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Kiani YS, Jabeen I. Challenges of Protein-Protein Docking of the Membrane Proteins. Methods Mol Biol 2024; 2780:203-255. [PMID: 38987471 DOI: 10.1007/978-1-0716-3985-6_12] [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] [Indexed: 07/12/2024]
Abstract
Despite the recent advances in the determination of high-resolution membrane protein (MP) structures, the structural and functional characterization of MPs remains extremely challenging, mainly due to the hydrophobic nature, low abundance, poor expression, purification, and crystallization difficulties associated with MPs. Whereby the major challenges/hurdles for MP structure determination are associated with the expression, purification, and crystallization procedures. Although there have been significant advances in the experimental determination of MP structures, only a limited number of MP structures (approximately less than 1% of all) are available in the Protein Data Bank (PDB). Therefore, the structures of a large number of MPs still remain unresolved, which leads to the availability of widely unplumbed structural and functional information related to MPs. As a result, recent developments in the drug discovery realm and the significant biological contemplation have led to the development of several novel, low-cost, and time-efficient computational methods that overcome the limitations of experimental approaches, supplement experiments, and provide alternatives for the characterization of MPs. Whereby the fine tuning and optimizations of these computational approaches remains an ongoing endeavor.Computational methods offer a potential way for the elucidation of structural features and the augmentation of currently available MP information. However, the use of computational modeling can be extremely challenging for MPs mainly due to insufficient knowledge of (or gaps in) atomic structures of MPs. Despite the availability of numerous in silico methods for 3D structure determination the applicability of these methods to MPs remains relatively low since all methods are not well-suited or adequate for MPs. However, sophisticated methods for MP structure predictions are constantly being developed and updated to integrate the modifications required for MPs. Currently, different computational methods for (1) MP structure prediction, (2) stability analysis of MPs through molecular dynamics simulations, (3) modeling of MP complexes through docking, (4) prediction of interactions between MPs, and (5) MP interactions with its soluble partner are extensively used. Towards this end, MP docking is widely used. It is notable that the MP docking methods yet few in number might show greater potential in terms of filling the knowledge gap. In this chapter, MP docking methods and associated challenges have been reviewed to improve the applicability, accuracy, and the ability to model macromolecular complexes.
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Affiliation(s)
- Yusra Sajid Kiani
- School of Interdisciplinary Engineering and Sciences (SINES), National University of Sciences and Technology (NUST), Islamabad, Pakistan
| | - Ishrat Jabeen
- School of Interdisciplinary Engineering and Sciences (SINES), National University of Sciences and Technology (NUST), Islamabad, Pakistan.
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2
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You X, Zhu S, Sheng H, Liu Z, Wang D, Wang M, Xu X, He F, Fang H, Zhang F, Wang D, Hao Z, Wang R, Xiao Y, Wan J, Wang GL, Ning Y. The rice peroxisomal receptor PEX5 negatively regulates resistance to rice blast fungus Magnaporthe oryzae. Cell Rep 2023; 42:113315. [PMID: 37862164 DOI: 10.1016/j.celrep.2023.113315] [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: 07/21/2022] [Revised: 08/22/2023] [Accepted: 10/06/2023] [Indexed: 10/22/2023] Open
Abstract
The receptor protein PEX5, an important component of peroxisomes, regulates growth, development, and immunity in yeast and mammals. PEX5 also influences growth and development in plants, but whether it participates in plant immunity has remained unclear. Here, we report that knockdown of OsPEX5 enhances resistance to the rice blast fungus Magnaporthe oryzae. We demonstrate that OsPEX5 interacts with the E3 ubiquitin ligase APIP6, a positive regulator of plant immunity. APIP6 ubiquitinates OsPEX5 in vitro and promotes its degradation in vivo via the 26S proteasome pathway. In addition, OsPEX5 interacts with the aldehyde dehydrogenase OsALDH2B1, which functions in growth-defense trade-offs in rice. OsPEX5 stabilizes OsALDH2B1 to enhance its repression of the defense-related gene OsAOS2. Our study thus uncovers a previously unrecognized hierarchical regulatory mechanism in which an E3 ubiquitin ligase targets a peroxisome receptor protein that negatively regulates immunity in rice by stabilizing an aldehyde dehydrogenase that suppresses defense gene expression.
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Affiliation(s)
- Xiaoman You
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Shanshan Zhu
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agriculture Sciences, Beijing 100081, China
| | - Haowen Sheng
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; College of Agronomy, Hunan Agricultural University, Changsha, China
| | - Zheng Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Dan Wang
- College of Agronomy, Hunan Agricultural University, Changsha, China
| | - Min Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Xiao Xu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Feng He
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Hong Fang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Fan Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Debao Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Zeyun Hao
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Ruyi Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Yinghui Xiao
- College of Agronomy, Hunan Agricultural University, Changsha, China
| | - Jianmin Wan
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agriculture Sciences, Beijing 100081, China
| | - Guo-Liang Wang
- Department of Plant Pathology, The Ohio State University, Columbus, OH 43210, USA
| | - Yuese Ning
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
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Kawka M, Płocińska R, Płociński P, Pawełczyk J, Słomka M, Gatkowska J, Dzitko K, Dziadek B, Dziadek J. The functional response of human monocyte-derived macrophages to serum amyloid A and Mycobacterium tuberculosis infection. Front Immunol 2023; 14:1238132. [PMID: 37781389 PMCID: PMC10540855 DOI: 10.3389/fimmu.2023.1238132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Accepted: 08/28/2023] [Indexed: 10/03/2023] Open
Abstract
Introduction In the course of tuberculosis (TB), the level of major acute phase protein, namely serum amyloid A (hSAA-1), increases up to a hundredfold in the pleural fluids of infected individuals. Tubercle bacilli infecting the human host can be opsonized by hSAA-1, which affects bacterial entry into human macrophages and their intracellular multiplication. Methods We applied global RNA sequencing to evaluate the functional response of human monocyte-derived macrophages (MDMs), isolated from healthy blood donors, under elevated hSAA-1 conditions and during infection with nonopsonized and hSAA-1-opsonized Mycobacterium tuberculosis (Mtb). In the same infection model, we also examined the functional response of mycobacteria to the intracellular environment of macrophages in the presence and absence of hSAA-1. The RNASeq analysis was validated using qPCR. The functional response of MDMs to hSAA-1 and/or tubercle bacilli was also evaluated for selected cytokines at the protein level by applying the Milliplex system. Findings Transcriptomes of MDMs cultured in the presence of hSAA-1 or infected with Mtb showed a high degree of similarity for both upregulated and downregulated genes involved mainly in processes related to cell division and immune response, respectively. Among the most induced genes, across both hSAA-1 and Mtb infection conditions, CXCL8, CCL15, CCL5, IL-1β, and receptors for IL-7 and IL-2 were identified. We also observed the same pattern of upregulated pro-inflammatory cytokines (TNFα, IL-6, IL-12, IL-18, IL-23, and IL-1) and downregulated anti-inflammatory cytokines (IL-10, TGFβ, and antimicrobial peptide cathelicidin) in the hSAA-1 treated-MDMs or the phagocytes infected with tubercle bacilli. At this early stage of infection, Mtb genes affected by the inside microenvironment of MDMs are strictly involved in iron scavenging, adaptation to hypoxia, low pH, and increasing levels of CO2. The genes for the synthesis and transport of virulence lipids, but not cholesterol/fatty acid degradation, were also upregulated. Conclusion Elevated serum hSAA-1 levels in tuberculosis enhance the response of host phagocytes to infection, including macrophages that have not yet been in contact with mycobacteria. SAA induces antigen processing and presentation processes by professional phagocytes reversing the inhibition caused by Mtb infection.
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Affiliation(s)
- Malwina Kawka
- Department of Molecular Microbiology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Renata Płocińska
- Institute of Medical Biology, Polish Academy of Sciences, Lodz, Poland
| | | | - Jakub Pawełczyk
- Institute of Medical Biology, Polish Academy of Sciences, Lodz, Poland
| | - Marcin Słomka
- Biobank Lab, Department of Oncobiology and Epigenetics, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Justyna Gatkowska
- Department of Molecular Microbiology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Katarzyna Dzitko
- Department of Molecular Microbiology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Bożena Dziadek
- Department of Molecular Microbiology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Jarosław Dziadek
- Institute of Medical Biology, Polish Academy of Sciences, Lodz, Poland
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Heat shock protein Hspa13 regulates endoplasmic reticulum and cytosolic proteostasis through modulation of protein translocation. J Biol Chem 2022; 298:102597. [PMID: 36244454 PMCID: PMC9691929 DOI: 10.1016/j.jbc.2022.102597] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 09/29/2022] [Accepted: 10/03/2022] [Indexed: 11/06/2022] Open
Abstract
Most eukaryotic secretory proteins are cotranslationally translocated through Sec61 into the endoplasmic reticulum (ER). Because these proteins have evolved to fold in the ER, their mistargeting is associated with toxicity. Genetic experiments have implicated the ER heat shock protein 70 (Hsp70) Hspa13/STCH as involved in processing of nascent secretory proteins. Herein, we evaluate the role of Hspa13 in protein import and the maintenance of cellular proteostasis in human cells, primarily using the human embryonic kidney 293T cell line. We find that Hspa13 interacts primarily with the Sec61 translocon and its associated factors. Hspa13 overexpression inhibits translocation of the secreted protein transthyretin, leading to accumulation and aggregation of immature transthyretin in the cytosol. ATPase-inactive mutants of Hspa13 further inhibit translocation and maturation of secretory proteins. While Hspa13 overexpression inhibits cell growth and ER quality control, we demonstrate that HSPA13 knockout destabilizes proteostasis and increases sensitivity to ER disruption. Thus, we propose that Hspa13 regulates import through the translocon to maintain both ER and cytosolic protein homeostasis. The raw mass spectrometry data associated with this article have been deposited in the PRIDE archive and can be accessed at PXD033498.
