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Wu Y, Hu X, Wei Z, Lin Q. Cellular Regulation of Macropinocytosis. Int J Mol Sci 2024; 25:6963. [PMID: 39000072 PMCID: PMC11241348 DOI: 10.3390/ijms25136963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 06/17/2024] [Accepted: 06/23/2024] [Indexed: 07/16/2024] Open
Abstract
Interest in macropinocytosis has risen in recent years owing to its function in tumorigenesis, immune reaction, and viral infection. Cancer cells utilize macropinocytosis to acquire nutrients to support their uncontrolled proliferation and energy consumption. Macropinocytosis, a highly dynamic endocytic and vesicular process, is regulated by a series of cellular signaling pathways. The activation of small GTPases in conjunction with phosphoinositide signaling pivotally regulates the process of macropinocytosis. In this review, we summarize important findings about the regulation of macropinocytosis and provide information to increase our understanding of the regulatory mechanism underlying it.
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Affiliation(s)
- Yumeng Wu
- School of Medicine, Jiangsu University, Zhenjiang 212013, China
| | - Xiao Hu
- School of Medicine, Jiangsu University, Zhenjiang 212013, China
| | - Zhixiao Wei
- School of Medicine, Jiangsu University, Zhenjiang 212013, China
| | - Qiong Lin
- School of Medicine, Jiangsu University, Zhenjiang 212013, China
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2
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Chen H, Zhao P, Zhang C, Ming X, Zhang C, Jung YS, Qian Y. Veratramine inhibits porcine epidemic diarrhea virus entry through macropinocytosis by suppressing PI3K/Akt pathway. Virus Res 2024; 339:199260. [PMID: 37923169 PMCID: PMC10661853 DOI: 10.1016/j.virusres.2023.199260] [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: 07/24/2023] [Revised: 10/30/2023] [Accepted: 10/30/2023] [Indexed: 11/07/2023]
Abstract
Porcine epidemic diarrhea (PED) is a contagious intestinal disease caused by α-coronavirus porcine epidemic diarrhea virus (PEDV). At present, no effective vaccine is available to prevent the disease. Therefore, research for novel antivirals is important. This study aimed to identify the antiviral mechanism of Veratramine (VAM), which actively inhibits PEDV replication with a 50 % inhibitory concentration (IC50) of ∼5 µM. Upon VAM treatment, both PEDV-nucleocapsid (N) protein level and virus titer decreased significantly. The time-of-addition assay results showed that VAM could inhibit PEDV replication by blocking viral entry. Importantly, VAM could inhibit PEDV-induced phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) activity and further suppress micropinocytosis, which is required for PEDV entry. In addition, PI3K inhibitor LY294002 showed anti-PEDV activity by blocking viral entry as well. Taken together, VAM possessed anti-PEDV properties against the entry stage of PEDV by inhibiting the macropinocytosis pathway by suppressing the PI3K/Akt pathway. VAM could be considered as a lead compound for the development of anti-PEDV drugs and may be used during the viral entry stage of PEDV infection.
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Affiliation(s)
- Huan Chen
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province, China; One Health Laboratory, Jiangsu Province Foreign Expert Workstation, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Pu Zhao
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province, China; One Health Laboratory, Jiangsu Province Foreign Expert Workstation, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Caisheng Zhang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province, China; One Health Laboratory, Jiangsu Province Foreign Expert Workstation, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Xin Ming
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province, China; One Health Laboratory, Jiangsu Province Foreign Expert Workstation, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Chaofeng Zhang
- Sino-Jan Joint Lab of Natural Health Products Research, School of Traditional Chinese Medicine, China Pharmaceutical University, Nanjing, China
| | - Yong-Sam Jung
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province, China; One Health Laboratory, Jiangsu Province Foreign Expert Workstation, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.
| | - Yingjuan Qian
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province, China; One Health Laboratory, Jiangsu Province Foreign Expert Workstation, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China; Jiangsu Agri-Animal Husbandry Vocational College, Veterinary Bio-Pharmaceutical, Jiangsu Key Laboratory for High-Tech Research and Development of Veterinary Biopharmaceuticals, Taizhou, Jiangsu, China.
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Miao L, Wei Y, Lu X, Jiang M, Liu Y, Li P, Ren Y, Zhang H, Chen W, Han B, Lu W. Interaction of 2D nanomaterial with cellular barrier: Membrane attachment and intracellular trafficking. Adv Drug Deliv Rev 2024; 204:115131. [PMID: 37977338 DOI: 10.1016/j.addr.2023.115131] [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: 08/29/2023] [Revised: 10/05/2023] [Accepted: 10/27/2023] [Indexed: 11/19/2023]
Abstract
The cell membrane serves as a barrier against the free entry of foreign substances into the cell. Limited by factors such as solubility and targeting, it is difficult for some drugs to pass through the cell membrane barrier and exert the expected therapeutic effect. Two-dimensional nanomaterial (2D NM) has the advantages of high drug loading capacity, flexible modification, and multimodal combination therapy, making them a novel drug delivery vehicle for drug membrane attachment and intracellular transport. By modulating the surface properties of nanocarriers, it is capable of carrying drugs to break through the cell membrane barrier and achieve precise treatment. In this review, we review the classification of various common 2D NMs, the primary parameters affecting their adhesion to cell membranes, and the uptake mechanisms of intracellular transport. Furthermore, we discuss the therapeutic potential of 2D NMs for several major disorders. We anticipate this review will deepen researchers' understanding of the interaction of 2D NM drug carriers with cell membrane barriers, and provide insights for the subsequent development of novel intelligent nanomaterials capable of intracellular transport.
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Affiliation(s)
- Li Miao
- Key Laboratory of Xinjiang Phytomedicine Resources and Utilization of Ministry of Education, School of Pharmacy, Shihezi University, Shihezi 832000, China
| | - Yaoyao Wei
- Key Laboratory of Xinjiang Phytomedicine Resources and Utilization of Ministry of Education, School of Pharmacy, Shihezi University, Shihezi 832000, China
| | - Xue Lu
- Key Laboratory of Xinjiang Phytomedicine Resources and Utilization of Ministry of Education, School of Pharmacy, Shihezi University, Shihezi 832000, China
| | - Min Jiang
- Key Laboratory of Xinjiang Phytomedicine Resources and Utilization of Ministry of Education, School of Pharmacy, Shihezi University, Shihezi 832000, China; State Key Laboratory of Natural and Biomimetic Drugs, and School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Yixuan Liu
- State Key Laboratory of Natural and Biomimetic Drugs, and School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Peishan Li
- State Key Laboratory of Natural and Biomimetic Drugs, and School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Yuxin Ren
- State Key Laboratory of Natural and Biomimetic Drugs, and School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Hua Zhang
- Key Laboratory of Xinjiang Phytomedicine Resources and Utilization of Ministry of Education, School of Pharmacy, Shihezi University, Shihezi 832000, China.
| | - Wen Chen
- Key Laboratory of Xinjiang Phytomedicine Resources and Utilization of Ministry of Education, School of Pharmacy, Shihezi University, Shihezi 832000, China.
| | - Bo Han
- Key Laboratory of Xinjiang Phytomedicine Resources and Utilization of Ministry of Education, School of Pharmacy, Shihezi University, Shihezi 832000, China.
| | - Wanliang Lu
- State Key Laboratory of Natural and Biomimetic Drugs, and School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
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Wallings RL, Mark JR, Staley HA, Gillett DA, Neighbarger N, Kordasiewicz H, Hirst WD, Tansey MG. Totally tubular: ASO-mediated knock-down of G2019S -Lrrk2 modulates lysosomal tubule-associated antigen presentation in macrophages. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.14.549028. [PMID: 37503274 PMCID: PMC10370014 DOI: 10.1101/2023.07.14.549028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Genetic variation around the LRRK2 gene affects risk of both familial and sporadic Parkinson's disease (PD). LRRK2 levels have become an appealing target for potential PD-therapeutics with LRRK2 antisense oligonucleotides (ASOs) now in clinical trials. However, LRRK2 has been suggested to play a fundamental role in peripheral immunity, and it is currently unknown if targeting increased LRRK2 levels in peripheral immune cells will be beneficial or deleterious. Furthermore, the precise role of LRRK2 in immune cells is currently unknown, although it has been suggested that LRRK2-mediated lysosomal function may be crucial to immune responses. Here, it was observed that G2019S macrophages exhibited increased stimulation-dependent lysosomal tubule formation (LTF) and MHC-II trafficking from the perinuclear lysosome to the plasma membrane in an mTOR dependent manner with concomitant increases in pro-inflammatory cytokine release. Both ASO-mediated knock down of mutant Lrrk 2 and LRRK2 kinase inhibition ameliorated this phenotype and decreased these immune responses in control cells. Given the critical role of antigen presentation, lysosomal function, and cytokine release in macrophages, it is likely LRRK2-targetting therapies may have therapeutic value with regards to mutant LRRK2 but deleterious effects on the peripheral immune system, such as altered pathogen control and infection resolution.
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5
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Salloum G, Bresnick AR, Backer JM. Macropinocytosis: mechanisms and regulation. Biochem J 2023; 480:335-362. [PMID: 36920093 DOI: 10.1042/bcj20210584] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/22/2023] [Accepted: 02/27/2023] [Indexed: 03/16/2023]
Abstract
Macropinocytosis is defined as an actin-dependent but coat- and dynamin-independent endocytic uptake process, which generates large intracellular vesicles (macropinosomes) containing a non-selective sampling of extracellular fluid. Macropinocytosis provides an important mechanism of immune surveillance by dendritic cells and macrophages, but also serves as an essential nutrient uptake pathway for unicellular organisms and tumor cells. This review examines the cell biological mechanisms that drive macropinocytosis, as well as the complex signaling pathways - GTPases, lipid and protein kinases and phosphatases, and actin regulatory proteins - that regulate macropinosome formation, internalization, and disposition.
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Affiliation(s)
- Gilbert Salloum
- Department of Molecular Pharamacology, Albert Einstein College of Medicine, Bronx, NY, U.S.A
| | - Anne R Bresnick
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, U.S.A
| | - Jonathan M Backer
- Department of Molecular Pharamacology, Albert Einstein College of Medicine, Bronx, NY, U.S.A
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, U.S.A
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Da Graça J, Morel E. Canonical and Non-Canonical Roles of SNX1 and SNX2 in Endosomal Membrane Dynamics. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2023; 6:25152564231217867. [PMID: 38033809 PMCID: PMC10683387 DOI: 10.1177/25152564231217867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 11/07/2023] [Accepted: 11/15/2023] [Indexed: 12/02/2023]
Abstract
Sorting nexins (SNXs) are a family of membrane-binding proteins known to play a critical role in regulating endocytic pathway sorting and endosomal membrane trafficking. Among them, SNX1 and SNX2 are members of the SNX-BAR subfamily and possess a membrane-curvature domain and a phosphoinositide-binding domain, which enables their stabilization at the phosphatidylinositol-3-phosphate (PI3P)-positive surface of endosomes. While their binding to PI3P-positive platforms facilitates interaction with endosomal partners and stabilization at the endosomal membrane, their SNX-BAR region is pivotal for generating membrane tubulation from endosomal compartments. In this context, their primary identified biological roles-and their partnership-are tightly associated with the retromer and endosomal SNX-BAR sorting complex for promoting exit 1 complex trafficking, facilitating the transport of cargoes from early endosomes to the secretory pathway. However, recent literature indicates that these proteins also possess biological functions in other aspects of endosomal features and sorting processes. Notably, SNX2 has been found to regulate endosome-endoplasmic reticulum (ER) contact sites through its interaction with VAP proteins at the ER membrane. Furthermore, data from our laboratory show that SNX1 and SNX2 are involved in the tubulation of early endosomes toward ER sites associated with autophagy initiation during starvation. These findings shed light on a novel role of SNXs in inter-organelle tethering and communication. In this concise review, we will explore the non-retromer functions of SNX1 and SNX2, specifically focusing on their involvement in endosomal membrane dynamics during stress sensing and autophagy-associated processes.
