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Liao YC, Pang S, Li WP, Shtengel G, Choi H, Schaefer K, Xu CS, Lippincott-Schwartz J. COPII with ALG2 and ESCRTs control lysosome-dependent microautophagy of ER exit sites. Dev Cell 2024; 59:1410-1424.e4. [PMID: 38593803 DOI: 10.1016/j.devcel.2024.03.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 09/23/2023] [Accepted: 03/12/2024] [Indexed: 04/11/2024]
Abstract
Endoplasmic reticulum exit sites (ERESs) are tubular outgrowths of endoplasmic reticulum that serve as the earliest station for protein sorting and export into the secretory pathway. How these structures respond to different cellular conditions remains unclear. Here, we report that ERESs undergo lysosome-dependent microautophagy when Ca2+ is released by lysosomes in response to nutrient stressors such as mTOR inhibition or amino acid starvation in mammalian cells. Targeting and uptake of ERESs into lysosomes were observed by super-resolution live-cell imaging and focus ion beam scanning electron microscopy (FIB-SEM). The mechanism was ESCRT dependent and required ubiquitinated SEC31, ALG2, and ALIX, with a knockout of ALG2 or function-blocking mutations of ALIX preventing engulfment of ERESs by lysosomes. In vitro, reconstitution of the pathway was possible using lysosomal lipid-mimicking giant unilamellar vesicles and purified recombinant components. Together, these findings demonstrate a pathway of lysosome-dependent ERES microautophagy mediated by COPII, ALG2, and ESCRTS induced by nutrient stress.
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Affiliation(s)
| | - Song Pang
- HHMI Janelia Research Campus, Ashburn, VA, USA; Yale School of Medicine, New Haven, CT, USA
| | - Wei-Ping Li
- HHMI Janelia Research Campus, Ashburn, VA, USA
| | | | - Heejun Choi
- HHMI Janelia Research Campus, Ashburn, VA, USA
| | | | - C Shan Xu
- HHMI Janelia Research Campus, Ashburn, VA, USA; Yale School of Medicine, New Haven, CT, USA
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2
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Pust S, Brech A, Wegner CS, Stenmark H, Haglund K. Vesicle-mediated transport of ALIX and ESCRT-III to the intercellular bridge during cytokinesis. Cell Mol Life Sci 2023; 80:235. [PMID: 37523003 PMCID: PMC10390626 DOI: 10.1007/s00018-023-04864-y] [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: 12/19/2022] [Revised: 07/07/2023] [Accepted: 07/08/2023] [Indexed: 08/01/2023]
Abstract
Cellular abscission is the final step of cytokinesis that leads to the physical separation of the two daughter cells. The scaffold protein ALIX and the ESCRT-I protein TSG101 contribute to recruiting ESCRT-III to the midbody, which orchestrates the final membrane scission of the intercellular bridge. Here, we addressed the transport mechanisms of ALIX and ESCRT-III subunit CHMP4B to the midbody. Structured illumination microscopy revealed gradual accumulation of ALIX at the midbody, resulting in the formation of spiral-like structures extending from the midbody to the abscission site, which strongly co-localized with CHMP4B. Live-cell microscopy uncovered that ALIX appeared together with CHMP4B in vesicular structures, whose motility was microtubule-dependent. Depletion of ALIX led to structural alterations of the midbody and delayed recruitment of CHMP4B, resulting in delayed abscission. Likewise, depletion of the kinesin-1 motor KIF5B reduced the motility of ALIX-positive vesicles and delayed midbody recruitment of ALIX, TSG101 and CHMP4B, accompanied by impeded abscission. We propose that ALIX, TSG101 and CHMP4B are associated with endosomal vesicles transported on microtubules by kinesin-1 to the cytokinetic bridge and midbody, thereby contributing to their function in abscission.
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Affiliation(s)
- Sascha Pust
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, 0379, Oslo, Norway.
- Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Montebello, 0379, Oslo, Norway.
| | - Andreas Brech
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, 0379, Oslo, Norway
- Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Montebello, 0379, Oslo, Norway
| | - Catherine Sem Wegner
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, 0379, Oslo, Norway
- Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Montebello, 0379, Oslo, Norway
| | - Harald Stenmark
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, 0379, Oslo, Norway
- Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Montebello, 0379, Oslo, Norway
| | - Kaisa Haglund
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, 0379, Oslo, Norway.
- Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Montebello, 0379, Oslo, Norway.
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3
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Xie QH, Wang WM, Yang JG, Xia HF, Xiao BL, Chen GH, Huang J, Li RF, Chen G. ALIX promotes cell migration and invasion of head and neck squamous cell carcinoma by regulating the expression of MMP9, MMP14, VEGF-C. Arch Oral Biol 2023; 151:105696. [PMID: 37086494 DOI: 10.1016/j.archoralbio.2023.105696] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 04/05/2023] [Accepted: 04/08/2023] [Indexed: 04/24/2023]
Abstract
OBJECTIVE The poor survival rate of head and neck squamous cell carcinoma (HNSCC), one of the most prevalent human cancer, is attributed to frequent locoregional recurrence and lymph node metastases. Though it is reported that the expression of ALG-2 interacting protein X (ALIX) closely correlates with the progression of various tumors, its role in HNSCC remains unclear. The present study aims to investigate the role of ALIX in the development of HNSCC. DESIGN With immunohistochemical staining, the expression levels of ALIX and series of related functional proteins were compared in normal mucosal (n = 18), HNSCC tissues (n = 54), and metastatic lymph nodes (n = 11). Further, the correlation analysis was performed among the proteins detected. By knocking down ALIX in HNSCC cell lines, the correlation of ALIX with the proteins was verified in vitro. The role of ALIX in proliferation, migration, and invasion of HNSCC cells was further studied by flow cytometry, wounding healing, and transwell assays, respectively. RESULTS Higher expression level of ALIX was revealed in HNSCC samples, especially in metastatic lymph nodes, than in normal mucosal tissues. Accordingly, increasing levels of MMP9, MMP14, and VEGF-C were also discovered in metastatic lymph nodes and significantly correlated with the expression of ALIX. In vitro assays demonstrated that the knockdown of ALIX reduced both the transcriptional and protein levels of MMP9, MMP14, and VEGF-C, together with suppressed migration and weakened invasion of HNSCC cell lines. CONCLUSIONS ALIX up-regulated the expression of MMP9, MMP14 and VEGF-C, and promoted migration and invasion of HNSCC cells.
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Affiliation(s)
- Qi-Hui Xie
- The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China; Department of Oral and Maxillofacial Surgery, School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Wei-Ming Wang
- Department of Oral and Maxillofacial Surgery, Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Jie-Gang Yang
- The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China; Department of Oral and Maxillofacial Surgery, School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Hou-Fu Xia
- The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China; Department of Oral and Maxillofacial Surgery, School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Bo-Lin Xiao
- The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Gao-Hong Chen
- The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Jue Huang
- The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Rui-Fang Li
- The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
| | - Gang Chen
- The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China; Department of Oral and Maxillofacial Surgery, School and Hospital of Stomatology, Wuhan University, Wuhan, China; TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan 430071, China; Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, China.
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4
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Role of calcium-sensor proteins in cell membrane repair. Biosci Rep 2023; 43:232522. [PMID: 36728029 PMCID: PMC9970828 DOI: 10.1042/bsr20220765] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 01/20/2023] [Accepted: 02/01/2023] [Indexed: 02/03/2023] Open
Abstract
Cell membrane repair is a critical process used to maintain cell integrity and survival from potentially lethal chemical, and mechanical membrane injury. Rapid increases in local calcium levels due to a membrane rupture have been widely accepted as a trigger for multiple membrane-resealing models that utilize exocytosis, endocytosis, patching, and shedding mechanisms. Calcium-sensor proteins, such as synaptotagmins (Syt), dysferlin, S100 proteins, and annexins, have all been identified to regulate, or participate in, multiple modes of membrane repair. Dysfunction of membrane repair from inefficiencies or genetic alterations in these proteins contributes to diseases such as muscular dystrophy (MD) and heart disease. The present review covers the role of some of the key calcium-sensor proteins and their involvement in membrane repair.
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5
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Romano JD, Mayoral J, Guevara RB, Rivera-Cuevas Y, Carruthers VB, Weiss LM, Coppens I. Toxoplasma gondii scavenges mammalian host organelles through the usurpation of host ESCRT-III and Vps4A. J Cell Sci 2023; 136:jcs260159. [PMID: 36718630 PMCID: PMC10022688 DOI: 10.1242/jcs.260159] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 01/19/2023] [Indexed: 02/01/2023] Open
Abstract
Intracellular pathogens exploit cellular resources through host cell manipulation. Within its nonfusogenic parasitophorous vacuole (PV), Toxoplasma gondii targets host nutrient-filled organelles and sequesters them into the PV through deep invaginations of the PV membrane (PVM) that ultimately detach from this membrane. Some of these invaginations are generated by an intravacuolar network (IVN) of parasite-derived tubules attached to the PVM. Here, we examined the usurpation of host ESCRT-III and Vps4A by the parasite to create PVM buds and vesicles. CHMP4B associated with the PVM/IVN, and dominant-negative (DN) CHMP4B formed many long PVM invaginations containing CHMP4B filaments. These invaginations were shorter in IVN-deficient parasites, suggesting cooperation between the IVN and ESCRT. In infected cells expressing Vps4A-DN, enlarged intra-PV structures containing host endolysosomes accumulated, reflecting defects in PVM scission. Parasite mutants lacking T. gondii (Tg)GRA14 or TgGRA64, which interact with ESCRT, reduced CHMP4B-DN-induced PVM invaginations and intra-PV host organelles, with greater defects in a double knockout, revealing the exploitation of ESCRT to scavenge host organelles by Toxoplasma.
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Affiliation(s)
- Julia D. Romano
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Joshua Mayoral
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Rebekah B. Guevara
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Yolanda Rivera-Cuevas
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Vern B. Carruthers
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Louis M. Weiss
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
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6
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The Roles of Exosomal Proteins: Classification, Function, and Applications. Int J Mol Sci 2023; 24:ijms24043061. [PMID: 36834471 PMCID: PMC9961790 DOI: 10.3390/ijms24043061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/24/2023] [Accepted: 01/26/2023] [Indexed: 02/09/2023] Open
Abstract
Exosome, a subpopulation of extracellular vesicles, plays diverse roles in various biological processes. As one of the most abundant components of exosomes, exosomal proteins have been revealed to participate in the development of many diseases, such as carcinoma, sarcoma, melanoma, neurological disorders, immune responses, cardiovascular diseases, and infection. Thus, understanding the functions and mechanisms of exosomal proteins potentially assists clinical diagnosis and targeted delivery of therapies. However, current knowledge about the function and application of exosomal proteins is still limited. In this review, we summarize the classification of exosomal proteins, and the roles of exosomal proteins in exosome biogenesis and disease development, as well as in the clinical applications.
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7
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Wenzel DM, Mackay DR, Skalicky JJ, Paine EL, Miller MS, Ullman KS, Sundquist WI. Comprehensive analysis of the human ESCRT-III-MIT domain interactome reveals new cofactors for cytokinetic abscission. eLife 2022; 11:e77779. [PMID: 36107470 PMCID: PMC9477494 DOI: 10.7554/elife.77779] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 08/09/2022] [Indexed: 11/13/2022] Open
Abstract
The 12 related human ESCRT-III proteins form filaments that constrict membranes and mediate fission, including during cytokinetic abscission. The C-terminal tails of polymerized ESCRT-III subunits also bind proteins that contain Microtubule-Interacting and Trafficking (MIT) domains. MIT domains can interact with ESCRT-III tails in many different ways to create a complex binding code that is used to recruit essential cofactors to sites of ESCRT activity. Here, we have comprehensively and quantitatively mapped the interactions between all known ESCRT-III tails and 19 recombinant human MIT domains. We measured 228 pairwise interactions, quantified 60 positive interactions, and discovered 18 previously unreported interactions. We also report the crystal structure of the SPASTIN MIT domain in complex with the IST1 C-terminal tail. Three MIT enzymes were studied in detail and shown to: (1) localize to cytokinetic midbody membrane bridges through interactions with their specific ESCRT-III binding partners (SPASTIN-IST1, KATNA1-CHMP3, and CAPN7-IST1), (2) function in abscission (SPASTIN, KATNA1, and CAPN7), and (3) function in the 'NoCut' abscission checkpoint (SPASTIN and CAPN7). Our studies define the human MIT-ESCRT-III interactome, identify new factors and activities required for cytokinetic abscission and its regulation, and provide a platform for analyzing ESCRT-III and MIT cofactor interactions in all ESCRT-mediated processes.
