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Lee A, Davis JH. NCOA4 initiates ferritinophagy by binding GATE16 using two highly avid short linear interaction motifs. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.09.597909. [PMID: 38895392 PMCID: PMC11185777 DOI: 10.1101/2024.06.09.597909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Cells carefully regulate cytosolic iron, which is a vital enzymatic cofactor, yet is toxic in excess. In mammalian cells, surplus iron is sequestered in ferritin cages that, in iron limiting conditions, are degraded through the selective autophagy pathway ferritinophagy to liberate free iron. Prior work identified the ferritinophagy receptor protein NCOA4, which links ferritin and LC3/GABARAP-family member GATE16, effectively tethering ferritin to the autophagic machinery. Here, we elucidate the molecular mechanism underlying this interaction, discovering two short linear motifs in NCOA4 that each bind GATE16 with weak affinity. These binding motifs are highly avid and, in concert, support high-affinity NCOA4•GATE16 complex formation. We further find the minimal NCOA4383-522 fragment bearing these motifs is sufficient for ferritinophagy and that both motifs are necessary for this activity. This work suggests a general mechanism wherein selective autophagy receptors can distinguish between the inactive soluble pools of LC3/GABARAPs and the active membrane-conjugated forms that drive autophagy. Finally, we find that iron decreases NCOA4383-522's affinity for GATE16, providing a plausible mechanism for iron-dependent regulation of ferritinophagy.
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Affiliation(s)
- April Lee
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Joseph H. Davis
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
- Program in Computational and Systems Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
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2
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Jia C, Tian L, Cheng C, Zhang J, Al-Nusaif M, Li T, Yang H, Lin Y, Li S, Le W. α-Synuclein reduces acetylserotonin O-methyltransferase mediated melatonin biosynthesis by microtubule-associated protein 1 light chain 3 beta-related degradation pathway. Cell Mol Life Sci 2024; 81:61. [PMID: 38279053 DOI: 10.1007/s00018-023-05053-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 10/16/2023] [Accepted: 11/13/2023] [Indexed: 01/28/2024]
Abstract
Previous studies have demonstrated that α-synuclein (α-SYN) is closely associated with rapid eye movement sleep behavior disorder (RBD) related to several neurodegenerative disorders. However, the exact molecular mechanisms are still rarely investigated. In the present study, we found that in the α-SYNA53T induced RBD-like behavior mouse model, the melatonin level in the plasma and pineal gland were significantly decreased. To elucidate the underlying mechanism of α-SYN-induced melatonin reduction, we investigated the effect of α-SYN in melatonin biosynthesis. Our findings showed that α-SYN reduced the level and activity of melatonin synthesis enzyme acetylserotonin O-methyltransferase (ASMT) in the pineal gland and in the cell cultures. In addition, we found that microtubule-associated protein 1 light chain 3 beta (LC3B) as an important autophagy adapter is involved in the degradation of ASMT. Immunoprecipitation assays revealed that α-SYN increases the binding between LC3B and ASMT, leading to ASMT degradation and a consequent reduction in melatonin biosynthesis. Collectively, our results demonstrate the molecular mechanisms of α-SYN in melatonin biosynthesis, indicating that melatonin is an important molecule involved in the α-SYN-associated RBD-like behaviors, which may provide a potential therapeutic target for RBD of Parkinson's disease.
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Affiliation(s)
- Congcong Jia
- Liaoning Provincial Key Laboratory for Research on the Pathogenic Mechanisms of Neurological Diseases, The First Affiliated Hospital, Dalian Medical University, Dalian, 116021, China
| | - Lulu Tian
- Liaoning Provincial Key Laboratory for Research on the Pathogenic Mechanisms of Neurological Diseases, The First Affiliated Hospital, Dalian Medical University, Dalian, 116021, China
| | - Cheng Cheng
- Liaoning Provincial Key Laboratory for Research on the Pathogenic Mechanisms of Neurological Diseases, The First Affiliated Hospital, Dalian Medical University, Dalian, 116021, China
| | - Jun Zhang
- Liaoning Provincial Key Laboratory for Research on the Pathogenic Mechanisms of Neurological Diseases, The First Affiliated Hospital, Dalian Medical University, Dalian, 116021, China
| | - Murad Al-Nusaif
- Liaoning Provincial Key Laboratory for Research on the Pathogenic Mechanisms of Neurological Diseases, The First Affiliated Hospital, Dalian Medical University, Dalian, 116021, China
| | - Tianbai Li
- Liaoning Provincial Key Laboratory for Research on the Pathogenic Mechanisms of Neurological Diseases, The First Affiliated Hospital, Dalian Medical University, Dalian, 116021, China
| | - Huijia Yang
- Liaoning Provincial Key Laboratory for Research on the Pathogenic Mechanisms of Neurological Diseases, The First Affiliated Hospital, Dalian Medical University, Dalian, 116021, China
| | - Yushan Lin
- Liaoning Provincial Key Laboratory for Research on the Pathogenic Mechanisms of Neurological Diseases, The First Affiliated Hospital, Dalian Medical University, Dalian, 116021, China
| | - Song Li
- Liaoning Provincial Key Laboratory for Research on the Pathogenic Mechanisms of Neurological Diseases, The First Affiliated Hospital, Dalian Medical University, Dalian, 116021, China
| | - Weidong Le
- Liaoning Provincial Key Laboratory for Research on the Pathogenic Mechanisms of Neurological Diseases, The First Affiliated Hospital, Dalian Medical University, Dalian, 116021, China.
