1
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Ma Y, Yan G, Zhang J, Xiong J, Miao W. Cip1, a CDK regulator, determines heterothallic mating or homothallic selfing in a protist. Proc Natl Acad Sci U S A 2024; 121:e2315531121. [PMID: 38498704 PMCID: PMC10990102 DOI: 10.1073/pnas.2315531121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 02/20/2024] [Indexed: 03/20/2024] Open
Abstract
Mating type (sex) plays a crucial role in regulating sexual reproduction in most extant eukaryotes. One of the functions of mating types is ensuring self-incompatibility to some extent, thereby promoting genetic diversity. However, heterothallic mating is not always the best mating strategy. For example, in low-density populations or specific environments, such as parasitic ones, species may need to increase the ratio of potential mating partners. Consequently, many species allow homothallic selfing (i.e., self-fertility or intraclonal mating). Throughout the extensive evolutionary history of species, changes in environmental conditions have influenced mating strategies back and forth. However, the mechanisms through which mating-type recognition regulates sexual reproduction and the dynamics of mating strategy throughout evolution remain poorly understood. In this study, we show that the Cip1 protein is responsible for coupling sexual reproduction initiation to mating-type recognition in the protozoal eukaryote Tetrahymena thermophila. Deletion of the Cip1 protein leads to the loss of the selfing-avoidance function of mating-type recognition, resulting in selfing without mating-type recognition. Further experiments revealed that Cip1 is a regulatory subunit of the Cdk19-Cyc9 complex, which controls the initiation of sexual reproduction. These results reveal a mechanism that regulates the choice between mating and selfing. This mechanism also contributes to the debate about the ancestral state of sexual reproduction.
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Affiliation(s)
- Yang Ma
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan430072, China
| | - Guanxiong Yan
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan430072, China
| | - Jing Zhang
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan430072, China
| | - Jie Xiong
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan430072, China
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Chinese Academy of Sciences, Wuhan430072, China
| | - Wei Miao
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan430072, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing100049, China
- Key laboratory of Lake and Watershed Science for Water Security, Chinese Academy of Sciences, Nanjing210000, China
- Institute of Hydrobiology, Hubei Hongshan Laboratory, Wuhan430000, China
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2
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Silva MG, Bastos RG, Laughery JM, Alzan HF, Rathinasamy VA, Cooke BM, Suarez CE. Vaccination of cattle with the Babesia bovis sexual-stage protein HAP2 abrogates parasite transmission by Rhipicephalus microplus ticks. NPJ Vaccines 2023; 8:140. [PMID: 37758790 PMCID: PMC10533483 DOI: 10.1038/s41541-023-00741-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 09/15/2023] [Indexed: 09/29/2023] Open
Abstract
The apicomplexan parasite Babesia bovis is responsible for bovine babesiosis, a poorly controlled tick-borne disease of global impact. The widely conserved gametocyte protein HAPLESS2/GCS1 (HAP2) is uniquely expressed on the surface of B. bovis sexual stage parasites and is a candidate for transmission-blocking vaccines (TBV). Here, we tested whether vaccination of calves with recombinant HAP2 (rHAP2) interferes with the transmission of B. bovis by competent ticks. Calves vaccinated with rHAP2 (n = 3), but not control animals (n = 3) developed antibodies specific to the vaccine antigen. Vaccinated and control animals were infested with Rhipicephalus microplus larvae and subsequently infected with virulent blood stage B. bovis parasites by needle inoculation, with all animals developing clinical signs of acute babesiosis. Engorged female ticks fed on the infected calves were collected for oviposition, hatching, and obtention of larvae. Transmission feeding was then conducted using pools of larvae derived from ticks fed on rHAP2-vaccinated or control calves. Recipient calves (n = 3) exposed to larvae derived from control animals, but none of the recipient calves (n = 3) challenged with larvae from ticks fed on rHAP2-vaccinated animals, developed signs of acute babesiosis within 11 days after tick infestation. Antibodies against B. bovis antigens and parasite DNA were found in all control recipient animals, but not in any of the calves exposed to larvae derived from HAP2-vaccinated animals, consistent with the absence of B. bovis infection via tick transmission. Overall, our results are consistent with the abrogation of parasite tick transmission in rHAP2-vaccinated calves, confirming this antigen as a prime TBV candidate against B. bovis.