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Affiliation(s)
- Dawn M Wenzel
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
| | - Douglas R Mackay
- Department of Oncological Sciences, Huntsman Cancer Institute, University of UtahSalt Lake CityUnited States
| | - Jack J Skalicky
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
| | - Elliott L Paine
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
| | - Matthew S Miller
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
| | - Katharine S Ullman
- Department of Oncological Sciences, Huntsman Cancer Institute, University of UtahSalt Lake CityUnited States
| | - Wesley I Sundquist
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
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8
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Dumont V, Lehtonen S. PACSIN proteins in vivo: Roles in development and physiology. Acta Physiol (Oxf) 2022; 234:e13783. [PMID: 34990060 PMCID: PMC9285741 DOI: 10.1111/apha.13783] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 11/15/2021] [Accepted: 01/01/2022] [Indexed: 12/22/2022]
Abstract
Protein kinase C and casein kinase substrate in neurons (PACSINs), or syndapins (synaptic dynamin‐associated proteins), are a family of proteins involved in the regulation of cell cytoskeleton, intracellular trafficking and signalling. Over the last twenty years, PACSINs have been mostly studied in the in vitro and ex vivo settings, and only in the last decade reports on their function in vivo have emerged. We first summarize the identification, structure and cellular functions of PACSINs, and then focus on the relevance of PACSINs in vivo. During development in various model organisms, PACSINs participate in diverse processes, such as neural crest cell development, gastrulation, laterality development and neuromuscular junction formation. In mouse, PACSIN2 regulates angiogenesis during retinal development and in human, PACSIN2 associates with monosomy and embryonic implantation. In adulthood, PACSIN1 has been extensively studied in the brain and shown to regulate neuromorphogenesis, receptor trafficking and synaptic plasticity. Several genetic studies suggest a role for PACSIN1 in the development of schizophrenia, which is also supported by the phenotype of mice depleted of PACSIN1. PACSIN2 plays an essential role in the maintenance of intestinal homeostasis and participates in kidney repair processes after injury. PACSIN3 is abundant in muscle tissue and necessary for caveolar biogenesis to create membrane reservoirs, thus controlling muscle function, and has been linked to certain genetic muscular disorders. The above examples illustrate the importance of PACSINs in diverse physiological or tissue repair processes in various organs, and associations to diseases when their functions are disturbed.
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Affiliation(s)
- Vincent Dumont
- Department of Pathology and Research Program for Clinical and Molecular Metabolism Faculty of Medicine University of Helsinki Helsinki Finland
| | - Sanna Lehtonen
- Department of Pathology and Research Program for Clinical and Molecular Metabolism Faculty of Medicine University of Helsinki Helsinki Finland
- Department of Pathology University of Helsinki Helsinki Finland
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9
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Hepatitis C virus (HCV)-induced ROS/JNK signaling pathway activates the E3 ubiquitin ligase Itch to promote the release of HCV particles via polyubiquitylation of VPS4A. J Virol 2022; 96:e0181121. [PMID: 35044214 DOI: 10.1128/jvi.01811-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We previously reported that hepatitis C virus (HCV) infection activates the reactive oxygen species (ROS)/c-Jun N-terminal kinase (JNK) signaling pathway. However, the roles of ROS/JNK activation in the HCV life cycle still remain unclear. We sought to identify a novel role of ROS/JNK signaling pathway in the HCV life cycle. Immunoblot analysis revealed that HCV-induced ROS/JNK activation promoted phosphorylation of Itch, a HECT-type E3 ubiquitin ligase, leading to activation of Itch. The siRNA-knockdown of Itch significantly reduced the extracellular HCV infectivity titers, HCV RNA, and HCV core protein without affecting intracellular HCV infectivity titers, HCV RNA, and HCV proteins, suggesting that Itch is involved in release of HCV particles. HCV-mediated JNK/Itch activation specifically promoted polyubiquitylation of an AAA-type ATPase VPS4A, but not VPS4B, required to form multivesicular bodies. Site-directed mutagenesis revealed that two lysine residues (K23 and K121) on VPS4A were important for VPS4A polyubiquitylation. The siRNA-knockdown of VPS4A, but not VPS4B, significantly reduced extracellular HCV infectivity titers. Co-immunoprecipitation analysis revealed that HCV infection specifically enhanced the interaction between CHMP1B, a subunit of endosomal sorting complexes required for transport (ESCRT)-III complex, and VPS4A, but not VPS4B, whereas VPS4A K23R/K121R greatly reduced the interaction with CHMP1B. HCV infection significantly increased ATPase activity of VPS4A, but not VPS4A K23R/K121R or VPS4B, suggesting that HCV-mediated polyubiquitylation of VPS4A contributes to activation of VPS4A. Taken together, we propose that HCV-induced ROS/JNK/Itch signaling pathway promotes VPS4A polyubiquitylation, leading to enhanced VPS4A-CHMP1B interaction and promotion of VPS4A ATPase activity, thereby promoting the release of HCV particles. IMPORTANCE ROS/JNK signaling pathway contributes to liver diseases, including steatosis, metabolic disorders, and hepatocellular carcinoma. We previously reported that HCV activates the ROS/JNK signaling pathway, leading to the enhancement of hepatic gluconeogenesis and apoptosis induction. This study further demonstrates that HCV-induced ROS/JNK signaling pathway activates the E3 ubiquitin ligase Itch to promote release of HCV particles via polyubiquitylation of VPS4A. We provide evidence suggesting that HCV infection promotes the ROS/JNK/Itch signaling pathway and ESCRT/VPS4A machinery to release infectious HCV particles. Our results may lead to a better understanding of the mechanistic details of HCV particle release.
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10
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Siering O, Cattaneo R, Pfaller CK. C Proteins: Controllers of Orderly Paramyxovirus Replication and of the Innate Immune Response. Viruses 2022; 14:v14010137. [PMID: 35062341 PMCID: PMC8778822 DOI: 10.3390/v14010137] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 01/07/2022] [Accepted: 01/09/2022] [Indexed: 01/07/2023] Open
Abstract
Particles of many paramyxoviruses include small amounts of proteins with a molecular weight of about 20 kDa. These proteins, termed “C”, are basic, have low amino acid homology and some secondary structure conservation. C proteins are encoded in alternative reading frames of the phosphoprotein gene. Some viruses express nested sets of C proteins that exert their functions in different locations: In the nucleus, they interfere with cellular transcription factors that elicit innate immune responses; in the cytoplasm, they associate with viral ribonucleocapsids and control polymerase processivity and orderly replication, thereby minimizing the activation of innate immunity. In addition, certain C proteins can directly bind to, and interfere with the function of, several cytoplasmic proteins required for interferon induction, interferon signaling and inflammation. Some C proteins are also required for efficient virus particle assembly and budding. C-deficient viruses can be grown in certain transformed cell lines but are not pathogenic in natural hosts. C proteins affect the same host functions as other phosphoprotein gene-encoded proteins named V but use different strategies for this purpose. Multiple independent systems to counteract host defenses may ensure efficient immune evasion and facilitate virus adaptation to new hosts and tissue environments.
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Affiliation(s)
- Oliver Siering
- Division of Veterinary Medicine, Paul-Ehrlich-Institute, 63225 Langen, Germany;
| | - Roberto Cattaneo
- Department of Molecular Medicine, Mayo Clinic, Rochester, MN 55906, USA
- Correspondence: (R.C.); (C.K.P.)
| | - Christian K. Pfaller
- Division of Veterinary Medicine, Paul-Ehrlich-Institute, 63225 Langen, Germany;
- Correspondence: (R.C.); (C.K.P.)
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11
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Xue N, Song L, Song Q, Santos-Sacchi J, Wu H, Navaratnam D. Genes related to SNPs identified by Genome-wide association studies of age-related hearing loss show restriction to specific cell types in the adult mouse cochlea. Hear Res 2021; 410:108347. [PMID: 34536825 DOI: 10.1016/j.heares.2021.108347] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 08/19/2021] [Accepted: 08/28/2021] [Indexed: 01/11/2023]
Abstract
ARHL has been thought to result from disordered hair cell function and their loss. ARHL has a significant genetic component. We sought to determine the expression in the cochlea of genes associated with single nucleotide polymorphisms linked to ARHL. We find widespread and varying expression of genes associated with these SNPs in subtypes of cells in the cochlea identified by single-cell RNA sequencing. Genes associated with SNPs with the highest significance were preferentially expressed highly in hair cells, while genes associated with SNPs with a lower significance were expressed more universally. In addition, we find significant overlap with genesets associated with Alzheimer's disease suggesting shared mechanisms, and genesets enriched for apical cell polarity and vesicle recycling suggesting mechanisms of cell death/ dysfunction with ageing.
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Affiliation(s)
- Na Xue
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China; Department of Neurology, Yale School of Medicine, New Haven, CT, USA
| | - Lei Song
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China; Department of Surgery, Yale School of Medicine, New Haven, CT, USA
| | - Qiang Song
- Department of Surgery, Yale School of Medicine, New Haven, CT, USA; Department of Neurology, Yale School of Medicine, New Haven, CT, USA
| | - Joseph Santos-Sacchi
- Department of Surgery, Yale School of Medicine, New Haven, CT, USA; Department of Cell and Molecular Physiology, Yale School of Medicine, New Haven, CT, USA
| | - Hao Wu
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.
| | - Dhasakumar Navaratnam
- Department of Surgery, Yale School of Medicine, New Haven, CT, USA; Department of Neurology, Yale School of Medicine, New Haven, CT, USA.
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12
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Adding Some "Splice" to Stress Eating: Autophagy, ESCRT and Alternative Splicing Orchestrate the Cellular Stress Response. Genes (Basel) 2021; 12:genes12081196. [PMID: 34440370 PMCID: PMC8393842 DOI: 10.3390/genes12081196] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 07/29/2021] [Accepted: 07/30/2021] [Indexed: 12/12/2022] Open
Abstract
Autophagy is a widely studied self-renewal pathway that is essential for degrading damaged cellular organelles or recycling biomolecules to maintain cellular homeostasis, particularly under cellular stress. This pathway initiates with formation of an autophagosome, which is a double-membrane structure that envelopes cytosolic components and fuses with a lysosome to facilitate degradation of the contents. The endosomal sorting complexes required for transport (ESCRT) proteins play an integral role in controlling autophagosome fusion events and disruption to this machinery leads to autophagosome accumulation. Given the central role of autophagy in maintaining cellular health, it is unsurprising that dysfunction of this process is associated with many human maladies including cancer and neurodegenerative diseases. The cell can also rapidly respond to cellular stress through alternative pre-mRNA splicing that enables adaptive changes to the cell's proteome in response to stress. Thus, alternative pre-mRNA splicing of genes that are involved in autophagy adds another layer of complexity to the cell's stress response. Consequently, the dysregulation of alternative splicing of genes associated with autophagy and ESCRT may also precipitate disease states by either reducing the ability of the cell to respond to stress or triggering a maladaptive response that is pathogenic. In this review, we summarize the diverse roles of the ESCRT machinery and alternative splicing in regulating autophagy and how their dysfunction can have implications for human disease.
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13
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Abstract
Extracellular vesicles (EVs) refer to vesicles that are released by cells into the extracellular space. EVs mediate cell-to-cell communication via delivery of functional biomolecules between host and recipient cells. EVs can be categorised based on their mode of biogenesis and secretion and include apoptotic bodies, ectosomes or shedding microvesicles and exosomes among others. EVs have gained immense interest in recent years owing to their implications in pathophysiological conditions. Indeed, EVs have been proven useful in clinical applications as potential drug delivery vehicles and as source of diagnostic biomarkers. Despite the growing body of evidence supporting the clinical benefits, the processes involved in the biogenesis of EVs are poorly understood. Hence, it is critical to gain a deeper understanding of the underlying molecular machineries that ultimately govern the biogenesis and secretion of EVs. This chapter discusses the current knowledge on molecular mechanisms involved in the biogenesis of various subtypes of EVs.
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Affiliation(s)
- Taeyoung Kang
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Ishara Atukorala
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Suresh Mathivanan
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia.