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Affiliation(s)
- Juliane Da Graça
- Université Paris Cité, INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, Paris, France
| | - Etienne Morel
- Université Paris Cité, INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, Paris, France
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7
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Lučiūnaitė A, Dalgėdienė I, Žilionis R, Mašalaitė K, Norkienė M, Šinkūnas A, Gedvilaitė A, Kučinskaitė-Kodzė I, Žvirblienė A. Activation of NLRP3 Inflammasome by Virus-Like Particles of Human Polyomaviruses in Macrophages. Front Immunol 2022; 13:831815. [PMID: 35355981 PMCID: PMC8959312 DOI: 10.3389/fimmu.2022.831815] [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: 12/08/2021] [Accepted: 02/08/2022] [Indexed: 11/21/2022] Open
Abstract
Viral antigens can activate phagocytes, inducing inflammation, but the mechanisms are barely explored. The aim of this study is to investigate how viral oligomeric proteins of different structures induce inflammatory response in macrophages. Human THP-1 cell line was used to prepare macrophages that were treated with filamentous nucleocapsid-like particles (NLPs) of paramyxoviruses and spherical virus-like particles (VLPs) of human polyomaviruses. The effects of viral proteins on cell viability, pro-inflammatory cytokines’ production, and NLRP3 inflammasome activation were investigated. Filamentous NLPs did not induce inflammation while spherical VLPs mediated inflammatory response followed by NLRP3 inflammasome activation. Inhibitors of cathepsins and K+ efflux decreased IL-1β release and cell death, indicating a complex inflammasome activation process. A similar activation pattern was observed in primary human macrophages. Single-cell RNAseq analysis of THP-1 cells revealed several cell activation states different in inflammation-related genes. This study provides new insights into the interaction of viral proteins with immune cells and suggests that structural properties of oligomeric proteins may define cell activation pathways.
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Affiliation(s)
- Asta Lučiūnaitė
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Indrė Dalgėdienė
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Rapolas Žilionis
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania.,R&D Department, Droplet Genomics, Vilnius, Lithuania
| | - Kristina Mašalaitė
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Milda Norkienė
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | | | - Alma Gedvilaitė
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | | | - Aurelija Žvirblienė
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania
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Cui L, Hunter MR, Sonzini S, Pereira S, Romanelli SM, Liu K, Li W, Liang L, Yang B, Mahmoudi N, Desai AS. Mechanistic Studies of an Automated Lipid Nanoparticle Reveal Critical Pharmaceutical Properties Associated with Enhanced mRNA Functional Delivery In Vitro and In Vivo. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2105832. [PMID: 34914866 DOI: 10.1002/smll.202105832] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 11/21/2021] [Indexed: 06/14/2023]
Abstract
Recently, lipid nanoparticles (LNPs) have attracted attention due to their emergent use for COVID-19 mRNA vaccines. The success of LNPs can be attributed to ionizable lipids, which enable functional intracellular delivery. Previously, the authors established an automated high-throughput platform to screen ionizable lipids and identified that the LNPs generated using this automated technique show comparable or increased mRNA functional delivery in vitro as compared to LNPs prepared using traditional microfluidics techniques. In this study, the authors choose one benchmark lipid, DLin-MC3-DMA (MC3), and investigate whether the automated formulation technique can enhance mRNA functional delivery in vivo. Interestingly, a 4.5-fold improvement in mRNA functional delivery in vivo by automated LNPs as compared to LNPs formulated by conventional microfluidics techniques, is observed. Mechanistic studies reveal that particles with large size accommodate more mRNA per LNP, possess more hydrophobic surface, are more hemolytic, bind a larger protein corona, and tend to accumulate more in macropinocytosomes, which may quantitatively benefit mRNA cytosolic delivery. These data suggest that mRNA loading per particle is a critical factor that accounts for the enhanced mRNA functional delivery of automated LNPs. These mechanistic findings provide valuable insight underlying the enhanced mRNA functional delivery to accelerate future mRNA LNP product development.
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Affiliation(s)
- Lili Cui
- Advanced Drug Delivery, Pharmaceutical Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge, CB21 6GH, UK
| | - Morag R Hunter
- Advanced Drug Delivery, Pharmaceutical Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge, CB21 6GH, UK
| | - Silvia Sonzini
- Advanced Drug Delivery, Pharmaceutical Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge, CB21 6GH, UK
| | - Sara Pereira
- Advanced Drug Delivery, Pharmaceutical Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge, CB21 6GH, UK
| | - Steven M Romanelli
- University of Michigan Medical School, Department of Molecular & Integrative Physiology, Ann Arbor, MI, 48109-5624, USA
| | - Kai Liu
- Advanced Drug Delivery, Pharmaceutical Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, 43183, Sweden
| | - Weimin Li
- Advanced Drug Delivery, Pharmaceutical Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge, CB21 6GH, UK
| | - Lihuan Liang
- Bioscience Renal, Research and Early Development, Cardiovascular, Renal & Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Cambridge, CB21 6GH, UK
| | - Bin Yang
- Advanced Drug Delivery, Pharmaceutical Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge, CB21 6GH, UK
| | - Najet Mahmoudi
- Rutherford Appleton Laboratory, ISIS Facility, Science and Technology Facilities Council, Didcot, OX11 0QX, UK
| | - Arpan S Desai
- Advanced Drug Delivery, Pharmaceutical Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge, CB21 6GH, UK
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Means N, Elechalawar CK, Chen WR, Bhattacharya R, Mukherjee P. Revealing macropinocytosis using nanoparticles. Mol Aspects Med 2022; 83:100993. [PMID: 34281720 PMCID: PMC8761201 DOI: 10.1016/j.mam.2021.100993] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 07/12/2021] [Indexed: 02/03/2023]
Abstract
Endocytosis mechanisms are one of the methods that cells use to interact with their environments. Endocytosis mechanisms vary from the clathrin-mediated endocytosis to the receptor independent macropinocytosis. Macropinocytosis is a niche of endocytosis that is quickly becoming more relevant in various fields of research since its discovery in the 1930s. Macropinocytosis has several distinguishing factors from other receptor-mediated forms of endocytosis, including: types of extracellular material for uptake, signaling cascade, and niche uses between cell types. Nanoparticles (NPs) are an important tool for various applications, including drug delivery and disease treatment. However, surface engineering of NPs could be tailored to target them inside the cells exploiting different endocytosis pathways, such as endocytosis versus macropinocytosis. Such surface engineering of NPs mainly, size, charge, shape and the core material will allow identification of new adapter molecules regulating different endocytosis process and provide further insight into how cells tweak these pathways to meet their physiological need. In this review, we focus on the description of macropinocytosis, a lesser studied endocytosis mechanism than the conventional receptor mediated endocytosis. Additionally, we will discuss nanoparticle endocytosis (including macropinocytosis), and how the physio-chemical properties of the NP (size, charge, and surface coating) affect their intracellular uptake and exploiting them as tools to identify new adapter molecules regulating these processes.
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Affiliation(s)
- Nicolas Means
- Department of Pathology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | | | - Wei R Chen
- Stephenson School of Biomedical Engineering, Gallogly College of Engineering, University of Oklahoma, Norman, OK, 73019, USA
| | - Resham Bhattacharya
- Peggy and Charles Stephenson Cancer Center, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Priyabrata Mukherjee
- Department of Pathology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Peggy and Charles Stephenson Cancer Center, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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10
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Activation of Non-Canonical Autophagic Pathway through Inhibition of Non-Integrin Laminin Receptor in Neuronal Cells. Cells 2022; 11:cells11030466. [PMID: 35159276 PMCID: PMC8833926 DOI: 10.3390/cells11030466] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 01/20/2022] [Accepted: 01/27/2022] [Indexed: 12/05/2022] Open
Abstract
To fight neurodegenerative diseases, several therapeutic strategies have been proposed that, to date, are either ineffective or at the early preclinical stages. Intracellular protein aggregates represent the cause of about 70% of neurodegenerative disorders, such as Alzheimer’s disease. Thus, autophagy, i.e., lysosomal degradation of macromolecules, could be employed in this context as a therapeutic strategy. Searching for a compound that stimulates this process led us to the identification of a 37/67kDa laminin receptor inhibitor, NSC48478. We have analysed the effects of this small molecule on the autophagic process in mouse neuronal cells and found that NSC48478 induces the conversion of microtubule-associated protein 1A/1B-light chain 3 (LC3-I) into the LC3-phosphatidylethanolamine conjugate (LC3-II). Interestingly, upon NSC48478 treatment, the contribution of membranes to the autophagic process derived mainly from the non-canonical m-TOR-independent endocytic pathway, involving the Rab proteins that control endocytosis and vesicle recycling. Finally, qRT-PCR analysis suggests that, while the expression of key genes linked to canonical autophagy was unchanged, the main genes related to the positive regulation of endocytosis (pinocytosis and receptor mediated), along with genes regulating vesicle fusion and autolysosomal maturation, were upregulated under NSC48478 conditions. These results strongly suggest that 37/67 kDa inhibitor could be a useful tool for future studies in pathological conditions.
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11
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Ecker M, Schregle R, Kapoor-Kaushik N, Rossatti P, Betzler VM, Kempe D, Biro M, Ariotti N, Redpath GMI, Rossy J. SNX9-induced membrane tubulation regulates CD28 cluster stability and signalling. eLife 2022; 11:e67550. [PMID: 35050850 PMCID: PMC8786313 DOI: 10.7554/elife.67550] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 01/12/2022] [Indexed: 12/12/2022] Open
Abstract
T cell activation requires engagement of a cognate antigen by the T cell receptor (TCR) and the co-stimulatory signal of CD28. Both TCR and CD28 aggregate into clusters at the plasma membrane of activated T cells. While the role of TCR clustering in T cell activation has been extensively investigated, little is known about how CD28 clustering contributes to CD28 signalling. Here, we report that upon CD28 triggering, the BAR-domain protein sorting nexin 9 (SNX9) is recruited to CD28 clusters at the immunological synapse. Using three-dimensional correlative light and electron microscopy, we show that SNX9 generates membrane tubulation out of CD28 clusters. Our data further reveal that CD28 clusters are in fact dynamic structures and that SNX9 regulates their stability as well as CD28 phosphorylation and the resulting production of the cytokine IL-2. In summary, our work suggests a model in which SNX9-mediated tubulation generates a membrane environment that promotes CD28 triggering and downstream signalling events.
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Affiliation(s)
- Manuela Ecker
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences and the ARC Centre of Excellence in Advanced Molecular Imaging, University of New South WalesSydneyAustralia
| | - Richard Schregle
- Biotechnology Institute Thurgau (BITg) at the University of KonstanzKreuzlingenSwitzerland
- Department of Biology, University of KonstanzKonstanzGermany
| | - Natasha Kapoor-Kaushik
- Electron Microscopy Unit, Mark Wainwright Analytical Centre, University of New South WalesSydneyAustralia
| | - Pascal Rossatti
- Biotechnology Institute Thurgau (BITg) at the University of KonstanzKreuzlingenSwitzerland
| | - Verena M Betzler
- Biotechnology Institute Thurgau (BITg) at the University of KonstanzKreuzlingenSwitzerland
| | - Daryan Kempe
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences and the ARC Centre of Excellence in Advanced Molecular Imaging, University of New South WalesSydneyAustralia
| | - Maté Biro
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences and the ARC Centre of Excellence in Advanced Molecular Imaging, University of New South WalesSydneyAustralia
| | - Nicholas Ariotti
- Electron Microscopy Unit, Mark Wainwright Analytical Centre, University of New South WalesSydneyAustralia
- Institute for Molecular Bioscience (IMB), University of QueenslandBrisbaneAustralia
| | - Gregory MI Redpath
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences and the ARC Centre of Excellence in Advanced Molecular Imaging, University of New South WalesSydneyAustralia
| | - Jeremie Rossy
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences and the ARC Centre of Excellence in Advanced Molecular Imaging, University of New South WalesSydneyAustralia
- Biotechnology Institute Thurgau (BITg) at the University of KonstanzKreuzlingenSwitzerland
- Department of Biology, University of KonstanzKonstanzGermany
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12
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Lo HP, Lim YW, Xiong Z, Martel N, Ferguson C, Ariotti N, Giacomotto J, Rae J, Floetenmeyer M, Moradi SV, Gao Y, Tillu VA, Xia D, Wang H, Rahnama S, Nixon SJ, Bastiani M, Day RD, Smith KA, Palpant NJ, Johnston WA, Alexandrov K, Collins BM, Hall TE, Parton RG. Cavin4 interacts with Bin1 to promote T-tubule formation and stability in developing skeletal muscle. J Cell Biol 2021; 220:e201905065. [PMID: 34633413 PMCID: PMC8513623 DOI: 10.1083/jcb.201905065] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/02/2021] [Accepted: 09/20/2021] [Indexed: 11/22/2022] Open
Abstract
The cavin proteins are essential for caveola biogenesis and function. Here, we identify a role for the muscle-specific component, Cavin4, in skeletal muscle T-tubule development by analyzing two vertebrate systems, mouse and zebrafish. In both models, Cavin4 localized to T-tubules, and loss of Cavin4 resulted in aberrant T-tubule maturation. In zebrafish, which possess duplicated cavin4 paralogs, Cavin4b was shown to directly interact with the T-tubule-associated BAR domain protein Bin1. Loss of both Cavin4a and Cavin4b caused aberrant accumulation of interconnected caveolae within the T-tubules, a fragmented T-tubule network enriched in Caveolin-3, and an impaired Ca2+ response upon mechanical stimulation. We propose a role for Cavin4 in remodeling the T-tubule membrane early in development by recycling caveolar components from the T-tubule to the sarcolemma. This generates a stable T-tubule domain lacking caveolae that is essential for T-tubule function.