- Institute of Neurology, Sichuan Academy of Medical Sciences, Sichuan Provincial Hospital, Chengdu, 610072, China.
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3
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Panda SP, Singh V. The Dysregulated MAD in Mad: A Neuro-theranostic Approach Through the Induction of Autophagic Biomarkers LC3B-II and ATG. Mol Neurobiol 2023; 60:5214-5236. [PMID: 37273153 DOI: 10.1007/s12035-023-03402-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 05/24/2023] [Indexed: 06/06/2023]
Abstract
The word mad has historically been associated with the psyche, emotions, and abnormal behavior. Dementia is a common symptom among psychiatric disorders or mad (schizophrenia, depression, bipolar disorder) patients. Autophagy/mitophagy is a protective mechanism used by cells to get rid of dysfunctional cellular organelles or mitochondria. Autophagosome/mitophagosome abundance in autophagy depends on microtubule-associated protein light chain 3B (LC3B-II) and autophagy-triggering gene (ATG) which functions as an autophagic biomarker for phagophore production and quick mRNA disintegration. Defects in either LC3B-II or the ATG lead to dysregulated mitophagy-and-autophagy-linked dementia (MAD). The impaired MAD is closely associated with schizophrenia, depression, and bipolar disorder. The pathomechanism of psychosis is not entirely known, which is the severe limitation of today's antipsychotic drugs. However, the reviewed circuit identifies new insights that may be especially helpful in targeting biomarkers of dementia. Neuro-theranostics can also be achieved by manufacturing either bioengineered bacterial and mammalian cells or nanocarriers (liposomes, polymers, and nanogels) loaded with both imaging and therapeutic materials. The nanocarriers must cross the BBB and should release both diagnostic agents and therapeutic agents in a controlled manner to prove their effectiveness against psychiatric disorders. In this review, we highlighted the potential of microRNAs (miRs) as neuro-theranostics in the treatment of dementia by targeting autophagic biomarkers LC3B-II and ATG. Focus was also placed on the potential for neuro-theranostic nanocells/nanocarriers to traverse the BBB and induce action against psychiatric disorders. The neuro-theranostic approach can provide targeted treatment for mental disorders by creating theranostic nanocarriers.
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Affiliation(s)
- Siva Prasad Panda
- Institute of Pharmaceutical Research, GLA University, Uttar Pradesh, Mathura, India.
| | - Vikrant Singh
- Research Scholar, Institute of Pharmaceutical Research, GLA University, Uttar Pradesh, Mathura, India
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4
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Fas BA, Maiani E, Sora V, Kumar M, Mashkoor M, Lambrughi M, Tiberti M, Papaleo E. The conformational and mutational landscape of the ubiquitin-like marker for autophagosome formation in cancer. Autophagy 2021; 17:2818-2841. [PMID: 33302793 PMCID: PMC8525936 DOI: 10.1080/15548627.2020.1847443] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 10/28/2020] [Accepted: 11/03/2020] [Indexed: 02/06/2023] Open
Abstract
Macroautophagy/autophagy is a cellular process to recycle damaged cellular components, and its modulation can be exploited for disease treatments. A key autophagy player is the ubiquitin-like protein MAP1LC3B/LC3B. Mutations and changes in MAP1LC3B expression occur in cancer samples. However, the investigation of the effects of these mutations on MAP1LC3B protein structure is still missing. Despite many LC3B structures that have been solved, a comprehensive study, including dynamics, has not yet been undertaken. To address this knowledge gap, we assessed nine physical models for biomolecular simulations for their capabilities to describe the structural ensemble of MAP1LC3B. With the resulting MAP1LC3B structural ensembles, we characterized the impact of 26 missense mutations from pan-cancer studies with different approaches, and we experimentally validated our prediction for six variants using cellular assays. Our findings shed light on damaging or neutral mutations in MAP1LC3B, providing an atlas of its modifications in cancer. In particular, P32Q mutation was found detrimental for protein stability with a propensity to aggregation. In a broader context, our framework can be applied to assess the pathogenicity of protein mutations or to prioritize variants for experimental studies, allowing to comprehensively account for different aspects that mutational events alter in terms of protein structure and function.Abbreviations: ATG: autophagy-related; Cα: alpha carbon; CG: coarse-grained; CHARMM: Chemistry at Harvard macromolecular mechanics; CONAN: contact analysis; FUNDC1: FUN14 domain containing 1; FYCO1: FYVE and coiled-coil domain containing 1; GABARAP: GABA type A receptor-associated protein; GROMACS: Groningen machine for chemical simulations; HP: hydrophobic pocket; LIR: LC3 interacting region; MAP1LC3B/LC3B microtubule associated protein 1 light chain 3 B; MD: molecular dynamics; OPTN: optineurin; OSF: open software foundation; PE: phosphatidylethanolamine, PLEKHM1: pleckstrin homology domain-containing family M 1; PSN: protein structure network; PTM: post-translational modification; SA: structural alphabet; SLiM: short linear motif; SQSTM1/p62: sequestosome 1; WT: wild-type.