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Larios J, Mercier V, Roux A, Gruenberg J. ALIX- and ESCRT-III-dependent sorting of tetraspanins to exosomes. J Cell Biol 2020; 219:133723. [PMID: 32049272 PMCID: PMC7054990 DOI: 10.1083/jcb.201904113] [Citation(s) in RCA: 201] [Impact Index Per Article: 50.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 10/31/2019] [Accepted: 12/18/2019] [Indexed: 12/12/2022] Open
Abstract
The intraluminal vesicles (ILVs) of endosomes mediate the delivery of activated signaling receptors and other proteins to lysosomes for degradation, but they also modulate intercellular communication when secreted as exosomes. The formation of ILVs requires four complexes, ESCRT-0, -I, -II, and -III, with ESCRT-0, -I, and -II presumably involved in cargo sorting and ESCRT-III in membrane deformation and fission. Here, we report that an active form of the ESCRT-associated protein ALIX efficiently recruits ESCRT-III proteins to endosomes. This recruitment occurs independently of other ESCRTs but requires lysobisphosphatidic acid (LBPA) in vivo, and can be reconstituted on supported bilayers in vitro. Our data indicate that this ALIX- and ESCRT-III-dependent pathway promotes the sorting and delivery of tetraspanins to exosomes. We conclude that ALIX provides an additional pathway of ILV formation, secondary to the canonical pathway, and that this pathway controls the targeting of exosomal proteins.
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Affiliation(s)
- Jorge Larios
- Department of Biochemistry, Université de Genève, Geneva, Switzerland
| | - Vincent Mercier
- Department of Biochemistry, Université de Genève, Geneva, Switzerland
| | - Aurélien Roux
- Department of Biochemistry, Université de Genève, Geneva, Switzerland
| | - Jean Gruenberg
- Department of Biochemistry, Université de Genève, Geneva, Switzerland
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15
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The Penta-EF-Hand ALG-2 Protein Interacts with the Cytosolic Domain of the SOCE Regulator SARAF and Interferes with Ubiquitination. Int J Mol Sci 2020; 21:ijms21176315. [PMID: 32878247 PMCID: PMC7504102 DOI: 10.3390/ijms21176315] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 08/24/2020] [Accepted: 08/29/2020] [Indexed: 12/18/2022] Open
Abstract
ALG-2 is a penta-EF-hand Ca2+-binding protein and interacts with a variety of proteins in mammalian cells. In order to find new ALG-2-binding partners, we searched a human protein database and retrieved sequences containing the previously identified ALG-2-binding motif type 2 (ABM-2). After selecting 12 high-scored sequences, we expressed partial or full-length GFP-fused proteins in HEK293 cells and performed a semi-quantitative in vitro binding assay. SARAF, a negative regulator of store-operated Ca2+ entry (SOCE), showed the strongest binding activity. Biochemical analysis of Strep-tagged and GFP-fused SARAF proteins revealed ubiquitination that proceeded during pulldown assays under certain buffer conditions. Overexpression of ALG-2 interfered with ubiquitination of wild-type SARAF but not ubiquitination of the F228S mutant that had impaired ALG-2-binding activity. The SARAF cytosolic domain (CytD) contains two PPXY motifs targeted by the WW domains of NEDD4 family E3 ubiquitin ligases. The PPXY motif proximal to the ABM-2 sequence was found to be more important for both in-cell ubiquitination and post-cell lysis ubiquitination. A ubiquitination-defective mutant of SARAF with Lys-to-Arg substitutions in the CytD showed a slower degradation rate by half-life analysis. ALG-2 promoted Ca2+-dependent CytD-to-CytD interactions of SARAF. The ALG-2 dimer may modulate the stability of SARAF by sterically blocking ubiquitination and by bridging SARAF molecules at the CytDs.
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16
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Lokapally A, Neuhaus H, Herfurth J, Hollemann T. Interplay of TRIM2 E3 Ubiquitin Ligase and ALIX/ESCRT Complex: Control of Developmental Plasticity During Early Neurogenesis. Cells 2020; 9:cells9071734. [PMID: 32698497 PMCID: PMC7409263 DOI: 10.3390/cells9071734] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/13/2020] [Accepted: 07/15/2020] [Indexed: 01/26/2023] Open
Abstract
Tripartite motif 2 (TRIM2) drives neurite outgrowth and polarization, is involved in axon specification, and confers neuroprotective functions during rapid ischemia. The mechanisms controlling neuronal cell fate determination and differentiation are fundamental for neural development. Here, we show that in Xenopus, trim2 knockdown affects primary neurogenesis and neural progenitor cell survival. Embryos also suffer from severe craniofacial malformation, a reduction in brain volume, and the loss of motor sensory function. Using a high-throughput LC-MS/MS approach with GST-Trim2 as bait, we pulled down ALG-2 interacting protein X (Alix) from Xenopus embryonic lysates. We demonstrate that the expression of trim2/TRIM2 and alix/ALIX overlap during larval development and on a cellular level in cell culture. Interestingly, trim2 morphants showed a clustering and apoptosis of neural progenitors, which are phenotypic hallmarks that are also observed in Alix KO mice. Therefore, we propose that the interaction of Alix and Trim2 plays a key role in the determination and differentiation of neural progenitors via the modulation of cell proliferation/apoptosis during neurogenesis.
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Affiliation(s)
- Ashwin Lokapally
- Institute for Physiological Chemistry, Martin-Luther University Halle-Wittenberg, Hollystrasse 1, 06114 Halle, Germany; (A.L.); (H.N.); (J.H.)
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
| | - Herbert Neuhaus
- Institute for Physiological Chemistry, Martin-Luther University Halle-Wittenberg, Hollystrasse 1, 06114 Halle, Germany; (A.L.); (H.N.); (J.H.)
| | - Juliane Herfurth
- Institute for Physiological Chemistry, Martin-Luther University Halle-Wittenberg, Hollystrasse 1, 06114 Halle, Germany; (A.L.); (H.N.); (J.H.)
| | - Thomas Hollemann
- Institute for Physiological Chemistry, Martin-Luther University Halle-Wittenberg, Hollystrasse 1, 06114 Halle, Germany; (A.L.); (H.N.); (J.H.)
- Correspondence:
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17
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Exploring Extracellular Vesicles Biogenesis in Hypothalamic Cells through a Heavy Isotope Pulse/Trace Proteomic Approach. Cells 2020; 9:cells9051320. [PMID: 32466345 PMCID: PMC7291124 DOI: 10.3390/cells9051320] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 05/13/2020] [Accepted: 05/21/2020] [Indexed: 12/17/2022] Open
Abstract
Studies have shown that the process of extracellular vesicles (EVs) secretion and lysosome status are linked. When the lysosome is under stress, the cells would secrete more EVs to maintain cellular homeostasis. However, the process that governs lysosomal activity and EVs secretion remains poorly defined and we postulated that certain proteins essential for EVs biogenesis are constantly synthesized and preferentially sorted to the EVs rather than the lysosome. A pulsed stable isotope labelling of amino acids in cell culture (pSILAC) based quantitative proteomics methodology was employed to study the preferential localization of the newly synthesized proteins into the EVs over lysosome in mHypoA 2/28 hypothalamic cell line. Through proteomic analysis, we found numerous newly synthesized lysosomal enzymes—such as the cathepsin proteins—that preferentially localize into the EVs over the lysosome. Chemical inhibition against cathepsin D promoted EVs secretion and a change in the EVs protein composition and therefore indicates its involvement in EVs biogenesis. In conclusion, we applied a heavy isotope pulse/trace proteomic approach to study EVs biogenesis in hypothalamic cells. The results demonstrated the regulation of EVs secretion by the cathepsin proteins that may serve as a potential therapeutic target for a range of neurological disorder associated with energy homeostasis.
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MiR-93 is related to poor prognosis in pancreatic cancer and promotes tumor progression by targeting microtubule dynamics. Oncogenesis 2020; 9:43. [PMID: 32366853 PMCID: PMC7198506 DOI: 10.1038/s41389-020-0227-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 04/05/2020] [Accepted: 04/15/2020] [Indexed: 01/18/2023] Open
Abstract
Biomarkers and effective therapeutic agents to improve the dismal prognosis of pancreatic ductal adenocarcinoma (PDAC) are urgently required. We aimed to analyze the prognostic value and mechanistic action of miR-93 in PDAC. Correlation of miR-93 tumor levels from 83 PDAC patients and overall survival (OS) was analyzed by Kaplan-Meier. MiR-93 depletion in PANC-1 and MIA PaCa-2 cells was achieved by CRISPR/Cas9 and miR-93 overexpression in HPDE cells by retroviral transduction. Cell proliferation, migration and invasion, cell cycle analysis, and in vivo tumor xenografts in nude mice were assessed. Proteomic analysis by mass spectrometry and western-blot was also performed. Finally, miR-93 direct binding to candidate mRNA targets was evaluated by luciferase reporter assays. High miR-93 tumor levels are significantly correlated with a worst prognosis in PDAC patients. MiR-93 abolition altered pancreatic cancer cells phenotype inducing a significant increase in cell size and a significant decrease in cell invasion and proliferation accompanied by a G2/M arrest. In vivo, lack of miR-93 significantly impaired xenograft tumor growth. Conversely, miR-93 overexpression induced a pro-tumorigenic behavior by significantly increasing cell proliferation, migration, and invasion. Proteomic analysis unveiled a large group of deregulated proteins, mainly related to G2/M phase, microtubule dynamics, and cytoskeletal remodeling. CRMP2, MAPRE1, and YES1 were confirmed as direct targets of miR-93. MiR-93 exerts oncogenic functions by targeting multiple genes involved in microtubule dynamics at different levels, thus affecting the normal cell division rate. MiR-93 or its direct targets (CRMP2, MAPRE1, or YES1) are new potential therapeutic targets for PDAC.
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The Flemmingsome reveals an ESCRT-to-membrane coupling via ALIX/syntenin/syndecan-4 required for completion of cytokinesis. Nat Commun 2020; 11:1941. [PMID: 32321914 PMCID: PMC7176721 DOI: 10.1038/s41467-020-15205-z] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 02/21/2020] [Indexed: 12/29/2022] Open
Abstract
Cytokinesis requires the constriction of ESCRT-III filaments on the side of the midbody, where abscission occurs. After ESCRT recruitment at the midbody, it is not known how the ESCRT-III machinery localizes to the abscission site. To reveal actors involved in abscission, we obtained the proteome of intact, post-abscission midbodies (Flemmingsome) and identified 489 proteins enriched in this organelle. Among these proteins, we further characterized a plasma membrane-to-ESCRT module composed of the transmembrane proteoglycan syndecan-4, ALIX and syntenin, a protein that bridges ESCRT-III/ALIX to syndecans. The three proteins are highly recruited first at the midbody then at the abscission site, and their depletion delays abscission. Mechanistically, direct interactions between ALIX, syntenin and syndecan-4 are essential for proper enrichment of the ESCRT-III machinery at the abscission site, but not at the midbody. We propose that the ESCRT-III machinery must be physically coupled to a membrane protein at the cytokinetic abscission site for efficient scission, uncovering common requirements in cytokinesis, exosome formation and HIV budding.
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20
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The Integrity of the YxxL Motif of Ebola Virus VP24 Is Important for the Transport of Nucleocapsid-Like Structures and for the Regulation of Viral RNA Synthesis. J Virol 2020; 94:JVI.02170-19. [PMID: 32102881 DOI: 10.1128/jvi.02170-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Accepted: 02/15/2020] [Indexed: 12/15/2022] Open
Abstract
While it is well appreciated that late domains in the viral matrix proteins are crucial to mediate efficient virus budding, little is known about roles of late domains in the viral nucleocapsid proteins. Here, we characterized the functional relevance of a YxxL motif with potential late-domain function in the Ebola virus nucleocapsid protein VP24. Mutations in the YxxL motif had two opposing effects on the functions of VP24. On the one hand, the mutation affected the regulatory function of VP24 in viral RNA transcription and replication, which correlated with an increased incorporation of minigenomes into released transcription- and replication-competent virus-like particles (trVLPs). Consequently, cells infected with those trVLPs showed higher levels of viral transcription. On the other hand, mutations of the YxxL motif greatly impaired the intracellular transport of nucleocapsid-like structures (NCLSs) composed of the viral proteins NP, VP35, and VP24 and the length of released trVLPs. Attempts to rescue recombinant Ebola virus expressing YxxL-deficient VP24 failed, underlining the importance of this motif for the viral life cycle.IMPORTANCE Ebola virus (EBOV) causes a severe fever with high case fatality rates and, so far, no available specific therapy. Understanding the interplay between viral and host proteins is important to identify new therapeutic approaches. VP24 is one of the essential nucleocapsid components and is necessary to regulate viral RNA synthesis and condense viral nucleocapsids before their transport to the plasma membrane. Our functional analyses of the YxxL motif in VP24 suggested that it serves as an interface between nucleocapsid-like structures (NCLSs) and cellular proteins, promoting intracellular transport of NCLSs in an Alix-independent manner. Moreover, the YxxL motif is necessary for the inhibitory function of VP24 in viral RNA synthesis. A failure to rescue EBOV encoding VP24 with a mutated YxxL motif indicated that the integrity of the YxxL motif is essential for EBOV growth. Thus, this motif might represent a potential target for antiviral interference.
