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PRC
| | - Peng-Yuan Yang
- Obstetrics and Gynecology Hospital of Fudan University, State Key Lab of Genetic Engineering, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PRC
| | - Yun Wei
- Obstetrics and Gynecology Hospital of Fudan University, State Key Lab of Genetic Engineering, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PRC; Key Laboratory of Reproduction Regulation of NPFPC (SIPPR,IRD) and Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200032, PRC
| | - Yun-Zi Mao
- Obstetrics and Gynecology Hospital of Fudan University, State Key Lab of Genetic Engineering, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PRC; Key Laboratory of Reproduction Regulation of NPFPC (SIPPR,IRD) and Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200032, PRC
| | - Peng-Cheng Lin
- Key Laboratory for Tibet Plateau Phytochemistry of Qinghai Province, College of Pharmacy, Qinghai University for Nationalities, Xining 810007, PRC
| | - Jian-Yuan Zhao
- Obstetrics and Gynecology Hospital of Fudan University, State Key Lab of Genetic Engineering, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PRC; State Key Laboratory of Biotherapy/ Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, PRC
| | - Yanhui Xu
- Obstetrics and Gynecology Hospital of Fudan University, State Key Lab of Genetic Engineering, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PRC; Fudan University Shanghai Cancer Center, Fudan University, Shanghai 200032, PRC; CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, PRC.
| | - Wei Xu
- Obstetrics and Gynecology Hospital of Fudan University, State Key Lab of Genetic Engineering, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PRC; Key Laboratory of Reproduction Regulation of NPFPC (SIPPR,IRD) and Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200032, PRC.
| | - Shi-Min Zhao
- Obstetrics and Gynecology Hospital of Fudan University, State Key Lab of Genetic Engineering, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PRC; Key Laboratory of Reproduction Regulation of NPFPC (SIPPR,IRD) and Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200032, PRC; State Key Laboratory of Biotherapy/ Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, PRC.
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685
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Shih YT, Hsueh YP. The involvement of endoplasmic reticulum formation and protein synthesis efficiency in VCP- and ATL1-related neurological disorders. J Biomed Sci 2018; 25:2. [PMID: 29310658 PMCID: PMC5757295 DOI: 10.1186/s12929-017-0403-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 12/26/2017] [Indexed: 12/13/2022] Open
Abstract
The endoplasmic reticulum (ER) is the biggest organelle in cells and is involved in versatile cellular processes. Formation and maintenance of ER morphology are regulated by a series of proteins controlling membrane fusion and curvature. At least six different ER morphology regulators have been demonstrated to be involved in neurological disorders-including Valosin-containing protein (VCP), Atlastin-1 (ATL1), Spastin (SPAST), Reticulon 2 (RTN2), Receptor expression enhancing protein 1 (REEP1) and RAB10-suggesting a critical role of ER formation in neuronal activity and function. Among these genes, mutations in VCP gene involve in inclusion body myopathy with Paget disease of bone and frontotemporal dementia (IBMPFD), familial amyotrophic lateral sclerosis (ALS), autism spectrum disorders (ASD), and hereditary spastic paraplegia (HSP). ATL1 is also one of causative genes of HSP. RAB10 is associated with Parkinson's disease (PD). A recent study showed that VCP and ATL1 work together to regulate dendritic spine formation by controlling ER formation and consequent protein synthesis efficiency. RAB10 shares the same function with VCP and ATL1 to control ER formation and protein synthesis efficiency but acts independently. Increased protein synthesis by adding extra leucine to cultured neurons ameliorated dendritic spine deficits caused by VCP and ATL1 deficiencies, strengthening the significance of protein synthesis in VCP- and ATL1-regulated dendritic spine formation. These findings provide new insight into the roles of ER and protein synthesis in controlling dendritic spine formation and suggest a potential etiology of neurodegenerative disorders caused by mutations in VCP, ATL1 and other genes encoding proteins regulating ER formation and morphogenesis.
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Affiliation(s)
- Yu-Tzu Shih
- Institute of Molecular Biology, Academia Sinica, 128, Academia Rd., Sec. 2, Taipei, 11529, Taiwan
| | - Yi-Ping Hsueh
- Institute of Molecular Biology, Academia Sinica, 128, Academia Rd., Sec. 2, Taipei, 11529, Taiwan.