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Affiliation(s)
- Burcu Aykac Fas
- Computational Biology Laboratory, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Emiliano Maiani
- Computational Biology Laboratory, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Valentina Sora
- Computational Biology Laboratory, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Mukesh Kumar
- Computational Biology Laboratory, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Maliha Mashkoor
- Computational Biology Laboratory, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Matteo Lambrughi
- Computational Biology Laboratory, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Matteo Tiberti
- Computational Biology Laboratory, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Elena Papaleo
- Computational Biology Laboratory, Danish Cancer Society Research Center, Copenhagen, Denmark
- Translational Disease Systems Biology, Faculty of Health and Medical Sciences, Novo Nordisk Foundation Center for Protein Research University of Copenhagen, Copenhagen, Denmark
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5
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Tang Y, Li Y, Xin D, Chen L, Xiong Z, Yu X. Icariin alleviates osteoarthritis by regulating autophagy of chondrocytes by mediating PI3K/AKT/mTOR signaling. Bioengineered 2021; 12:2984-2999. [PMID: 34167449 PMCID: PMC8806900 DOI: 10.1080/21655979.2021.1943602] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Osteoarthritis (OA) is a chronic degenerative disease that significantly impacts the quality of life of the elderly population. Recently, the pathogenesis of OA has been reported to involve autophagy in chondrocytes. Intriguingly, icariin, one of the main components of epimedium, exerts multiple pharmacological effects, including a protective effect against chondrocyte damage. Thus, we aimed to investigate the therapeutic effect of icariin on OA and its potential underlying mechanism by using a rat model of OA. After treatment with icariin or an autophagy activator (rapamycin) or inhibitor (3-methyladenine), OA chondrocyte viability was measured using the CCK-8 assay, apoptosis in the chondrocytes was evaluated using the acridine orange-propidium iodide assay and flow cytometry, and OA tissue pathological state was assessed using micro-CT scanning and safranin O staining. Furthermore, immunohistochemical staining was used to measure the expression level of Beclin-1 and immunofluorescence labeling was used to visualize LC3 expression, and western blotting was used to determine the expression levels of autophagy proteins and key proteins in the PI3K signaling pathway. The apoptotic rate of OA chondrocytes was markedly elevated by 3-methyladenine and suppressed by rapamycin and icariin; autophagy genes were drastically downregulated in the 3-methyladenine group and upregulated in the rapamycin and icariin groups; and the PI3K/AKT/mTOR signaling pathway was activated by 3-methyladenine and inhibited by rapamycin and icariin. Notably, following treatment with rapamycin and icariin, the severe pathological state in OA cartilage tissues was substantially alleviated, and this was accompanied by activated autophagy and inhibited PI3K signaling in the cartilage tissues. Taken together, these findings indicate that icariin alleviates OA by regulating the autophagy of chondrocytes by mediating PI3K/AKT/mTOR signaling.
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Affiliation(s)
- Yanghua Tang
- Department of Orthopedics, Hospital of Traditional Chinese Medicine of Xiaoshan District, Hangzhou, Zhejiang, China
| | - Yongfu Li
- Department of Orthopedics, The Second People's Hospital of Tonglu, Hangzhou, Zhejiang, China
| | - Dawei Xin
- Department of Orthopedics, Hospital of Traditional Chinese Medicine of Xiaoshan District, Hangzhou, Zhejiang, China
| | - Lin Chen
- Department of Orthopedics, The Second People's Hospital of Tonglu, Hangzhou, Zhejiang, China
| | - Zhenfei Xiong
- Department of Orthopedics, The Second People's Hospital of Tonglu, Hangzhou, Zhejiang, China
| | - Xuezi Yu
- Department of Orthopedics, Xixi Hospital of Hangzhou, Hangzhou, Zhejiang, China
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6
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Xu C, Wang L, Fozouni P, Evjen G, Chandra V, Jiang J, Lu C, Nicastri M, Bretz C, Winkler JD, Amaravadi R, Garcia BA, Adams PD, Ott M, Tong W, Johansen T, Dou Z, Berger SL. SIRT1 is downregulated by autophagy in senescence and ageing. Nat Cell Biol 2020; 22:1170-1179. [PMID: 32989246 PMCID: PMC7805578 DOI: 10.1038/s41556-020-00579-5] [Citation(s) in RCA: 228] [Impact Index Per Article: 57.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 08/17/2020] [Indexed: 12/01/2022]
Abstract
SIRT1 (Sir2) is an NAD+-dependent deacetylase that plays critical roles in a broad range of biological events, including metabolism, the immune response and ageing1-5. Although there is strong interest in stimulating SIRT1 catalytic activity, the homeostasis of SIRT1 at the protein level is poorly understood. Here we report that macroautophagy (hereafter referred to as autophagy), a catabolic membrane trafficking pathway that degrades cellular components through autophagosomes and lysosomes, mediates the downregulation of mammalian SIRT1 protein during senescence and in vivo ageing. In senescence, nuclear SIRT1 is recognized as an autophagy substrate and is subjected to cytoplasmic autophagosome-lysosome degradation, via the autophagy protein LC3. Importantly, the autophagy-lysosome pathway contributes to the loss of SIRT1 during ageing of several tissues related to the immune and haematopoietic system in mice, including the spleen, thymus, and haematopoietic stem and progenitor cells, as well as in CD8+CD28- T cells from aged human donors. Our study reveals a mechanism in the regulation of the protein homeostasis of SIRT1 and suggests a potential strategy to stabilize SIRT1 to promote productive ageing.