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21
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Masoudi M, Seki M, Yazdanparast R, Yachie N, Aburatani H. A genome-scale CRISPR/Cas9 knockout screening reveals SH3D21 as a sensitizer for gemcitabine. Sci Rep 2019; 9:19188. [PMID: 31844142 PMCID: PMC6915784 DOI: 10.1038/s41598-019-55893-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 12/03/2019] [Indexed: 11/17/2022] Open
Abstract
Gemcitabine, 2',2'-difluoro-2'-deoxycytidine, is used as a pro-drug in treatment of variety of solid tumour cancers including pancreatic cancer. After intake, gemcitabine is transferred to the cells by the membrane nucleoside transporter proteins. Once inside the cells, it is converted to gemcitabine triphosphate followed by incorporation into DNA chains where it causes inhibition of DNA replication and thereby cell cycle arrest and apoptosis. Currently gemcitabine is the standard drug for treatment of pancreatic cancer and despite its widespread use its effect is moderate. In this study, we performed a genome-scale CRISPR/Cas9 knockout screening on pancreatic cancer cell line Panc1 to explore the genes that are important for gemcitabine efficacy. We found SH3D21 as a novel gemcitabine sensitizer implying it may act as a therapeutic target for improvement of gemcitabine efficacy in treatment of pancreatic cancer.
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Affiliation(s)
- Mohammad Masoudi
- Molecular Biology Department, Graduate School of Medicine, The University of Tokyo, Tokyo, 153-8904, Japan
- Genome Science Division, Research Center for Advance Science and Technology, The University of Tokyo, Tokyo, 153-8904, Japan
- Synthetic Biology Division, Research Center for Advance Science and Technology, The University of Tokyo, Tokyo, 153-8904, Japan
- Molecular Biology Laboratory, Institute of Biochemistry and Biophysics, University of Tehran, Tehran, 13145-1384, Iran
| | - Motoaki Seki
- Synthetic Biology Division, Research Center for Advance Science and Technology, The University of Tokyo, Tokyo, 153-8904, Japan
| | - Razieh Yazdanparast
- Molecular Biology Laboratory, Institute of Biochemistry and Biophysics, University of Tehran, Tehran, 13145-1384, Iran.
| | - Nozomu Yachie
- Synthetic Biology Division, Research Center for Advance Science and Technology, The University of Tokyo, Tokyo, 153-8904, Japan
| | - Hiroyuki Aburatani
- Molecular Biology Department, Graduate School of Medicine, The University of Tokyo, Tokyo, 153-8904, Japan.
- Genome Science Division, Research Center for Advance Science and Technology, The University of Tokyo, Tokyo, 153-8904, Japan.
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22
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Maki M. Structures and functions of penta-EF-hand calcium-binding proteins and their interacting partners: enigmatic relationships between ALG-2 and calpain-7. Biosci Biotechnol Biochem 2019; 84:651-660. [PMID: 31814542 DOI: 10.1080/09168451.2019.1700099] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The penta-EF-hand (PEF) protein family includes ALG-2 (gene name, PDCD6) and its paralogs as well as classical calpain family members. ALG-2 is a prototypic PEF protein that is widely distributed in eukaryotes and interacts with a variety of proteins in a Ca2+-dependent manner. Mammalian ALG-2 and its interacting partners have various modulatory roles including roles in cell death, signal transduction, membrane repair, ER-to-Golgi vesicular transport, and RNA processing. Some ALG-2-interacting proteins are key factors that function in the endosomal sorting complex required for transport (ESCRT) system. On the other hand, mammalian calpain-7 (CAPN7) lacks the PEF domain but contains two microtubule-interacting and trafficking (MIT) domains in tandem. CAPN7 interacts with a subset of ESCRT-III proteins through the MIT domains and regulates EGF receptor downregulation. Structures and functions of ALG-2 and those of its interacting partners as well as relationships with the calpain family are reviewed in this article.
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Affiliation(s)
- Masatoshi Maki
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
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23
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Ageta H, Tsuchida K. Post-translational modification and protein sorting to small extracellular vesicles including exosomes by ubiquitin and UBLs. Cell Mol Life Sci 2019; 76:4829-4848. [PMID: 31363817 PMCID: PMC11105257 DOI: 10.1007/s00018-019-03246-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 07/06/2019] [Accepted: 07/23/2019] [Indexed: 02/06/2023]
Abstract
Exosomes, a type of small extracellular vesicles (sEVs), are secreted membrane vesicles that are derived from various cell types, including cancer cells, mesenchymal stem cells, and immune cells via multivesicular bodies (MVBs). These sEVs contain RNAs (mRNA, miRNA, lncRNA, and rRNA), lipids, DNA, proteins, and metabolites, all of which mediate cell-to-cell communication. This communication is known to be implicated in a diverse set of diseases such as cancers and their metastases and degenerative diseases. The molecular mechanisms, by which proteins are modified and sorted to sEVs, are not fully understood. Various cellular processes, including degradation, transcription, DNA repair, cell cycle, signal transduction, and autophagy, are known to be associated with ubiquitin and ubiquitin-like proteins (UBLs). Recent studies have revealed that ubiquitin and UBLs also regulate MVBs and protein sorting to sEVs. Ubiquitin-like 3 (UBL3)/membrane-anchored Ub-fold protein (MUB) acts as a post-translational modification (PTM) factor to regulate efficient protein sorting to sEVs. In this review, we focus on the mechanism of PTM by ubiquitin and UBLs and the pathway of protein sorting into sEVs and discuss the potential biological significance of these processes.
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Affiliation(s)
- Hiroshi Ageta
- Division for Therapies Against Intractable Diseases, Institute for Comprehensive Medical Science, Fujita Health University, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi, 470-1192, Japan
| | - Kunihiro Tsuchida
- Division for Therapies Against Intractable Diseases, Institute for Comprehensive Medical Science, Fujita Health University, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi, 470-1192, Japan.
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24
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Hoffman HK, Fernandez MV, Groves NS, Freed EO, van Engelenburg SB. Genomic tagging of endogenous human ESCRT-I complex preserves ESCRT-mediated membrane-remodeling functions. J Biol Chem 2019; 294:16266-16281. [PMID: 31519756 PMCID: PMC6827313 DOI: 10.1074/jbc.ra119.009372] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 09/10/2019] [Indexed: 12/19/2022] Open
Abstract
The endosomal sorting complexes required for transport (ESCRT) machinery drives membrane scission for diverse cellular functions that require budding away from the cytosol, including cell division and transmembrane receptor trafficking and degradation. The ESCRT machinery is also hijacked by retroviruses, such as HIV-1, to release virions from infected cells. The crucial roles of the ESCRTs in cellular physiology and viral disease make it imperative to understand the membrane scission mechanism. Current methodological limitations, namely artifacts caused by overexpression of ESCRT subunits, obstruct our understanding of the spatiotemporal organization of the endogenous human ESCRT machinery. Here, we used CRISPR/Cas9-mediated knock-in to tag the critical ESCRT-I component tumor susceptibility 101 (Tsg101) with GFP at its native locus in two widely used human cell types, HeLa epithelial cells and Jurkat T cells. We validated this approach by assessing the function of these knock-in cell lines in cytokinesis, receptor degradation, and virus budding. Using this probe, we measured the incorporation of endogenous Tsg101 in released HIV-1 particles, supporting the notion that the ESCRT machinery initiates virus abscission by scaffolding early-acting ESCRT-I within the head of the budding virus. We anticipate that these validated cell lines will be a valuable tool for interrogating dynamics of the native human ESCRT machinery.
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Affiliation(s)
- Huxley K Hoffman
- Molecular and Cellular Biophysics Program, Department of Biological Sciences, University of Denver, Denver, Colorado 80210
| | - Melissa V Fernandez
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, Center for Cancer Research, NCI-Frederick, National Institutes of Health, Frederick, Maryland 21702
| | - Nicholas S Groves
- Molecular and Cellular Biophysics Program, Department of Biological Sciences, University of Denver, Denver, Colorado 80210
| | - Eric O Freed
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, Center for Cancer Research, NCI-Frederick, National Institutes of Health, Frederick, Maryland 21702
| | - Schuyler B van Engelenburg
- Molecular and Cellular Biophysics Program, Department of Biological Sciences, University of Denver, Denver, Colorado 80210
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25
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Salim S, Nasir J, Chen PE. Overexpression of the dopamine receptor-interacting protein Alix/AIP1 modulates NMDA receptor-triggered cell death. FEBS Lett 2019; 593:1381-1391. [PMID: 31077357 DOI: 10.1002/1873-3468.13434] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 04/25/2019] [Accepted: 05/01/2019] [Indexed: 01/13/2023]
Abstract
Alix/AIP1 is an adaptor protein involved in apoptosis, endocytic membrane trafficking and brain development. Alix has been found within the human postsynaptic density (PSD) and, since NMDA receptors (NMDARs) are central components of the PSD, we hypothesized that the close proximity of both proteins may allow Alix to influence the downstream pathways following NMDAR activation. NMDARs play important roles in excitotoxicity and we evaluated the effects of recombinant Alix in an NMDAR cell death assay. Overexpression of Alix with NMDARs increases the potency of NMDAR- induced cell death compared to cells expressing only NMDARs, and this requires expression of the Alix C-terminal region. Therefore, we demonstrate a previously unreported role for Alix as a potential modulator of NMDAR function.
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Affiliation(s)
- Sharifah Salim
- Centres for Biomedical Sciences and Gene & Cell Therapy, School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey, UK
| | - Jamal Nasir
- Molecular Biosciences Research Group, Faculty of Health & Society, University of Northampton, Waterside Campus, Northampton, UK
| | - Philip E Chen
- Centres for Biomedical Sciences and Gene & Cell Therapy, School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey, UK
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26
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Shibata H. Adaptor functions of the Ca 2+-binding protein ALG-2 in protein transport from the endoplasmic reticulum. Biosci Biotechnol Biochem 2018; 83:20-32. [PMID: 30259798 DOI: 10.1080/09168451.2018.1525274] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Apoptosis-linked gene 2 (ALG-2) is a Ca2+-binding protein with five repetitive EF-hand motifs, named penta-EF-hand (PEF) domain. It interacts with various target proteins and functions as a Ca2+-dependent adaptor in diverse cellular activities. In the cytoplasm, ALG-2 is predominantly localized to a specialized region of the endoplasmic reticulum (ER), called the ER exit site (ERES), through its interaction with Sec31A. Sec31A is an outer coat protein of coat protein complex II (COPII) and is recruited from the cytosol to the ERES to form COPII-coated transport vesicles. I will overview current knowledge of the physiological significance of ALG-2 in regulating ERES localization of Sec31A and the following adaptor functions of ALG-2, including bridging Sec31A and annexin A11 to stabilize Sec31A at the ERES, polymerizing the Trk-fused gene (TFG) product, and linking MAPK1-interacting and spindle stabilizing (MISS)-like (MISSL) and microtubule-associated protein 1B (MAP1B) to promote anterograde transport from the ER.
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Affiliation(s)
- Hideki Shibata
- a Department of Applied Biosciences, Graduate School of Bioagricultural Sciences , Nagoya University , Chikusa-ku , Nagoya , Japan
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27
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Concerted ESCRT and clathrin recruitment waves define the timing and morphology of intraluminal vesicle formation. Nat Commun 2018; 9:2932. [PMID: 30050131 PMCID: PMC6062606 DOI: 10.1038/s41467-018-05345-8] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 06/29/2018] [Indexed: 01/09/2023] Open
Abstract
The endosomal sorting complex required for transport (ESCRT) machinery mediates cargo sorting, membrane deformation and membrane scission on the surface of endosomes, generating intraluminal vesicles (ILVs) to degrade signaling receptors. By live-cell imaging of individual endosomes in human cells, we find that ESCRT proteins are recruited in a repetitive pattern: ESCRT-0 and -I show a gradual and linear recruitment and dissociation, whereas ESCRT-III and its regulatory ATPase VPS4 display fast and transient dynamics. Electron microscopy shows that ILVs are formed consecutively, starting immediately after endocytic uptake of cargo proteins and correlating with the repeated ESCRT recruitment waves, unraveling the timing of ILV formation. Clathrin, recruited by ESCRT-0, is required for timely ESCRT-0 dissociation, efficient ILV formation, correct ILV size and cargo degradation. Thus, cargo sorting and ILV formation occur by concerted, coordinated and repetitive recruitment waves of individual ESCRT subcomplexes and are controlled by clathrin. Intraluminal vesicles are formed by the endosomal sorting complex required for transport (ESCRT) machinery. Here, the authors unravel the timing of vesicle budding, and that endosomal clathrin regulates concerted recruitment of ESCRT subcomplexes, required for efficient membrane remodeling.