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5
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Parys JB, Van Coppenolle F. Sec61 complex/translocon: The role of an atypical ER Ca 2+-leak channel in health and disease. Front Physiol 2022; 13:991149. [PMID: 36277220 PMCID: PMC9582130 DOI: 10.3389/fphys.2022.991149] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 09/20/2022] [Indexed: 11/02/2023] Open
Abstract
The heterotrimeric Sec61 protein complex forms the functional core of the so-called translocon that forms an aqueous channel in the endoplasmic reticulum (ER). The primary role of the Sec61 complex is to allow protein import in the ER during translation. Surprisingly, a completely different function in intracellular Ca2+ homeostasis has emerged for the Sec61 complex, and the latter is now accepted as one of the major Ca2+-leak pathways of the ER. In this review, we first discuss the structure of the Sec61 complex and focus on the pharmacology and regulation of the Sec61 complex as a Ca2+-leak channel. Subsequently, we will pay particular attention to pathologies that are linked to Sec61 mutations, such as plasma cell deficiency and congenital neutropenia. Finally, we will explore the relevance of the Sec61 complex as a Ca2+-leak channel in various pathophysiological (ER stress, apoptosis, ischemia-reperfusion) and pathological (type 2 diabetes, cancer) settings.
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Affiliation(s)
- Jan B. Parys
- Laboratory for Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine & Leuven Kanker Instituut, KU Leuven, Leuven, Belgium
| | - Fabien Van Coppenolle
- CarMeN Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, Lyon, France
- Groupement Hospitalier EST, Department of Cardiology, Hospices Civils de Lyon, Lyon, France
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6
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Yu Z, Shen X, Hu C, Zeng J, Wang A, Chen J. Molecular Mechanisms of Isolated Polycystic Liver Diseases. Front Genet 2022; 13:846877. [PMID: 35571028 PMCID: PMC9104337 DOI: 10.3389/fgene.2022.846877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 03/23/2022] [Indexed: 11/13/2022] Open
Abstract
Polycystic liver disease (PLD) is a rare autosomal dominant disorder including two genetically and clinically distinct forms: autosomal dominant polycystic kidney disease (ADPKD) and isolated polycystic liver disease (PCLD). The main manifestation of ADPKD is kidney cysts, while PCLD has predominantly liver presentations with mild or absent kidney cysts. Over the past decade, PRKCSH, SEC63, ALG8, and LRP5 have been candidate genes of PCLD. Recently, more candidate genes such as GANAB, SEC61B, and ALR9 were also reported in PCLD patients. This review focused on all candidate genes of PCLD, including the newly established novel candidate genes. In addition, we also discussed some other genes which might also contribute to the disease.
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Affiliation(s)
- Ziqi Yu
- Munich Medical Research School, LMU Munich, Munich, Germany
| | - Xiang Shen
- Munich Medical Research School, LMU Munich, Munich, Germany
| | - Chong Hu
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital of Nanchang Medical College, Jiangxi Provincial People's Hospital, Nanchang, China
| | - Jun Zeng
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital of Nanchang Medical College, Jiangxi Provincial People's Hospital, Nanchang, China
| | - Aiyao Wang
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital of Nanchang Medical College, Jiangxi Provincial People's Hospital, Nanchang, China
| | - Jianyong Chen
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital of Nanchang Medical College, Jiangxi Provincial People's Hospital, Nanchang, China
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7
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Huynh MS, Hooda Y, Li YR, Jagielnicki M, Lai CCL, Moraes TF. Reconstitution of surface lipoprotein translocation through the slam translocon. eLife 2022; 11:72822. [PMID: 35475756 PMCID: PMC9090332 DOI: 10.7554/elife.72822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 04/26/2022] [Indexed: 11/13/2022] Open
Abstract
Surface lipoproteins (SLPs) are peripherally attached to the outer leaflet of the outer membrane in many Gram-negative bacteria, playing significant roles in nutrient acquisition and immune evasion in the host. While the factors that are involved in the synthesis and delivery of SLPs in the inner membrane are well characterized, the molecular machinery required for the movement of SLPs to the surface are still not fully elucidated. In this study, we investigated the translocation of a SLP TbpB through a Slam1-dependent pathway. Using purified components, we developed an in vitro translocation assay where unfolded TbpB is transported through Slam1-containing proteoliposomes, confirming Slam1 as an outer membrane translocon. While looking to identify factors to increase translocation efficiency, we discovered the periplasmic chaperone Skp interacted with TbpB in the periplasm of Escherichia coli. The presence of Skp was found to increase the translocation efficiency of TbpB in the reconstituted translocation assays. A knockout of Skp in Neisseria meningitidis revealed that Skp is essential for functional translocation of TbpB to the bacterial surface. Taken together, we propose a pathway for surface destined lipoproteins, where Skp acts as a holdase for Slam-mediated TbpB translocation across the outer membrane.
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Affiliation(s)
- Minh Sang Huynh
- Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Yogesh Hooda
- MRC Laboratory of Molecular Biology, University of Cambridge, Cambridge, United Kingdom
| | - Yuzi Raina Li
- Department of Biochemistry, University of Toronto, Toronto, Canada
| | | | | | - Trevor F Moraes
- Department of Biochemistry, University of Toronto, Toronto, Canada
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8
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Jiang Y, Wang D, Wang W, Xu D. Computational methods for protein localization prediction. Comput Struct Biotechnol J 2021; 19:5834-5844. [PMID: 34765098 PMCID: PMC8564054 DOI: 10.1016/j.csbj.2021.10.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 10/12/2021] [Accepted: 10/13/2021] [Indexed: 12/16/2022] Open
Abstract
The accurate annotation of protein localization is crucial in understanding protein function in tandem with a broad range of applications such as pathological analysis and drug design. Since most proteins do not have experimentally-determined localization information, the computational prediction of protein localization has been an active research area for more than two decades. In particular, recent machine-learning advancements have fueled the development of new methods in protein localization prediction. In this review paper, we first categorize the main features and algorithms used for protein localization prediction. Then, we summarize a list of protein localization prediction tools in terms of their coverage, characteristics, and accessibility to help users find suitable tools based on their needs. Next, we evaluate some of these tools on a benchmark dataset. Finally, we provide an outlook on the future exploration of protein localization methods.
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Affiliation(s)
- Yuexu Jiang
- Department of Electrical Engineering and Computer Science, Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | - Duolin Wang
- Department of Electrical Engineering and Computer Science, Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | - Weiwei Wang
- Department of Electrical Engineering and Computer Science, Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | - Dong Xu
- Department of Electrical Engineering and Computer Science, Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
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9
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Lyu Z, Genereux JC. Methodologies for Measuring Protein Trafficking across Cellular Membranes. Chempluschem 2021; 86:1397-1415. [PMID: 34636167 DOI: 10.1002/cplu.202100304] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/19/2021] [Indexed: 12/11/2022]
Abstract
Nearly all proteins are synthesized in the cytosol. The majority of this proteome must be trafficked elsewhere, such as to membranes, to subcellular compartments, or outside of the cell. Proper trafficking of nascent protein is necessary for protein folding, maturation, quality control and cellular and organismal health. To better understand cellular biology, molecular and chemical technologies to properly characterize protein trafficking (and mistrafficking) have been developed and applied. Herein, we take a biochemical perspective to review technologies that enable spatial and temporal measurement of protein distribution, focusing on both the most widely adopted methodologies and exciting emerging approaches.
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Affiliation(s)
- Ziqi Lyu
- Department of Chemistry, University of California, Riverside, 501 Big Springs Road, 92521, Riverside, CA, USA
| | - Joseph C Genereux
- Department of Chemistry, University of California, Riverside, 501 Big Springs Road, 92521, Riverside, CA, USA
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10
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Chen X, Chen J, Zhuo BY, Yang X, Luo MB. Simulation study for the pulling translocation of a polymer globule. Polym J 2021. [DOI: 10.1038/s41428-021-00502-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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11
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Abstract
Folding of proteins is essential so that they can exert their functions. For proteins that transit the secretory pathway, folding occurs in the endoplasmic reticulum (ER) and various chaperone systems assist in acquiring their correct folding/subunit formation. N-glycosylation is one of the most conserved posttranslational modification for proteins, and in eukaryotes it occurs in the ER. Consequently, eukaryotic cells have developed various systems that utilize N-glycans to dictate and assist protein folding, or if they consistently fail to fold properly, to destroy proteins for quality control and the maintenance of homeostasis of proteins in the ER.
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12
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Winogradoff D, John S, Aksimentiev A. Protein unfolding by SDS: the microscopic mechanisms and the properties of the SDS-protein assembly. NANOSCALE 2020; 12:5422-5434. [PMID: 32080694 PMCID: PMC7291819 DOI: 10.1039/c9nr09135a] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The effects of detergent sodium dodecyl sulfate (SDS) on protein structure and dynamics are fundamental to the most common laboratory technique used to separate proteins and determine their molecular weights: polyacrylamide gel electrophoresis. However, the mechanism by which SDS induces protein unfolding and the microstructure of protein-SDS complexes remain largely unknown. Here, we report a detailed account of SDS-induced unfolding of two proteins-I27 domain of titin and β-amylase-obtained through all-atom molecular dynamics simulations. Both proteins were found to spontaneously unfold in the presence of SDS at boiling water temperature on the time scale of several microseconds. The protein unfolding was found to occur via two distinct mechanisms in which specific interactions of individual SDS molecules disrupt the protein's secondary structure. In the final state of the unfolding process, the proteins are found to wrap around SDS micelles in a fluid necklace-and-beads configuration, where the number and location of bound micelles changes dynamically. The global conformation of the protein was found to correlate with the number of SDS micelles bound to it, whereas the number of SDS molecules directly bound to the protein was found to define the relaxation time scale of the unfolded protein. Our microscopic characterization of SDS-protein interactions sets the stage for future refinement of SDS-enabled protein characterization methods, including protein fingerprinting and sequencing using a solid-state nanopore.