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Affiliation(s)
- Marta G Silva
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
| | - Reginaldo G Bastos
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
- Animal Disease Research Unit, United States Department of Agricultural - Agricultural Research Service, Pullman, WA, USA
| | - Jacob M Laughery
- Animal Disease Research Unit, United States Department of Agricultural - Agricultural Research Service, Pullman, WA, USA
| | - Heba F Alzan
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
- Parasitology and Animal Diseases Department, National Research Center, Dokki, Giza, Egypt
| | - Vignesh A Rathinasamy
- Australian Institute of Tropical Health & Medicine, James Cook University, Cairns, QLD, Australia
| | - Brian M Cooke
- Australian Institute of Tropical Health & Medicine, James Cook University, Cairns, QLD, Australia
| | - Carlos E Suarez
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA, USA.
- Animal Disease Research Unit, United States Department of Agricultural - Agricultural Research Service, Pullman, WA, USA.
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3
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Krauchunas AR, Marcello MR, Looper A, Mei X, Putiri E, Singaravelu G, Ahmed II, Singson A. The EGF-motif-containing protein SPE-36 is a secreted sperm protein required for fertilization in C. elegans. Curr Biol 2023; 33:3056-3064.e5. [PMID: 37453426 PMCID: PMC10529607 DOI: 10.1016/j.cub.2023.06.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Revised: 03/17/2023] [Accepted: 06/19/2023] [Indexed: 07/18/2023]
Abstract
Identified through forward genetics, spe-9 was the first gene to be identified in C. elegans as necessary for fertilization.1 Since then, genetic screens in C. elegans have led to the identification of nine additional sperm genes necessary for fertilization (including spe-51 reported by Mei et al.2 and the spe-36 gene reported here).3,4,5,6,7,8,9 This includes spe-45, which encodes an immunoglobulin-containing protein similar to the mammalian protein IZUMO1, and spe-42 and spe-49, which are homologous to vertebrate DCST2 and DCST1, respectively.4,7,8,10,11,12,13 Mutations in any one of these genes result in healthy adult animals that are sterile. Sperm from these mutants have normal morphology, migrate to and maintain their position at the site of fertilization in the reproductive tract, and make contact with eggs but fail to fertilize the eggs. This same phenotype is observed in mammals lacking Izumo1, Spaca6, Tmem95, Sof1, FIMP, or Dcst1 and Dcst2.10,14,15,16,17,18,19 Here we report the discovery of SPE-36 as a sperm-derived secreted protein that is necessary for fertilization. Mutations in the Caenorhabditis elegans spe-36 gene result in a sperm-specific fertilization defect. Sperm from spe-36 mutants look phenotypically normal, are motile, and can migrate to the site of fertilization. However, sperm that do not produce SPE-36 protein cannot fertilize. Surprisingly, spe-36 encodes a secreted EGF-motif-containing protein that functions cell autonomously. The genetic requirement for secreted sperm-derived proteins for fertilization sheds new light on the complex nature of fertilization and represents a paradigm-shifting discovery in the molecular understanding of fertilization.