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Affiliation(s)
- Caiyue Xu
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA,Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Lu Wang
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA,Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Parinaz Fozouni
- Gladstone Institutes, San Francisco, CA, 94158, USA,Department of Medicine, University of California, San Francisco, San Francisco, CA, 94125, USA
| | - Gry Evjen
- Molecular Cancer Research Group, Institute of Medical Biology, University of Tromsø- The Arctic University of Norway, Tromsø 9037, Norway
| | - Vemika Chandra
- Division of Hematology, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA,Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Jing Jiang
- Division of Hematology, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA,Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA,Current address: Institute of Translational Medicine, School of Medicine, Yangzhou University, Yangzhou, Jiangsu, 225001, China
| | - Congcong Lu
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA,Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Michael Nicastri
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Corey Bretz
- Sanford Burnham Prebys Medical Discovery Institute, San Diego, CA, 92037, USA
| | - Jeffrey D. Winkler
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Ravi Amaravadi
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Benjamin A. Garcia
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA,Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Peter D. Adams
- Sanford Burnham Prebys Medical Discovery Institute, San Diego, CA, 92037, USA
| | - Melanie Ott
- Gladstone Institutes, San Francisco, CA, 94158, USA,Department of Medicine, University of California, San Francisco, San Francisco, CA, 94125, USA
| | - Wei Tong
- Division of Hematology, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA,Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Terje Johansen
- Molecular Cancer Research Group, Institute of Medical Biology, University of Tromsø- The Arctic University of Norway, Tromsø 9037, Norway
| | - Zhixun Dou
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. .,Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. .,Center for Regenerative Medicine, Massachusetts General Hospital, Boston, MA, USA. .,Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA. .,Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA.
| | - Shelley L. Berger
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA,Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA,Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA,Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, 19104, USA,Correspondence should be addressed to S.L.B. () or Z.D. ()
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7
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Liu X, Chen Z, Han Z, Liu Y, Wu X, Peng Y, Di W, Lan R, Sun B, Xu B, Xu W. AMPK-mediated degradation of Nav1.5 through autophagy. FASEB J 2019; 33:5366-5376. [PMID: 30759345 DOI: 10.1096/fj.201801583rr] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The voltage-gated cardiac sodium channel, Nav1.5, is the key component that controls cardiac excitative electrical impulse and propagation. However, the dynamic alterations of Nav1.5 during cardiac ischemia and reperfusion (I/R) are seldom reported. We found that the protein levels of rat cardiac Nav1.5 were significantly decreased in response to cardiac I/R injury. By simulating I/R injury in cells through activating AMPK by glucose deprivation, AMPK activator treatment, or hypoxia and reoxygenation (H/R), we found that Nav1.5 was down-regulated by AMPK-mediated autophagic degradation. Furthermore, AMPK was found to phosphorylate Nav1.5 at threonine (T) 101, which then regulates the interaction between Nav1.5 and the autophagic adaptor protein, microtubule-associated protein 1 light chain 3 (LC3), by exposing the LC3-interacting region adjacent to T101 in Nav1.5. This study highlights an instrumental role of AMPK in mediating the autophagic degradation of Nav1.5 during cardiac I/R injury.-Liu, X., Chen, Z., Han, Z., Liu, Y., Wu, X., Peng, Y., Di, W., Lan, R., Sun, B., Xu, B., Xu, W. AMPK-mediated degradation of Nav1.5 through autophagy.
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Affiliation(s)
- Xuehua Liu
- Department of Ultrasound Diagnosis, Drum Tower Hospital, Nanjing University Medical School, Nanjing, China.,Department of Cardiology, Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Zheng Chen
- Department of Cardiology, Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Zhonglin Han
- Department of Cardiology, Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Yu Liu
- Department of Cardiology, Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Xiang Wu
- Department of Cardiology, Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Yuzhu Peng
- Department of Cardiology, Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Wencheng Di
- Department of Cardiology, Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Rongfang Lan
- Department of Cardiology, Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Bugao Sun
- Department of Ultrasound Diagnosis, Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Biao Xu
- Department of Cardiology, Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Wei Xu
- Department of Cardiology, Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
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8
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Song T, Su H, Yin W, Wang L, Huang R. Acetylation modulates
LC
3 stability and cargo recognition. FEBS Lett 2019; 593:414-422. [DOI: 10.1002/1873-3468.13327] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Revised: 01/08/2019] [Accepted: 01/08/2019] [Indexed: 02/06/2023]
Affiliation(s)
- Tingting Song
- Life Sciences Institute Zhejiang University Hangzhou China
| | - Haifeng Su
- Institute of Neuroscience State Key Laboratory of Neuroscience CAS Center for Excellence in Brain Science and Intelligence Technology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Shanghai China
| | - Wei Yin