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ESCRT machinery components are required for Orthobunyavirus particle production in Golgi compartments. PLoS Pathog 2018; 14:e1007047. [PMID: 29723305 PMCID: PMC5953487 DOI: 10.1371/journal.ppat.1007047] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 05/15/2018] [Accepted: 04/18/2018] [Indexed: 01/10/2023] Open
Abstract
Peribunyaviridae is a large family of RNA viruses with several members that cause mild to severe diseases in humans and livestock. Despite their importance in public heath very little is known about the host cell factors hijacked by these viruses to support assembly and cell egress. Here we show that assembly of Oropouche virus, a member of the genus Orthobunyavirus that causes a frequent arboviral infection in South America countries, involves budding of virus particles toward the lumen of Golgi cisternae. As viral replication progresses, these Golgi subcompartments become enlarged and physically separated from Golgi stacks, forming Oropouche viral factory (Vfs) units. At the ultrastructural level, these virally modified Golgi cisternae acquire an MVB appearance, and while they lack typical early and late endosome markers, they become enriched in endosomal complex required for transport (ESCRT) proteins that are involved in MVB biogenesis. Further microscopy and viral replication analysis showed that functional ESCRT machinery is required for efficient Vf morphogenesis and production of infectious OROV particles. Taken together, our results indicate that OROV attracts ESCRT machinery components to Golgi cisternae to mediate membrane remodeling events required for viral assembly and budding at these compartments. This represents an unprecedented mechanism of how viruses hijack host cell components for coordinated morphogenesis.
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Cho HJ, Mook-Jung I. O
‐GlcNAcylation regulates endoplasmic reticulum exit sites through
Sec31A
modification in conventional secretory pathway. FASEB J 2018; 32:4641-4657. [DOI: 10.1096/fj.201701523r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Hyun Jin Cho
- Department of Biochemistry and Biomedical SciencesCollege of MedicineSeoul National UniversitySeoulSouth Korea
| | - Inhee Mook-Jung
- Department of Biochemistry and Biomedical SciencesCollege of MedicineSeoul National UniversitySeoulSouth Korea
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Kadota T, Fujita Y, Yoshioka Y, Araya J, Kuwano K, Ochiya T. Emerging role of extracellular vesicles as a senescence-associated secretory phenotype: Insights into the pathophysiology of lung diseases. Mol Aspects Med 2018; 60:92-103. [DOI: 10.1016/j.mam.2017.11.005] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 11/03/2017] [Accepted: 11/10/2017] [Indexed: 12/22/2022]
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Haqqani AS, Delaney CE, Brunette E, Baumann E, Farrington GK, Sisk W, Eldredge J, Ding W, Tremblay TL, Stanimirovic DB. Endosomal trafficking regulates receptor-mediated transcytosis of antibodies across the blood brain barrier. J Cereb Blood Flow Metab 2018; 38:727-740. [PMID: 29140158 PMCID: PMC5888858 DOI: 10.1177/0271678x17740031] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Current methods for examining antibody trafficking are either non-quantitative such as immunocytochemistry or require antibody labeling with tracers. We have developed a multiplexed quantitative method for antibody 'tracking' in endosomal compartments of brain endothelial cells. Rat brain endothelial cells were co-incubated with blood-brain barrier (BBB)-crossing FC5, monovalent FC5Fc or bivalent FC5Fc fusion antibodies and control antibodies. Endosomes were separated using sucrose-density gradient ultracentrifugation and analyzed using multiplexed mass spectrometry to simultaneously quantify endosomal markers, receptor-mediated transcytosis (RMT) receptors and the co-incubated antibodies in each fraction. The quantitation showed that markers of early endosomes were enriched in high-density fractions (HDF), whereas markers of late endosomes and lysosomes were enriched in low-density fractions (LDF). RMT receptors, including transferrin receptor, showed a profile similar to that of early endosome markers. The in vitro BBB transcytosis rates of antibodies were directly proportional to their partition into early endosome fractions of brain endothelial cells. Addition of the Fc domain resulted in facilitated antibody 'redistribution' from LDF into HDF and additionally into multivesicular bodies (MVB). Sorting of various FC5 antibody formats away from late endosomes and lysosomes and into early endosomes and a subset of MVB results in increased antibody transcytosis at the abluminal side of the BBB.
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Affiliation(s)
- Arsalan S Haqqani
- 1 National Research Council of Canada, Human Health Therapeutics Portfolio, Ottawa, ON, Canada
| | - Christie E Delaney
- 1 National Research Council of Canada, Human Health Therapeutics Portfolio, Ottawa, ON, Canada
| | - Eric Brunette
- 1 National Research Council of Canada, Human Health Therapeutics Portfolio, Ottawa, ON, Canada
| | - Ewa Baumann
- 1 National Research Council of Canada, Human Health Therapeutics Portfolio, Ottawa, ON, Canada
| | | | - William Sisk
- 2 2191 Biogen Inc ., Cambridge Center, Cambridge, MA, USA
| | - John Eldredge
- 2 2191 Biogen Inc ., Cambridge Center, Cambridge, MA, USA
| | - Wen Ding
- 1 National Research Council of Canada, Human Health Therapeutics Portfolio, Ottawa, ON, Canada
| | - Tammy-Lynn Tremblay
- 1 National Research Council of Canada, Human Health Therapeutics Portfolio, Ottawa, ON, Canada
| | - Danica B Stanimirovic
- 1 National Research Council of Canada, Human Health Therapeutics Portfolio, Ottawa, ON, Canada
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Rajagopal C, Harikumar KB. The Origin and Functions of Exosomes in Cancer. Front Oncol 2018; 8:66. [PMID: 29616188 PMCID: PMC5869252 DOI: 10.3389/fonc.2018.00066] [Citation(s) in RCA: 182] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 02/27/2018] [Indexed: 01/09/2023] Open
Abstract
Exosomes are nanovesicles having a maximum size of 150 nm and is a newly emerging focus in various fields of research. Its role in cargo trafficking along with its differential expression is associated with the disrupted homeostasis and provides an opportunity to defend against different diseases like cancer. Furthermore, exosomes are rich in cargos, which contain proteins and nucleic acids that directly reflect the metabolic state of the cells from which it originates. This review summarizes recent studies on tumor-derived exosomes with an overview about biogenesis, their functions and potential of using as diagnostic and prognostic markers. We also discussed the current challenges and microfluidic-based detection approaches that might improve the detection of exosomes in different settings. More intricate studies of the molecular mechanisms in angiogenesis, pre-metastatic niche formation, and metastasis can give more promising insights and novel strategies in oncotherapeutics.
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Affiliation(s)
- Chitra Rajagopal
- Cancer Research Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, India
| | - K B Harikumar
- Cancer Research Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, India
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Frankel EB, Audhya A. ESCRT-dependent cargo sorting at multivesicular endosomes. Semin Cell Dev Biol 2018; 74:4-10. [PMID: 28797838 PMCID: PMC5803488 DOI: 10.1016/j.semcdb.2017.08.020] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 08/02/2017] [Accepted: 08/05/2017] [Indexed: 01/26/2023]
Abstract
The endosomal sorting complex required for transport (ESCRT) machinery is composed of five multi-subunit protein complexes, which act cooperatively at specialized endosomes to facilitate the movement of specific cargoes from the limiting membrane into vesicles that bud into the endosome lumen. Over the past decade, numerous proteins, lipids, and RNAs have been shown to be incorporated into intralumenal vesicles (ILVs), but the mechanisms by which these unique cargoes are captured are only now becoming better understood. Here, we discuss the potential roles that the ESCRT machinery plays during cargo sorting at multivesicular endosomes (MVEs).
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Affiliation(s)
- E B Frankel
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, 440 Henry Mall, Madison, WI, 53706, USA
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, 440 Henry Mall, Madison, WI, 53706, USA.
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ESCRT-III Membrane Trafficking Misregulation Contributes To Fragile X Syndrome Synaptic Defects. Sci Rep 2017; 7:8683. [PMID: 28819289 PMCID: PMC5561180 DOI: 10.1038/s41598-017-09103-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 07/19/2017] [Indexed: 12/12/2022] Open
Abstract
The leading cause of heritable intellectual disability (ID) and autism spectrum disorders (ASD), Fragile X syndrome (FXS), is caused by loss of the mRNA-binding translational suppressor Fragile X Mental Retardation Protein (FMRP). In the Drosophila FXS disease model, we found FMRP binds shrub mRNA (human Chmp4) to repress Shrub expression, causing overexpression during the disease state early-use critical period. The FXS hallmark is synaptic overelaboration causing circuit hyperconnectivity. Testing innervation of a central brain learning/memory center, we found FMRP loss and Shrub overexpression similarly increase connectivity. The ESCRT-III core protein Shrub has a central role in endosome-to-multivesicular body membrane trafficking, with synaptic requirements resembling FMRP. Consistently, we found FMRP loss and Shrub overexpression similarly elevate endosomes and result in the arrested accumulation of enlarged intraluminal vesicles within synaptic boutons. Importantly, genetic correction of Shrub levels in the FXS model prevents synaptic membrane trafficking defects and strongly restores innervation. These results reveal a new molecular mechanism underpinning the FXS disease state.
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Smith BN, Topp SD, Fallini C, Shibata H, Chen HJ, Troakes C, King A, Ticozzi N, Kenna KP, Soragia-Gkazi A, Miller JW, Sato A, Dias DM, Jeon M, Vance C, Wong CH, de Majo M, Kattuah W, Mitchell JC, Scotter EL, Parkin NW, Sapp PC, Nolan M, Nestor PJ, Simpson M, Weale M, Lek M, Baas F, Vianney de Jong JM, Ten Asbroek ALMA, Redondo AG, Esteban-Pérez J, Tiloca C, Verde F, Duga S, Leigh N, Pall H, Morrison KE, Al-Chalabi A, Shaw PJ, Kirby J, Turner MR, Talbot K, Hardiman O, Glass JD, De Belleroche J, Maki M, Moss SE, Miller C, Gellera C, Ratti A, Al-Sarraj S, Brown RH, Silani V, Landers JE, Shaw CE. Mutations in the vesicular trafficking protein annexin A11 are associated with amyotrophic lateral sclerosis. Sci Transl Med 2017; 9:eaad9157. [PMID: 28469040 PMCID: PMC6599403 DOI: 10.1126/scitranslmed.aad9157] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 08/16/2016] [Accepted: 01/04/2017] [Indexed: 01/05/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder. We screened 751 familial ALS patient whole-exome sequences and identified six mutations including p.D40G in the ANXA11 gene in 13 individuals. The p.D40G mutation was absent from 70,000 control whole-exome sequences. This mutation segregated with disease in two kindreds and was present in another two unrelated cases (P = 0.0102), and all mutation carriers shared a common founder haplotype. Annexin A11-positive protein aggregates were abundant in spinal cord motor neurons and hippocampal neuronal axons in an ALS patient carrying the p.D40G mutation. Transfected human embryonic kidney cells expressing ANXA11 with the p.D40G mutation and other N-terminal mutations showed altered binding to calcyclin, and the p.R235Q mutant protein formed insoluble aggregates. We conclude that mutations in ANXA11 are associated with ALS and implicate defective intracellular protein trafficking in disease pathogenesis.