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Affiliation(s)
- Amber R Krauchunas
- Waksman Institute and Department of Genetics, Rutgers University, Piscataway, NJ 08854, USA; Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA.
| | | | - A'Maya Looper
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Xue Mei
- Waksman Institute and Department of Genetics, Rutgers University, Piscataway, NJ 08854, USA
| | - Emily Putiri
- Waksman Institute and Department of Genetics, Rutgers University, Piscataway, NJ 08854, USA
| | | | - Iqra I Ahmed
- Department of Biology, Pace University, New York, NY 11231, USA
| | - Andrew Singson
- Waksman Institute and Department of Genetics, Rutgers University, Piscataway, NJ 08854, USA
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4
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Azimi FC, Dean TT, Minari K, Basso LGM, Vance TDR, Serrão VHB. A Frame-by-Frame Glance at Membrane Fusion Mechanisms: From Viral Infections to Fertilization. Biomolecules 2023; 13:1130. [PMID: 37509166 PMCID: PMC10377500 DOI: 10.3390/biom13071130] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 07/09/2023] [Accepted: 07/12/2023] [Indexed: 07/30/2023] Open
Abstract
Viral entry and fertilization are distinct biological processes that share a common mechanism: membrane fusion. In viral entry, enveloped viruses attach to the host cell membrane, triggering a series of conformational changes in the viral fusion proteins. This results in the exposure of a hydrophobic fusion peptide, which inserts into the host membrane and brings the viral and host membranes into close proximity. Subsequent structural rearrangements in opposing membranes lead to their fusion. Similarly, membrane fusion occurs when gametes merge during the fertilization process, though the exact mechanism remains unclear. Structural biology has played a pivotal role in elucidating the molecular mechanisms underlying membrane fusion. High-resolution structures of the viral and fertilization fusion-related proteins have provided valuable insights into the conformational changes that occur during this process. Understanding these mechanisms at a molecular level is essential for the development of antiviral therapeutics and tools to influence fertility. In this review, we will highlight the biological importance of membrane fusion and how protein structures have helped visualize both common elements and subtle divergences in the mechanisms behind fusion; in addition, we will examine the new tools that recent advances in structural biology provide researchers interested in a frame-by-frame understanding of membrane fusion.
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Affiliation(s)
- Farshad C Azimi
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Trevor T Dean
- Pharmaceutical Sciences, University of Illinois Chicago, Chicago, IL 60612, USA
| | - Karine Minari
- Biomolecular Cryo-Electron Microscopy Facility, University of California-Santa Cruz, Santa Cruz, CA 95064, USA
| | - Luis G M Basso
- Laboratório de Ciências Físicas, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Rio de Janeiro 28013-602, Brazil
| | - Tyler D R Vance
- Department of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Vitor Hugo B Serrão
- Biomolecular Cryo-Electron Microscopy Facility, University of California-Santa Cruz, Santa Cruz, CA 95064, USA
- Department of Chemistry and Biochemistry, University of California-Santa Cruz, Santa Cruz, CA 95064, USA
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5
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Gert KRB, Panser K, Surm J, Steinmetz BS, Schleiffer A, Jovine L, Moran Y, Kondrashov F, Pauli A. Divergent molecular signatures in fish Bouncer proteins define cross-fertilization boundaries. Nat Commun 2023; 14:3506. [PMID: 37316475 DOI: 10.1038/s41467-023-39317-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 06/05/2023] [Indexed: 06/16/2023] Open
Abstract
Molecular compatibility between gametes is a prerequisite for successful fertilization. As long as a sperm and egg can recognize and bind each other via their surface proteins, gamete fusion may occur even between members of separate species, resulting in hybrids that can impact speciation. The egg membrane protein Bouncer confers species specificity to gamete interactions between medaka and zebrafish, preventing their cross-fertilization. Here, we leverage this specificity to uncover distinct amino acid residues and N-glycosylation patterns that differentially influence the function of medaka and zebrafish Bouncer and contribute to cross-species incompatibility. Curiously, in contrast to the specificity observed for medaka and zebrafish Bouncer, seahorse and fugu Bouncer are compatible with both zebrafish and medaka sperm, in line with the pervasive purifying selection that dominates Bouncer's evolution. The Bouncer-sperm interaction is therefore the product of seemingly opposing evolutionary forces that, for some species, restrict fertilization to closely related fish, and for others, allow broad gamete compatibility that enables hybridization.