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Affiliation(s)
- David Winogradoff
- Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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13
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Liu B, Lee G, Wu J, Deming J, Kuei C, Harrington A, Wang L, Towne J, Lovenberg T, Liu C, Sun S. The PAR2 signal peptide prevents premature receptor cleavage and activation. PLoS One 2020; 15:e0222685. [PMID: 32078628 PMCID: PMC7032737 DOI: 10.1371/journal.pone.0222685] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 02/03/2020] [Indexed: 11/19/2022] Open
Abstract
Unlike closely related GPCRs, protease-activated receptors (PAR1, PAR2, PAR3, and PAR4) have a predicted signal peptide at their N-terminus, which is encoded by a separate exon, suggesting that the signal peptides of PARs may serve an important and unique function, specific for PARs. In this report, we show that the PAR2 signal peptide, when fused to the N-terminus of IgG-Fc, effectively induced IgG-Fc secretion into culture medium, thus behaving like a classical signal peptide. The presence of PAR2 signal peptide has a strong effect on PAR2 cell surface expression, as deletion of the signal peptide (PAR2ΔSP) led to dramatic reduction of the cell surface expression and decreased responses to trypsin or the synthetic peptide ligand (SLIGKV). However, further deletion of the tethered ligand region (SLIGKV) at the N-terminus rescued the cell surface receptor expression and the response to the synthetic peptide ligand, suggesting that the signal peptide of PAR2 may be involved in preventing PAR2 from intracellular protease activation before reaching the cell surface. Supporting this hypothesis, an Arg36Ala mutation on PAR2ΔSP, which disabled the trypsin activation site, increased the receptor cell surface expression and the response to ligand stimulation. Similar effects were observed when PAR2ΔSP expressing cells were treated with protease inhibitors. Our findings indicated that there is a role of the PAR2 signal peptide in preventing the premature activation of PAR2 from intracellular protease cleavage before reaching the cells surface. The same mechanism may also apply to PAR1, PAR3, and PAR4.
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Affiliation(s)
- Belinda Liu
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Grace Lee
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Jiejun Wu
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Janise Deming
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Chester Kuei
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Anthony Harrington
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Lien Wang
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Jennifer Towne
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Timothy Lovenberg
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Changlu Liu
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Siquan Sun
- Janssen Research & Development, LLC, San Diego, California, United States of America
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14
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Bender J, Schmidt C. Mass spectrometry of membrane protein complexes. Biol Chem 2020; 400:813-829. [PMID: 30956223 DOI: 10.1515/hsz-2018-0443] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 02/25/2019] [Indexed: 12/24/2022]
Abstract
Membrane proteins are key players in the cell. Due to their hydrophobic nature they require solubilising agents such as detergents or membrane mimetics during purification and, consequently, are challenging targets in structural biology. In addition, their natural lipid environment is crucial for their structure and function further hampering their analysis. Alternative approaches are therefore required when the analysis by conventional techniques proves difficult. In this review, we highlight the broad application of mass spectrometry (MS) for the characterisation of membrane proteins and their interactions with lipids. We show that MS unambiguously identifies the protein and lipid components of membrane protein complexes, unravels their three-dimensional arrangements and further provides clues of protein-lipid interactions.
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Affiliation(s)
- Julian Bender
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Centre, Martin Luther University Halle-Wittenberg, Institute for Biochemistry and Biotechnology, Kurt-Mothes-Str. 3a, D-06120 Halle, Germany
| | - Carla Schmidt
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Centre, Martin Luther University Halle-Wittenberg, Institute for Biochemistry and Biotechnology, Kurt-Mothes-Str. 3a, D-06120 Halle, Germany
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15
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Impact of bacterial chaperonin GroEL–GroES on bacteriorhodopsin folding and membrane integration. BIOPHYSICS REPORTS 2019. [DOI: 10.1007/s41048-019-0090-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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16
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Graham JB, Canniff NP, Hebert DN. TPR-containing proteins control protein organization and homeostasis for the endoplasmic reticulum. Crit Rev Biochem Mol Biol 2019; 54:103-118. [PMID: 31023093 DOI: 10.1080/10409238.2019.1590305] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The endoplasmic reticulum (ER) is a complex, multifunctional organelle comprised of a continuous membrane and lumen that is organized into a number of functional regions. It plays various roles including protein translocation, folding, quality control, secretion, calcium signaling, and lipid biogenesis. Cellular protein homeostasis is maintained by a complicated chaperone network, and the largest functional family within this network consists of proteins containing tetratricopeptide repeats (TPRs). TPRs are well-studied structural motifs that mediate intermolecular protein-protein interactions, supporting interactions with a wide range of ligands or substrates. Seven TPR-containing proteins have thus far been shown to localize to the ER and control protein organization and homeostasis within this multifunctional organelle. Here, we discuss the roles of these proteins in controlling ER processes and organization. The crucial roles that TPR-containing proteins play in the ER are highlighted by diseases or defects associated with their mutation or disruption.
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Affiliation(s)
- Jill B Graham
- a Molecular Cellular Biology Program , University of Massachusetts , Amherst , MA , USA.,b Biochemistry and Molecular Biology Department , University of Massachusetts , Amherst , MA , USA
| | - Nathan P Canniff
- a Molecular Cellular Biology Program , University of Massachusetts , Amherst , MA , USA.,b Biochemistry and Molecular Biology Department , University of Massachusetts , Amherst , MA , USA
| | - Daniel N Hebert
- a Molecular Cellular Biology Program , University of Massachusetts , Amherst , MA , USA.,b Biochemistry and Molecular Biology Department , University of Massachusetts , Amherst , MA , USA
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17
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Pei J, Kinch LN, Grishin NV. FlyXCDB—A Resource for Drosophila Cell Surface and Secreted Proteins and Their Extracellular Domains. J Mol Biol 2018; 430:3353-3411. [DOI: 10.1016/j.jmb.2018.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 05/31/2018] [Accepted: 06/02/2018] [Indexed: 02/06/2023]
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18
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Bridges RJ, Bradbury NA. Cystic Fibrosis, Cystic Fibrosis Transmembrane Conductance Regulator and Drugs: Insights from Cellular Trafficking. Handb Exp Pharmacol 2018; 245:385-425. [PMID: 29460152 DOI: 10.1007/164_2018_103] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The eukaryotic cell is organized into membrane-delineated compartments that are characterized by specific cadres of proteins sustaining biochemically distinct cellular processes. The appropriate subcellular localization of proteins is key to proper organelle function and provides a physiological context for cellular processes. Disruption of normal trafficking pathways for proteins is seen in several genetic diseases, where a protein's absence for a specific subcellular compartment leads to organelle disruption, and in the context of an individual, a disruption of normal physiology. Importantly, several drug therapies can also alter protein trafficking, causing unwanted side effects. Thus, a deeper understanding of trafficking pathways needs to be appreciated as novel therapeutic modalities are proposed. Despite the promising efficacy of novel therapeutic agents, the intracellular bioavailability of these compounds has proved to be a potential barrier, leading to failures in treatments for various diseases and disorders. While endocytosis of drug moieties provides an efficient means of getting material into cells, the subsequent release and endosomal escape of materials into the cytosol where they need to act has been a barrier. An understanding of cellular protein/lipid trafficking pathways has opened up strategies for increasing drug bioavailability. Approaches to enhance endosomal exit have greatly increased the cytosolic bioavailability of drugs and will provide a means of investigating previous drugs that may have been shelved due to their low cytosolic concentration.
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Affiliation(s)
- Robert J Bridges
- Department of Physiology and Biophysics, Chicago Medical School, North Chicago, IL, USA
| | - Neil A Bradbury
- Department of Physiology and Biophysics, Chicago Medical School, North Chicago, IL, USA.
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19
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Protein aggregation: From background to inhibition strategies. Int J Biol Macromol 2017; 103:208-219. [DOI: 10.1016/j.ijbiomac.2017.05.048] [Citation(s) in RCA: 111] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 05/11/2017] [Accepted: 05/12/2017] [Indexed: 01/01/2023]
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20
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Wang W, Subramani S. Role of PEX5 ubiquitination in maintaining peroxisome dynamics and homeostasis. Cell Cycle 2017; 16:2037-2045. [PMID: 28933989 PMCID: PMC5731411 DOI: 10.1080/15384101.2017.1376149] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 08/24/2017] [Accepted: 09/01/2017] [Indexed: 12/15/2022] Open
Abstract
Peroxisomes are essential and dynamic organelles that allow cells to rapidly adapt and cope with changing environments and/or physiological conditions by modulation of both peroxisome biogenesis and turnover. Peroxisome biogenesis involves the assembly of peroxisome membranes and the import of peroxisomal matrix proteins. The latter depends on the receptor, PEX5, which recognizes peroxisomal matrix proteins in the cytosol directly or indirectly, and transports them to the peroxisomal lumen. In this review, we discuss the role of PEX5 ubiquitination in both peroxisome biogenesis and turnover, specifically in PEX5 receptor recycling, stability and abundance, as well as its role in pexophagy (autophagic degradation of peroxisomes).
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Affiliation(s)
- Wei Wang
- Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Suresh Subramani
- Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
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21
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Fang Y, Liu Z, Chen Z, Xu X, Xiao M, Yu Y, Zhang Y, Zhang X, Du Y, Jiang C, Zhao Y, Wang Y, Fan B, Terheyden-Keighley D, Liu Y, Shi L, Hui Y, Zhang X, Zhang B, Feng H, Ma L, Zhang Q, Jin G, Yang Y, Xiang B, Liu L, Zhang X. Smad5 acts as an intracellular pH messenger and maintains bioenergetic homeostasis. Cell Res 2017; 27:1083-1099. [PMID: 28675158 PMCID: PMC5587853 DOI: 10.1038/cr.2017.85] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 02/22/2017] [Accepted: 05/23/2017] [Indexed: 12/16/2022] Open
Abstract
Both environmental cues and intracellular bioenergetic states profoundly affect intracellular pH (pHi). How a cell responds to pHi changes to maintain bioenergetic homeostasis remains elusive. Here we show that Smad5, a well-characterized downstream component of bone morphogenetic protein (BMP) signaling responds to pHi changes. Cold, basic or hypertonic conditions increase pHi, which in turn dissociates protons from the charged amino acid clusters within the MH1 domain of Smad5, prompting its relocation from the nucleus to the cytoplasm. On the other hand, heat, acidic or hypotonic conditions decrease pHi, blocking the nuclear export of Smad5, and thus causing its nuclear accumulation. Active nucleocytoplasmic shuttling of Smad5 induced by environmental changes and pHi fluctuation is independent of BMP signaling, carboxyl terminus phosphorylation and Smad4. In addition, ablation of Smad5 causes chronic and irreversible dysregulation of cellular bioenergetic homeostasis and disrupted normal neural developmental processes as identified in a differentiation model of human pluripotent stem cells. Importantly, these metabolic and developmental deficits in Smad5-deficient cells could be rescued only by cytoplasmic Smad5. Cytoplasmic Smad5 physically interacts with hexokinase 1 and accelerates glycolysis. Together, our findings indicate that Smad5 acts as a pHi messenger and maintains the bioenergetic homeostasis of cells by regulating cytoplasmic metabolic machinery.