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Affiliation(s)
- Bradley N Smith
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 125 Coldharbour Lane, Camberwell, SE5 9NU London, UK
| | - Simon D Topp
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 125 Coldharbour Lane, Camberwell, SE5 9NU London, UK
| | - Claudia Fallini
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Hideki Shibata
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Han-Jou Chen
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 125 Coldharbour Lane, Camberwell, SE5 9NU London, UK
| | - Claire Troakes
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 125 Coldharbour Lane, Camberwell, SE5 9NU London, UK
| | - Andrew King
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 125 Coldharbour Lane, Camberwell, SE5 9NU London, UK
| | - Nicola Ticozzi
- Department of Neurology and Laboratory of Neuroscience, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Auxologico Italiano, 20149 Milan, Italy
- Department of Pathophysiology and Transplantation, "Dino Ferrari" Center, University of Milan, 20122 Milan, Italy
| | - Kevin P Kenna
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Athina Soragia-Gkazi
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 125 Coldharbour Lane, Camberwell, SE5 9NU London, UK
| | - Jack W Miller
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 125 Coldharbour Lane, Camberwell, SE5 9NU London, UK
| | - Akane Sato
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Diana Marques Dias
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 125 Coldharbour Lane, Camberwell, SE5 9NU London, UK
| | - Maryangel Jeon
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Caroline Vance
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 125 Coldharbour Lane, Camberwell, SE5 9NU London, UK
| | - Chun Hao Wong
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 125 Coldharbour Lane, Camberwell, SE5 9NU London, UK
| | - Martina de Majo
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 125 Coldharbour Lane, Camberwell, SE5 9NU London, UK
| | - Wejdan Kattuah
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 125 Coldharbour Lane, Camberwell, SE5 9NU London, UK
| | - Jacqueline C Mitchell
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 125 Coldharbour Lane, Camberwell, SE5 9NU London, UK
| | - Emma L Scotter
- Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, New Zealand
| | - Nicholas W Parkin
- Molecular Genetics Laboratory, Viapath, Genetics Centre, Guy's Hospital, Great Maze Pond, SE1 9RT London, UK
| | - Peter C Sapp
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Matthew Nolan
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 125 Coldharbour Lane, Camberwell, SE5 9NU London, UK
| | - Peter J Nestor
- German Center for Neurodegenerative Diseases, Leipziger Str. 44, 39120 Magdeburg, Germany
| | - Michael Simpson
- Medical & Molecular Genetics, Division of Genetics and Molecular Medicine, King's College London, Guy's Tower, London Bridge, SE1 9RT London, UK
| | - Michael Weale
- Medical & Molecular Genetics, Division of Genetics and Molecular Medicine, King's College London, Guy's Tower, London Bridge, SE1 9RT London, UK
| | - Monkel Lek
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA
- Program in Medical and Population Genetics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA 02142, USA
| | - Frank Baas
- Department of Genome Analysis, University of Amsterdam, Academic Medical Centre, P.O. Box 22700, 1100DE Amsterdam, Netherlands
| | - J M Vianney de Jong
- Department of Genome Analysis, University of Amsterdam, Academic Medical Centre, P.O. Box 22700, 1100DE Amsterdam, Netherlands
| | - Anneloor L M A Ten Asbroek
- Department of Genome Analysis, University of Amsterdam, Academic Medical Centre, P.O. Box 22700, 1100DE Amsterdam, Netherlands
| | - Alberto Garcia Redondo
- Unidad de ELA, Instituto de Investigación Hospital 12 de Octubre de Madrid, SERMAS, and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), U-723 Madrid, Spain
| | - Jesús Esteban-Pérez
- Unidad de ELA, Instituto de Investigación Hospital 12 de Octubre de Madrid, SERMAS, and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), U-723 Madrid, Spain
| | - Cinzia Tiloca
- Department of Neurology and Laboratory of Neuroscience, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Auxologico Italiano, 20149 Milan, Italy
- Department of Pathophysiology and Transplantation, "Dino Ferrari" Center, University of Milan, 20122 Milan, Italy
| | - Federico Verde
- Department of Neurology and Laboratory of Neuroscience, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Auxologico Italiano, 20149 Milan, Italy
- Department of Pathophysiology and Transplantation, "Dino Ferrari" Center, University of Milan, 20122 Milan, Italy
| | - Stefano Duga
- Department of Biomedical Sciences, Humanitas University, Rozzano, Milan, Italy
- Humanitas Clinical and Research Center, Via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Nigel Leigh
- Trafford Centre for Medical Research, Brighton and Sussex Medical School, BN1 9RY Brighton, UK
| | - Hardev Pall
- School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Karen E Morrison
- University of Southampton, Southampton General Hospital, SO16 6YD, UK
| | - Ammar Al-Chalabi
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 125 Coldharbour Lane, Camberwell, SE5 9NU London, UK
| | - Pamela J Shaw
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Janine Kirby
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Martin R Turner
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford, UK
| | - Kevin Talbot
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford, UK
| | - Orla Hardiman
- Academic Unit of Neurology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Republic of Ireland
| | - Jonathan D Glass
- Department of Neurology, Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Jacqueline De Belleroche
- Neurogenetics Group, Division of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, Burlington Danes Building, Du Cane Road, W12 0NN London, UK
| | - Masatoshi Maki
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Stephen E Moss
- Institute of Ophthalmology, University College London, 11-43 Bath Street, EC1V 9EL London, UK
| | - Christopher Miller
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 125 Coldharbour Lane, Camberwell, SE5 9NU London, UK
| | - Cinzia Gellera
- Unit of Genetics of Neurodegenerative and Metabolic Diseases, Fondazione IRCCS Istituto Neurologico "Carlo Besta," 20133 Milan, Italy
| | - Antonia Ratti
- Department of Neurology and Laboratory of Neuroscience, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Auxologico Italiano, 20149 Milan, Italy
- Department of Pathophysiology and Transplantation, "Dino Ferrari" Center, University of Milan, 20122 Milan, Italy
| | - Safa Al-Sarraj
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 125 Coldharbour Lane, Camberwell, SE5 9NU London, UK
| | - Robert H Brown
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Vincenzo Silani
- Department of Neurology and Laboratory of Neuroscience, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Auxologico Italiano, 20149 Milan, Italy
- Department of Pathophysiology and Transplantation, "Dino Ferrari" Center, University of Milan, 20122 Milan, Italy
| | - John E Landers
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Christopher E Shaw
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 125 Coldharbour Lane, Camberwell, SE5 9NU London, UK.
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Maki M, Takahara T, Shibata H. Multifaceted Roles of ALG-2 in Ca(2+)-Regulated Membrane Trafficking. Int J Mol Sci 2016; 17:ijms17091401. [PMID: 27571067 PMCID: PMC5037681 DOI: 10.3390/ijms17091401] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 08/18/2016] [Accepted: 08/19/2016] [Indexed: 12/15/2022] Open
Abstract
ALG-2 (gene name: PDCD6) is a penta-EF-hand Ca2+-binding protein and interacts with a variety of proteins in a Ca2+-dependent fashion. ALG-2 recognizes different types of identified motifs in Pro-rich regions by using different hydrophobic pockets, but other unknown modes of binding are also used for non-Pro-rich proteins. Most ALG-2-interacting proteins associate directly or indirectly with the plasma membrane or organelle membranes involving the endosomal sorting complex required for transport (ESCRT) system, coat protein complex II (COPII)-dependent ER-to-Golgi vesicular transport, and signal transduction from membrane receptors to downstream players. Binding of ALG-2 to targets may induce conformational change of the proteins. The ALG-2 dimer may also function as a Ca2+-dependent adaptor to bridge different partners and connect the subnetwork of interacting proteins.
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Affiliation(s)
- Masatoshi Maki
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
| | - Terunao Takahara
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
| | - Hideki Shibata
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
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37
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Ding J, Zhao J, Sun L, Mi Z, Cen S. Citron kinase enhances ubiquitination of HIV-1 Gag protein and intracellular HIV-1 budding. Arch Virol 2016; 161:2441-8. [DOI: 10.1007/s00705-016-2933-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 06/12/2016] [Indexed: 11/30/2022]
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Montaño S, Orozco E, Correa-Basurto J, Bello M, Chávez-Munguía B, Betanzos A. Heterodimerization of the Entamoeba histolytica EhCPADH virulence complex through molecular dynamics and protein-protein docking. J Biomol Struct Dyn 2016; 35:486-503. [PMID: 26861050 DOI: 10.1080/07391102.2016.1151831] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
EhCPADH is a protein complex involved in the virulence of Entamoeba histolytica, the protozoan responsible for human amebiasis. It is formed by the EhCP112 cysteine protease and the EhADH adhesin. To explore the molecular basis of the complex formation, three-dimensional models were built for both proteins and molecular dynamics simulations (MDS) and docking calculations were performed. Results predicted that the pEhCP112 proenzyme and the mEhCP112 mature enzyme were globular and peripheral membrane proteins. Interestingly, in pEhCP112, the propeptide appeared hiding the catalytic site (C167, H329, N348); while in mEhCP112, this site was exposed and its residues were found structurally closer than in pEhCP112. EhADH emerged as an extended peripheral membrane protein with high fluctuation in Bro1 and V shape domains. 500 ns-long MDS and protein-protein docking predictions evidenced different heterodimeric complexes with the lowest free energy. pEhCP112 interacted with EhADH by the propeptide and C-terminal regions and mEhCP112 by the C-terminal through hydrogen bonds. In contrast, EhADH bound to mEhCP112 by 442-479 residues, adjacent to the target cell-adherence region (480-600 residues), and by the Bro1 domain (9-349 residues). Calculations of the effective binding free energy and per residue free energy decomposition showed that EhADH binds to mEhCP112 with a higher binding energy than to pEhCP112, mainly through van der Waals interactions and the nonpolar part of solvation energy. The EhADH and EhCP112 structural relationship was validated in trophozoites by immunofluorescence, TEM, and immunoprecipitation assays. Experimental findings fair agreed with in silico results.
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Affiliation(s)
- Sarita Montaño
- a Departamento de Infectómica y Patogénesis Molecular , Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN) , Ave. IPN 2508, San Pedro Zacatenco, México, D.F. 07360 , Mexico
| | - Esther Orozco
- a Departamento de Infectómica y Patogénesis Molecular , Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN) , Ave. IPN 2508, San Pedro Zacatenco, México, D.F. 07360 , Mexico
| | - José Correa-Basurto
- b Laboratorio de Modelado Molecular, Bioinformática y Diseño de Fármacos , Escuela Superior de Medicina del Instituto Politécnico Nacional (ESM-IPN) , Plan de San Luis y Díaz Mirón s/n, Miguel Hidalgo, Casco de Santo Tomas, México, D.F. 11340 , Mexico
| | - Martiniano Bello
- b Laboratorio de Modelado Molecular, Bioinformática y Diseño de Fármacos , Escuela Superior de Medicina del Instituto Politécnico Nacional (ESM-IPN) , Plan de San Luis y Díaz Mirón s/n, Miguel Hidalgo, Casco de Santo Tomas, México, D.F. 11340 , Mexico
| | - Bibiana Chávez-Munguía
- a Departamento de Infectómica y Patogénesis Molecular , Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN) , Ave. IPN 2508, San Pedro Zacatenco, México, D.F. 07360 , Mexico
| | - Abigail Betanzos
- a Departamento de Infectómica y Patogénesis Molecular , Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN) , Ave. IPN 2508, San Pedro Zacatenco, México, D.F. 07360 , Mexico
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Connolly KD, Guschina IA, Yeung V, Clayton A, Draman MS, Von Ruhland C, Ludgate M, James PE, Rees DA. Characterisation of adipocyte-derived extracellular vesicles released pre- and post-adipogenesis. J Extracell Vesicles 2015; 4:29159. [PMID: 26609807 PMCID: PMC4661001 DOI: 10.3402/jev.v4.29159] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 10/07/2015] [Accepted: 10/28/2015] [Indexed: 01/01/2023] Open
Abstract
Extracellular vesicles (EVs) are submicron vesicles released from many cell types, including adipocytes. EVs are implicated in the pathogenesis of obesity-driven cardiovascular disease, although the characteristics of adipocyte-derived EVs are not well described. We sought to define the characteristics of adipocyte-derived EVs before and after adipogenesis, hypothesising that adipogenesis would affect EV structure, molecular composition and function. Using 3T3-L1 cells, EVs were harvested at day 0 and day 15 of differentiation. EV and cell preparations were visualised by electron microscopy and EVs quantified by nanoparticle tracking analysis (NTA). EVs were then assessed for annexin V positivity using flow cytometry; lipid and phospholipid composition using 2D thin layer chromatography and gas chromatography; and vesicular protein content by an immuno-phenotyping assay. Pre-adipogenic cells are connected via a network of protrusions and EVs at both time points display classic EV morphology. EV concentration is elevated prior to adipogenesis, particularly in exosomes and small microvesicles. Parent cells contain higher proportions of phosphatidylserine (PS) and show higher annexin V binding. Both cells and EVs contain an increased proportion of arachidonic acid at day 0. PREF-1 was increased at day 0 whilst adiponectin was higher at day 15 indicating EV protein content reflects the stage of adipogenesis of the cell. Our data suggest that EV production is higher in cells before adipogenesis, particularly in vesicles <300 nm. Cells at this time point possess a greater proportion of PS (required for EV generation) whilst corresponding EVs are enriched in signalling fatty acids, such as arachidonic acid, and markers of adipogenesis, such as PREF-1 and PPARγ.