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686
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Abstract
The mammalian target of rapamycin (mTOR) senses nutrients and growth factors to coordinate cell growth, metabolism and autophagy. Extensive research has mapped the signaling pathways regulated by mTOR that are involved in human diseases, such as cancer, and in diabetes and ageing. Recently, however, new studies have demonstrated important roles for mTOR in promoting the differentiation of adult stem cells, driving the growth and proliferation of stem and progenitor cells, and dictating the differentiation program of multipotent stem cell populations. Here, we review these advances, providing an overview of mTOR signaling and its role in murine and human stem and progenitor cells.
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Affiliation(s)
- Delong Meng
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Anderson R Frank
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jenna L Jewell
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA .,Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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687
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DEPDC5 deficiency contributes to resistance to leucine starvation via p62 accumulation in hepatocellular carcinoma. Sci Rep 2018; 8:106. [PMID: 29311600 PMCID: PMC5758822 DOI: 10.1038/s41598-017-18323-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 12/08/2017] [Indexed: 12/12/2022] Open
Abstract
Decrease in blood concentration of branched-chain amino acids, especially leucine, is known to promote liver carcinogenesis in patients with chronic liver disease, but the mechanism is unclear. We herein established hepatocellular carcinoma (HCC) cells knocked out for DEPDC5 by using the CRISPR/Cas9 system, and elucidated that cell viability of the DEPDC5 knockout (DEPDC5-KO) cells was higher than that of the DEPDC5 wild-type (DEPDC5-WT) under leucine starvation. Considering that autophagy deficiency might be involved in acquired resistance to leucine deprivation, we observed reduction of LC3-II followed by accumulation of p62 in the DEPDC5-KO, which induced reactive oxygen species (ROS) tolerance. DEPDC5 overexpression suppressed cell proliferation and tumorigenicity in immunocompromised mice, and triggered p62 degradation with increased ROS susceptibility. In clinical specimens of HCC patients, decreased expression of DEPDC5 was positively correlated with p62 overexpression, and the progression-free (PFS) and overall survival (OS) were worse in the DEPDC5-negative cases than in the DEPDC5-positive. Moreover, multivariate analysis demonstrated DEPDC5 was an independent prognostic factor for both PFS and OS. Thus, DEPDC5 inactivation enhanced ROS resistance in HCC under the leucine-depleted conditions of chronic liver disease, contributing to poor patient outcome. It could be a potential target for cancer therapy with oxidative stress control.
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688
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Persaud A, Cormerais Y, Pouyssegur J, Rotin D. Dynamin inhibitors block activation of mTORC1 by amino acids independently of dynamin. J Cell Sci 2018; 131:jcs.211755. [PMID: 29150487 DOI: 10.1242/jcs.211755] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 11/08/2017] [Indexed: 02/04/2023] Open
Abstract
mTORC1 plays a crucial role in protein synthesis and cell proliferation and growth. It is activated by growth factors and amino acids, including essential amino acids (EAAs), such as leucine; Leu enters cells via the Leu transporter LAT1-4F2hc (also known as SLC7A5-SLC3A2) and potentially via endocytosis. Here, we investigated the contribution of the different routes of Leu entry into cells to mTORC1 activation using pharmacological inhibitors and cells that lack LAT1 or dynamin-1, -2 and -3. Our results show that LAT1 is the major route of Leu entry into cells and mTORC1 activation (∼70%), whereas dynamin-dependent endocytosis and macropinocytosis contribute minimally to both (5-15%). However, macropinocytosis contributes significantly (∼40%) to activation of mTORC1 by other EAAs. Surprisingly, the dynamin inhibitors dynasore and Dyngo 4A, which minimally inhibited Leu uptake, abolished mTORC1 activation independently of dynamin. Instead, dynasore inhibited RagA binding to Raptor, reduced mTORC1 recruitment to the lysosome, and inhibited Akt activation and TSC2-S939 phosphorylation; this resulted in inhibition of Rheb and mTORC1 activity. Our results suggest that these commonly used inhibitors of dynamin and endocytosis are potent suppressors of mTORC1 activation via off-target effects and not via dynamin inhibition.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Avinash Persaud
- Program in Cell Biology, The Hospital for Sick Children, and Biochemistry Department, University of Toronto, Toronto, Ontario, Canada, M5G 0A4
| | - Yann Cormerais
- Medical Biology Department, Centre Scientifique de Monaco (CSM), 98000 Monaco
| | - Jacques Pouyssegur
- Medical Biology Department, Centre Scientifique de Monaco (CSM), 98000 Monaco.,Université Côte d'Azur, IRCAN, CNRS, Inserm, Centre A Lacassagne, Nice 06189, France
| | - Daniela Rotin
- Program in Cell Biology, The Hospital for Sick Children, and Biochemistry Department, University of Toronto, Toronto, Ontario, Canada, M5G 0A4