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Affiliation(s)
- Yujiang Fang
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
| | - Zhongliang Liu
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
| | - Zhenyu Chen
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
| | - Xiangjie Xu
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
| | - Mengtao Xiao
- China Novartis Institutes for BioMedical Research, Shanghai 201203, China
| | - Yanyan Yu
- China Novartis Institutes for BioMedical Research, Shanghai 201203, China
| | - Yuanyuan Zhang
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
| | - Xiaobai Zhang
- The School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Yanhua Du
- The School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Cizhong Jiang
- The School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Yuzheng Zhao
- Synthetic Biology and Biotechnology Laboratory, State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing Technology, East China University of Science and Technology, Shanghai 200237, China
| | - Yiran Wang
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
| | - Beibei Fan
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
| | - Daniel Terheyden-Keighley
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
| | - Yang Liu
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
| | - Lei Shi
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
| | - Yi Hui
- Department of Anatomy and Neurobiology, the Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
| | - Xin Zhang
- Department of Anatomy and Neurobiology, the Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
| | - Bowen Zhang
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
| | - Hexi Feng
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
| | - Lin Ma
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
| | - Quanbin Zhang
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
| | - Guohua Jin
- Department of Anatomy and Neurobiology, the Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
| | - Yi Yang
- Synthetic Biology and Biotechnology Laboratory, State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing Technology, East China University of Science and Technology, Shanghai 200237, China
| | - Bin Xiang
- China Novartis Institutes for BioMedical Research, Shanghai 201203, China
| | - Ling Liu
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
- Tongji University Advanced Institute of Translational Medicine, Shanghai 200092, China
| | - Xiaoqing Zhang
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
- Tongji University Advanced Institute of Translational Medicine, Shanghai 200092, China
- The Collaborative Innovation Center for Brain Science, Tongji University, Shanghai 200092, China
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22
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van de Laarschot LFM, Drenth JPH. Genetics and mechanisms of hepatic cystogenesis. Biochim Biophys Acta Mol Basis Dis 2017; 1864:1491-1497. [PMID: 28782656 DOI: 10.1016/j.bbadis.2017.08.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 08/02/2017] [Accepted: 08/03/2017] [Indexed: 12/20/2022]
Abstract
Polycystic liver disease (PLD) is a heterogeneous genetic condition. PKD1 and PKD2 germline mutations are found in patients with autosomal dominant polycystic kidney disease (ADPKD). Autosomal dominant polycystic liver disease (ADPLD) is associated with germline mutations in PRKCSH, SEC63, LRP5, and recently ALG8 and SEC61. GANAB mutations are found in both patient groups. Loss of heterozygosity of PLD-genes in cyst epithelium contributes to the development of hepatic cysts. A genetic interaction network is implied in hepatic cystogenesis that connects the endoplasmic glycoprotein control mechanisms and polycystin expression and localization. Wnt signalling could be the major downstream signalling pathway that results in hepatic cyst growth. PLD in ADPLD and ADPKD probably results from changes in one common final pathway that initiates cyst growth. This article is part of a Special Issue entitled: Cholangiocytes in Health and Diseaseedited by Jesus Banales, Marco Marzioni, Nicholas LaRusso and Peter Jansen.
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Affiliation(s)
| | - J P H Drenth
- Department of Gastroenterology and Hepatology, Radboudumc, Nijmegen, The Netherlands.
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23
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Miller C, Cai Y, Patton T, Graves SH, Li H, Sabbatini ME. RCAD/BiP pathway is necessary for the proper synthesis of digestive enzymes and secretory function of the exocrine pancreas. Am J Physiol Gastrointest Liver Physiol 2017; 312:G314-G326. [PMID: 28104585 DOI: 10.1152/ajpgi.00176.2016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 01/11/2017] [Accepted: 01/16/2017] [Indexed: 02/07/2023]
Abstract
Alcoholism causes an imbalance of endoplasmic reticulum (ER) homeostasis in pancreatic acini. In those cells, the ER is involved in the synthesis and folding of pancreatic enzymes. Ubiquitin-fold modifier 1 (Ufm1) is part of a novel ubiquitin-like modification system involved in maintaining ER homeostasis. Among the components of the Ufm1 system, Regulator of C53 and DDRGK1 (RCAD) has recently been identified as a Ufm1-specific E3 ligase that promotes ufmylation of DDRGK1, an RCAD-interacting protein. We determined the importance of RCAD in the proper synthesis and secretion of pancreatic enzymes using mice with genetically deleted RCAD. The pancreas of RCAD-deficient mice was of normal size and histology. Using quantitative PCR and Western blotting, we found that amylase was upregulated in pancreas organs from RCAD-knockout (KO) mice. Constitutive amylase secretion was much higher in isolated pancreatic acini from RCAD KO mice, whereas CCK-stimulated amylase secretion was disturbed. RCAD deficiency caused a downregulation in expression of ER chaperone BiP, which affected ER homeostasis and activated both apoptosis and trypsin. We also found that both RCAD and DDRGK1 transcript levels were upregulated in pancreatic acini from alcohol-preferring rats. Elevated expression of RCAD and DDRGK1 was associated with increased ER stress and UPR activation. Because of the lack of BiP expression, caspase 3 and trypsin activation we enhanced in RCAD-deficient pancreatic acini upon treatment with ethanol and CCK. In conclusion, the RCAD/BiP pathway is required for proper synthesis and secretion of pancreatic enzymes. In alcoholism, increased levels of components of the Ufm1 system could prevent the deleterious effects of alcohol in the pancreas by regulating BiP levels.NEW & NOTEWORTHY RCAD/BiP pathway is required for the proper synthesis and secretion of amylase from pancreatic acini, as well as for the maintenance of the ER homeostasis. In alcoholism, the exocrine pancreas could increase the levels of components of the Ufm1 system to protect itself from alcohol's deleterious effects by regulating the expression of ER chaperone BiP.
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Affiliation(s)
- Camille Miller
- Department of Biological Sciences, Augusta University, Augusta, Georgia
| | - Yafei Cai
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Cancer Center, Augusta University, Augusta, Georgia; and
| | - Tadd Patton
- Department of Psychological Sciences, Augusta University, Augusta, Georgia
| | | | - Honglin Li
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Cancer Center, Augusta University, Augusta, Georgia; and
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24
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Fujimoto K, Kinoshita M, Tanaka H, Okuzaki D, Shimada Y, Kayama H, Okumura R, Furuta Y, Narazaki M, Tamura A, Hatakeyama S, Ikawa M, Tsuchiya K, Watanabe M, Kumanogoh A, Tsukita S, Takeda K. Regulation of intestinal homeostasis by the ulcerative colitis-associated gene RNF186. Mucosal Immunol 2017; 10:446-459. [PMID: 27381925 DOI: 10.1038/mi.2016.58] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 06/02/2016] [Indexed: 02/04/2023]
Abstract
Genome-wide association studies and subsequent deep sequencing analysis have identified susceptible loci for inflammatory bowel diseases (IBDs) including ulcerative colitis (UC). A gene encoding RING finger protein 186 (RNF186) is located within UC-susceptible loci. However, it is unclear whether RNF186 is involved in IBD pathogenesis. Here, we show that RNF186 controls protein homeostasis in colonic epithelia and regulates intestinal inflammation. RNF186, which was highly expressed in colonic epithelia, acted as an E3 ligase mediating polyubiquitination of its substrates. Permeability of small organic molecules was augmented in the intestine of Rnf186-/- mice. Increased expression of several RNF186 substrates, such as occludin, was found in Rnf186-/- colonic epithelia. The disturbed protein homeostasis in Rnf186-/- mice correlated with enhanced endoplasmic reticulum (ER) stress in colonic epithelia and increased sensitivity to intestinal inflammation after dextran sulfate sodium (DSS) treatment. Introduction of an UC-associated Rnf186 mutation led to impaired E3 ligase activity and increased sensitivity to DSS-induced intestinal inflammation in mice. Thus, RNF186 maintains gut homeostasis by controlling ER stress in colonic epithelia.