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Affiliation(s)
- Harriet P. Lo
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Ye-Wheen Lim
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Zherui Xiong
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Nick Martel
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Charles Ferguson
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Nicholas Ariotti
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Jean Giacomotto
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
- Queensland Centre for Mental Health Research, West Moreton Hospital and Health Service and University of Queensland, Brisbane, Queensland, Australia
| | - James Rae
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Matthias Floetenmeyer
- Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, Queensland, Australia
| | - Shayli Varasteh Moradi
- CSIRO–Queensland University of Technology Synthetic Biology Alliance, ARC Centre of Excellence in Synthetic Biology, Centre for Agriculture and the Bioeconomy, School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Ya Gao
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Vikas A. Tillu
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Di Xia
- Genome Innovation Hub, The University of Queensland, Brisbane, Queensland, Australia
| | - Huang Wang
- Translational Research Institute, Mater Research Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Samira Rahnama
- CSIRO–Queensland University of Technology Synthetic Biology Alliance, ARC Centre of Excellence in Synthetic Biology, Centre for Agriculture and the Bioeconomy, School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Susan J. Nixon
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Michele Bastiani
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Ryan D. Day
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Kelly A. Smith
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Nathan J. Palpant
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Wayne A. Johnston
- CSIRO–Queensland University of Technology Synthetic Biology Alliance, ARC Centre of Excellence in Synthetic Biology, Centre for Agriculture and the Bioeconomy, School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Kirill Alexandrov
- CSIRO–Queensland University of Technology Synthetic Biology Alliance, ARC Centre of Excellence in Synthetic Biology, Centre for Agriculture and the Bioeconomy, School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Brett M. Collins
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Thomas E. Hall
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Robert G. Parton
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
- Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, Queensland, Australia
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13
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Musser JM, Schippers KJ, Nickel M, Mizzon G, Kohn AB, Pape C, Ronchi P, Papadopoulos N, Tarashansky AJ, Hammel JU, Wolf F, Liang C, Hernández-Plaza A, Cantalapiedra CP, Achim K, Schieber NL, Pan L, Ruperti F, Francis WR, Vargas S, Kling S, Renkert M, Polikarpov M, Bourenkov G, Feuda R, Gaspar I, Burkhardt P, Wang B, Bork P, Beck M, Schneider TR, Kreshuk A, Wörheide G, Huerta-Cepas J, Schwab Y, Moroz LL, Arendt D. Profiling cellular diversity in sponges informs animal cell type and nervous system evolution. Science 2021; 374:717-723. [PMID: 34735222 DOI: 10.1126/science.abj2949] [Citation(s) in RCA: 78] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Jacob M Musser
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Klaske J Schippers
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Michael Nickel
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Friedrich-Schiller-Universität Jena, Institut für Zoologie und Evolutionsforschung mit Phyletischem Museum, Ernst-Haeckel-Haus und Biologiedidaktik, 07743 Jena, Germany.,GeoBio-Center, Ludwig-Maximilians-Universität München, 80333 München, Germany
| | - Giulia Mizzon
- Electron Microscopy Core Facility, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Andrea B Kohn
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA
| | - Constantin Pape
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Paolo Ronchi
- Electron Microscopy Core Facility, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Nikolaos Papadopoulos
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | | | - Jörg U Hammel
- Friedrich-Schiller-Universität Jena, Institut für Zoologie und Evolutionsforschung mit Phyletischem Museum, Ernst-Haeckel-Haus und Biologiedidaktik, 07743 Jena, Germany.,Institute for Materials Physics, Helmholtz-Zentrum Hereon, 21502 Geesthacht, Germany
| | - Florian Wolf
- Friedrich-Schiller-Universität Jena, Institut für Zoologie und Evolutionsforschung mit Phyletischem Museum, Ernst-Haeckel-Haus und Biologiedidaktik, 07743 Jena, Germany
| | - Cong Liang
- Center for Applied Mathematics, Tianjin University, Tianjin 300072, China
| | - Ana Hernández-Plaza
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM) and Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28223 Madrid, Spain
| | - Carlos P Cantalapiedra
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM) and Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28223 Madrid, Spain
| | - Kaia Achim
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Nicole L Schieber
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Leslie Pan
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Fabian Ruperti
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Collaboration for joint Ph.D. degree between EMBL and Heidelberg University, Faculty of Biosciences 69117 Heidelberg, Germany
| | - Warren R Francis
- Department of Earth and Environmental Sciences, Paleontology & Geobiology, Ludwig-Maximilians-Universität München, 80333 München, Germany
| | - Sergio Vargas
- Department of Earth and Environmental Sciences, Paleontology & Geobiology, Ludwig-Maximilians-Universität München, 80333 München, Germany
| | - Svenja Kling
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Centre for Organismal Studies (COS), University of Heidelberg, 69120 Heidelberg, Germany
| | - Maike Renkert
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Maxim Polikarpov
- Hamburg Unit c/o DESY, European Molecular Biology Laboratory, Hamburg, 22607 Germany.,Department of Information Technology and Electrical Engineering, ETH Zurich, CH-8092 Zurich, Switzerland
| | - Gleb Bourenkov
- Hamburg Unit c/o DESY, European Molecular Biology Laboratory, Hamburg, 22607 Germany
| | - Roberto Feuda
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Imre Gaspar
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Department of Totipotency, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Pawel Burkhardt
- Sars International Centre for Marine Molecular Biology, University of Bergen, 5008 Bergen, Norway
| | - Bo Wang
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA.,Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Peer Bork
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Martin Beck
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Thomas R Schneider
- Hamburg Unit c/o DESY, European Molecular Biology Laboratory, Hamburg, 22607 Germany
| | - Anna Kreshuk
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Gert Wörheide
- GeoBio-Center, Ludwig-Maximilians-Universität München, 80333 München, Germany.,Department of Earth and Environmental Sciences, Paleontology & Geobiology, Ludwig-Maximilians-Universität München, 80333 München, Germany.,Bayerische Staatssammlung für Paläontologie und Geologie (SNSB), 80333 München, Germany
| | - Jaime Huerta-Cepas
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM) and Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28223 Madrid, Spain.,Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Yannick Schwab
- Electron Microscopy Core Facility, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Leonid L Moroz
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA.,Department of Neuroscience and Brain Institute, University of Florida, Gainesville, FL 32610, USA.,McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Detlev Arendt
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Centre for Organismal Studies (COS), University of Heidelberg, 69120 Heidelberg, Germany
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14
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Chlamydia trachomatis TmeA Directly Activates N-WASP To Promote Actin Polymerization and Functions Synergistically with TarP during Invasion. mBio 2021; 12:mBio.02861-20. [PMID: 33468693 PMCID: PMC7845632 DOI: 10.1128/mbio.02861-20] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The increasing genetic tractability of Chlamydia trachomatis is accelerating the ability to characterize the unique infection biology of this obligate intracellular parasite. These efforts are leading to a greater understanding of the molecular events associated with key virulence requirements. Chlamydia trachomatis is a medically significant human pathogen and is an epithelial-tropic obligate intracellular parasite. Invasion of nonprofessional phagocytes represents a crucial step in the infection process and has likely promoted the evolution of a redundant mechanism and routes of entry. Like many other viral and invasive bacterial pathogens, manipulation of the host cell cytoskeleton represents a focal point in Chlamydia entry. The advent of genetic techniques in C. trachomatis, such as creation of complete gene deletions via fluorescence-reported allelic exchange mutagenesis (FRAEM), is providing important tools to unravel the contributions of bacterial factors in these complex pathways. The type III secretion chaperone Slc1 directs delivery of at least four effectors during the invasion process. Two of these, TarP and TmeA, have been associated with manipulation of actin networks and are essential for normal levels of invasion. The functions of TarP are well established, whereas TmeA is less well characterized. We leverage chlamydial genetics and proximity labeling here to provide evidence that TmeA directly targets host N-WASP to promote Arp2/3-dependent actin polymerization. Our work also shows that TmeA and TarP influence separate, yet synergistic pathways to accomplish chlamydial entry. These data further support an appreciation that a pathogen, confined by a reductionist genome, retains the ability to commit considerable resources to accomplish bottle-neck steps during the infection process.
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15
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Hall TE, Martel N, Ariotti N, Xiong Z, Lo HP, Ferguson C, Rae J, Lim YW, Parton RG. In vivo cell biological screening identifies an endocytic capture mechanism for T-tubule formation. Nat Commun 2020; 11:3711. [PMID: 32709891 PMCID: PMC7381618 DOI: 10.1038/s41467-020-17486-w] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 06/26/2020] [Indexed: 11/09/2022] Open
Abstract
The skeletal muscle T-tubule is a specialized membrane domain essential for coordinated muscle contraction. However, in the absence of genetically tractable systems the mechanisms involved in T-tubule formation are unknown. Here, we use the optically transparent and genetically tractable zebrafish system to probe T-tubule development in vivo. By combining live imaging of transgenic markers with three-dimensional electron microscopy, we derive a four-dimensional quantitative model for T-tubule formation. To elucidate the mechanisms involved in T-tubule formation in vivo, we develop a quantitative screen for proteins that associate with and modulate early T-tubule formation, including an overexpression screen of the entire zebrafish Rab protein family. We propose an endocytic capture model involving firstly, formation of dynamic endocytic tubules at transient nucleation sites on the sarcolemma, secondly, stabilization by myofibrils/sarcoplasmic reticulum and finally, delivery of membrane from the recycling endosome and Golgi complex.
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Affiliation(s)
- Thomas E Hall
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia.
| | - Nick Martel
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Nicholas Ariotti
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia.,Electron Microscope Unit, Mark Wainwright Analytical Centre, The University of New South Wales, Kensington, Australia
| | - Zherui Xiong
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Harriet P Lo
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Charles Ferguson
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia
| | - James Rae
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Ye-Wheen Lim
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Robert G Parton
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia. .,Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, QLD, 4072, Australia.
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16
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Walpole GFW, Grinstein S. Endocytosis and the internalization of pathogenic organisms: focus on phosphoinositides. F1000Res 2020; 9. [PMID: 32494357 PMCID: PMC7233180 DOI: 10.12688/f1000research.22393.1] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/07/2020] [Indexed: 12/18/2022] Open
Abstract
Despite their comparatively low abundance in biological membranes, phosphoinositides are key to the regulation of a diverse array of signaling pathways and direct membrane traffic. The role of phosphoinositides in the initiation and progression of endocytic pathways has been studied in considerable depth. Recent advances have revealed that distinct phosphoinositide species feature prominently in clathrin-dependent and -independent endocytosis as well as in phagocytosis and macropinocytosis. Moreover, a variety of intracellular and cell-associated pathogens have developed strategies to commandeer host cell phosphoinositide metabolism to gain entry and/or metabolic advantage, thereby promoting their survival and proliferation. Here, we briefly survey the current knowledge on the involvement of phosphoinositides in endocytosis, phagocytosis, and macropinocytosis and highlight several examples of molecular mimicry employed by pathogens to either “hitch a ride” on endocytic pathways endogenous to the host or create an entry path of their own.