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689
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Owens DJ. Nutritional Support to Counteract Muscle Atrophy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1088:483-495. [PMID: 30390266 DOI: 10.1007/978-981-13-1435-3_22] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Malnutrition is an important factor contributing to muscle atrophy. Both underfeeding and obesity have negative consequences for the preservation of muscle mass and function. In addition, adequate nutrition on an exercise background is an efficacious strategy to counteract the severity of muscle loss associated with numerous clinical muscle wasting conditions. As such, significant research efforts have been dedicated to identifying optimal calorie control and the requirements of particular macro- and micronutrients in attenuating muscle atrophy. This chapter will explore current nutrition strategies with robust evidence to counteract muscle atrophy with a particular focus on protein, as well presenting evidence for other promising emergent strategies.
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Affiliation(s)
- Daniel John Owens
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, UK.
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690
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Moreira D, Estaquier J, Cordeiro-da-Silva A, Silvestre R. Metabolic Crosstalk Between Host and Parasitic Pathogens. EXPERIENTIA SUPPLEMENTUM (2012) 2018; 109:421-458. [PMID: 30535608 DOI: 10.1007/978-3-319-74932-7_12] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A complex network that embraces parasite-host intrinsic factors and the microenvironment regulated the interaction between a parasite and its host. Nutritional pressures exerted by both elements of this duet thus dictate this host-parasite niche. To survive and proliferate inside a host and a harsh nutritional environment, the parasites modulate different nutrient sensing pathways to subvert host metabolic pathways. Such mechanism is able to change the flux of distinct nutrients/metabolites diverting them to be used by the parasites. Apart from this nutritional strategy, the scavenging of nutrients, particularly host fatty acids, constitutes a critical mechanism to fulfil parasite nutritional requirements, ultimately defining the host metabolic landscape. The host metabolic alterations that result from host-parasite metabolic coupling can certainly be considered important targets to improve diagnosis and also for the development of future therapies. Metabolism is in fact considered a key element within this complex interaction, its modulation being crucial to dictate the final infection outcome.
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Affiliation(s)
- Diana Moreira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
- i3S-Instituto de Investigacão e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- Departamento de Ciências Bioloógicas, Faculdade de Farmaácia, Universidade do Porto, Porto, Portugal
| | - Jérôme Estaquier
- CNRS FR 3636, Université Paris Descartes, Paris, France
- Centre de Recherche du CHU de Québec, Université Laval, Québec, Canada
| | - Anabela Cordeiro-da-Silva
- i3S-Instituto de Investigacão e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- Departamento de Ciências Bioloógicas, Faculdade de Farmaácia, Universidade do Porto, Porto, Portugal
| | - Ricardo Silvestre
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal.
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691
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Hesketh GG, Wartosch L, Davis LJ, Bright NA, Luzio JP. The Lysosome and Intracellular Signalling. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2018; 57:151-180. [PMID: 30097775 DOI: 10.1007/978-3-319-96704-2_6] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In addition to being the terminal degradative compartment of the cell's endocytic and autophagic pathways, the lysosome is a multifunctional signalling hub integrating the cell's response to nutrient status and growth factor/hormone signalling. The cytosolic surface of the limiting membrane of the lysosome is the site of activation of the multiprotein complex mammalian target of rapamycin complex 1 (mTORC1), which phosphorylates numerous cell growth-related substrates, including transcription factor EB (TFEB). Under conditions in which mTORC1 is inhibited including starvation, TFEB becomes dephosphorylated and translocates to the nucleus where it functions as a master regulator of lysosome biogenesis. The signalling role of lysosomes is not limited to this pathway. They act as an intracellular Ca2+ store, which can release Ca2+ into the cytosol for both local effects on membrane fusion and pleiotropic effects within the cell. The relationship and crosstalk between the lysosomal and endoplasmic reticulum (ER) Ca2+ stores play a role in shaping intracellular Ca2+ signalling. Lysosomes also perform other signalling functions, which are discussed. Current views of the lysosomal compartment recognize its dynamic nature. It includes endolysosomes, autolysosome and storage lysosomes that are constantly engaged in fusion/fission events and lysosome regeneration. How signalling is affected by individual lysosomal organelles being at different stages of these processes and/or at different sites within the cell is poorly understood, but is discussed.