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Affiliation(s)
- Katherine D Connolly
- Institute of Molecular and Experimental Medicine, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Irina A Guschina
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Vincent Yeung
- Institute of Cancer Genetics, School of Medicine, Velindre Cancer Centre, Cardiff University, Cardiff, United Kingdom
| | - Aled Clayton
- Institute of Cancer Genetics, School of Medicine, Velindre Cancer Centre, Cardiff University, Cardiff, United Kingdom
| | - Mohd Shazli Draman
- Institute of Molecular and Experimental Medicine, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Christopher Von Ruhland
- Central Biotechnology Services, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Marian Ludgate
- Institute of Molecular and Experimental Medicine, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Philip E James
- School of Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - D Aled Rees
- Institute of Molecular and Experimental Medicine, School of Medicine, Cardiff University, Cardiff, United Kingdom;
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40
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Labyntsev AJ, Korotkevych NV, Kolybo DV, Komisarenko SV. EFFECT OF DIPHTHERIA TOXIN T-DOMAIN ON ENDOSOMAL pH. UKRAINIAN BIOCHEMICAL JOURNAL 2015; 87:13-23. [PMID: 26547959 DOI: 10.15407/ubj87.04.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
A key step in the mode of cytotoxic action of diphtheria toxin (DT) is the transfer of its catalytic domain (Cd) from endosomes into the cytosol. The main activity in this process is performed by the transport domain (Td), but the molecular mechanism of its action remains unknown. We have previously shown that Td can have some influence on the endosomal transport of DT The aim of this work was to study the effect of diphtheria toxin on the toxin compartmentalization in the intracellular transporting pathway and endosomal pH. We used recombinant fragments of DT which differed only by the presence of Td in their structure, fused with fluorescent proteins. It was shown that the toxin fragment with Td moved slower by the pathway early-late endosomes-lysosomes, and had a slightly different pattern of colocalization with endosomal markers than DT fragment without Td. In addition, endosomes containing DT fragments with Td had a constant pH of about 6.5 from the 10th to 50th minute of observation, for the same time endosomes containing DT fragments without Td demonstrated a decrease in pH from 6.3 to 5.5. These results indicate that Td inhibits acidification of endosomal medium. One of possible explanations for this may be the effect of the ion channel formed by the T-domain on the process of the endosomal acidification. This property of Td may not only inhibit maturation of endosomes but also inhibit activation of endosomal pH-dependent proteases, and this promotes successful transport of Cd into the cell cytosol.
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41
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Parkinson MDJ, Piper SC, Bright NA, Evans JL, Boname JM, Bowers K, Lehner PJ, Luzio JP. A non-canonical ESCRT pathway, including histidine domain phosphotyrosine phosphatase (HD-PTP), is used for down-regulation of virally ubiquitinated MHC class I. Biochem J 2015; 471:79-88. [PMID: 26221024 PMCID: PMC4613529 DOI: 10.1042/bj20150336] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 07/21/2015] [Accepted: 07/28/2015] [Indexed: 11/17/2022]
Abstract
The Kaposi's sarcoma-associated herpes virus (KSHV) K3 viral gene product effectively down-regulates cell surface MHC class I. K3 is an E3 ubiquitin ligase that promotes Lys(63)-linked polyubiquitination of MHC class I, providing the signal for clathrin-mediated endocytosis. Endocytosis is followed by sorting into the intralumenal vesicles (ILVs) of multivesicular bodies (MVBs) and eventual delivery to lysosomes. The sorting of MHC class I into MVBs requires many individual proteins of the four endosomal sorting complexes required for transport (ESCRTs). In HeLa cells expressing the KSHV K3 ubiquitin ligase, the effect of RNAi-mediated depletion of individual proteins of the ESCRT-0 and ESCRT-I complexes and three ESCRT-III proteins showed that these are required to down-regulate MHC class I. However, depletion of proteins of the ESCRT-II complex or of the ESCRT-III protein, VPS20 (vacuolar protein sorting 20)/CHMP6 (charged MVB protein 6), failed to prevent the loss of MHC class I from the cell surface. Depletion of histidine domain phosphotyrosine phosphatase (HD-PTP) resulted in an increase in the cell surface concentration of MHC class I in HeLa cells expressing the KSHV K3 ubiquitin ligase. Rescue experiments with wild-type (WT) and mutant HD-PTP supported the conclusion that HD-PTP acts as an alternative to ESCRT-II and VPS20/CHMP6 as a link between the ESCRT-I and those ESCRT-III protein(s) necessary for ILV formation. Thus, the down-regulation of cell surface MHC class I, polyubiquitinated by the KSHV K3 ubiquitin ligase, does not employ the canonical ESCRT pathway, but instead utilizes an alternative pathway in which HD-PTP replaces ESCRT-II and VPS20/CHMP6.
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Affiliation(s)
- Michael D J Parkinson
- Department of Clinical Biochemistry, Cambridge Institute for Medical Research, University of Cambridge School of Clinical Medicine, Wellcome Trust/MRC Building, Biomedical Campus, Hills Road, Cambridge, CB2 0XY, U.K
| | - Siân C Piper
- Department of Clinical Biochemistry, Cambridge Institute for Medical Research, University of Cambridge School of Clinical Medicine, Wellcome Trust/MRC Building, Biomedical Campus, Hills Road, Cambridge, CB2 0XY, U.K
| | - Nicholas A Bright
- Department of Clinical Biochemistry, Cambridge Institute for Medical Research, University of Cambridge School of Clinical Medicine, Wellcome Trust/MRC Building, Biomedical Campus, Hills Road, Cambridge, CB2 0XY, U.K
| | - Jennifer L Evans
- Department of Clinical Biochemistry, Cambridge Institute for Medical Research, University of Cambridge School of Clinical Medicine, Wellcome Trust/MRC Building, Biomedical Campus, Hills Road, Cambridge, CB2 0XY, U.K
| | - Jessica M Boname
- Department of Medicine, Cambridge Institute for Medical Research, University of Cambridge School of Clinical Medicine, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, U.K
| | - Katherine Bowers
- Department of Clinical Biochemistry, Cambridge Institute for Medical Research, University of Cambridge School of Clinical Medicine, Wellcome Trust/MRC Building, Biomedical Campus, Hills Road, Cambridge, CB2 0XY, U.K
| | - Paul J Lehner
- Department of Medicine, Cambridge Institute for Medical Research, University of Cambridge School of Clinical Medicine, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, U.K
| | - J Paul Luzio
- Department of Clinical Biochemistry, Cambridge Institute for Medical Research, University of Cambridge School of Clinical Medicine, Wellcome Trust/MRC Building, Biomedical Campus, Hills Road, Cambridge, CB2 0XY, U.K.
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Arabidopsis ALIX is required for the endosomal localization of the deubiquitinating enzyme AMSH3. Proc Natl Acad Sci U S A 2015; 112:E5543-51. [PMID: 26324913 DOI: 10.1073/pnas.1510516112] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Ubiquitination is a signal for various cellular processes, including for endocytic degradation of plasma membrane cargos. Ubiquitinating as well as deubiquitinating enzymes (DUBs) can regulate these processes by modifying the ubiquitination status of target protein. Although accumulating evidence points to the important regulatory role of DUBs, the molecular basis of their regulation is still not well understood. Associated molecule with the SH3 domain of signal transduction adaptor molecule (STAM) (AMSH) is a conserved metalloprotease DUB in eukaryotes. AMSH proteins interact with components of the endosomal sorting complex required for transport (ESCRT) and are implicated in intracellular trafficking. To investigate how the function of AMSH is regulated at the cellular level, we carried out an interaction screen for the Arabidopsis AMSH proteins and identified the Arabidopsis homolog of apoptosis-linked gene-2 interacting protein X (ALIX) as a protein interacting with AMSH3 in vitro and in vivo. Analysis of alix knockout mutants in Arabidopsis showed that ALIX is essential for plant growth and development and that ALIX is important for the biogenesis of the vacuole and multivesicular bodies (MVBs). Cell biological analysis revealed that ALIX and AMSH3 colocalize on late endosomes. Although ALIX did not stimulate AMSH3 activity in vitro, in the absence of ALIX, AMSH3 localization on endosomes was abolished. Taken together, our data indicate that ALIX could function as an important regulator for AMSH3 function at the late endosomes.
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43
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Unravelling the pivotal role of Alix in MVB sorting and silencing of the activated EGFR. Biochem J 2015; 466:475-87. [PMID: 25510652 DOI: 10.1042/bj20141156] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Endosomal sorting complex required for transport (ESCRT)-III-mediated membrane invagination and scission are a critical step in multivesicular body (MVB) sorting of ubiquitinated membrane receptors, and generally thought to be required for degradation of these receptors in lysosomes. The adaptor protein Alix is critically involved in multiple ESCRT-III-mediated, membrane-remodelling processes in mammalian cells. However, Alix knockdown does not inhibit degradation of the activated epidermal growth factor receptor (EGFR) in mammalian cell lines, leading to a widely held notion that Alix is not critically involved in MVB sorting of ubiquitinated membrane receptors in mammalian cells. In the present study, we demonstrate that, despite its non-essential role in degradation of the activated EGFR, Alix plays a critical role in its MVB sorting and silencing Epidermal growth factor (EGF) stimulation of mammalian cell lines induces Alix's interaction with the ubiquitinated EGFR via the Alix V domain, and increases Alix's association with membrane-bound charged multivesicular body protein 4 (CHMP4) via the Alix Bro1 domain. Under both continuous and pulse-chase EGF stimulation conditions, inhibition of Alix's interaction with membrane-bound CHMP4, inhibition of Alix dimerization through the V domain or Alix knockdown dramatically inhibits MVB sorting of the activated EGFR and promotes sustained activation of extracellular-signal regulated kinase (ERK)1/2. Under the continuous EGF stimulation conditions, these cell treatments also retard degradation of the activated EGFR. These findings indicate that Alix is critically involved in MVB sorting of ubiquitinated membrane receptors in mammalian cells.
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Murrow L, Malhotra R, Debnath J. ATG12-ATG3 interacts with Alix to promote basal autophagic flux and late endosome function. Nat Cell Biol 2015; 17:300-10. [PMID: 25686249 PMCID: PMC4344874 DOI: 10.1038/ncb3112] [Citation(s) in RCA: 211] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 01/14/2015] [Indexed: 12/20/2022]
Abstract
The ubiquitin-like molecule ATG12 is required for the early steps of autophagy. Recently, we identified ATG3, the E2-like enzyme required for LC3 lipidation during autophagy, as an ATG12 conjugation target. Here, we demonstrate that cells lacking ATG12-ATG3 have impaired basal autophagic flux, accumulation of perinuclear late endosomes, and impaired endolysosomal trafficking. Furthermore, we identify an interaction between ATG12-ATG3 and the ESCRT-associated protein Alix (also known as PDCD6IP) and demonstrate that ATG12-ATG3 controls multiple Alix-dependent processes including late endosome distribution, exosome biogenesis and viral budding. Similar to ATG12-ATG3, Alix is functionally required for efficient basal, but not starvation-induced, autophagy. Overall, these results identify a link between the core autophagy and ESCRT machineries and uncover a role for ATG12-ATG3 in late endosome function that is distinct from the canonical role of either ATG in autophagosome formation.
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Affiliation(s)
- Lyndsay Murrow
- Department of Pathology and Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, California 94143 USA
- Biomedical Sciences Graduate Program, University of California San Francisco, San Francisco, California 94143 USA
| | - Ritu Malhotra
- Department of Pathology and Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, California 94143 USA
| | - Jayanta Debnath
- Department of Pathology and Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, California 94143 USA
- Biomedical Sciences Graduate Program, University of California San Francisco, San Francisco, California 94143 USA
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45
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Shen J, Liu Y, Song Y, Li L, Duan C, Zhou Y, Ke K. CHMP4B, ESCRT-III associating protein, associated with neuronal apoptosis following intracerebral hemorrhage. Brain Res 2014; 1597:1-13. [PMID: 25478783 DOI: 10.1016/j.brainres.2014.11.043] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 11/19/2014] [Accepted: 11/20/2014] [Indexed: 12/17/2022]
Abstract
Charged multivesicular body protein (CHMP) represents a family of small helical proteins that contain an N-terminal basically charged region and a smaller C-terminal acidic region, which are highly conserved in all eukaryotes. CHMP4B, a core component of the endosomal sorting complex required for transport (ESCRT)-III, is requisite for endosomal sorting and other biological processes. Here, we demonstrate that CHMP4B may be involved in neuronal apoptosis in the processes of intracerebral hemorrhage (ICH). From the results of Western blot, immunohistochemistry and immunofluorescence, we obtained a significant up-regulation of CHMP4B in neurons adjacent to the hematoma following ICH. Increasing CHMP4B level was found to be accompanied by the up-regulation of Fas receptor (Fas), Fas ligand (FasL), active caspase-8, and active caspase-3. Besides, CHMP4B co-localized well with Fas and active caspase-3 in neurons, indicating its potential role in neuronal apoptosis. What's more, our in vitro study, using CHMP4B RNA interference in PC12 cells, further confirmed that CHMP4B might exert its pro-apoptotic function on neuronal apoptosis through extrinsic pathway. Thus, CHMP4B may play a role in promoting the brain damage following ICH.