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Affiliation(s)
- Glenn F W Walpole
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Sergio Grinstein
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Keenan Research Centre of the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada
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17
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Wall AA, Condon ND, Luo L, Stow JL. Rab8a localisation and activation by Toll-like receptors on macrophage macropinosomes. Philos Trans R Soc Lond B Biol Sci 2020; 374:20180151. [PMID: 30966999 DOI: 10.1098/rstb.2018.0151] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Macropinocytosis is a prevalent and essential pathway in macrophages where it contributes to anti-microbial responses and innate immune cell functions. Cell surface ruffles give rise to phagosomes and to macropinosomes as multi-functional compartments that contribute to environmental sampling, pathogen entry, plasma membrane turnover and receptor signalling. Rapid, high resolution, lattice light sheet imaging demonstrates the dynamic nature of macrophage ruffling. Pathogen-mediated activation of surface and endosomal Toll-like receptors (TLRs) in macrophages upregulates macropinocytosis. Here, using multiple forms of imaging and microscopy, we track membrane-associated, fluorescently-tagged Rab8a expressed in live macrophages, using a variety of cell markers to demonstrate Rab8a localization and its enrichment on early macropinosomes. Production of a novel biosensor and its use for quantitative FRET analysis in live cells, pinpoints macropinosomes as the site for TLR-induced activation of Rab8a. We have previously shown that TLR signalling, cytokine outputs and macrophage programming are regulated by the GTPase Rab8a with PI3 Kγ as its effector. Finally, we highlight another effector, the phosphatase OCRL, which is located on macropinosomes and interacts with Rab8a, suggesting that Rab8a may operate on multiple levels to modulate phosphoinositides in macropinosomes. These findings extend our understanding of macropinosomes as regulatory compartments for innate immune function in macrophages. This article is part of the Theo Murphy meeting issue 'Macropinocytosis'.
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Affiliation(s)
- Adam A Wall
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research, University of Queensland , Brisbane, Queensland 4072 , Australia
| | - Nicholas D Condon
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research, University of Queensland , Brisbane, Queensland 4072 , Australia
| | - Lin Luo
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research, University of Queensland , Brisbane, Queensland 4072 , Australia
| | - Jennifer L Stow
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research, University of Queensland , Brisbane, Queensland 4072 , Australia
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18
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Abl family tyrosine kinases govern IgG extravasation in the skin in a murine pemphigus model. Nat Commun 2019; 10:4432. [PMID: 31570755 PMCID: PMC6769004 DOI: 10.1038/s41467-019-12232-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 08/28/2019] [Indexed: 01/02/2023] Open
Abstract
The pathway of homeostatic IgG extravasation is not fully understood, in spite of its importance for the maintenance of host immunity, the management of autoantibody-mediated disorders, and the use of antibody-based biologics. Here we show in a murine model of pemphigus, a prototypic cutaneous autoantibody-mediated disorder, that blood-circulating IgG extravasates into the skin in a time- and dose-dependent manner under homeostatic conditions. This IgG extravasation is unaffected by depletion of Fcγ receptors, but is largely attenuated by specific ablation of dynamin-dependent endocytic vesicle formation in blood endothelial cells (BECs). Among dynamin-dependent endocytic vesicles, IgG co-localizes well with caveolae in cultured BECs. An Abl family tyrosine kinase inhibitor imatinib, which reduces caveolae-mediated endocytosis, impairs IgG extravasation in the skin and attenuates the murine pemphigus manifestations. Our study highlights the kinetics of IgG extravasation in vivo, which might be a clue to understand the pathological mechanism of autoantibody-mediated autoimmune disorders. How antibody reaches tissues from circulation is critical for understanding antibody-mediated immunity. Here the authors show that IgG extravasation in the skin is mediated by endothelial caveolin transport independently of FcR, and is targetable by imatinib, which reduces IgG-dependent pathology in a mouse model of pemphigus.
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19
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Mustafa TA, Mohammed-Rasheed MA. Accumulation and cytotoxicity assessment of TAT-IONPs on cancerous mammalian cells. Anim Biotechnol 2019; 32:100-105. [PMID: 31476967 DOI: 10.1080/10495398.2019.1658595] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Nanotechnology is a fast-growing research technology. Nanoparticles have intensive scientific applications in many fields. Depending on the physical and chemical characteristics of a nanoparticle, it can be used either as a treatment agent to fight disease or as a delivery vehicle to transport the therapeutic drug to a specified biological organ, tissue, and cell. Cytotoxicity evaluation of nanoparticles is one of the primary concerns in clinical practices to avoid unpredicted or undesirable interactions that could worsen the case. Iron oxide nanoparticle (IONP) is the most utilized nanoparticle in medical fields for treatment, diagnostic, and imaging. This paper is designated to investigate the cytotoxicity of IONPs that decorated with Trans-Activator of Transcription (TAT) protein. WST-1 assay and flow cytometry were used to assess the cytotoxicity of TAT-IONPs, which showed no significant cytotoxic effect on mammalian breast cancer cells (MCF-7). Nanoparticles accumulation in the cell's cytoplasm was evaluated from TEM images by measuring the size of the endosome. The results indicate that TAT-IONPs can be used as a safe and non-toxic nanoplatform for targeted delivery at 50 µg/ml or less. Also, they present an approach by which the area of intracellular endosome can be assessed from the TEM images of fixed cells. In this study, the endosome size increased in a time-dependent manner.
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Affiliation(s)
- Thikra A Mustafa
- College of Veterinary Medicine, University of Kirkuk, Kirkuk, Iraq
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20
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Lee CHR, Mohamed Hussain K, Chu JJH. Macropinocytosis dependent entry of Chikungunya virus into human muscle cells. PLoS Negl Trop Dis 2019; 13:e0007610. [PMID: 31449523 PMCID: PMC6730948 DOI: 10.1371/journal.pntd.0007610] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 09/06/2019] [Accepted: 07/08/2019] [Indexed: 12/23/2022] Open
Abstract
Chikungunya virus (CHIKV) is a re-emerging arbovirus known to cause chronic myalgia and arthralgia with high morbidity. CHIKV is now considered endemic in many countries across Asia and Africa. In this study, the susceptibility of various human, mammalian and mosquito cell lines to CHIKV infection was evaluated. CHIKV infection was found to be cell-type dependent and virus strain-specific. Furthermore, SJCRH30 (human rhabdomyosarcoma cell line) was showed to be highly permissive to CHIKV infection, with maximum production of infectious virions observed at 12 h.p.i. Pre-infection treatment of SJCRH30 with various inhibitors of endocytosis, including monodansylcadaverine (receptor-mediated endocytic inhibitor), dynasore (clathrin-mediated endocytic inhibitor), as well as filipin (caveolin-mediated endocytosis inhibitor), resulted in minimal inhibition of CHIKV infection. In contrast, dose-dependent inhibition of CHIKV infection was observed with the treatment of macropinocytosis inhibitor, 5-(N-ethyl-N-isopropyl)amiloride (EIPA). Furthermore, siRNA-mediated knockdown of sortin nexin 9 (SNX9) a protein involved in macropinosome formation, also resulted in a significant dose-dependent reduction in viral titre. By performing a virus entry assay, CHIKV particles were also observed to colocalize with FITC-dextran, a macropinosome marker. This study shows for the first time, that the infectious entry of CHIKV into human muscle cells is mediated by macropinocytosis. Together, the data from this study may pave the way for the development of specific inhibitors that target the entry process of CHIKV into cells. This study revealed the differences in susceptibility of various human, mammalian and mosquito cell lines to CHIKV infection. CHIKV infection was found to be cell-type dependent and virus-strain specific. Additionally, two human muscle cell lines, SJCRH30 (rhabdomyosarcoma cell line) and HSMM (human skeletal muscle myoblasts), were shown to be highly susceptible to infection by different CHIKV strains. Pre-infection treatment of SJCRH30 and HSMM with a macropinocytosis inhibitor, 5-(N-ethyl-N-isopropyl)amiloride (EIPA) showed a dose-dependent inhibition. Additionally, knockdown of a protein involved in macropinocytosis formation, SNX9, revealed that CHIKV infection of SJCRH30 cells relies on macropinocytosis. Results were confirmed with a FITC-dextran assay, which showed colocalisation between CHIKV particles and macropinosomes during viral entry. Overall, this study may contribute to the development of therapeutic interventions using specific inhibitors that target the entry of CHIKV into muscle cells.
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Affiliation(s)
- Ching Hua, Regina Lee
- Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Khairunnisa Mohamed Hussain
- Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Justin Jang Hann Chu
- Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Collaborative and Translational Unit for HFMD Singapore, Singapore, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- * E-mail:
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21
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Bashant KR, Vassallo A, Herold C, Berner R, Menschner L, Subburayalu J, Kaplan MJ, Summers C, Guck J, Chilvers ER, Toepfner N. Real-time deformability cytometry reveals sequential contraction and expansion during neutrophil priming. J Leukoc Biol 2019; 105:1143-1153. [PMID: 30835869 PMCID: PMC7587463 DOI: 10.1002/jlb.ma0718-295rr] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Revised: 02/08/2019] [Accepted: 02/14/2019] [Indexed: 12/19/2022] Open
Abstract
It has become increasingly apparent that the biomechanical properties of neutrophils impact on their trafficking through the circulation and in particularly through the pulmonary capillary bed. The retention of polarized or shape-changed neutrophils in the lungs was recently proposed to contribute to acute respiratory distress syndrome pathogenesis. Accordingly, this study tested the hypothesis that neutrophil priming is coupled to morpho-rheological (MORE) changes capable of altering cell function. We employ real-time deformability cytometry (RT-DC), a recently developed, rapid, and sensitive way to assess the distribution of size, shape, and deformability of thousands of cells within seconds. During RT-DC analysis, neutrophils can be easily identified within anticoagulated "whole blood" due to their unique granularity and size, thus avoiding the need for further isolation techniques, which affect biomechanical cell properties. Hence, RT-DC is uniquely suited to describe the kinetics of MORE cell changes. We reveal that, following activation or priming, neutrophils undergo a short period of cell shrinking and stiffening, followed by a phase of cell expansion and softening. In some contexts, neutrophils ultimately recover their un-primed mechanical phenotype. The mechanism(s) underlying changes in human neutrophil size are shown to be Na+ /H+ antiport-dependent and are predicted to have profound implications for neutrophil movement through the vascular system in health and disease.
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Affiliation(s)
- Kathleen R Bashant
- Department of Medicine, University of Cambridge, Cambridge, UK
- National Institutes of Health, Bethesda, Maryland, USA
| | | | | | - Reinhard Berner
- Department of Pediatrics, University Clinic Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Leonhard Menschner
- Department of Pediatrics, University Clinic Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | | | | | | | - Jochen Guck
- Center for Molecular and Cellular Bioengineering, Biotechnology Center, Technische Universität Dresden, Dresden, Germany
| | | | - Nicole Toepfner
- Department of Pediatrics, University Clinic Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
- Center for Molecular and Cellular Bioengineering, Biotechnology Center, Technische Universität Dresden, Dresden, Germany
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22
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Klein O, Sagi-Eisenberg R. Anaphylactic Degranulation of Mast Cells: Focus on Compound Exocytosis. J Immunol Res 2019; 2019:9542656. [PMID: 31011586 PMCID: PMC6442490 DOI: 10.1155/2019/9542656] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Accepted: 12/26/2018] [Indexed: 01/15/2023] Open
Abstract
Anaphylaxis is a notorious type 2 immune response which may result in a systemic response and lead to death. A precondition for the unfolding of the anaphylactic shock is the secretion of inflammatory mediators from mast cells in response to an allergen, mostly through activation of the cells via the IgE-dependent pathway. While mast cells are specialized secretory cells that can secrete through a variety of exocytic modes, the most predominant mode exerted by the mast cell during anaphylaxis is compound exocytosis-a specialized form of regulated exocytosis where secretory granules fuse to one another. Here, we review the modes of regulated exocytosis in the mast cell and focus on compound exocytosis. We review historical landmarks in the research of compound exocytosis in mast cells and the methods available for investigating compound exocytosis. We also review the molecular mechanisms reported to underlie compound exocytosis in mast cells and expand further with reviewing key findings from other cell types. Finally, we discuss the possible reasons for the mast cell to utilize compound exocytosis during anaphylaxis, the conflicting evidence in different mast cell models, and the open questions in the field which remain to be answered.