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Affiliation(s)
- Geoffrey G Hesketh
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON, M5G 1X5, Canada
| | - Lena Wartosch
- Department of Clinical Biochemistry and Cambridge Institute for Medical Research, School of Clinical Medicine, Wellcome Trust/MRC Building, University of Cambridge, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, UK
| | - Luther J Davis
- Department of Clinical Biochemistry and Cambridge Institute for Medical Research, School of Clinical Medicine, Wellcome Trust/MRC Building, University of Cambridge, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, UK
| | - Nicholas A Bright
- Department of Clinical Biochemistry and Cambridge Institute for Medical Research, School of Clinical Medicine, Wellcome Trust/MRC Building, University of Cambridge, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, UK
| | - J Paul Luzio
- Department of Clinical Biochemistry and Cambridge Institute for Medical Research, School of Clinical Medicine, Wellcome Trust/MRC Building, University of Cambridge, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, UK.
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692
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Abstract
PURPOSE OF REVIEW The current review aims to provide an update on the recent biomedical interest in oncogenic branched-chain amino acid (BCAA) metabolism, and discusses the advantages of using BCAAs and expression of BCAA-related enzymes in the treatment and diagnosis of cancers. RECENT FINDINGS An accumulating body of evidence demonstrates that BCAAs are essential nutrients for cancer growth and are used by tumors in various biosynthetic pathways and as a source of energy. In addition, BCAA metabolic enzymes, such as the cytosolic branched-chain aminotransferase 1 (BCAT1) and mitochondrial branched-chain aminotransferase 2, have emerged as useful prognostic cancer markers. BCAT1 expression commonly correlates with more aggressive cancer growth and progression, and has attracted substantial scientific attention in the past few years. These studies have found the consequences of BCAT1 disruption to be heterogeneous; not all cancers share the same requirements for BCAA metabolites and the function of BCAT1 appears to vary between cancer types. SUMMARY Both oncogenic mutations and cancer tissue-of-origin influence BCAA metabolism and expression of BCAA-associated metabolic enzymes. These new discoveries need to be taken into consideration during the development of new cancer therapies that target BCAA metabolism.
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Affiliation(s)
- Elitsa A. Ananieva
- Department of Biochemistry and Nutrition, Des Moines University, Des Moines, Iowa
| | - Adam C. Wilkinson
- Department of Genetics, Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Lorry I. Lokey Stem Cell Research Building, Stanford, California, USA
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693
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Choi YK, Park KG. Targeting Glutamine Metabolism for Cancer Treatment. Biomol Ther (Seoul) 2018; 26:19-28. [PMID: 29212303 PMCID: PMC5746034 DOI: 10.4062/biomolther.2017.178] [Citation(s) in RCA: 196] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Revised: 11/04/2017] [Accepted: 11/09/2017] [Indexed: 02/06/2023] Open
Abstract
Rapidly proliferating cancer cells require energy and cellular building blocks for their growth and ability to maintain redox balance. Many studies have focused on understanding how cancer cells adapt their nutrient metabolism to meet the high demand of anabolism required for proliferation and maintaining redox balance. Glutamine, the most abundant amino acid in plasma, is a well-known nutrient used by cancer cells to increase proliferation as well as survival under metabolic stress conditions. In this review, we provide an overview of the role of glutamine metabolism in cancer cell survival and growth and highlight the mechanisms by which glutamine metabolism affects cancer cell signaling. Furthermore, we summarize the potential therapeutic approaches of targeting glutamine metabolism for the treatment of numerous types of cancer.