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Affiliation(s)
- Jiabing Shen
- Department of Neurology, Affiliated Hospital of Nantong University, Nantong 226001, Jiangsu Province, China; Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Medical College of Nantong University, Nantong, Jiangsu Province 226001, China
| | - Yonghua Liu
- Department of Pathogen Biology, Medical College, Nantong University, Nantong 226001, Jiangsu Province, China; Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Medical College of Nantong University, Nantong, Jiangsu Province 226001, China
| | - Yan Song
- Department of Neurology, Affiliated Hospital of Nantong University, Nantong 226001, Jiangsu Province, China; Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Medical College of Nantong University, Nantong, Jiangsu Province 226001, China
| | - Lei Li
- Department of Neurology, Affiliated Hospital of Nantong University, Nantong 226001, Jiangsu Province, China
| | - Chengwei Duan
- The Jiangsu Province Key Laboratory of Neuroregeneration, Nantong University, Nantong, China; Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Medical College of Nantong University, Nantong, Jiangsu Province 226001, China
| | - Ying Zhou
- Department of Pathogen Biology, Medical College, Nantong University, Nantong 226001, Jiangsu Province, China; Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Medical College of Nantong University, Nantong, Jiangsu Province 226001, China
| | - Kaifu Ke
- Department of Neurology, Affiliated Hospital of Nantong University, Nantong 226001, Jiangsu Province, China; Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Medical College of Nantong University, Nantong, Jiangsu Province 226001, China.
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46
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Panjwani N. Role of galectins in re-epithelialization of wounds. ANNALS OF TRANSLATIONAL MEDICINE 2014; 2:89. [PMID: 25405164 DOI: 10.3978/j.issn.2305-5839.2014.09.09] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 09/09/2014] [Indexed: 12/18/2022]
Abstract
Re-epithelialization is a critical contributing process in wound healing in the human body. When this process is compromised, impaired or delayed, serious disorders of wound healing may result that are painful, difficult to treat, and affect a variety of human tissues. Recent studies have demonstrated that members of the galectin class of β-galactoside-binding proteins modulate re-epithelialization of wounds by novel carbohydrate-based recognition systems. Galectins constitute a family of widely distributed carbohydrate-binding proteins with the affinity for the β-galactoside-containing glycans found on many cell surface and extracellular matrix (ECM) glycoproteins. There are 15 members of the mammalian galectin family that so far have been identified. Studies of the role of galectins in wound healing have revealed that galectin-3 promotes re-epithelialization of corneal, intestinal and skin wounds; galectin-7 promotes re-epithelialization of corneal, skin, kidney and uterine wounds; and galectins-2 and -4 promote re-epithelialization of intestinal wounds. Promising prospects for developing novel therapeutic strategies for the treatment of problematic, slow- or non-healing wounds are implicit in the findings that galectins stimulate the re-epithelialization of wounds of the cornea, skin, intestinal tract and kidney. Molecular mechanisms by which galectins modulate the process of wound healing are beginning to emerge and are described in this review.
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Affiliation(s)
- Noorjahan Panjwani
- New England Eye Center, Departments of Ophthalmology and Developmental, Molecular, and Chemical Biology, Tufts University School of Medicine, Boston, MA 02111, USA
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47
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Amorim NA, da Silva EML, de Castro RO, da Silva-Januário ME, Mendonça LM, Bonifacino JS, da Costa LJ, daSilva LLP. Interaction of HIV-1 Nef protein with the host protein Alix promotes lysosomal targeting of CD4 receptor. J Biol Chem 2014; 289:27744-56. [PMID: 25118280 DOI: 10.1074/jbc.m114.560193] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Nef is an accessory protein of human immunodeficiency viruses that promotes viral replication and progression to AIDS through interference with various host trafficking and signaling pathways. A key function of Nef is the down-regulation of the coreceptor CD4 from the surface of the host cells. Nef-induced CD4 down-regulation involves at least two independent steps as follows: acceleration of CD4 endocytosis by a clathrin/AP-2-dependent pathway and targeting of internalized CD4 to multivesicular bodies (MVBs) for eventual degradation in lysosomes. In a previous work, we found that CD4 targeting to the MVB pathway was independent of CD4 ubiquitination. Here, we report that this targeting depends on a direct interaction of Nef with Alix/AIP1, a protein associated with the endosomal sorting complexes required for transport (ESCRT) machinery that assists with cargo recruitment and intraluminal vesicle formation in MVBs. We show that Nef interacts with both the Bro1 and V domains of Alix. Depletion of Alix or overexpression of the Alix V domain impairs lysosomal degradation of CD4 induced by Nef. In contrast, the V domain overexpression does not prevent cell surface removal of CD4 by Nef or protein targeting to the canonical ubiquitination-dependent MVB pathway. We also show that the Nef-Alix interaction occurs in late endosomes that are enriched in internalized CD4. Together, our results indicate that Alix functions as an adaptor for the ESCRT-dependent, ubiquitin-independent targeting of CD4 to the MVB pathway induced by Nef.
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Affiliation(s)
- Nathaly A Amorim
- From the Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP 14049-900, Brazil
| | - Eulália M L da Silva
- From the Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP 14049-900, Brazil
| | - Rodrigo O de Castro
- From the Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP 14049-900, Brazil
| | - Mara E da Silva-Januário
- From the Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP 14049-900, Brazil
| | - Luiza M Mendonça
- the Department of Virology, Institute of Microbiology Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-590, Brazil, and
| | - Juan S Bonifacino
- the Cell Biology and Metabolism Program, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, Maryland 20892
| | - Luciana J da Costa
- the Department of Virology, Institute of Microbiology Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-590, Brazil, and
| | - Luis L P daSilva
- From the Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP 14049-900, Brazil,
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VPS37 isoforms differentially modulate the ternary complex formation of ALIX, ALG-2, and ESCRT-I. Biosci Biotechnol Biochem 2013; 77:1715-21. [PMID: 23924735 DOI: 10.1271/bbb.130280] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The endosomal sorting complex required for transport (ESCRT) system comprises a series of protein complexes that play essential roles in multivesicular body (MVB) sorting of ubiquitylated membrane proteins, enveloped RNA virus budding, and cytokinesis in mammalian cells. The complex, named ESCRT-I, consists of four subunits (TSG101, VPS28, VPS37, and MVB12). There are four VPS37 isoforms. We have reported that ALIX (an ALG-2-interacting protein and accessory protein in the ESCRT system) is physically linked with TSG101 by ALG-2 in a Ca²⁺-dependent manner, but the role of ALG-2 as an adaptor protein for the ESCRT-I complex remains unknown. To characterize this adaptor function, initially we investigated the binding of ALG-2 to ESCRT-I complexes containing each one of the four different VPS37 isoforms by two approaches: first, Far-Western blot analysis with biotin-labeled ALG-2 probe, and second, a pulldown assay to determine the binding of the four recombinant ESCRT-I complexes to Strep-tagged ALG-2 after co-expression in HEK293T cells. VPS37B and VPS37C appeared to interact with ALG-2 in a stronger manner than TSG101 does. The results of in vitro binding assays using purified recombinant proteins indicated that ALG-2 functions as a Ca²⁺-dependent adaptor protein that bridges ALIX and ESCRT-I to form a ternary complex, ESCRT-I/ALIX/ALG-2.
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49
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Sette P, Nagashima K, Piper RC, Bouamr F. Ubiquitin conjugation to Gag is essential for ESCRT-mediated HIV-1 budding. Retrovirology 2013; 10:79. [PMID: 23895345 PMCID: PMC3751857 DOI: 10.1186/1742-4690-10-79] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 07/24/2013] [Indexed: 01/05/2023] Open
Abstract
Background HIV-1 relies on the host ESCRTs for release from cells. HIV-1 Gag engages ESCRTs by directly binding TSG101 or Alix. ESCRTs also sort ubiquitinated membrane proteins through endosomes to facilitate their lysosomal degradation. The ability of ESCRTs to recognize and process ubiquitinated proteins suggests that ESCRT-dependent viral release may also be controlled by ubiquitination. Although both Gag and ESCRTs undergo some level of ubiquitination, definitive demonstration that ubiquitin is required for viral release is lacking. Here we suppress ubiquitination at viral budding sites by fusing the catalytic domain of the Herpes Simplex UL36 deubiquitinating enzyme (DUb) onto TSG101, Alix, or Gag. Results Expressing DUb-TSG101 suppressed Alix-independent HIV-1 release and viral particles remained tethered to the cell surface. DUb-TSG101 had no effect on budding of MoMLV or EIAV, two retroviruses that rely on the ESCRT machinery for exit. Alix-dependent virus release such as EIAV’s, and HIV-1 lacking access to TSG101, was instead dramatically blocked by co-expressing DUb-Alix. Finally, Gag-DUb was unable to support virus release and dominantly interfered with release of wild type HIV-1. Fusion of UL36 did not effect interactions with Alix, TSG101, or Gag and all of the inhibitory effects of UL36 fusion were abolished when its catalytic activity was ablated. Accordingly, Alix, TSG101 and Gag fused to inactive UL36 functionally replaced their unfused counterparts. Interestingly, coexpression of the Nedd4-2s ubiquitin ligase suppressed the ability of DUb-TSG101 to inhibit HIV-1 release while also restoring detectable Gag ubiquitination at the membrane. Similarly, incorporation of Gag-Ub fusion proteins into virions lifted DUb-ESCRT inhibitory effect. In contrast, Nedd4-2s did not suppress the inhibition mediated by Gag-DUb despite restoring robust ubiquitination of TSG101/ESCRT-I at virus budding sites. Conclusions These studies demonstrate a necessary and natural role for ubiquitin in ESCRT-dependent viral release and indicate a critical role for ubiquitination of Gag rather than ubiquitination of ESCRTs themselves.
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Affiliation(s)
- Paola Sette
- Viral Budding Unit, Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 4 Center Dr, Bethesda, MD 20894, USA
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50
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Yu Q, Zhou C, Wang J, Chen L, Zheng S, Zhang J. A functional insertion/deletion polymorphism in the promoter of PDCD6IP is associated with the susceptibility of hepatocellular carcinoma in a Chinese population. DNA Cell Biol 2013; 32:451-7. [PMID: 23777424 DOI: 10.1089/dna.2013.2061] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. Apart from environmental factors such as hepatitis B virus (HBV) or hepatitis C virus, alcohol abuse, and exposure to dietary aflatoxin, genetic factors are also involved in the pathogenesis of HCC. By analyzing 390 HCC cases and 431 healthy controls in a Chinese population, we used a candidate gene approach to evaluate the association between a 15-bp insertion/deletion (indel) polymorphism (rs28381975) in the promoter region of the programmed cell death 6 interacting protein (PDCD6IP) gene and HCC susceptibility. Logistic regression analysis demonstrated that subjects carrying ins/del or ins/ins genotypes had significantly increased risk for HCC than individuals carrying del/del genotypes (adjusted odds ratio=1.39, 95% confidence interval=1.01-1.91, p=0.033]. Carrying the 15-bp insertion allele was associated with a 1.26-fold risk for HCC (95% CI=1.04-1.54, p=0.018). Moreover, significant differences were observed within HCC patients concerning genotypic frequencies of rs28381975 after stratifying by tumor stages and HBV infection. Computational modeling suggests that rs28381975 could disrupt the binding patterns of c-rel, a key subunit of nuclear factor-kappaB transcription factor. Further luciferase-based transient transfection assays revealed that rs28381975 can affect the promoter activity of PDCD6IP, indicating its possible functional significance. Taken together, our data suggest that common genetic variations in PDCD6IP may influence HCC risk, possibly through promoter activity-mediated regulation. Replication of our studies in other populations and further functional analysis will strengthen our understanding of this association.
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Affiliation(s)
- Qiang Yu
- Department of Gastroenterology, Suzhou Municipal Hospital, Affiliated to Nanjing Medical University, Suzhou, Jiangsu, China
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