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Affiliation(s)
- Ofir Klein
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ronit Sagi-Eisenberg
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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23
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Itai N, Shimazu T, Kimura T, Ibe I, Yamashita R, Kaburagi Y, Dohi T, Tonozuka T, Takao T, Nishikawa A. The phosphorylation of sorting nexin 5 at serine 226 regulates retrograde transport and macropinocytosis. PLoS One 2018; 13:e0207205. [PMID: 30419003 PMCID: PMC6231649 DOI: 10.1371/journal.pone.0207205] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 10/26/2018] [Indexed: 11/30/2022] Open
Abstract
Sorting nexin 5 (SNX5), a member of sorting nexin family, plays an important role in membrane trafficking, including the retrograde trafficking of the cation independent mannose 6-phosphate receptor (CI-M6PR) and macropinocytosis. Using ESI-LCMS/MS analysis, we confirmed that SNX5 serine 226 is phosphorylated. Since SNX5 forms heterodimers with SNX1 or SNX2, we examined the effect of phosphorylation at S226 on the heterodimer formations. Wild-type and mutants of SNX5, in which S226 was mutated to a glutamic acid or an alanine, were expressed in 8505C cells. In pull-down assays using SNX5 as bait, only the S226E mutant failed to precipitate both SNX1 and SNX2. Confocal microscopy data indicated that the wild type and S226A mutant were colocalized with SNX1 and SNX2 in endosomes, but the S226E was not. SNX5 and SNX6 support each other's functions and are involved with CI-M6PR retrograde trafficking. In SNX5 and SNX6 double knockdown cells, CI-M6PR was dispersed and colocalized with the endosomal marker EEA1. In a rescue experiment using SNX5 mutants, the S226A rescued CI-M6PR localization, similar to control cells, but S226E did not. Furthermore, the decrease in the uptake of dextran by macropinocytosis in SNX5 knockdown cells was recovered by the expression of rescue-wild type or S226A mutant, but not by the rescue-S226E mutant. These observations indicate that SNX5 constitutive phosphorylation that mimics the mutant S226E decreases the active SNX5 in these cells. The phosphorylation of SNX5 regulates the dimerization with SNX1 or SNX2, and this suggests that it controls membrane trafficking and protein sorting.
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Affiliation(s)
- Nao Itai
- Division of Applied Biological Chemistry, United graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, Japan
| | - Tsukasa Shimazu
- Department of Applied Biological Science, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, Japan
| | - Takayuki Kimura
- Department of Applied Biological Science, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, Japan
| | - Issei Ibe
- Department of Applied Biological Science, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, Japan
| | - Ryo Yamashita
- Department of Diabetic Complications, Diabetes Research Center, Research Institute, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo, Japan
| | - Yasushi Kaburagi
- Department of Diabetic Complications, Diabetes Research Center, Research Institute, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo, Japan
| | - Taeko Dohi
- Department of Gastroenterology, Research Center for Hepatitis and Immunology, Research Institute, National Center for Global Health and Medicine, 1-7-1 Kohnodai, Ichikawa, Chiba, Japan
| | - Takashi Tonozuka
- Division of Applied Biological Chemistry, United graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, Japan
| | - Toshifumi Takao
- Laboratory of Protein Profiling and Functional Proteomics, Institute for Protein Research, Osaka University, 3–2 Yamadaoka, Suita, Osaka, Japan
| | - Atsushi Nishikawa
- Division of Applied Biological Chemistry, United graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, Japan
- Department of Applied Biological Science, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, Japan
- * E-mail:
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24
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Klein O, Roded A, Hirschberg K, Fukuda M, Galli SJ, Sagi-Eisenberg R. Imaging FITC-dextran as a Reporter for Regulated Exocytosis. J Vis Exp 2018. [PMID: 29985342 DOI: 10.3791/57936] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Regulated exocytosis is a process by which cargo, which is stored in secretory granules (SGs), is released in response to a secretory trigger. Regulated exocytosis is fundamental for intercellular communication and is a key mechanism for the secretion of neurotransmitters, hormones, inflammatory mediators, and other compounds, by a variety of cells. At least three distinct mechanisms are known for regulated exocytosis: full exocytosis, where a single SG fully fuses with the plasma membrane, kiss-and-run exocytosis, where a single SG transiently fuses with the plasma membrane, and compound exocytosis, where several SGs fuse with each other, prior to or after SG fusion with the plasma membrane. The type of regulated exocytosis undertaken by a cell is often dictated by the type of secretory trigger. However, in many cells, a single secretory trigger can activate multiple modes of regulated exocytosis simultaneously. Despite their abundance and importance across cell types and species, the mechanisms that determine the different modes of secretion are largely unresolved. One of the main challenges in investigating the different modes of regulated exocytosis, is the difficulty in distinguishing between them as well as exploring them separately. Here we describe the use of fluorescein isothiocyanate (FITC)-dextran as an exocytosis reporter, and live cell imaging, to differentiate between the different pathways of regulated exocytosis, focusing on compound exocytosis, based on the robustness and duration of the exocytic events.
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Affiliation(s)
- Ofir Klein
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University
| | - Amit Roded
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University
| | - Koret Hirschberg
- Department of Pathology, Sackler Faculty of Medicine, Tel Aviv University
| | - Mitsunori Fukuda
- Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University
| | - Stephen J Galli
- Departments of Pathology and of Microbiology and Immunology and Sean N. Parker Center for Allergy and Asthma Research, School of Medicine, Stanford University
| | - Ronit Sagi-Eisenberg
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University;
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25
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Chlamydia exploits filopodial capture and a macropinocytosis-like pathway for host cell entry. PLoS Pathog 2018; 14:e1007051. [PMID: 29727463 PMCID: PMC5955597 DOI: 10.1371/journal.ppat.1007051] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 05/16/2018] [Accepted: 04/21/2018] [Indexed: 01/08/2023] Open
Abstract
Pathogens hijack host endocytic pathways to force their own entry into eukaryotic target cells. Many bacteria either exploit receptor-mediated zippering or inject virulence proteins directly to trigger membrane reorganisation and cytoskeletal rearrangements. By contrast, extracellular C. trachomatis elementary bodies (EBs) apparently employ facets of both the zipper and trigger mechanisms and are only ~400 nm in diameter. Our cryo-electron tomography of C. trachomatis entry revealed an unexpectedly diverse array of host structures in association with invading EBs, suggesting internalisation may progress by multiple, potentially redundant routes or several sequential events within a single pathway. Here we performed quantitative analysis of actin organisation at chlamydial entry foci, highlighting filopodial capture and phagocytic cups as dominant and conserved morphological structures early during internalisation. We applied inhibitor-based screening and employed reporters to systematically assay and visualise the spatio-temporal contribution of diverse endocytic signalling mediators to C. trachomatis entry. In addition to the recognised roles of the Rac1 GTPase and its associated nucleation-promoting factor (NPF) WAVE, our data revealed an additional unrecognised pathway sharing key hallmarks of macropinocytosis: i) amiloride sensitivity, ii) fluid-phase uptake, iii) recruitment and activity of the NPF N-WASP, and iv) the localised generation of phosphoinositide-3-phosphate (PI3P) species. Given their central role in macropinocytosis and affinity for PI3P, we assessed the role of SNX-PX-BAR family proteins. Strikingly, SNX9 was specifically and transiently enriched at C. trachomatis entry foci. SNX9-/- cells exhibited a 20% defect in EB entry, which was enhanced to 60% when the cells were infected without sedimentation-induced EB adhesion, consistent with a defect in initial EB-host interaction. Correspondingly, filopodial capture of C. trachomatis EBs was specifically attenuated in SNX9-/- cells, implicating SNX9 as a central host mediator of filopodial capture early during chlamydial entry. Our findings identify an unanticipated complexity of signalling underpinning cell entry by this major human pathogen, and suggest intriguing parallels with viral entry mechanisms. Chlamydia trachomatis remains the leading bacterial agent of sexually transmitted disease worldwide and causes a form of blindness called trachoma in Developing nations, which is recognised by the World Health Organisation as a neglected tropical disease. Despite this burden, we know comparatively little about how it causes disease at a molecular level. Chlamydia must live inside human cells to survive, and here we study the mechanism of how it enters cells, which is critical to the lifecycle. We study how the bacterium exploits signalling pathways inside the cell to its own advantage to deform the cell membrane by reorganising the underlying cell skeleton, and identify new factors involved in this process. Our findings suggest intriguing similarities with how some viruses enter cells. A better understanding of these processes may help to develop future vaccines and new treatments.
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26
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Interaction of Human Cytomegalovirus Tegument Proteins ppUL35 and ppUL35A with Sorting Nexin 5 Regulates Glycoprotein B (gpUL55) Localization. J Virol 2018; 92:JVI.00013-18. [PMID: 29444945 DOI: 10.1128/jvi.00013-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 02/07/2018] [Indexed: 12/13/2022] Open
Abstract
Human cytomegalovirus (HCMV) is a widespread human pathogen that causes asymptomatic infection in healthy individuals but poses a serious threat to immunocompromised patients. During the late phase of HCMV infection, the viral capsid is transported to the cytoplasmic viral assembly center (cVAC), where it is enclosed by the tegument protein layer and the viral envelope. The cVAC consists of circularly arranged vesicles from the trans-Golgi and endosomal networks. The HCMV gene UL35 encodes ppUL35 and its shorter form, ppUL35A. We have previously shown that the UL35 gene is involved in HCMV assembly, but it is unknown how UL35 proteins regulate viral assembly. Here we show that sorting nexin 5 (SNX5), a component of the retromer and part of the retrograde transport pathway, interacts with UL35 proteins. Expression of wild-type proteins but not mutants defective in SNX5 binding resulted in the cellular redistribution of the cation-independent mannose-6-phosphate receptor (CI-M6PR), indicating that UL35 proteins bind and negatively regulate SNX5 to modulate cellular transport pathways. Furthermore, binding of UL35 proteins to SNX5 was required for efficient viral replication and for transport of the most abundant HCMV glycoprotein B (gB; gpUL55) to the cVAC. These results indicate that ppUL35 and ppUL35A control the localization of the essential gB through the regulation of a retrograde transport pathway. Thus, this work is the first to define a molecular interaction between a tegument protein and a vesicular transport factor to regulate glycoprotein localization.IMPORTANCE Human cytomegalovirus is ubiquitously present in the healthy population, but reactivation or reinfection can cause serious, life-threatening infections in immunocompromised patients. For completion of its lytic cycle, human cytomegalovirus induces formation of an assembly center where mature virus particles are formed from multiple viral proteins. Viral glycoproteins use separate vesicular pathways for transport to the assembly center, which are incompletely understood. Our research identified a viral structural protein which affects the localization of one of the major glycoproteins. We could link this change in glycoprotein localization to an interaction of the structural protein with a cellular protein involved in regulation of vesicle transport. This increases our understanding of how the virus intersects into cellular regulatory pathways to enhance its own replication.
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27
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Liebl D, Qi X, Zhe Y, Barnett TC, Teasdale RD. SopB-Mediated Recruitment of SNX18 Facilitates Salmonella Typhimurium Internalization by the Host Cell. Front Cell Infect Microbiol 2017; 7:257. [PMID: 28664153 PMCID: PMC5471308 DOI: 10.3389/fcimb.2017.00257] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 05/31/2017] [Indexed: 11/16/2022] Open
Abstract
To invade epithelial cells, Salmonella enterica serovar Typhimurium (S. Typhimurium) induces macropinocytosis through the action of virulence proteins delivered across the host cell membrane via a type III secretion system. We show that after docking at the plasma membrane S. Typhimurium triggers rapid recruitment of cytosolic SNX18, a SH3-PX-BAR domain sorting nexin protein, to the bacteria-induced membrane ruffles and to the nascent Salmonella-containing vacuole. SNX18 recruitment required the inositol-phosphatase activity of the Salmonella effector SopB and an intact phosphoinositide-binding site within the PX domain of SNX18, but occurred independently of Rho-GTPases Rac1 and Cdc42 activation. SNX18 promotes formation of the SCV from the plasma membrane by acting as a scaffold to recruit Dynamin-2 and N-WASP in a process dependent on the SH3 domain of SNX18. Quantification of bacteria uptake revealed that overexpression of SNX18 increased bacteria internalization, whereas a decrease was detected in cells overexpressing the phosphoinositide-binding mutant R303Q, the ΔSH3 mutant, and in cells where endogenous levels of SNX18 were knocked-down. This study identifies SNX18 as a novel target of SopB and suggests a mechanism where S. Typhimurium engages host factors via local manipulation of phosphoinositide composition at the site of invasion to orchestrate the internalization process.