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Affiliation(s)
- Yeon-Kyung Choi
- Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu 41944, Republic of Korea
| | - Keun-Gyu Park
- Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu 41944, Republic of Korea
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694
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Andrew R, Izzo AA. Principles of pharmacological research of nutraceuticals. Br J Pharmacol 2017; 174:1177-1194. [PMID: 28500635 DOI: 10.1111/bph.13779] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
LINKED ARTICLES This article is part of a themed section on Principles of Pharmacological Research of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.11/issuetoc.
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Affiliation(s)
- Ruth Andrew
- Centre for Cardiovascular Research, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - Angelo A Izzo
- Department of Pharmacy, School of Medicine and Surgery, University of Naples Federico II, Naples, Italy
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695
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Zhang J, Zhang X, Liu Y, Su Z, Dawar FU, Dan H, He Y, Gui JF, Mei J. Leucine mediates autophagosome-lysosome fusion and improves sperm motility by activating the PI3K/Akt pathway. Oncotarget 2017; 8:111807-111818. [PMID: 29340093 PMCID: PMC5762361 DOI: 10.18632/oncotarget.22910] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 11/16/2017] [Indexed: 12/13/2022] Open
Abstract
Amino acid supplementation is an efficient and effective strategy to increase sperm quality. In our research, a comparative study was conducted to screen free amino acids to improve sperm motility, and we found that leucine was the most efficient one. Leucine treatment increases sperm motility depending on the activation of PI3K/Akt signaling pathway, while the chemical inhibitor of PI3K/Akt signal could reduce the amount of pAkt activated by leucine treatment. Moreover, leucine treatment improved the expression of P62 and LC3-II, substantially suppressed the autophagy process in zebrafish testis. In vitro studies showed that leucine could reduce the fusion of autophagosome and lysosome that was indicated by the co-localization of EGFP-LC3 and lysosome marker. Two chemical modulators of autophagy, such as LY294002 (the inhibitor of PI3K/Akt signal) and chloroquine were administered to investigate the process of autophagy on zebrafish sperm motility. LY294002 inhibited autophagosome formation to reduced sperm motility, while chloroquine inhibited the fusion of autophagosome and lysosome to improve sperm motility. Our data suggest that short-term treatment with leucine could increase zebrafish sperm motility by affecting the autophagy and inhibiting the fusion of autophagosome and lysosomes, depending on the activation of PI3K/Akt signaling pathway.
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Affiliation(s)
- Jin Zhang
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China
| | - Xuemei Zhang
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China
| | - Yingjie Liu
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China
| | - Zihao Su
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China
| | - Farman Ullah Dawar
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China
| | - Hong Dan
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China
| | - Yan He
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China
| | - Jian-Fang Gui
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, University of the Chinese Academy of Sciences, Wuhan 430072, China
| | - Jie Mei
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China
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696
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mTORC1 as the main gateway to autophagy. Essays Biochem 2017; 61:565-584. [PMID: 29233869 PMCID: PMC5869864 DOI: 10.1042/ebc20170027] [Citation(s) in RCA: 356] [Impact Index Per Article: 50.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 10/19/2017] [Accepted: 10/20/2017] [Indexed: 12/16/2022]
Abstract
Cells and organisms must coordinate their metabolic activity with changes in their environment to ensure their growth only when conditions are favourable. In order to maintain cellular homoeostasis, a tight regulation between the synthesis and degradation of cellular components is essential. At the epicentre of the cellular nutrient sensing is the mechanistic target of rapamycin complex 1 (mTORC1) which connects environmental cues, including nutrient and growth factor availability as well as stress, to metabolic processes in order to preserve cellular homoeostasis. Under nutrient-rich conditions mTORC1 promotes cell growth by stimulating biosynthetic pathways, including synthesis of proteins, lipids and nucleotides, and by inhibiting cellular catabolism through repression of the autophagic pathway. Its close signalling interplay with the energy sensor AMP-activated protein kinase (AMPK) dictates whether the cell actively favours anabolic or catabolic processes. Underlining the role of mTORC1 in the coordination of cellular metabolism, its deregulation is linked to numerous human diseases ranging from metabolic disorders to many cancers. Although mTORC1 can be modulated by a number of different inputs, amino acids represent primordial cues that cannot be compensated for by any other stimuli. The understanding of how amino acids signal to mTORC1 has increased considerably in the last years; however this area of research remains a hot topic in biomedical sciences. The current ideas and models proposed to explain the interrelationship between amino acid sensing, mTORC1 signalling and autophagy is the subject of the present review.