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Affiliation(s)
- Kosuke Fujimoto
- Laboratory of Immune Regulation, Department of Microbiology and Immunology, Graduate School of Medicine, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan.,Core Research for Evolutional Science and Technology, Japan Agency for Medical Research and Development, Tokyo, Japan.,Department of Respiratory Medicine, Allergy and Rheumatic Diseases, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Makoto Kinoshita
- Laboratory of Immune Regulation, Department of Microbiology and Immunology, Graduate School of Medicine, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan.,Core Research for Evolutional Science and Technology, Japan Agency for Medical Research and Development, Tokyo, Japan
| | - Hiroo Tanaka
- Laboratory of Biological Science, Graduate School of Frontier Biosciences and Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Daisuke Okuzaki
- DNA-Chip Development Center for Infectious Diseases, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Yosuke Shimada
- Laboratory of Immune Regulation, Department of Microbiology and Immunology, Graduate School of Medicine, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan.,Core Research for Evolutional Science and Technology, Japan Agency for Medical Research and Development, Tokyo, Japan
| | - Hisako Kayama
- Laboratory of Immune Regulation, Department of Microbiology and Immunology, Graduate School of Medicine, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan.,Core Research for Evolutional Science and Technology, Japan Agency for Medical Research and Development, Tokyo, Japan
| | - Ryu Okumura
- Laboratory of Immune Regulation, Department of Microbiology and Immunology, Graduate School of Medicine, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan.,Core Research for Evolutional Science and Technology, Japan Agency for Medical Research and Development, Tokyo, Japan
| | - Yoki Furuta
- Laboratory of Immune Regulation, Department of Microbiology and Immunology, Graduate School of Medicine, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan.,Core Research for Evolutional Science and Technology, Japan Agency for Medical Research and Development, Tokyo, Japan
| | - Masashi Narazaki
- Department of Respiratory Medicine, Allergy and Rheumatic Diseases, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Atsushi Tamura
- Laboratory of Biological Science, Graduate School of Frontier Biosciences and Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Shigetsugu Hatakeyama
- Department of Biochemistry, Graduate School of Medicine, Hokkaido University, Hokkaido, Japan
| | - Masahito Ikawa
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Kiichiro Tsuchiya
- Department of Gastroenterology and Hepatology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Mamoru Watanabe
- Department of Gastroenterology and Hepatology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Atsushi Kumanogoh
- Core Research for Evolutional Science and Technology, Japan Agency for Medical Research and Development, Tokyo, Japan.,Department of Respiratory Medicine, Allergy and Rheumatic Diseases, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Sachiko Tsukita
- Core Research for Evolutional Science and Technology, Japan Agency for Medical Research and Development, Tokyo, Japan.,Laboratory of Biological Science, Graduate School of Frontier Biosciences and Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Kiyoshi Takeda
- Laboratory of Immune Regulation, Department of Microbiology and Immunology, Graduate School of Medicine, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan.,Core Research for Evolutional Science and Technology, Japan Agency for Medical Research and Development, Tokyo, Japan
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25
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Endoplasmic Reticulum Stress Enhances Mitochondrial Metabolic Activity in Mammalian Adrenals and Gonads. Mol Cell Biol 2016; 36:3058-3074. [PMID: 27697863 DOI: 10.1128/mcb.00411-16] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 09/23/2016] [Indexed: 01/21/2023] Open
Abstract
The acute response to stress consists of a series of physiological programs to promote survival by generating glucocorticoids and activating stress response genes that increase the synthesis of many chaperone proteins specific to individual organelles. In the endoplasmic reticulum (ER), short-term stress triggers activation of the unfolded protein response (UPR) module that either leads to neutralization of the initial stress or adaptation to it; chronic stress favors cell death. UPR induces expression of the transcription factor, C/EBP homology protein (CHOP), and its deletion protects against the lethal consequences of prolonged UPR. Here, we show that stress-induced CHOP expression coincides with increased metabolic activity. During stress, the ER and mitochondria come close to each other, resulting in the formation of a complex consisting of the mitochondrial translocase, translocase of outer mitochondrial membrane 22 (Tom22), steroidogenic acute regulatory protein (StAR), and 3β-hydroxysteroid dehydrogenase type 2 (3βHSD2) via its intermembrane space (IMS)-exposed charged unstructured loop region. Stress increased the circulation of phosphates, which elevated pregnenolone synthesis by 2-fold by increasing the stability of 3βHSD2 and its association with the mitochondrion-associated ER membrane (MAM) and mitochondrial proteins. In summary, cytoplasmic CHOP plays a central role in coordinating the interaction of MAM proteins with the outer mitochondrial membrane translocase, Tom22, to activate metabolic activity in the IMS by enhanced phosphate circulation.
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26
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Pfeffer S, Dudek J, Zimmermann R, Förster F. Organization of the native ribosome-translocon complex at the mammalian endoplasmic reticulum membrane. Biochim Biophys Acta Gen Subj 2016; 1860:2122-9. [PMID: 27373685 DOI: 10.1016/j.bbagen.2016.06.024] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 06/24/2016] [Accepted: 06/28/2016] [Indexed: 11/17/2022]
Abstract
BACKGROUND In eukaryotic cells, many proteins have to be transported across or inserted into the endoplasmic reticulum membrane during their biogenesis on the ribosome. This process is facilitated by the protein translocon, a highly dynamic multi-subunit membrane protein complex. SCOPE OF REVIEW The aim of this review is to summarize the current structural knowledge about protein translocon components in mammals. MAJOR CONCLUSIONS Various structural biology approaches have been used in synergy to characterize the translocon in recent years. X-ray crystallography and cryoelectron microscopy single particle analysis have yielded highly detailed insights into the structure and functional mechanism of the protein-conducting channel Sec61, which constitutes the functional core of the translocon. Cryoelectron tomography and subtomogram analysis have advanced our understanding of the overall structure, molecular organization and compositional heterogeneity of the translocon in a native membrane environment. Tomography densities at subnanometer resolution revealed an intricate network of interactions between the ribosome, Sec61 and accessory translocon components that assist in protein transport, membrane insertion and maturation. GENERAL SIGNIFICANCE The protein translocon is a gateway for approximately one third of all synthesized proteins and numerous human diseases are associated with malfunctioning of its components. Thus, detailed insights into the structure and molecular organization of the translocon will not only advance our understanding of membrane protein biogenesis in general, but they can potentially pave the way for novel therapeutic approaches against human diseases.
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Affiliation(s)
- Stefan Pfeffer
- Max-Planck Institute of Biochemistry, Department of Molecular Structural Biology, D-82152 Martinsried, Germany
| | - Johanna Dudek
- Saarland University, Medical Biochemistry and Molecular Biology, D-66421 Homburg, Germany
| | - Richard Zimmermann
- Saarland University, Medical Biochemistry and Molecular Biology, D-66421 Homburg, Germany.
| | - Friedrich Förster
- Max-Planck Institute of Biochemistry, Department of Molecular Structural Biology, D-82152 Martinsried, Germany; Cryo-Electron Microscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
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27
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Heaton NS, Moshkina N, Fenouil R, Gardner TJ, Aguirre S, Shah PS, Zhao N, Manganaro L, Hultquist JF, Noel J, Sachs D, Hamilton J, Leon PE, Chawdury A, Tripathi S, Melegari C, Campisi L, Hai R, Metreveli G, Gamarnik AV, García-Sastre A, Greenbaum B, Simon V, Fernandez-Sesma A, Krogan NJ, Mulder LCF, van Bakel H, Tortorella D, Taunton J, Palese P, Marazzi I. Targeting Viral Proteostasis Limits Influenza Virus, HIV, and Dengue Virus Infection. Immunity 2016; 44:46-58. [PMID: 26789921 DOI: 10.1016/j.immuni.2015.12.017] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 10/26/2015] [Accepted: 10/28/2015] [Indexed: 12/22/2022]
Abstract
Viruses are obligate parasites and thus require the machinery of the host cell to replicate. Inhibition of host factors co-opted during active infection is a strategy hosts use to suppress viral replication and a potential pan-antiviral therapy. To define the cellular proteins and processes required for a virus during infection is thus crucial to understanding the mechanisms of virally induced disease. In this report, we generated fully infectious tagged influenza viruses and used infection-based proteomics to identify pivotal arms of cellular signaling required for influenza virus growth and infectivity. Using mathematical modeling and genetic and pharmacologic approaches, we revealed that modulation of Sec61-mediated cotranslational translocation selectively impaired glycoprotein proteostasis of influenza as well as HIV and dengue viruses and led to inhibition of viral growth and infectivity. Thus, by studying virus-human protein-protein interactions in the context of active replication, we have identified targetable host factors for broad-spectrum antiviral therapies.
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Affiliation(s)
- Nicholas S Heaton
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Natasha Moshkina
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Romain Fenouil
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Thomas J Gardner
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Sebastian Aguirre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Priya S Shah
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Nan Zhao
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Lara Manganaro
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Judd F Hultquist
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Justine Noel
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - David Sachs
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Jennifer Hamilton
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Paul E Leon
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Amit Chawdury
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Division of Hematology and Oncology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Shashank Tripathi
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Camilla Melegari
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Laura Campisi
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Rong Hai
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Giorgi Metreveli
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Andrea V Gamarnik
- Fundación Instituto Leloir-CONICET, Avenida Patricias Argentinas 435, Buenos Aires 1405, Argentina
| | - Adolfo García-Sastre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Benjamin Greenbaum
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Division of Hematology and Oncology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Viviana Simon
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Ana Fernandez-Sesma
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Nevan J Krogan
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Lubbertus C F Mulder
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Harm van Bakel
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Domenico Tortorella
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Jack Taunton
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Peter Palese
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Ivan Marazzi
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA.
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Peroxisomal protein import pores. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:821-7. [DOI: 10.1016/j.bbamcr.2015.10.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 10/14/2015] [Accepted: 10/16/2015] [Indexed: 02/06/2023]
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Gumbart JC, Chipot C. Decrypting protein insertion through the translocon with free-energy calculations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1663-71. [PMID: 26896694 DOI: 10.1016/j.bbamem.2016.02.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 02/11/2016] [Accepted: 02/12/2016] [Indexed: 12/23/2022]
Abstract
Protein insertion into a membrane is a complex process involving numerous players. The most prominent of these players is the Sec translocon complex, a conserved protein-conducting channel present in the cytoplasmic membrane of bacteria and the membrane of the endoplasmic reticulum in eukaryotes. The last decade has seen tremendous leaps forward in our understanding of how insertion is managed by the translocon and its partners, coming from atomic-detailed structures, innovative experiments, and well-designed simulations. In this review, we discuss how experiments and simulations, hand-in-hand, teased out the secrets of the translocon-facilitated membrane insertion process. In particular, we focus on the role of free-energy calculations in elucidating membrane insertion. Amazingly, despite all its apparent complexity, protein insertion into membranes is primarily driven by simple thermodynamic and kinetic principles. This article is part of a Special Issue entitled: Membrane proteins edited by J.C. Gumbart and Sergei Noskov.
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Affiliation(s)
- James C Gumbart
- School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA.
| | - Christophe Chipot
- Laboratoire International Associé Centre National de la Recherche Scientifique and University of Illinois at Urbana-Champaign, UMR n° 7565, Université de Lorraine, B.P. 70239, 54506 Vandœuvre-lès-Nancy, France; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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30
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Abstract
Through thousands of years of reciprocal coevolution, Mycobacterium tuberculosis has become one of humanity's most successful pathogens, acquiring the ability to establish latent or progressive infection and persist even in the presence of a fully functioning immune system. The ability of M. tuberculosis to avoid immune-mediated clearance is likely to reflect a highly evolved and coordinated program of immune evasion strategies that interfere with both innate and adaptive immunity. These include the manipulation of their phagosomal environment within host macrophages, the selective avoidance or engagement of pattern recognition receptors, modulation of host cytokine production, and the manipulation of antigen presentation to prevent or alter the quality of T-cell responses. In this article we review an extensive array of published studies that have begun to unravel the sophisticated program of specific mechanisms that enable M. tuberculosis and other pathogenic mycobacteria to persist and replicate in the face of considerable immunological pressure from their hosts. Unraveling the mechanisms by which M. tuberculosis evades or modulates host immune function is likely to be of major importance for the development of more effective new vaccines and targeted immunotherapy against tuberculosis.