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Affiliation(s)
- David Liebl
- Institute for Molecular Bioscience, The University of QueenslandBrisbane, QLD, Australia
| | - Xiaying Qi
- Institute for Molecular Bioscience, The University of QueenslandBrisbane, QLD, Australia
| | - Yang Zhe
- Institute for Molecular Bioscience, The University of QueenslandBrisbane, QLD, Australia
| | - Timothy C Barnett
- Australian Infectious Diseases Research Centre, The University of QueenslandBrisbane, QLD, Australia.,School of Chemistry and Molecular Biosciences, The University of QueenslandBrisbane, QLD, Australia
| | - Rohan D Teasdale
- Institute for Molecular Bioscience, The University of QueenslandBrisbane, QLD, Australia.,Australian Infectious Diseases Research Centre, The University of QueenslandBrisbane, QLD, Australia.,School of Biomedical Sciences, The University of QueenslandBrisbane, QLD, Australia
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28
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Buckley CM, King JS. Drinking problems: mechanisms of macropinosome formation and maturation. FEBS J 2017; 284:3778-3790. [DOI: 10.1111/febs.14115] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 04/25/2017] [Accepted: 05/17/2017] [Indexed: 11/30/2022]
Affiliation(s)
- Catherine M. Buckley
- Department of Biomedical Sciences Centre for Membrane Interactions and Dynamics University of Sheffield UK
- Bateson Centre University of Sheffield UK
| | - Jason S. King
- Department of Biomedical Sciences Centre for Membrane Interactions and Dynamics University of Sheffield UK
- Bateson Centre University of Sheffield UK
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29
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Paul B, Kim HS, Kerr MC, Huston WM, Teasdale RD, Collins BM. Structural basis for the hijacking of endosomal sorting nexin proteins by Chlamydia trachomatis. eLife 2017; 6. [PMID: 28226239 PMCID: PMC5348129 DOI: 10.7554/elife.22311] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 02/19/2017] [Indexed: 12/17/2022] Open
Abstract
During infection chlamydial pathogens form an intracellular membrane-bound replicative niche termed the inclusion, which is enriched with bacterial transmembrane proteins called Incs. Incs bind and manipulate host cell proteins to promote inclusion expansion and provide camouflage against innate immune responses. Sorting nexin (SNX) proteins that normally function in endosomal membrane trafficking are a major class of inclusion-associated host proteins, and are recruited by IncE/CT116. Crystal structures of the SNX5 phox-homology (PX) domain in complex with IncE define the precise molecular basis for these interactions. The binding site is unique to SNX5 and related family members SNX6 and SNX32. Intriguingly the site is also conserved in SNX5 homologues throughout evolution, suggesting that IncE captures SNX5-related proteins by mimicking a native host protein interaction. These findings thus provide the first mechanistic insights both into how chlamydial Incs hijack host proteins, and how SNX5-related PX domains function as scaffolds in protein complex assembly.
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Affiliation(s)
- Blessy Paul
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Hyun Sung Kim
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Markus C Kerr
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | | | - Rohan D Teasdale
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Brett M Collins
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
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30
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Bendris N, Schmid SL. Endocytosis, Metastasis and Beyond: Multiple Facets of SNX9. Trends Cell Biol 2016; 27:189-200. [PMID: 27989654 DOI: 10.1016/j.tcb.2016.11.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 11/01/2016] [Accepted: 11/03/2016] [Indexed: 11/26/2022]
Abstract
Sorting nexin (SNX)9 was first discovered as an endocytic accessory protein involved in clathrin-mediated endocytosis. However, recent data suggest that SNX9 is a multifunctional scaffold that coordinates membrane trafficking and remodeling with changes in actin dynamics to affect diverse cellular processes. Here, we review the accumulated knowledge on SNX9 with an emphasis on its recently identified roles in clathrin-independent endocytic pathways, cell invasion, and cell division, which have implications for SNX9 function in human disease, including cancer.
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Affiliation(s)
- Nawal Bendris
- Department of Cell Biology, The University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Sandra L Schmid
- Department of Cell Biology, The University of Texas Southwestern Medical Center, Dallas, TX, USA.
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31
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Buckley CM, Gopaldass N, Bosmani C, Johnston SA, Soldati T, Insall RH, King JS. WASH drives early recycling from macropinosomes and phagosomes to maintain surface phagocytic receptors. Proc Natl Acad Sci U S A 2016; 113:E5906-E5915. [PMID: 27647881 PMCID: PMC5056073 DOI: 10.1073/pnas.1524532113] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Macropinocytosis is an ancient mechanism that allows cells to harvest nutrients from extracellular media, which also allows immune cells to sample antigens from their surroundings. During macropinosome formation, bulk plasma membrane is internalized with all its integral proteins. It is vital for cells to salvage these proteins before degradation, but the mechanisms for sorting them are not known. Here we describe the evolutionarily conserved recruitment of the WASH (WASP and SCAR homolog) complex to both macropinosomes and phagosomes within a minute of internalization. Using Dictyostelium, we demonstrate that WASH drives protein sorting and recycling from macropinosomes and is thus essential to maintain surface receptor levels and sustain phagocytosis. WASH functionally interacts with the retromer complex at both early and late phases of macropinosome maturation, but mediates recycling via retromer-dependent and -independent pathways. WASH mutants consequently have decreased membrane levels of integrins and other surface proteins. This study reveals an important pathway enabling cells to sustain macropinocytosis without bulk degradation of plasma membrane components.
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Affiliation(s)
- Catherine M Buckley
- Department of Biomedical Sciences, Centre for Membrane Interactions and Dynamics, University of Sheffield, Sheffield S10 2TN, United Kingdom; Bateson Centre, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Navin Gopaldass
- Department of Biochemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Cristina Bosmani
- Department of Biochemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Simon A Johnston
- Bateson Centre, University of Sheffield, Sheffield S10 2TN, United Kingdom; Department of Infection, Immunity and Cardiovascular Sciences, University of Sheffield Medical School, Sheffield S10 2RX, United Kingdom
| | - Thierry Soldati
- Department of Biochemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Robert H Insall
- Beatson Institute for Cancer Research, Glasgow G61 1BD, United Kingdom
| | - Jason S King
- Department of Biomedical Sciences, Centre for Membrane Interactions and Dynamics, University of Sheffield, Sheffield S10 2TN, United Kingdom; Bateson Centre, University of Sheffield, Sheffield S10 2TN, United Kingdom;
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32
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Ard R, Mulatz K, Pomoransky JL, Parks RJ, Trinkle-Mulcahy L, Bell JC, Gee SH. Regulation of Macropinocytosis by Diacylglycerol Kinase ζ. PLoS One 2015; 10:e0144942. [PMID: 26701304 PMCID: PMC4689489 DOI: 10.1371/journal.pone.0144942] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 11/25/2015] [Indexed: 12/02/2022] Open
Abstract
Macropinosomes arise from the closure of plasma membrane ruffles to bring about the non-selective uptake of nutrients and solutes into cells. The morphological changes underlying ruffle formation and macropinosome biogenesis are driven by actin cytoskeleton rearrangements under the control of the Rho GTPase Rac1. We showed previously that Rac1 is activated by diacylglycerol kinase ζ (DGKζ), which phosphorylates diacylglycerol to yield phosphatidic acid. Here, we show DGKζ is required for optimal macropinocytosis induced by growth factor stimulation of mouse embryonic fibroblasts. Time-lapse imaging of live cells and quantitative analysis revealed DGKζ was associated with membrane ruffles and nascent macropinosomes. Macropinocytosis was attenuated in DGKζ-null cells, as determined by live imaging and vaccinia virus uptake experiments. Moreover, macropinosomes that did form in DGKζ-null cells were smaller than those found in wild type cells. Rescue of this defect required DGKζ catalytic activity, consistent with it also being required for Rac1 activation. A constitutively membrane bound DGKζ mutant substantially increased the size of macropinosomes and potentiated the effect of a constitutively active Rac1 mutant on macropinocytosis. Collectively, our results suggest DGKζ functions in concert with Rac1 to regulate macropinocytosis.
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Affiliation(s)
- Ryan Ard
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Rd, Ottawa, ON, K1H 8M5, Canada
- Centre for Neuromuscular Disease, University of Ottawa, Ottawa, ON, Canada
| | - Kirk Mulatz
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Rd, Ottawa, ON, K1H 8M5, Canada
- Centre for Neuromuscular Disease, University of Ottawa, Ottawa, ON, Canada
| | - Julia L. Pomoransky
- Centre for Innovative Cancer Research, Ottawa Hospital Research Institute, 503 Smyth Road, 3rd floor ORCC, Ottawa, ON, K1H 1C4, Canada
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Robin J. Parks
- Centre for Neuromuscular Disease, University of Ottawa, Ottawa, ON, Canada
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
- Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON, K1H 8L6, Canada
| | - Laura Trinkle-Mulcahy
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Rd, Ottawa, ON, K1H 8M5, Canada
- Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, ON, Canada
| | - John C. Bell
- Centre for Innovative Cancer Research, Ottawa Hospital Research Institute, 503 Smyth Road, 3rd floor ORCC, Ottawa, ON, K1H 1C4, Canada
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Stephen H. Gee
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Rd, Ottawa, ON, K1H 8M5, Canada
- Centre for Neuromuscular Disease, University of Ottawa, Ottawa, ON, Canada
- * E-mail:
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Ish-Shalom E, Meirow Y, Sade-Feldman M, Kanterman J, Wang L, Mizrahi O, Klieger Y, Baniyash M. Impaired SNX9 Expression in Immune Cells during Chronic Inflammation: Prognostic and Diagnostic Implications. THE JOURNAL OF IMMUNOLOGY 2015; 196:156-67. [PMID: 26608909 DOI: 10.4049/jimmunol.1402877] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 10/25/2015] [Indexed: 11/19/2022]
Abstract
Chronic inflammation is associated with immunosuppression and downregulated expression of the TCR CD247. In searching for new biomarkers that could validate the impaired host immune status under chronic inflammatory conditions, we discovered that sorting nexin 9 (SNX9), a protein that participates in early stages of clathrin-mediated endocytosis, is downregulated as well under such conditions. SNX9 expression was affected earlier than CD247 by the generated harmful environment, suggesting that it is a potential marker sensing the generated immunosuppressive condition. We found that myeloid-derived suppressor cells, which are elevated in the course of chronic inflammation, are responsible for the observed SNX9 reduced expression. Moreover, SNX9 downregulation is reversible, as its expression levels return to normal and immune functions are restored when the inflammatory response and/or myeloid-derived suppressor cells are neutralized. SNX9 downregulation was detected in numerous mouse models for pathologies characterized by chronic inflammation such as chronic infection (Leishmania donovani), cancer (melanoma and colorectal carcinoma), and an autoimmune disease (rheumatoid arthritis). Interestingly, reduced levels of SNX9 were also observed in blood samples from colorectal cancer patients, emphasizing the feasibility of its use as a diagnostic and prognostic biomarker sensing the host's immune status and inflammatory stage. Our new discovery of SNX9 as being regulated by chronic inflammation and its association with immunosuppression, in addition to the CD247 regulation under such conditions, show the global impact of chronic inflammation and the generated immune environment on different cellular pathways in a diverse spectrum of diseases.
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Affiliation(s)
- Eliran Ish-Shalom
- Lautenberg Center for General and Tumor Immunology, Israel-Canada Medical Research Institute, Faculty of Medicine, Hebrew University, Jerusalem 91120, Israel; and ImProDia Ltd., Herzliya Pituah 46723, Israel
| | - Yaron Meirow
- Lautenberg Center for General and Tumor Immunology, Israel-Canada Medical Research Institute, Faculty of Medicine, Hebrew University, Jerusalem 91120, Israel; and
| | - Moshe Sade-Feldman
- Lautenberg Center for General and Tumor Immunology, Israel-Canada Medical Research Institute, Faculty of Medicine, Hebrew University, Jerusalem 91120, Israel; and
| | - Julia Kanterman
- Lautenberg Center for General and Tumor Immunology, Israel-Canada Medical Research Institute, Faculty of Medicine, Hebrew University, Jerusalem 91120, Israel; and
| | - Lynn Wang
- Lautenberg Center for General and Tumor Immunology, Israel-Canada Medical Research Institute, Faculty of Medicine, Hebrew University, Jerusalem 91120, Israel; and
| | | | - Yair Klieger
- Lautenberg Center for General and Tumor Immunology, Israel-Canada Medical Research Institute, Faculty of Medicine, Hebrew University, Jerusalem 91120, Israel; and ImProDia Ltd., Herzliya Pituah 46723, Israel
| | - Michal Baniyash
- Lautenberg Center for General and Tumor Immunology, Israel-Canada Medical Research Institute, Faculty of Medicine, Hebrew University, Jerusalem 91120, Israel; and
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Hicks L, Liu G, Ukken FP, Lu S, Bollinger KE, O'Connor-Giles K, Gonsalvez GB. Depletion or over-expression of Sh3px1 results in dramatic changes in cell morphology. Biol Open 2015; 4:1448-61. [PMID: 26459243 PMCID: PMC4728355 DOI: 10.1242/bio.013755] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The mammalian Sorting Nexin 9 (Snx9) family consists of three paralogs: Snx9, Snx18 and Snx33. Most of the published literature to date has centered on the role of Snx9 in clathrin-mediated endocytosis (CME). Snx9 contains an Sh3 domain at its N-terminus and has been shown to interact with Dynamin and actin nucleation factors via this domain. In addition to the Sh3 domain, Snx9 also contains a C-terminal BAR domain. BAR domains are known to sense and/or induce membrane curvature. In addition to endocytosis, recent studies have implicated the Snx9 family in diverse processes such as autophagy, macropinocytosis, phagocytosis and mitosis. The Snx9 family is encoded by a single gene in Drosophila called sh3px1. In this report, we present our initial characterization of sh3px1. We found that depletion of Sh3px1 from Drosophila Schneider 2 (S2) cells resulted in defective lamellipodia formation. A similar phenotype has been reported upon depletion of Scar, the actin nucleation factor implicated in forming lamellipodia. In addition, we demonstrate that over-expression of Sh3px1 in S2 cells results in the formation of tubules as well as long protrusions. Formation of these structures required the C-terminal BAR domain as well as the adjacent Phox homology (PX) domain of Sh3px1. Furthermore, efficient protrusion formation by Sh3px1 required the actin nucleation factor Wasp. Tubules and protrusions were also generated upon over-expressing the mammalian orthologs Snx18 and Snx33 in S2 cells. By contrast, over-expressing Snx9 mostly induced long tubules. Summary: Proteins containing BAR domains are known to generate membrane curvature. Some BAR domains generate tubules upon over-expression in cells, whereas others generate membrane protrusions. We demonstrate that Sh3px1, the Drosophila ortholog of the Snx9 family, is capable of inducing both tubules and protrusions.