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697
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Antikainen H, Driscoll M, Haspel G, Dobrowolski R. TOR-mediated regulation of metabolism in aging. Aging Cell 2017; 16:1219-1233. [PMID: 28971552 PMCID: PMC5676073 DOI: 10.1111/acel.12689] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2017] [Indexed: 01/06/2023] Open
Abstract
Cellular metabolism is regulated by the mTOR kinase, a key component of the molecular nutrient sensor pathway that plays a central role in cellular survival and aging. The mTOR pathway promotes protein and lipid synthesis and inhibits autophagy, a process known for its contribution to longevity in several model organisms. The nutrient‐sensing pathway is regulated at the lysosomal membrane by a number of proteins for which deficiency triggers widespread aging phenotypes in tested animal models. In response to environmental cues, this recently discovered lysosomal nutrient‐sensing complex regulates autophagy transcriptionally through conserved factors, such as the transcription factors TFEB and FOXO, associated with lifespan extension. This key metabolic pathway strongly depends on nucleocytoplasmic compartmentalization, a cellular phenomenon gradually lost during aging. In this review, we discuss the current progress in understanding the contribution of mTOR‐regulating factors to autophagy and longevity. Furthermore, we review research on the regulation of metabolism conducted in multiple aging models, including Caenorhabditis elegans, Drosophila and mouse, and human iPSCs. We suggest that conserved molecular pathways have the strongest potential for the development of new avenues for treatment of age‐related diseases.
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Affiliation(s)
- Henri Antikainen
- Federated Department of Biological Sciences New Jersey Institute of Technology Rutgers University Newark NJ 07102 USA
| | - Monica Driscoll
- Department of Molecular Biology and Biochemistry Rutgers University Piscataway NJ 08854 USA
| | - Gal Haspel
- Federated Department of Biological Sciences New Jersey Institute of Technology Rutgers University Newark NJ 07102 USA
| | - Radek Dobrowolski
- Federated Department of Biological Sciences New Jersey Institute of Technology Rutgers University Newark NJ 07102 USA
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698
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Yonehara R, Nada S, Nakai T, Nakai M, Kitamura A, Ogawa A, Nakatsumi H, Nakayama KI, Li S, Standley DM, Yamashita E, Nakagawa A, Okada M. Structural basis for the assembly of the Ragulator-Rag GTPase complex. Nat Commun 2017; 8:1625. [PMID: 29158492 PMCID: PMC5696360 DOI: 10.1038/s41467-017-01762-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 10/13/2017] [Indexed: 12/31/2022] Open
Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) plays a central role in regulating cell growth and metabolism by responding to cellular nutrient conditions. The activity of mTORC1 is controlled by Rag GTPases, which are anchored to lysosomes via Ragulator, a pentameric protein complex consisting of membrane-anchored p18/LAMTOR1 and two roadblock heterodimers. Here we report the crystal structure of Ragulator in complex with the roadblock domains of RagA-C, which helps to elucidate the molecular basis for the regulation of Rag GTPases. In the structure, p18 wraps around the three pairs of roadblock heterodimers to tandemly assemble them onto lysosomes. Cellular and in vitro analyses further demonstrate that p18 is required for Ragulator-Rag GTPase assembly and amino acid-dependent activation of mTORC1. These results establish p18 as a critical organizing scaffold for the Ragulator-Rag GTPase complex, which may provide a platform for nutrient sensing on lysosomes. mTORC1 activity is controlled through Rag GTPases, which are anchored to the lysosome through the Ragulator. Here, the authors give molecular insights into Ragulator-Rag GTPase assembly and present the crystal structures of the Ragulator alone and in complex with the RagA-C roadblock domains.