- Core Facilities Zhejiang University School of Medicine Hangzhou China
| | - Liming Wang
- Life Sciences Institute Zhejiang University Hangzhou China
| | - Rui Huang
- Medical School Chongqing University China
- Key Laboratory for Biorheological Science and Technology Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants Bioengineering College Chongqing University China
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9
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Atg5 Supports Rickettsia australis Infection in Macrophages In Vitro and In Vivo. Infect Immun 2018; 87:IAI.00651-18. [PMID: 30297526 PMCID: PMC6300621 DOI: 10.1128/iai.00651-18] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 09/28/2018] [Indexed: 01/26/2023] Open
Abstract
Rickettsiae can cause life-threatening infections in humans. Macrophages are one of the initial targets for rickettsiae after inoculation by ticks. However, it remains poorly understood how rickettsiae remain free in macrophages prior to establishing their infection in microvascular endothelial cells. Here, we demonstrated that the concentration of Rickettsia australis was significantly greater in infected tissues of Atg5flox/flox mice than in the counterparts of Atg5flox/flox Lyz-Cre mice, in association with a reduced level of interleukin-1β (IL-1β) in serum. The greater concentration of R. australis in Atg5flox/flox bone marrow-derived macrophages (BMMs) than in Atg5flox/flox Lyz-Cre BMMs in vitro was abolished by exogenous treatment with recombinant IL-1β. Rickettsia australis induced significantly increased levels of light chain 3 (LC3) form II (LC3-II) and LC3 puncta in Atg5-competent BMMs but not in Atg5-deficient BMMs, while no p62 turnover was observed. Further analysis found the colocalization of LC3 with a small portion of R. australis and Rickettsia-containing double-membrane-bound vacuoles in the BMMs of B6 mice. Moreover, treatment with rapamycin significantly increased the concentrations of R. australis in B6 BMMs compared to those in the untreated B6 BMM controls. Taken together, our results demonstrate that Atg5 favors R. australis infection in mouse macrophages in association with a suppressed level of IL-1β production but not active autophagy flux. These data highlight the contribution of Atg5 in macrophages to the pathogenesis of rickettsial diseases.
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10
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Chen Y, Sun HQ, Eichorst JP, Albanesi JP, Yin H, Mueller JD. Comobility of GABARAP and Phosphatidylinositol 4-Kinase 2A on Cytoplasmic Vesicles. Biochemistry 2018; 57:3556-3559. [PMID: 29792687 DOI: 10.1021/acs.biochem.8b00224] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We previously reported that recruitment of the type IIA phosphatidylinositol 4-kinase (PI4K2A) to autophagosomes by GABARAP, a member of the Atg8 family of autophagy-related proteins, is important for autophagosome-lysosome fusion. Because both PI4K2A and GABARAP have also been implicated in the intracellular trafficking of plasma membrane receptors in the secretory/endocytic pathway, we characterized their interaction in cells under nonautophagic conditions. Fluorescence fluctuation spectroscopy measurements revealed that GABARAP exists predominantly as a cytosolic monomer in live cells, but is recruited to small cytoplasmic vesicles upon overexpression of PI4K2A. C-Terminal lipidation of GABARAP, which is essential for its autophagic activities, is not necessary for its recruitment to these PI4K2A-containing transport vesicles. However, a GABARAP truncation mutant lacking C-terminal residues 103-117 fails to bind to PI4K2A, is not recruited to cytoplasmic vesicles, and does not codistribute with PI4K2A on subcellular organelles. These observations suggest that the PI4K2A-GABARAP interaction plays a role in membrane trafficking both under autophagic and nonautophagic conditions.
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Affiliation(s)
- Yan Chen
- School of Physics and Astronomy , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | | | - John P Eichorst
- School of Physics and Astronomy , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | | | | | - Joachim D Mueller
- School of Physics and Astronomy , University of Minnesota , Minneapolis , Minnesota 55455 , United States
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11
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Nguyen TA, Puhl HL, Pham AK, Vogel SS. Auto-FPFA: An Automated Microscope for Characterizing Genetically Encoded Biosensors. Sci Rep 2018; 8:7374. [PMID: 29743504 PMCID: PMC5943267 DOI: 10.1038/s41598-018-25689-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 04/26/2018] [Indexed: 12/14/2022] Open
Abstract
Genetically encoded biosensors function by linking structural change in a protein construct, typically tagged with one or more fluorescent proteins, to changes in a biological parameter of interest (such as calcium concentration, pH, phosphorylation-state, etc.). Typically, the structural change triggered by alterations in the bio-parameter is monitored as a change in either fluorescent intensity, or lifetime. Potentially, other photo-physical properties of fluorophores, such as fluorescence anisotropy, molecular brightness, concentration, and lateral and/or rotational diffusion could also be used. Furthermore, while it is likely that multiple photo-physical attributes of a biosensor might be altered as a function of the bio-parameter, standard measurements monitor only a single photo-physical trait. This limits how biosensors are designed, as well as the accuracy and interpretation of biosensor measurements. Here we describe the design and construction of an automated multimodal-microscope. This system can autonomously analyze 96 samples in a micro-titer dish and for each sample simultaneously measure intensity (photon count), fluorescence lifetime, time-resolved anisotropy, molecular brightness, lateral diffusion time, and concentration. We characterize the accuracy and precision of this instrument, and then demonstrate its utility by characterizing three types of genetically encoded calcium sensors as well as a negative control.