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Affiliation(s)
- Lawrence Hicks
- Cellular Biology and Anatomy, Georgia Regents University, Augusta, GA 30912, USA
| | - Guojun Liu
- Cellular Biology and Anatomy, Georgia Regents University, Augusta, GA 30912, USA
| | - Fiona P Ukken
- Laboratory of Genetics, and Laboratory of Cell and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Sumin Lu
- Cellular Biology and Anatomy, Georgia Regents University, Augusta, GA 30912, USA
| | - Kathryn E Bollinger
- Cellular Biology and Anatomy, Georgia Regents University, Augusta, GA 30912, USA James and Jean Culver Vision Discovery Institute, Georgia Regents University, Augusta, GA 30912, USA
| | - Kate O'Connor-Giles
- Laboratory of Genetics, and Laboratory of Cell and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Graydon B Gonsalvez
- Cellular Biology and Anatomy, Georgia Regents University, Augusta, GA 30912, USA
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Lim JP, Gosavi P, Mintern JD, Ross EM, Gleeson PA. Sorting nexin 5 selectively regulates dorsal-ruffle-mediated macropinocytosis in primary macrophages. J Cell Sci 2015; 128:4407-19. [PMID: 26459636 DOI: 10.1242/jcs.174359] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 10/05/2015] [Indexed: 02/01/2023] Open
Abstract
The regulation of macropinocytosis, a specialised endocytosis pathway, is important for immune cell function. However, it is not known whether the biogenesis of macropinosomes involves one or more distinct pathways. We previously identified sorting nexin 5 (SNX5) as a regulator of macropinocytosis in macrophages. Here, we show that bone-marrow-derived macrophages from SNX5-knockout mice had a 60-70% reduction in macropinocytic uptake of dextran or ovalbumin, whereas phagocytosis and retrograde transport from the plasma membrane to the Golgi was unaffected. In contrast, deficiency of SNX5 had no effect on macropinocytosis or antigen presentation by dendritic cells. Activation of macrophages with CSF-1 resulted in a localisation of SNX5 to actin-rich ruffles in a manner dependent on receptor tyrosine kinases. SNX5-deficient macrophages showed a dramatic reduction in ruffling on the dorsal surface following CSF-1 receptor activation, whereas peripheral ruffling and cell migration were unaffected. We demonstrate that SNX5 is acting upstream of actin polymerisation following CSF-1 receptor activation. Overall, our findings reveal the important contribution of dorsal ruffing to receptor-activated macropinocytosis in primary macrophages and show that SNX5 selectively regulates macropinosomes derived from the dorsal ruffles.
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Affiliation(s)
- Jet Phey Lim
- The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Prajakta Gosavi
- The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Justine D Mintern
- The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Ellen M Ross
- The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Paul A Gleeson
- The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
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Li L, Wan T, Wan M, Liu B, Cheng R, Zhang R. The effect of the size of fluorescent dextran on its endocytic pathway. Cell Biol Int 2015; 39:531-9. [DOI: 10.1002/cbin.10424] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 12/19/2014] [Indexed: 02/05/2023]
Affiliation(s)
- Lei Li
- Key Laboratory of Molecular Biophysics of the Ministry of Education; College of Life Science and Technology; Huazhong University of Science and Technology; Wuhan 430074 P. R. China
| | - Tao Wan
- Key Laboratory of Molecular Biophysics of the Ministry of Education; College of Life Science and Technology; Huazhong University of Science and Technology; Wuhan 430074 P. R. China
| | - Min Wan
- Key Laboratory of Molecular Biophysics of the Ministry of Education; College of Life Science and Technology; Huazhong University of Science and Technology; Wuhan 430074 P. R. China
| | - Bei Liu
- Key Laboratory of Molecular Biophysics of the Ministry of Education; College of Life Science and Technology; Huazhong University of Science and Technology; Wuhan 430074 P. R. China
| | - Ran Cheng
- Key Laboratory of Molecular Biophysics of the Ministry of Education; College of Life Science and Technology; Huazhong University of Science and Technology; Wuhan 430074 P. R. China
| | - Rongying Zhang
- Key Laboratory of Molecular Biophysics of the Ministry of Education; College of Life Science and Technology; Huazhong University of Science and Technology; Wuhan 430074 P. R. China
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37
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Wang JTH, Teasdale RD, Liebl D. Macropinosome quantitation assay. MethodsX 2014; 1:36-41. [PMID: 26150932 PMCID: PMC4472846 DOI: 10.1016/j.mex.2014.05.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2014] [Accepted: 05/19/2014] [Indexed: 02/02/2023] Open
Abstract
In contrast to phagocytosis, macropinocytosis is not directly initiated by interactions between cell surface receptors and cargo ligands, but is a result of constitutive membrane ruffling driven by dynamic remodelling of cortical actin cytoskeleton in response to stimulation of growth factor receptors. Wang et al. (2010) [13] developed a reliable assay that allows quantitative assessment of the efficiency and kinetics of macropinosome biogenesis and/or maturation in cells where the function of a targeted protein has been perturbed by pharmacological inhibitors or by knock-down or knock-out approaches. In this manuscript we describe a modified quantitative protocol to measure the rate and volume of fluid phase uptake in adherent cells. This assay:uses fluorescent dextran, microscopy and semi-automated image analysis; allows quantitation of macropinosomes within large numbers of individual cells; can be applied also to non-homogenous cell populations including transiently transfected cell monolayers. We present the background necessary to consider when customising this protocol for application to new cell types or experimental variations.
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Affiliation(s)
- Jack T H Wang
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane 4072, Queensland, Australia ; School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane 4072, Australia
| | - Rohan D Teasdale
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane 4072, Queensland, Australia
| | - David Liebl
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane 4072, Queensland, Australia ; Dept. Bacterial Pathogenesis and Cellular Responses, Institute of Sciences Research and Technologies/CEA-Grenoble, Grenoble, France
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38
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Knowles BC, Roland JT, Krishnan M, Tyska MJ, Lapierre LA, Dickman PS, Goldenring JR, Shub MD. Myosin Vb uncoupling from RAB8A and RAB11A elicits microvillus inclusion disease. J Clin Invest 2014; 124:2947-62. [PMID: 24892806 DOI: 10.1172/jci71651] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 04/17/2014] [Indexed: 12/14/2022] Open
Abstract
Microvillus inclusion disease (MVID) is a severe form of congenital diarrhea that arises from inactivating mutations in the gene encoding myosin Vb (MYO5B). We have examined the association of mutations in MYO5B and disruption of microvillar assembly and polarity in enterocytes. Stable MYO5B knockdown (MYO5B-KD) in CaCo2-BBE cells elicited loss of microvilli, alterations in junctional claudins, and disruption of apical and basolateral trafficking; however, no microvillus inclusions were observed in MYO5B-KD cells. Expression of WT MYO5B in MYO5B-KD cells restored microvilli; however, expression of MYO5B-P660L, a MVID-associated mutation found within Navajo populations, did not rescue the MYO5B-KD phenotype but induced formation of microvillus inclusions. Microvilli establishment required interaction between RAB8A and MYO5B, while loss of the interaction between RAB11A and MYO5B induced microvillus inclusions. Using surface biotinylation and dual immunofluorescence staining in MYO5B-KD cells expressing mutant forms of MYO5B, we observed that early microvillus inclusions were positive for the sorting marker SNX18 and derived from apical membrane internalization. In patients with MVID, MYO5B-P660L results in global changes in polarity at the villus tips that could account for deficits in apical absorption, loss of microvilli, aberrant junctions, and losses in transcellular ion transport pathways, likely leading to the MVID clinical phenotype of neonatal secretory diarrhea.
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Sierecki E, Stevers LM, Giles N, Polinkovsky ME, Moustaqil M, Mureev S, Johnston WA, Dahmer-Heath M, Skalamera D, Gonda TJ, Gabrielli B, Collins BM, Alexandrov K, Gambin Y. Rapid mapping of interactions between Human SNX-BAR proteins measured in vitro by AlphaScreen and single-molecule spectroscopy. Mol Cell Proteomics 2014; 13:2233-45. [PMID: 24866125 DOI: 10.1074/mcp.m113.037275] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein dimerization and oligomerization is commonly used by nature to increase the structural and functional complexity of proteins. Regulated protein assembly is essential to transfer information in signaling, transcriptional, and membrane trafficking events. Here we show that a combination of cell-free protein expression, a proximity based interaction assay (AlphaScreen), and single-molecule fluorescence allow rapid mapping of homo- and hetero-oligomerization of proteins. We have applied this approach to the family of BAR domain-containing sorting nexin (SNX-BAR) proteins, which are essential regulators of membrane trafficking and remodeling in all eukaryotes. Dimerization of BAR domains is essential for creating a concave structure capable of sensing and inducing membrane curvature. We have systematically mapped 144 pairwise interactions between the human SNX-BAR proteins and generated an interaction matrix of preferred dimerization partners for each family member. We find that while nine SNX-BAR proteins are able to form homo-dimers, several including the retromer-associated SNX1, SNX2, and SNX5 require heteromeric interactions for dimerization. SNX2, SNX4, SNX6, and SNX8 show a promiscuous ability to bind other SNX-BAR proteins and we also observe a novel interaction with the SNX3 protein which lacks the BAR domain structure.
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Affiliation(s)
- Emma Sierecki
- From the ‡Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Loes M Stevers
- From the ‡Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Nichole Giles
- From the ‡Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Mark E Polinkovsky
- From the ‡Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Mehdi Moustaqil
- From the ‡Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Sergey Mureev
- From the ‡Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Wayne A Johnston
- From the ‡Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Mareike Dahmer-Heath
- §University of Queensland, Diamantina Institute, Translational Research Institute, Brisbane, Australia
| | - Dubravka Skalamera
- §University of Queensland, Diamantina Institute, Translational Research Institute, Brisbane, Australia
| | - Thomas J Gonda
- ¶School of Pharmacy, The University of Queensland, Brisbane, Australia
| | - Brian Gabrielli
- §University of Queensland, Diamantina Institute, Translational Research Institute, Brisbane, Australia
| | - Brett M Collins
- From the ‡Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Kirill Alexandrov
- From the ‡Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072 Australia;
| | - Yann Gambin
- From the ‡Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072 Australia
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40
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Commisso C, Flinn RJ, Bar-Sagi D. Determining the macropinocytic index of cells through a quantitative image-based assay. Nat Protoc 2014; 9:182-92. [PMID: 24385148 DOI: 10.1038/nprot.2014.004] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Macropinocytosis serves as an internalization pathway for extracellular fluid and its contents. Macropinocytosis is upregulated in oncogene-expressing cells and, recently, we have revealed a functional role for macropinocytosis in fueling cancer cell growth through the internalization of extracellular albumin, which is degraded into a usable source of intracellular amino acids. Assessing macropinocytosis has been challenging in the past because of the lack of reliable assays capable of quantitatively measuring this uptake mechanism. Here we describe a protocol for visualizing and quantifying the extent of macropinocytosis in cells both in culture and growing in vivo as tumor xenografts. By using this approach, the 'macropinocytic index' of a particular cell line or subcutaneous tumor can be ascertained within 1-2 d. The protocol can be carried out with multiple samples in parallel and can be easily adapted for a variety of cell types and xenograft or allograft mouse models.