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Affiliation(s)
- Ryo Yonehara
- Laboratory of Supramolecular Crystallography, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Shigeyuki Nada
- Department of Oncogene Research, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Tomokazu Nakai
- Department of Oncogene Research, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Masahiro Nakai
- Department of Oncogene Research, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Ayaka Kitamura
- Department of Oncogene Research, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Akira Ogawa
- Department of Oncogene Research, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Hirokazu Nakatsumi
- Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-0054, Japan
| | - Keiichi I Nakayama
- Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-0054, Japan
| | - Songling Li
- Department of Genome Informatics, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Daron M Standley
- Department of Genome Informatics, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Eiki Yamashita
- Laboratory of Supramolecular Crystallography, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Atsushi Nakagawa
- Laboratory of Supramolecular Crystallography, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Masato Okada
- Department of Oncogene Research, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
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699
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Biffo S, Manfrini N, Ricciardi S. Crosstalks between translation and metabolism in cancer. Curr Opin Genet Dev 2017; 48:75-81. [PMID: 29153483 DOI: 10.1016/j.gde.2017.10.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 10/23/2017] [Accepted: 10/24/2017] [Indexed: 12/26/2022]
Abstract
Albeit cancer patients' heterogeneity, all tumor cells have alterations of both metabolism and translation. The simplest explanation for this common feature is that several oncogenes coordinate a translational and metabolic reprogramming that is necessary for tumor cells to thrive. Overall, at least three oncogenic pathways, namely c-Myc, RAS and PI3K-mTOR, are known to affect both translation and metabolism by stimulating glycolysis and protein synthesis. The crosstalk between metabolite production and the translational machinery is, instead, less understood. What is known is that, on one side, translation initiation factors, such as eIF4E and eIF6, drive tumor growth and regulate metabolism through selective translation of nucleotide biosynthesis, glycolysis and fatty acid synthesis rate-limiting mRNAs, and on the other, that nutrient levels regulate the translational machinery by inducing full activity of translation factors. Therefore, translation and metabolism offer several therapeutic targets to be fully exploited in future studies.
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Affiliation(s)
- Stefano Biffo
- National Institute of Molecular Genetics "Romeo ed Enrica Invernizzi", INGM, 20122 Milano, Italy; Department of Biosciences, University of Milano, 20133 Milano, Italy.
| | - Nicola Manfrini
- National Institute of Molecular Genetics "Romeo ed Enrica Invernizzi", INGM, 20122 Milano, Italy
| | - Sara Ricciardi
- National Institute of Molecular Genetics "Romeo ed Enrica Invernizzi", INGM, 20122 Milano, Italy
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700
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Gu X, Orozco JM, Saxton RA, Condon KJ, Liu GY, Krawczyk PA, Scaria SM, Harper JW, Gygi SP, Sabatini DM. SAMTOR is an S-adenosylmethionine sensor for the mTORC1 pathway. Science 2017; 358:813-818. [PMID: 29123071 PMCID: PMC5747364 DOI: 10.1126/science.aao3265] [Citation(s) in RCA: 358] [Impact Index Per Article: 51.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Accepted: 09/29/2017] [Indexed: 11/02/2022]
Abstract
mTOR complex 1 (mTORC1) regulates cell growth and metabolism in response to multiple environmental cues. Nutrients signal via the Rag guanosine triphosphatases (GTPases) to promote the localization of mTORC1 to the lysosomal surface, its site of activation. We identified SAMTOR, a previously uncharacterized protein, which inhibits mTORC1 signaling by interacting with GATOR1, the GTPase activating protein (GAP) for RagA/B. We found that the methyl donor S-adenosylmethionine (SAM) disrupts the SAMTOR-GATOR1 complex by binding directly to SAMTOR with a dissociation constant of approximately 7 μM. In cells, methionine starvation reduces SAM levels below this dissociation constant and promotes the association of SAMTOR with GATOR1, thereby inhibiting mTORC1 signaling in a SAMTOR-dependent fashion. Methionine-induced activation of mTORC1 requires the SAM binding capacity of SAMTOR. Thus, SAMTOR is a SAM sensor that links methionine and one-carbon metabolism to mTORC1 signaling.
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Affiliation(s)
- Xin Gu
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Jose M Orozco
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Robert A Saxton
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Kendall J Condon
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Grace Y Liu
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Patrycja A Krawczyk
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Sonia M Scaria
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - J Wade Harper
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Steven P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - David M Sabatini
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
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