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Affiliation(s)
- Tuan A Nguyen
- Laboratory of Molecular Physiology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, 5625 Fishers Lane, Rockville, Maryland, USA
| | - Henry L Puhl
- Laboratory of Molecular Physiology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, 5625 Fishers Lane, Rockville, Maryland, USA
| | - An K Pham
- Laboratory of Molecular Physiology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, 5625 Fishers Lane, Rockville, Maryland, USA
| | - Steven S Vogel
- Laboratory of Molecular Physiology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, 5625 Fishers Lane, Rockville, Maryland, USA.
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12
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Lin KC, Lin MW, Hsu MN, Yu-Chen G, Chao YC, Tuan HY, Chiang CS, Hu YC. Graphene oxide sensitizes cancer cells to chemotherapeutics by inducing early autophagy events, promoting nuclear trafficking and necrosis. Am J Cancer Res 2018; 8:2477-2487. [PMID: 29721093 PMCID: PMC5928903 DOI: 10.7150/thno.24173] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 02/20/2018] [Indexed: 01/08/2023] Open
Abstract
Rationale: Cisplatin (CDDP) is a broad-spectrum anticancer drug but chemoresistance to CDDP impedes its wide use for cancer therapy. Autophagy is an event occurring in the cytoplasm and cytoplasmic LC3 puncta formation is a hallmark of autophagy. Graphene oxide (GO) is a nanomaterial that provokes autophagy in CT26 colon cancer cells and confers antitumor effects. Here we aimed to evaluate whether combined use of GO with CDDP (GO/CDDP) overcomes chemoresistance in different cancer cells and uncover the underlying mechanism. Methods: We treated different cancer cells with GO/CDDP and evaluated the cytotoxicity, death mechanism, autophagy induction and nuclear entry of CDDP. We further knocked down genes essential for autophagic flux and deciphered which step is critical to nuclear import and cell death. Finally, we performed immunoprecipitation, mass spectrometry and immunofluorescence labeling to evaluate the association of LC3 and CDDP. Results: We uncovered that combination of GO and CDDP (GO/CDDP) promoted the killing of not only CT26 cells, but also ovarian, cervical and prostate cancer cells. In the highly chemosensitized Skov-3 cells, GO/CDDP significantly enhanced concurrent nuclear import of CDDP and autophagy marker LC3 and elevated cell necrosis, which required autophagy initiation and progression but did not necessitate late autophagy events (e.g., autophagosome completion and autolysosome formation). The GO/CDDP-elicited nuclear trafficking and cell death also required importin α/β, and LC3 also co-migrated with CDDP and histone H1/H4 into the nucleus. In particular, GO/CDDP triggered histone H4 acetylation in the nucleus, which could decondense the chromosome and enable CDDP to more effectively access chromosomal DNA to trigger cell death. Conclusion: These findings shed light on the mechanisms of GO/CDDP-induced chemosensitization and implicate the potential applications of GO/CDDP to treat multiple cancers.
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Peixoto MS, de Oliveira Galvão MF, Batistuzzo de Medeiros SR. Cell death pathways of particulate matter toxicity. CHEMOSPHERE 2017; 188:32-48. [PMID: 28865791 DOI: 10.1016/j.chemosphere.2017.08.076] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 08/14/2017] [Accepted: 08/16/2017] [Indexed: 06/07/2023]
Abstract
Humans are exposed to various complex mixtures of particulate matter (PM) from different sources. Long-term exposure to high levels of these particulates has been linked to a diverse range of respiratory and cardiovascular diseases that have resulted in hospital admission. The evaluation of the effects of PM exposure on the mechanisms related to cell death has been a challenge for many researchers. Therefore, in this review, we have discussed the effects of airborne PM exposure on mechanisms related to cell death. For this purpose, we have compiled literature data on PM sources, the effects of exposure, and the assays and models used for evaluation, in order to establish comparisons between various studies. The analysis of this collected data suggested divergent responses to PM exposure that resulted in different cell death types (apoptosis, autophagy, and necrosis). In addition, PM induced oxidative stress within cells, which appeared to be an important factor in the determination of cell fate. When the levels of reactive oxygen species were overpowering, the cellular fate was directed toward cell death. This may be the underlying mechanism of the development or exacerbation of respiratory diseases, such as emphysema and chronic obstructive pulmonary diseases. In addition, PM was shown to cause DNA damage and the resulting mutations increased the risk of cancer. Furthermore, several conditions should be considered in the assessment of cell death in PM-exposed models, including the cell culture line, PM composition, and the interaction of the different cells types in in vivo models.
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Affiliation(s)
- Milena Simões Peixoto
- Graduate Program in Biochemistry, Biosciences Center, Federal University of Rio Grande do Norte, Natal, RN, Brazil.
| | - Marcos Felipe de Oliveira Galvão
- Graduate Program in Biochemistry, Biosciences Center, Federal University of Rio Grande do Norte, Natal, RN, Brazil; Department of Cell Biology and Genetics, Biosciences Center, Federal University of Rio Grande do Norte, Natal, RN, Brazil.