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31
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Abstract
Smart catalysts offer the control of chemical processes and sequences of transformations, and catalysts with unique catalytic behavior can afford chiral products or promote successive polymerization. To meet advanced demands, the key to constructing smart catalysts is to incorporate traditional catalytic functional groups with trigger-induced factors. Molecular machines with dynamic properties and particular topological structures have typical stimulus-responsive features. In recent years, scientists have made efforts to utilize molecular machines (molecular switches, rotaxanes, motors, etc.) as scaffolds to develop smart catalysts. This Minireview focuses on the achievements of developing catalysts encapsulated in molecular machines and their remarkable specialties. This strategy is believed to provide more potential applications in switchable reactions, asymmetric synthesis, and processive catalysis.
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Affiliation(s)
- Tiezheng Pan
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, 2699 Qianjin Avenue, Changchun, 130012, P.R. China
| | - Junqiu Liu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, 2699 Qianjin Avenue, Changchun, 130012, P.R. China.
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32
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Lamriben L, Graham JB, Adams BM, Hebert DN. N-Glycan-based ER Molecular Chaperone and Protein Quality Control System: The Calnexin Binding Cycle. Traffic 2016; 17:308-26. [PMID: 26676362 DOI: 10.1111/tra.12358] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 12/14/2015] [Accepted: 12/14/2015] [Indexed: 12/17/2022]
Abstract
Helenius and colleagues proposed over 20-years ago a paradigm-shifting model for how chaperone binding in the endoplasmic reticulum was mediated and controlled for a new type of molecular chaperone- the carbohydrate-binding chaperones, calnexin and calreticulin. While the originally established basics for this lectin chaperone binding cycle holds true today, there has been a number of important advances that have expanded our understanding of its mechanisms of action, role in protein homeostasis, and its connection to disease states that are highlighted in this review.
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Affiliation(s)
- Lydia Lamriben
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Jill B Graham
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Benjamin M Adams
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Daniel N Hebert
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA
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33
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Lin MH, Chen CP, Fischer WB. Patch formation of a viral channel forming protein within a lipid membrane – Vpu of HIV-1. MOLECULAR BIOSYSTEMS 2016; 12:1118-27. [DOI: 10.1039/c5mb00798d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Dimer-first formation leads to larger assemblies with potentially relevant structures.
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Affiliation(s)
- Meng-Han Lin
- Institute of Biophotonics
- School of Biomedical Science and Engineering and Biophotonics & Molecular Imaging Research Center (BMIRC)
- National Yang-Ming University
- Taipei 112
- Taiwan
| | - Chin-Pei Chen
- Institute of Biophotonics
- School of Biomedical Science and Engineering and Biophotonics & Molecular Imaging Research Center (BMIRC)
- National Yang-Ming University
- Taipei 112
- Taiwan
| | - Wolfgang B. Fischer
- Institute of Biophotonics
- School of Biomedical Science and Engineering and Biophotonics & Molecular Imaging Research Center (BMIRC)
- National Yang-Ming University
- Taipei 112
- Taiwan
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34
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Liu Z, Hu J. Mislocalization-related disease gene discovery using gene expression based computational protein localization prediction. Methods 2015; 93:119-27. [PMID: 26416496 DOI: 10.1016/j.ymeth.2015.09.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 09/17/2015] [Accepted: 09/21/2015] [Indexed: 01/09/2023] Open
Abstract
Protein sorting is an important mechanism for transporting proteins to their target subcellular locations after their synthesis. Mutations on genes may disrupt the well regulated protein sorting process, leading to a variety of mislocation related diseases. This paper proposes a methodology to discover such disease genes based on gene expression data and computational protein localization prediction. A kernel logistic regression based algorithm is used to successfully identify several candidate cancer genes which may cause cancers due to their mislocation within the cell. Our results also showed that compared to the gene co-expression network defined on Pearson correlation coefficients, the nonlinear Maximum Correlation Coefficients (MIC) based co-expression network give better results for subcellular localization prediction.
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Affiliation(s)
- Zhonghao Liu
- Department of Computer Science & Engineering, University of South Carolina, 301 Main Street, Columbia, SC 29208, United States
| | - Jianjun Hu
- Department of Computer Science & Engineering, University of South Carolina, 301 Main Street, Columbia, SC 29208, United States.
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35
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Di Girolamo M. Regulation of nucleocytoplasmic transport by ADP-ribosylation: the emerging role of karyopherin-β1 mono-ADP-ribosylation by ARTD15. Curr Top Microbiol Immunol 2015; 384:189-209. [PMID: 25037261 DOI: 10.1007/82_2014_421] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Post-translational modifications of a cellular protein by mono- and poly-ADP-ribosylation involve the cleavage of NAD (+) , with the release of its nicotinamide moiety. This is accompanied by the transfer of a single (mono-) or several (poly-) ADP-ribose molecules from NAD (+) to a specific amino-acid residue of the protein. Recent reports have shed new light on the correlation between NAD (+) -dependent ADP-ribosylation reactions and the endoplasmic reticulum, in addition to the well-documented roles of these reactions in the nucleus and mitochondria. We have demonstrated that ARTD15/PARP16 is a novel mono-ADP-ribosyltransferase with a new intracellular location, as it is associated with the endoplasmic reticulum. The endoplasmic reticulum, which is a membranous network of interconnected tubules and cisternae, is responsible for specialised cellular functions, including protein folding and protein transport. Maintenance of specialised cellular functions requires the correct flow of information between separate organelles that is made possible through the nucleocytoplasmic trafficking of proteins. ARTD15 appears to have a role in nucleocytoplasmic shuttling, through karyopherin-β1 mono-ADP-ribosylation. This is in line with the emerging role of ADP-ribosylation in the regulation of intracellular trafficking of cellular proteins. Indeed, other, ADP-ribosyltransferases like ARTD1/PARP1, have been reported to regulate nucleocytoplasmic trafficking of crucial proteins, including p53 and NF-κB, and as a consequence, to modulate the subcellular localisation of these proteins under both physiological and pathological conditions.
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Affiliation(s)
- Maria Di Girolamo
- G-Protein-Mediated Signalling Laboratory, Fondazione Mario Negri Sud, Via Nazionale 8/A, 66030, S. Maria Imbaro (CH), Italy,
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36
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The safety dance: biophysics of membrane protein folding and misfolding in a cellular context. Q Rev Biophys 2014; 48:1-34. [PMID: 25420508 DOI: 10.1017/s0033583514000110] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Most biological processes require the production and degradation of proteins, a task that weighs heavily on the cell. Mutations that compromise the conformational stability of proteins place both specific and general burdens on cellular protein homeostasis (proteostasis) in ways that contribute to numerous diseases. Efforts to elucidate the chain of molecular events responsible for diseases of protein folding address one of the foremost challenges in biomedical science. However, relatively little is known about the processes by which mutations prompt the misfolding of α-helical membrane proteins, which rely on an intricate network of cellular machinery to acquire and maintain their functional structures within cellular membranes. In this review, we summarize the current understanding of the physical principles that guide membrane protein biogenesis and folding in the context of mammalian cells. Additionally, we explore how pathogenic mutations that influence biogenesis may differ from those that disrupt folding and assembly, as well as how this may relate to disease mechanisms and therapeutic intervention. These perspectives indicate an imperative for the use of information from structural, cellular, and biochemical studies of membrane proteins in the design of novel therapeutics and in personalized medicine.
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37
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Fox RM, Andrew DJ. Transcriptional regulation of secretory capacity by bZip transcription factors. ACTA ACUST UNITED AC 2014; 10:28-51. [PMID: 25821458 PMCID: PMC4374484 DOI: 10.1007/s11515-014-1338-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Cells of specialized secretory organs expand their secretory pathways to accommodate the increased protein load necessary for their function. The endoplasmic reticulum (ER), the Golgi apparatus and the secretory vesicles, expand not only the membrane components but also the protein machinery required for increased protein production and transport. Increased protein load causes an ER stress response akin to the Unfolded Protein Response (UPR). Recent work has implicated several bZip transcription factors in the regulation of protein components of the early secretory pathway necessary to alleviate this stress. Here, we highlight eight bZip transcription factors in regulating secretory pathway component genes. These include components of the three canonical branches of the UPR-ATF4, XBP1, and ATF6, as well as the five members of the Creb3 family of transcription factors.We review findings from both invertebrate and vertebrate model systems suggesting that all of these proteins increase secretory capacity in response to increased protein load. Finally, we propose that the Creb3 family of factors may have a dual role in secretory cell differentiation by also regulating the pathways necessary for cell cycle exit during terminal differentiation.
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Affiliation(s)
- Rebecca M Fox
- The Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Deborah J Andrew
- The Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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38
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Prajapati SK, Culleton R, Singh OP. Protein trafficking in Plasmodium falciparum-infected red cells and impact of the expansion of exported protein families. Parasitology 2014; 141:1-11. [PMID: 25076418 DOI: 10.1017/s0031182014000948] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
SUMMARY Erythrocytes are extensively remodelled by the malaria parasite following invasion of the cell. Plasmodium falciparum encodes numerous virulence-associated and host-cell remodelling proteins that are trafficked to the cytoplasm, the cell membrane and the surface of the infected erythrocyte. The export of soluble proteins relies on a sequence directing entry into the secretory pathways in addition to an export signal. The export signal consisting of five amino acids is termed the Plasmodium export element (PEXEL) or the vacuole transport signal (VTS). Genome mining studies have revealed that PEXEL/VTS carrying protein families have expanded dramatically in P. falciparum compared with other malaria parasite species, possibly due to lineage-specific expansion linked to the unique requirements of P. falciparum for host-cell remodelling. The functional characterization of such genes and gene families may reveal potential drug targets that could inhibit protein trafficking in infected erythrocytes. This review highlights some of the recent advances and key knowledge gaps in protein trafficking pathways in P. falciparum-infected red cells and speculates on the impact of exported gene families in the trafficking pathway.