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Affiliation(s)
- Cosimo Commisso
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
| | - Rory J Flinn
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
| | - Dafna Bar-Sagi
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
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41
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Vranic S, Boggetto N, Contremoulins V, Mornet S, Reinhardt N, Marano F, Baeza-Squiban A, Boland S. Deciphering the mechanisms of cellular uptake of engineered nanoparticles by accurate evaluation of internalization using imaging flow cytometry. Part Fibre Toxicol 2013; 10:2. [PMID: 23388071 PMCID: PMC3599262 DOI: 10.1186/1743-8977-10-2] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 02/03/2013] [Indexed: 01/08/2023] Open
Abstract
Background The uptake of nanoparticles (NPs) by cells remains to be better characterized in order to understand the mechanisms of potential NP toxicity as well as for a reliable risk assessment. Real NP uptake is still difficult to evaluate because of the adsorption of NPs on the cellular surface. Results Here we used two approaches to distinguish adsorbed fluorescently labeled NPs from the internalized ones. The extracellular fluorescence was either quenched by Trypan Blue or the uptake was analyzed using imaging flow cytometry. We used this novel technique to define the inside of the cell to accurately study the uptake of fluorescently labeled (SiO2) and even non fluorescent but light diffracting NPs (TiO2). Time course, dose-dependence as well as the influence of surface charges on the uptake were shown in the pulmonary epithelial cell line NCI-H292. By setting up an integrative approach combining these flow cytometric analyses with confocal microscopy we deciphered the endocytic pathway involved in SiO2 NP uptake. Functional studies using energy depletion, pharmacological inhibitors, siRNA-clathrin heavy chain induced gene silencing and colocalization of NPs with proteins specific for different endocytic vesicles allowed us to determine macropinocytosis as the internalization pathway for SiO2 NPs in NCI-H292 cells. Conclusion The integrative approach we propose here using the innovative imaging flow cytometry combined with confocal microscopy could be used to identify the physico-chemical characteristics of NPs involved in their uptake in view to redesign safe NPs.
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Affiliation(s)
- Sandra Vranic
- Univ Paris Diderot, Sorbonne Paris Cité, Laboratory of Molecular and Cellular Responses to Xenobiotics, Unit of Functional and Adaptive Biology (BFA) EAC CNRS 4413, 5 rue Thomas Mann, Paris 75 013, France.
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42
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Bohdanowicz M, Grinstein S. Role of Phospholipids in Endocytosis, Phagocytosis, and Macropinocytosis. Physiol Rev 2013; 93:69-106. [DOI: 10.1152/physrev.00002.2012] [Citation(s) in RCA: 198] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Endocytosis, phagocytosis, and macropinocytosis are fundamental processes that enable cells to sample their environment, eliminate pathogens and apoptotic bodies, and regulate the expression of surface components. While a great deal of effort has been devoted over many years to understanding the proteins involved in these processes, the important contribution of phospholipids has only recently been appreciated. This review is an attempt to collate and analyze the rapidly emerging evidence documenting the role of phospholipids in clathrin-mediated endocytosis, phagocytosis, and macropinocytosis. A primer on phospholipid biosynthesis, catabolism, subcellular distribution, and transport is presented initially, for reference, together with general considerations of the effects of phospholipids on membrane curvature and charge. This is followed by a detailed analysis of the critical functions of phospholipids in the internalization processes and in the maturation of the resulting vesicles and vacuoles as they progress along the endo-lysosomal pathway.
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Affiliation(s)
- Michal Bohdanowicz
- Division of Cell Biology, Hospital for Sick Children, and Institute of Medical Sciences, University of Toronto, Toronto, Canada
| | - Sergio Grinstein
- Division of Cell Biology, Hospital for Sick Children, and Institute of Medical Sciences, University of Toronto, Toronto, Canada
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Abstract
The retromer complex is a vital element of the endosomal protein sorting machinery that is conserved across all eukaryotes. Retromer is most closely associated with the endosome-to-Golgi retrieval pathway and is necessary to maintain an active pool of hydrolase receptors in the trans-Golgi network. Recent progress in studies of retromer have identified new retromer-interacting proteins, including the WASH complex and cargo such as the Wntless/MIG-14 protein, which now extends the role of retromer beyond the endosome-to-Golgi pathway and has revealed that retromer is required for aspects of endosome-to-plasma membrane sorting and regulation of signalling events. The interactions between the retromer complex and other macromolecular protein complexes now show how endosomal protein sorting is coordinated with actin assembly and movement along microtubules, and place retromer squarely at the centre of a complex set of protein machinery that governs endosomal protein sorting. Dysregulation of retromer-mediated endosomal protein sorting leads to various pathologies, including neurodegenerative diseases such as Alzheimer disease and spastic paraplegia and the mechanisms underlying these pathologies are starting to be understood. In this Commentary, I will highlight recent advances in the understanding of retromer-mediated endosomal protein sorting and discuss how retromer contributes to a diverse set of physiological processes.
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Lim JP, Teasdale RD, Gleeson PA. SNX5 is essential for efficient macropinocytosis and antigen processing in primary macrophages. Biol Open 2012; 1:904-14. [PMID: 23213485 PMCID: PMC3507233 DOI: 10.1242/bio.20122204] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Accepted: 06/19/2012] [Indexed: 12/14/2022] Open
Abstract
Macropinocytosis mediates the bulk endocytosis of solute molecules, nutrients and antigens. As this endocytic pathway is considered important in functions associated with immune responses, the molecular mechanisms regulating this pathway in immune cells is of particular significance. However, the regulators of macropinocytosis in primary cells remain poorly defined. Members of the sorting nexin (SNX) family have been implicated in macropinosome biogenesis in cultured cells and here we have analyzed the role of two SNX family members, SNX1 and its binding partner SNX5, in macropinocytosis of mouse primary macrophages. We show that endogenous SNX1 and SNX5 are localised to newly-formed macropinosomes in primary mouse macrophages and, moreover, demonstrate that SNX5 plays an essential role in macropinosome biogenesis. Depletion of SNX5 in bone marrow-derived macrophages dramatically decreased both the number and size of macropinosomes. Depletion of SNX5 also resulted in dramatic reduction in uptake and processing of soluble ovalbumin in macrophages, indicating that the majority of antigen uptake and delivery to late endosomes is via macropinocytosis. By contrast, the absence of SNX1 had no effect on endogenous SNX5 localisation and macropinosome biogenesis using macrophages from SNX1 knockout mice. Therefore, SNX5 can function independently of SNX1 and is a modulator of macropinocytosis that influences the uptake and processing of soluble antigen in primary mouse macrophages.
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Affiliation(s)
- Jet Phey Lim
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne , Victoria 3010 , Australia
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de Curtis I, Meldolesi J. Cell surface dynamics – how Rho GTPases orchestrate the interplay between the plasma membrane and the cortical cytoskeleton. J Cell Sci 2012; 125:4435-44. [DOI: 10.1242/jcs.108266] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Small GTPases are known to regulate hundreds of cell functions. In particular, Rho family GTPases are master regulators of the cytoskeleton. By regulating actin nucleation complexes, Rho GTPases control changes in cell shape, including the extension and/or retraction of surface protrusions and invaginations. Protrusion and invagination of the plasma membrane also involves the interaction between the plasma membrane and the cortical cytoskeleton. This interplay between membranes and the cytoskeleton can lead to an increase or decrease in the plasma membrane surface area and its tension as a result of the fusion (exocytosis) or internalization (endocytosis) of membranous compartments, respectively. For a long time, the cytoskeleton and plasma membrane dynamics were investigated separately. However, studies from many laboratories have now revealed that Rho GTPases, their modulation of the cytoskeleton, and membrane traffic are closely connected during the dynamic remodeling of the cell surface. Arf- and Rab-dependent exocytosis of specific vesicles contributes to the targeting of Rho GTPases and their regulatory factors to discrete sites of the plasma membrane. Rho GTPases regulate the tethering of exocytic vesicles and modulate their subsequent fusion. They also have crucial roles in the different forms of endocytosis, where they participate in the sorting of membrane domains as well as the sculpting and sealing of membrane flasks and cups. Here, we discuss how cell surface dynamics depend on the orchestration of the cytoskeleton and the plasma membrane by Rho GTPases.
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46
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Insights into the PX (phox-homology) domain and SNX (sorting nexin) protein families: structures, functions and roles in disease. Biochem J 2011; 441:39-59. [DOI: 10.1042/bj20111226] [Citation(s) in RCA: 212] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The mammalian genome encodes 49 proteins that possess a PX (phox-homology) domain, responsible for membrane attachment to organelles of the secretory and endocytic system via binding of phosphoinositide lipids. The PX domain proteins, most of which are classified as SNXs (sorting nexins), constitute an extremely diverse family of molecules that play varied roles in membrane trafficking, cell signalling, membrane remodelling and organelle motility. In the present review, we present an overview of the family, incorporating recent functional and structural insights, and propose an updated classification of the proteins into distinct subfamilies on the basis of these insights. Almost all PX domain proteins bind PtdIns3P and are recruited to early endosomal membranes. Although other specificities and localizations have been reported for a select few family members, the molecular basis for binding to other lipids is still not clear. The PX domain is also emerging as an important protein–protein interaction domain, binding endocytic and exocytic machinery, transmembrane proteins and many other molecules. A comprehensive survey of the molecular interactions governed by PX proteins highlights the functional diversity of the family as trafficking cargo adaptors and membrane-associated scaffolds regulating cell signalling. Finally, we examine the mounting evidence linking PX proteins to different disorders, in particular focusing on their emerging importance in both pathogen invasion and amyloid production in Alzheimer's disease.
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Poulin R, Casero RA, Soulet D. Recent advances in the molecular biology of metazoan polyamine transport. Amino Acids 2011; 42:711-23. [PMID: 21814785 DOI: 10.1007/s00726-011-0987-y] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Accepted: 06/02/2011] [Indexed: 01/11/2023]
Abstract
Very limited molecular knowledge exists about the identity and protein components of the ubiquitous polyamine transporters found in animal cells. However, a number of reports have been published over the last 5 years on potential candidates for metazoan polyamine permeases. We review the available evidence on these putative polyamine permeases, as well as establish a useful "identikit picture" of the general polyamine transport system, based on its properties as found in a wide spectrum of mammalian cells. Any molecular candidate encoding a putative "general" polyamine permease should fit that provided portrait. The current models proposed for the mechanism of polyamine internalization in mammalian cells are also briefly reviewed.
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Affiliation(s)
- R Poulin
- Department of Molecular Biology, Medical Biochemistry and Pathology, Faculty of Medicine, Laval University, Quebec, Canada.
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Sandvig K, Pust S, Skotland T, van Deurs B. Clathrin-independent endocytosis: mechanisms and function. Curr Opin Cell Biol 2011; 23:413-20. [PMID: 21466956 DOI: 10.1016/j.ceb.2011.03.007] [Citation(s) in RCA: 178] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 03/07/2011] [Accepted: 03/11/2011] [Indexed: 12/17/2022]
Abstract
It is now about 20 years since we first wrote reviews about clathrin-independent endocytosis. The challenge at the time was to convince the reader about its existence. Then the suggestion came up that caveolae might be responsible for the uptake. However, clearly this could not be the case since a large fraction of the clathrin-independent uptake is dynamin-independent. Today, two decades later, the field has developed considerably. New techniques have enabled a detailed analysis of several clathrin-independent endocytic mechanisms, and caveolae have been found to be mostly stable structures having several functions of their own. This article aims at providing a brief update on the importance of clathrin-independent endocytic mechanisms, how the processes are regulated differentially, for instance on the poles of polarized cells, and the challenges in studying them.
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Affiliation(s)
- Kirsten Sandvig
- Department of Biochemistry, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway.
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Abstract
Macropinocytosis is a regulated form of endocytosis that mediates the non-selective uptake of solute molecules, nutrients and antigens. It is an actin-dependent process initiated from surface membrane ruffles that give rise to large endocytic vacuoles called macropinosomes. Macropinocytosis is important in a range of physiological processes; it is highly active in macrophages and dendritic cells where it is a major pathway for the capture of antigens, it is relevant to cell migration and tumour metastasis and it represents a portal of cell entry exploited by a range of pathogens. The molecular basis for the formation and maturation of macropinosomes has only recently begun to be defined. Here, we review the general characteristics of macropinocytosis, describe some of the regulators of this pathway, which have been identified to date and highlight strategies to explore the relevance of this endocytosis pathway in vivo.
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