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14
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Awan FM, Obaid A, Ikram A, Janjua HA. Mutation-Structure-Function Relationship Based Integrated Strategy Reveals the Potential Impact of Deleterious Missense Mutations in Autophagy Related Proteins on Hepatocellular Carcinoma (HCC): A Comprehensive Informatics Approach. Int J Mol Sci 2017; 18:ijms18010139. [PMID: 28085066 PMCID: PMC5297772 DOI: 10.3390/ijms18010139] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Revised: 11/14/2016] [Accepted: 11/16/2016] [Indexed: 12/13/2022] Open
Abstract
Autophagy, an evolutionary conserved multifaceted lysosome-mediated bulk degradation system, plays a vital role in liver pathologies including hepatocellular carcinoma (HCC). Post-translational modifications (PTMs) and genetic variations in autophagy components have emerged as significant determinants of autophagy related proteins. Identification of a comprehensive spectrum of genetic variations and PTMs of autophagy related proteins and their impact at molecular level will greatly expand our understanding of autophagy based regulation. In this study, we attempted to identify high risk missense mutations that are highly damaging to the structure as well as function of autophagy related proteins including LC3A, LC3B, BECN1 and SCD1. Number of putative structural and functional residues, including several sites that undergo PTMs were also identified. In total, 16 high-risk SNPs in LC3A, 18 in LC3B, 40 in BECN1 and 43 in SCD1 were prioritized. Out of these, 2 in LC3A (K49A, K51A), 1 in LC3B (S92C), 6 in BECN1 (S113R, R292C, R292H, Y338C, S346Y, Y352H) and 6 in SCD1 (Y41C, Y55D, R131W, R135Q, R135W, Y151C) coincide with potential PTM sites. Our integrated analysis found LC3B Y113C, BECN1 I403T, SCD1 R126S and SCD1 Y218C as highly deleterious HCC-associated mutations. This study is the first extensive in silico mutational analysis of the LC3A, LC3B, BECN1 and SCD1 proteins. We hope that the observed results will be a valuable resource for in-depth mechanistic insight into future investigations of pathological missense SNPs using an integrated computational platform.
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Affiliation(s)
- Faryal Mehwish Awan
- Department of Industrial Biotechnology, Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12 Islamabad 44000, Pakistan.
| | - Ayesha Obaid
- Department of Industrial Biotechnology, Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12 Islamabad 44000, Pakistan.
| | - Aqsa Ikram
- Department of Industrial Biotechnology, Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12 Islamabad 44000, Pakistan.
| | - Hussnain Ahmed Janjua
- Department of Industrial Biotechnology, Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12 Islamabad 44000, Pakistan.
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15
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Kraft LJ, Dowler J, Manral P, Kenworthy AK. Size, organization, and dynamics of soluble SQSTM1 and LC3-SQSTM1 complexes in living cells. Autophagy 2016; 12:1660-74. [PMID: 27442348 DOI: 10.1080/15548627.2016.1199299] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Selective macroautophagy/autophagy-with the help of molecular receptors-captures cargo for lysosomal degradation. Among the best-studied molecular receptors is SQSTM1/p62, a homo-oligomeric ubiquitin binding protein, which binds to both cargo and MAP1LC3B/LC3, a protein important for autophagosome biogenesis. Although the mechanisms underlying interaction of LC3 and SQSTM1 have been extensively studied, very little is known about the size or organization of soluble complexes formed between SQSTM1 and LC3 prior to phagophore (the autophagosome precursor) binding in live cells at the molecular level. To address this question, in the current study we use a combination of 2 microscopy-based approaches, FRET microscopy and confocal FRAP, to study the nanoscale properties of soluble SQSTM1 complexes and SQSTM1-LC3 complexes in living HeLa cells. We find that, independent of puncta, SQSTM1 oligomerizes to form very slowly diffusing complexes that contain multiple copies of SQSTM1 within FRET proximity of one another. Furthermore, we show that the interactions of soluble pools of LC3 and SQSTM1 can be readily detected by both FRAP and FRET. Finally, we uncover unexpected roles of SQSTM1's PB1 domain, a region of the protein involved in homo-oligomer formation, in complex formation. Taken together, these findings provide new insights into the nature of nanometer-sized protein complexes in the autophagy pathway.
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Affiliation(s)
- Lewis J Kraft
- a Chemical and Physical Biology Program , Vanderbilt University Medical Center , Nashville , TN , USA
| | - Jacob Dowler
- b Department of Molecular Physiology and Biophysics , Vanderbilt University Medical Center , Nashville , TN , USA
| | - Pallavi Manral
- b Department of Molecular Physiology and Biophysics , Vanderbilt University Medical Center , Nashville , TN , USA
| | - Anne K Kenworthy
- a Chemical and Physical Biology Program , Vanderbilt University Medical Center , Nashville , TN , USA.,b Department of Molecular Physiology and Biophysics , Vanderbilt University Medical Center , Nashville , TN , USA.,c Department of Cell and Developmental Biology , Vanderbilt University Medical Center , Nashville , TN , USA
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16
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Kraft LJ, Manral P, Dowler J, Kenworthy AK. Nuclear LC3 Associates with Slowly Diffusing Complexes that Survey the Nucleolus. Traffic 2016; 17:369-99. [PMID: 26728248 PMCID: PMC4975375 DOI: 10.1111/tra.12372] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 12/31/2015] [Accepted: 12/31/2015] [Indexed: 12/22/2022]
Abstract
MAP1LC3B (microtubule-associated protein 1 light chain 3, LC3) is a key component of the autophagy pathway, contributing to both cargo selection and autophagosome formation in the cytoplasm. Emerging evidence suggests that nuclear forms of LC3 are also functionally important; however, the mechanisms that facilitate the nuclear targeting and trafficking of LC3 between the nucleus and cytoplasm under steady-state conditions are poorly understood. In this study, we examine how residues known to regulate the interactions between LC3 and other proteins or RNA (F52 L53, R68-R70 and G120) contribute to its nuclear targeting, nucleocytoplasmic transport and association with nucleoli and other nuclear components. We find that residues F52 L53 and R68-70, but not G120, regulate targeting of LC3 to the nucleus, its rates of nucleocytoplasmic transport and the apparent sizes of LC3-associated complexes in the nucleus inferred from fluorescence recovery after photobleaching (FRAP) measurements. We also show that LC3 is enriched in nucleoli and its triple arginine motif is especially important for nucleolar targeting. Finally, we identify a series of candidate nuclear LC3-interacting proteins using mass spectrometry, including MAP1B, tubulin and several 40S ribosomal proteins. These findings suggest LC3 is retained in the nucleus in association with high-molecular weight complexes that continuously scan the nucleolus.