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Affiliation(s)
- Surendra K Prajapati
- Molecular Biology Division,National Institute of Malaria Research,New Delhi,India
| | - Richard Culleton
- Malaria Unit,Institute for Tropical Medicine (NEKKEN), Nagasaki University,Nagasaki,Japan
| | - Om P Singh
- Molecular Biology Division,National Institute of Malaria Research,New Delhi,India
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39
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40
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Nakatsukasa K, Kamura T, Brodsky JL. Recent technical developments in the study of ER-associated degradation. Curr Opin Cell Biol 2014; 29:82-91. [PMID: 24867671 DOI: 10.1016/j.ceb.2014.04.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 04/04/2014] [Accepted: 04/23/2014] [Indexed: 11/25/2022]
Abstract
Endoplasmic reticulum-associated degradation (ERAD) is a mechanism during which native and misfolded proteins are recognized and retrotranslocated across the ER membrane to the cytosol for degradation by the ubiquitin-proteasome system. Like other cellular pathways, the factors required for ERAD have been analyzed using both conventional genetic and biochemical approaches. More recently, however, an integrated top-down approach has identified a functional network that underlies the ERAD system. In turn, bottom-up reconstitution has become increasingly sophisticated and elucidated the molecular mechanisms underlying substrate recognition, ubiquitylation, retrotranslocation, and degradation. In addition, a live cell imaging technique and a site-specific in vivo photo-crosslinking approach have further dissected specific steps during ERAD. These technical developments have revealed an unexpected dynamicity of the membrane-associated ERAD complex. In this article, we will discuss how these technical developments have improved our understanding of the ERAD pathway and have led to new questions.
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Affiliation(s)
- Kunio Nakatsukasa
- Division of Biological Sciences, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan.
| | - Takumi Kamura
- Division of Biological Sciences, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA.
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41
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Wong QWL, Li J, Ng SR, Lim SG, Yang H, Vardy LA. RPL39L is an example of a recently evolved ribosomal protein paralog that shows highly specific tissue expression patterns and is upregulated in ESCs and HCC tumors. RNA Biol 2013; 11:33-41. [PMID: 24452241 DOI: 10.4161/rna.27427] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Ribosomal proteins (RPs) have been shown to be able to impart selectivity on the translating ribosome implicating them in gene expression control. Many ribosomal proteins are highly conserved and recently a number of ribosomal protein paralogs have been described in mammals. We examined the expression pattern of RPs in differentiating mouse Embryonic Stem Cells (ESCs), paying particular attention to the RP paralogs. We find the RP paralog Rpl39l is highly expressed in ESC and its expression strongly correlates with hepatocellular carcinoma tumor (HCC) samples with high tumor grading and alpha-fetoprotein level giving it diagnostic potential. We further screen the expression pattern of all RPs and their paralogs across 22 different tissues. We find that the more recently evolved RP paralogs show a much greater level of tissue-specific expression. We propose that these RP paralogs evolved more recently to provide a greater level of gene expression control to higher eukaryotes.
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Affiliation(s)
| | - Jia Li
- Cancer Science Institute; National University of Singapore; Singapore
| | - Sheng Rong Ng
- A*STAR Institute of Medical Biology; 8A Biomedical Grove; Immunos, Singapore
| | - Seng Gee Lim
- Department of Medicine; Yong Loo Lin School of Medicine; National University of Singapore; Singapore
| | - Henry Yang
- Cancer Science Institute; National University of Singapore; Singapore
| | - Leah A Vardy
- A*STAR Institute of Medical Biology; 8A Biomedical Grove; Immunos, Singapore; School of Biological Sciences; Nanyang Technological University; Singapore
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42
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Platta HW, Hagen S, Reidick C, Erdmann R. The peroxisomal receptor dislocation pathway: to the exportomer and beyond. Biochimie 2013; 98:16-28. [PMID: 24345375 DOI: 10.1016/j.biochi.2013.12.009] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 12/05/2013] [Indexed: 12/29/2022]
Abstract
The biogenesis of peroxisomes is an ubiquitin-dependent process. In particular, the import of matrix proteins into the peroxisomal lumen requires the modification of import receptors with ubiquitin. The matrix proteins are synthesized on free polyribosomes in the cytosol and are recognized by import receptors via a peroxisomal targeting sequence (PTS). Subsequent to the transport of the receptor/cargo-complex to the peroxisomal membrane and the release of the cargo into the peroxisomal lumen, the PTS-receptors are exported back to the cytosol for further rounds of matrix protein import. The exportomer represents the molecular machinery required for the retrotranslocation of the PTS-receptors. It comprises enzymes for the ubiquitination as well as for the ATP-dependent extraction of the PTS-receptors from the peroxisomal membrane. Furthermore, recent evidence indicates a mechanistic interconnection of the ATP-dependent removal of the PTS-receptors with the translocation of the matrix protein into the organellar lumen. Interestingly, the components of the peroxisomal exportomer seem also to be involved in cellular tasks that are distinct from the ubiquitination and dislocation of the peroxisomal PTS-receptors. This includes work that indicates a central function of this machinery in the export of peroxisomal matrix proteins in plants, while a subset of exportomer components is involved in the meiocyte formation in some fungi, the peroxisome-chloroplast contact during photorespiration in plants and possibly even the selective degradation of peroxisomes via pexophagy. In this review, we want to discuss the central role of the exportomer during matrix protein import, but also highlight distinct roles of exportomer constituents in additional cellular processes. This article is part of a Special Issue entitled: Peroxisomes: biogenesis, functions and diseases.
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Affiliation(s)
- Harald W Platta
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum, Germany.
| | - Stefanie Hagen
- Systembiochemie, Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
| | - Christina Reidick
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
| | - Ralf Erdmann
- Systembiochemie, Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum, Germany.
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43
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Hasan S, Platta HW, Erdmann R. Import of proteins into the peroxisomal matrix. Front Physiol 2013; 4:261. [PMID: 24069002 PMCID: PMC3781343 DOI: 10.3389/fphys.2013.00261] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 09/03/2013] [Indexed: 12/03/2022] Open
Abstract
Peroxisomes constitute a dynamic compartment in all nucleated cells. They fulfill diverse metabolic tasks in response to environmental changes and cellular demands. This adaptation is implemented by modulation of the enzyme content of the organelles, which is accomplished by dynamically operating peroxisomal protein transport machineries. Soluble import receptors recognize their newly synthesized cargo proteins in the cytosol and ferry them to the peroxisomal membrane. Subsequently, the cargo is translocated into the matrix, where the receptor is ubiquitinated and exported back to the cytosol for further rounds of matrix protein import. This review discusses the recent progress in our understanding of the peroxisomal matrix protein import and its regulation by ubiquitination events as well as the current view on the translocation mechanism of folded proteins into peroxisomes. This article is part of a Special Issue entitled: Origin and spatiotemporal dynamics of the peroxisomal endomembrane system.
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Affiliation(s)
- Sohel Hasan
- Systembiochemie, Medizinische Fakultät, Ruhr-Universität Bochum Bochum, Germany
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44
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Matthews K, Kalanon M, Chisholm SA, Sturm A, Goodman CD, Dixon MWA, Sanders PR, Nebl T, Fraser F, Haase S, McFadden GI, Gilson PR, Crabb BS, de Koning-Ward TF. The Plasmodium translocon of exported proteins (PTEX) component thioredoxin-2 is important for maintaining normal blood-stage growth. Mol Microbiol 2013; 89:1167-86. [PMID: 23869529 DOI: 10.1111/mmi.12334] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2013] [Indexed: 11/30/2022]
Abstract
Plasmodium parasites remodel their vertebrate host cells by translocating hundreds of proteins across an encasing membrane into the host cell cytosol via a putative export machinery termed PTEX. Previously PTEX150, HSP101 and EXP2 have been shown to be bona fide members of PTEX. Here we validate that PTEX88 and TRX2 are also genuine members of PTEX and provide evidence that expression of PTEX components are also expressed in early gametocytes, mosquito and liver stages, consistent with observations that protein export is not restricted to asexual stages. Although amenable to genetic tagging, HSP101, PTEX150, EXP2 and PTEX88 could not be genetically deleted in Plasmodium berghei, in keeping with the obligatory role this complex is postulated to have in maintaining normal blood-stage growth. In contrast, the putative thioredoxin-like protein TRX2 could be deleted, with knockout parasites displaying reduced grow-rates, both in vivo and in vitro, and reduced capacity to cause severe disease in a cerebral malaria model. Thus, while not essential for parasite survival, TRX2 may help to optimize PTEX activity. Importantly, the generation of TRX2 knockout parasites that display altered phenotypes provides a much-needed tool to dissect PTEX function.
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Affiliation(s)
- Kathryn Matthews
- School of Medicine, Deakin University, Waurn Ponds, Vic., 3216, Australia
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Platta HW, Hagen S, Erdmann R. The exportomer: the peroxisomal receptor export machinery. Cell Mol Life Sci 2013; 70:1393-411. [PMID: 22983384 PMCID: PMC11113987 DOI: 10.1007/s00018-012-1136-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2012] [Revised: 07/30/2012] [Accepted: 08/13/2012] [Indexed: 12/21/2022]
Abstract
Peroxisomes constitute a dynamic compartment of almost all eukaryotic cells. Depending on environmental changes and cellular demands peroxisomes can acquire diverse metabolic roles. The compartmentalization of peroxisomal matrix enzymes is a prerequisite to carry out their physiologic function. The matrix proteins are synthesized on free ribosomes in the cytosol and are ferried to the peroxisomal membrane by specific soluble receptors. Subsequent to cargo release into the peroxisomal matrix, the receptors are exported back to the cytosol to facilitate further rounds of matrix protein import. This dislocation step is accomplished by a remarkable machinery, which comprises enzymes required for the ubiquitination as well as the ATP-dependent extraction of the receptor from the membrane. Interestingly, receptor ubiquitination and dislocation are the only known energy-dependent steps in the peroxisomal matrix protein import process. The current view is that the export machinery of the receptors might function as molecular motor not only in the dislocation of the receptors but also in the import step of peroxisomal matrix protein by coupling ATP-dependent removal of the peroxisomal import receptor with cargo translocation into the organelle. In this review we will focus on the architecture and function of the peroxisomal receptor export machinery, the peroxisomal exportomer.