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Affiliation(s)
- Lewis J. Kraft
- Chemical and Physical Biology Program, Vanderbilt University, Nashville, Tennessee, USA
| | - Pallavi Manral
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Jacob Dowler
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Anne K. Kenworthy
- Chemical and Physical Biology Program, Vanderbilt University, Nashville, Tennessee, USA
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, USA
- Epithelial Biology Program, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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17
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Huang R, Xu Y, Wan W, Shou X, Qian J, You Z, Liu B, Chang C, Zhou T, Lippincott-Schwartz J, Liu W. Deacetylation of nuclear LC3 drives autophagy initiation under starvation. Mol Cell 2015; 57:456-66. [PMID: 25601754 DOI: 10.1016/j.molcel.2014.12.013] [Citation(s) in RCA: 456] [Impact Index Per Article: 50.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 10/30/2014] [Accepted: 12/05/2014] [Indexed: 01/07/2023]
Abstract
Shuttling of macromolecules between different cellular compartments helps regulate the timing and extent of different cellular activities. Here, we report that LC3, a key initiator of autophagy that cycles between the nucleus and cytoplasm, becomes selectively activated in the nucleus during starvation through deacetylation by the nuclear deacetylase Sirt1. Deacetylation of LC3 at K49 and K51 by Sirt1 allows LC3 to interact with the nuclear protein DOR and return to the cytoplasm with DOR, where it is able to bind Atg7 and other autophagy factors and undergo phosphatidylethanolamine conjugation to preautophagic membranes. The association of deacetylated LC3 with autophagic factors shifts LC3's distribution from the nucleus toward the cytoplasm. Thus, an acetylation-deacetylation cycle ensures that LC3 effectively redistributes in an activated form from nucleus to cytoplasm, where it plays a central role in autophagy to enable the cell to cope with the lack of external nutrients.
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Affiliation(s)
- Rui Huang
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cell Biology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Yinfeng Xu
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cell Biology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Wei Wan
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cell Biology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Xin Shou
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cell Biology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Jiali Qian
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cell Biology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Zhiyuan You
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cell Biology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Bo Liu
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cell Biology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Chunmei Chang
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cell Biology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Tianhua Zhou
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cell Biology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Jennifer Lippincott-Schwartz
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA
| | - Wei Liu
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cell Biology, Zhejiang University School of Medicine, Hangzhou 310058, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China.
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18
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Kyoung M, Russell SJ, Kohnhorst CL, Esemoto NN, An S. Dynamic architecture of the purinosome involved in human de novo purine biosynthesis. Biochemistry 2015; 54:870-80. [PMID: 25540829 DOI: 10.1021/bi501480d] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Enzymes in human de novo purine biosynthesis have been demonstrated to form a reversible, transient multienzyme complex, the purinosome, upon purine starvation. However, characterization of purinosomes has been limited to HeLa cells and has heavily relied on qualitative examination of their subcellular localization and reversibility under wide-field fluorescence microscopy. Quantitative approaches, which are particularly compatible with human disease-relevant cell lines, are necessary to explicitly understand the purinosome in live cells. In this work, human breast carcinoma Hs578T cells have been utilized to demonstrate the preferential utilization of the purinosome under purine-depleted conditions. In addition, we have employed a confocal microscopy-based biophysical technique, fluorescence recovery after photobleaching, to characterize kinetic properties of the purinosome in live Hs578T cells. Quantitative characterization of the diffusion coefficients of all de novo purine biosynthetic enzymes reveals the significant reduction of their mobile kinetics upon purinosome formation, the dynamic partitioning of each enzyme into the purinosome, and the existence of three intermediate species in purinosome assembly under purine starvation. We also demonstrate that the diffusion coefficient of the purine salvage enzyme, hypoxanthine phosphoribosyltransferase 1, is not sensitive to purine starvation, indicating exclusion of the salvage pathway from the purinosome. Furthermore, our biophysical characterization of nonmetabolic enzymes clarifies that purinosomes are spatiotemporally different cellular bodies from stress granules and cytoplasmic protein aggregates in both Hs578T and HeLa cells. Collectively, quantitative analyses of the purinosome in Hs578T cells led us to provide novel insights for the dynamic architecture of the purinosome assembly.
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Affiliation(s)
- Minjoung Kyoung
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County , 1000 Hilltop Circle, Baltimore, Maryland 21250, United States
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