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Affiliation(s)
- Harald W. Platta
- Abteilung für Systembiochemie, Medizinische Fakultät der Ruhr-Universität Bochum, Ruhr-Universität Bochum, Universitätsstr. 150, 44780 Bochum, Germany
| | - Stefanie Hagen
- Abteilung für Systembiochemie, Medizinische Fakultät der Ruhr-Universität Bochum, Ruhr-Universität Bochum, Universitätsstr. 150, 44780 Bochum, Germany
| | - Ralf Erdmann
- Abteilung für Systembiochemie, Medizinische Fakultät der Ruhr-Universität Bochum, Ruhr-Universität Bochum, Universitätsstr. 150, 44780 Bochum, Germany
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Ma X, Cline K. Mapping the signal peptide binding and oligomer contact sites of the core subunit of the pea twin arginine protein translocase. THE PLANT CELL 2013; 25:999-1015. [PMID: 23512851 PMCID: PMC3634702 DOI: 10.1105/tpc.112.107409] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 02/08/2013] [Accepted: 02/19/2013] [Indexed: 05/17/2023]
Abstract
Twin arginine translocation (Tat) systems of thylakoid and bacterial membranes transport folded proteins using the proton gradient as the sole energy source. Tat substrates have hydrophobic signal peptides with an essential twin arginine (RR) recognition motif. The multispanning cpTatC plays a central role in Tat operation: It binds the signal peptide, directs translocase assembly, and may facilitate translocation. An in vitro assay with pea (Pisum sativum) chloroplasts was developed to conduct mutagenesis and analysis of cpTatC functions. Ala scanning mutagenesis identified mutants defective in substrate binding and receptor complex assembly. Mutations in the N terminus (S1) and first stromal loop (S2) caused specific defects in signal peptide recognition. Cys matching between substrate and imported cpTatC confirmed that S1 and S2 directly and specifically bind the RR proximal region of the signal peptide. Mutations in four lumen-proximal regions of cpTatC were defective in receptor complex assembly. Copurification and Cys matching analyses suggest that several of the lumen proximal regions may be important for cpTatC-cpTatC interactions. Surprisingly, RR binding domains of adjacent cpTatCs directed strong cpTatC-cpTatC cross-linking. This suggests clustering of binding sites on the multivalent receptor complex and explains the ability of Tat to transport cross-linked multimers. Transport of substrate proteins cross-linked to the signal peptide binding site tentatively identified mutants impaired in the translocation step.
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Affiliation(s)
- Xianyue Ma
- Horticultural Sciences Department and Plant Molecular and Cellular Biology, University of Florida, Gainesville, Florida 32611
| | - Kenneth Cline
- Horticultural Sciences Department and Plant Molecular and Cellular Biology, University of Florida, Gainesville, Florida 32611
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Mislocalization and inhibition of acetyl-CoA carboxylase 1 by a synthetic small molecule. Biochem J 2013; 448:409-16. [PMID: 23067267 DOI: 10.1042/bj20121158] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Chromeceptin is a synthetic small molecule that inhibits insulin-induced adipogenesis of 3T3-L1 cells and impairs the function of IGF2 (insulin-like growth factor 2). The molecular target of this benzochromene derivative is MFP-2 (multifunctional protein 2). The interaction between chromeceptin and MFP-2 activates STAT6 (signal transducer and activator of transcription 6), which subsequently induces IGF inhibitory genes. It was not previously known how the binding of chromeceptin with MFP-2 blocks adipogenesis and activates STAT6. The results of the present study show that the chromeceptin-MFP-2 complex binds to and inhibits ACC1 (acetyl-CoA carboxylase 1), an enzyme important for the de novo synthesis of malonyl-CoA and fatty acids. The formation of this ternary complex removes ACC1 from the cytosol and sequesters it in peroxisomes under the guidance of Pex5p (peroxisomal-targeting signal type 1 receptor). As a result, chromeceptin impairs fatty acid synthesis from acetate where ACC1 is a rate-limiting enzyme. Overexpression of malonyl-CoA decarboxylase or siRNA (small interfering RNA) knockdown of ACC1 results in STAT6 activation, suggesting a role for malonyl-CoA in STAT6 signalling. The molecular mechanism of chromeceptin may provide a new pharmacological approach to selective inhibition of ACC1 for biological studies and pharmaceutical development.
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Zhou K, Ren Y, Lv J, Wang Y, Liu F, Zhou F, Zhao S, Chen S, Peng C, Zhang X, Guo X, Cheng Z, Wang J, Wu F, Jiang L, Wan J. Young Leaf Chlorosis 1, a chloroplast-localized gene required for chlorophyll and lutein accumulation during early leaf development in rice. PLANTA 2013; 237:279-92. [PMID: 23053539 DOI: 10.1007/s00425-012-1756-1] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Accepted: 08/28/2012] [Indexed: 05/08/2023]
Abstract
Chlorophyll (Chl) and lutein are the two most abundant and essential components in photosynthetic apparatus, and play critical roles in plant development. In this study, we characterized a rice mutant named young leaf chlorosis 1 (ylc1) from a ⁶⁰Co-irradiated population. Young leaves of the ylc1 mutant showed decreased levels of Chl and lutein compared to those of wild type, and transmission electron microscopy analysis revealed that the thylakoid lamellar structures were obviously loosely arranged. Whereas, the mutant turns green gradually and approaches normal green at the maximum tillering stage. The Young Leaf Chlorosis 1 (YLC1) gene was isolated via map-based cloning and identified to encode a protein of unknown function belonging to the DUF3353 superfamily. Complementation and RNA-interference tests confirmed the role of the YLC1 gene, which expressed in all tested rice tissues, especially in the leaves. Real-time PCR analyses showed that the expression levels of the genes associated with Chl biosynthesis and photosynthesis were affected in ylc1 mutant at different temperatures. In rice protoplasts, the YLC1 protein displayed a typical chloroplast location pattern. The N-terminal 50 amino acid residues were confirmed to be necessary and sufficient for chloroplast targeting. These data suggested that the YLC1 protein may be involved in Chl and lutein accumulation and chloroplast development at early leaf development in rice.
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Affiliation(s)
- Kunneng Zhou
- National Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
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Monk KR, Voas MG, Franzini-Armstrong C, Hakkinen IS, Talbot WS. Mutation of sec63 in zebrafish causes defects in myelinated axons and liver pathology. Dis Model Mech 2013; 6:135-45. [PMID: 22864019 PMCID: PMC3529346 DOI: 10.1242/dmm.009217] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Accepted: 07/19/2012] [Indexed: 12/17/2022] Open
Abstract
Mutations in SEC63 cause polycystic liver disease in humans. Sec63 is a member of the endoplasmic reticulum (ER) translocon machinery, although it is unclear how mutations in SEC63 lead to liver cyst formation in humans. Here, we report the identification and characterization of a zebrafish sec63 mutant, which was discovered in a screen for mutations that affect the development of myelinated axons. Accordingly, we show that disruption of sec63 in zebrafish leads to abnormalities in myelinating glia in both the central and peripheral nervous systems. In the vertebrate nervous system, segments of myelin are separated by the nodes of Ranvier, which are unmyelinated regions of axonal membrane containing a high density of voltage-gated sodium channels. We show that sec63 mutants have morphologically abnormal and reduced numbers of clusters of voltage-gated sodium channels in the spinal cord and along peripheral nerves. Additionally, we observed reduced myelination in both the central and peripheral nervous systems, as well as swollen ER in myelinating glia. Markers of ER stress are upregulated in sec63 mutants. Finally, we show that sec63 mutants develop liver pathology. As in glia, the primary defect, detectable at 5 dpf, is fragmentation and swelling of the ER, indicative of accumulation of proteins in the lumen. At 8 dpf, ER swelling is severe; other pathological features include disrupted bile canaliculi, altered cytoplasmic matrix and accumulation of large lysosomes. Together, our analyses of sec63 mutant zebrafish highlight the possible role of ER stress in polycystic liver disease and suggest that these mutants will serve as a model for understanding the pathophysiology of this disease and other abnormalities involving ER stress.
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Affiliation(s)
- Kelly R. Monk
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Developmental Biology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Matthew G. Voas
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Clara Franzini-Armstrong
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6058, USA
| | - Ian S. Hakkinen
- Department of Developmental Biology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - William S. Talbot
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
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Mades A, Gotthardt K, Awe K, Stieler J, Döring T, Füser S, Prange R. Role of human sec63 in modulating the steady-state levels of multi-spanning membrane proteins. PLoS One 2012; 7:e49243. [PMID: 23166619 PMCID: PMC3499540 DOI: 10.1371/journal.pone.0049243] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 10/08/2012] [Indexed: 12/31/2022] Open
Abstract
The Sec61 translocon of the endoplasmic reticulum (ER) membrane forms an aqueous pore, allowing polypeptides to be transferred across or integrated into membranes. Protein translocation into the ER can occur co- and posttranslationally. In yeast, posttranslational translocation involves the heptameric translocase complex including its Sec62p and Sec63p subunits. The mammalian ER membrane contains orthologs of yeast Sec62p and Sec63p, but their function is poorly understood. Here, we analyzed the effects of excess and deficit Sec63 on various ER cargoes using human cell culture systems. The overexpression of Sec63 reduces the steady-state levels of viral and cellular multi-spanning membrane proteins in a cotranslational mode, while soluble and single-spanning ER reporters are not affected. Consistent with this, the knock-down of Sec63 increases the steady-state pools of polytopic ER proteins, suggesting a substrate-specific and regulatory function of Sec63 in ER import. Overexpressed Sec63 exerts its down-regulating activity on polytopic protein levels independent of its Sec62-interacting motif, indicating that it may not act in conjunction with Sec62 in human cells. The specific action of Sec63 is further sustained by our observations that the up-regulation of either Sec62 or two other ER proteins with lumenal J domains, like ERdj1 and ERdj4, does not compromise the steady-state level of a multi-spanning membrane reporter. A J domain-specific mutation of Sec63, proposed to weaken its interaction with the ER resident BiP chaperone, reduces the down-regulating capacity of excess Sec63, suggesting an involvement of BiP in this process. Together, these results suggest that Sec63 may perform a substrate-selective quantity control function during cotranslational ER import.
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Affiliation(s)
- Andreas Mades
- Department of Medicine III, Hematology and Oncology, Johannes Gutenberg-University School of Medicine, Mainz, Germany
| | - Katherina Gotthardt
- Department of Medical Microbiology and Hygiene, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Karin Awe
- Department of Medical Microbiology and Hygiene, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Jens Stieler
- Department of Medical Microbiology and Hygiene, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Tatjana Döring
- Department of Medical Microbiology and Hygiene, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Sabine Füser
- Department of Medical Microbiology and Hygiene, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Reinhild Prange
- Department of Medical Microbiology and Hygiene, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
- * E-mail:
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