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Affiliation(s)
- Krista R B Gert
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030, Vienna, Austria
| | - Karin Panser
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria
| | - Joachim Surm
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, 9190401, Jerusalem, Israel
| | - Benjamin S Steinmetz
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria
- Institute of Molecular Systems Biology, Department of Biology, ETH Zürich, 8093, Zürich, Switzerland
| | - Alexander Schleiffer
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria
| | - Luca Jovine
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Yehu Moran
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, 9190401, Jerusalem, Israel
| | - Fyodor Kondrashov
- Institute of Science and Technology Austria, Klosterneuburg, Austria
- Evolutionary and Synthetic Biology Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Andrea Pauli
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria.
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6
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Shiba Y, Takahashi T, Ohashi Y, Ueda M, Mimuro A, Sugimoto J, Noguchi Y, Igawa T. Behavior of Male Gamete Fusogen GCS1/HAP2 and the Regulation in Arabidopsis Double Fertilization. Biomolecules 2023; 13:biom13020208. [PMID: 36830580 PMCID: PMC9953686 DOI: 10.3390/biom13020208] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/16/2023] [Accepted: 01/18/2023] [Indexed: 01/25/2023] Open
Abstract
In the sexual reproduction of flowering plants, two independent fertilization events occur almost simultaneously: two identical sperm cells fuse with either the egg cell or the central cell, resulting in embryo and endosperm development to produce a seed. GCS1/HAP2 is a sperm cell membrane protein essential for plasma membrane fusion with both female gametes. Other sperm membrane proteins, DMP8 and DMP9, are more important for egg cell fertilization than that of the central cell, suggesting its regulatory mechanism in GCS1/HAP2-driving gamete membrane fusion. To assess the GCS1/HAP2 regulatory cascade in the double fertilization system of flowering plants, we produced Arabidopsis transgenic lines expressing different GCS1/HAP2 variants and evaluated the fertilization in vivo. The fertilization pattern observed in GCS1_RNAi transgenic plants implied that sperm cells over the amount of GCS1/HAP2 required for fusion on their surface could facilitate membrane fusion with both female gametes. The cytological analysis of the dmp8dmp9 sperm cell arrested alone in an embryo sac supported GCS1/HAP2 distribution on the sperm surface. Furthermore, the fertilization failures with both female gametes were caused by GCS1/HAP2 secretion from the egg cell. These results provided a possible scenario of GCS1/HAP2 regulation, showing a potential scheme for capturing additional GCS1/HAP2-interacting proteins.
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Affiliation(s)
- Yuka Shiba
- Graduate School of Horticulture, Chiba University, Matsudo 648, Matsudo-shi 271-8510, Japan
| | - Taro Takahashi
- Graduate School of Horticulture, Chiba University, Matsudo 648, Matsudo-shi 271-8510, Japan
| | - Yukino Ohashi
- Graduate School of Horticulture, Chiba University, Matsudo 648, Matsudo-shi 271-8510, Japan
| | - Minako Ueda
- Graduate School of Life Sciences, Department of Ecological Developmental Adaptability Life Sciences, Tohoku University, 2-1-1 Katahira, Sendai 980-8577, Japan
- Suntory Rising Stars Encouragement Program in Life Sciences (SunRiSE), Sendai 980-8578, Japan
| | - Amane Mimuro
- Graduate School of Horticulture, Chiba University, Matsudo 648, Matsudo-shi 271-8510, Japan
| | - Jin Sugimoto
- Graduate School of Horticulture, Chiba University, Matsudo 648, Matsudo-shi 271-8510, Japan
| | - Yuka Noguchi
- Graduate School of Horticulture, Chiba University, Matsudo 648, Matsudo-shi 271-8510, Japan
| | - Tomoko Igawa
- Graduate School of Horticulture, Chiba University, Matsudo 648, Matsudo-shi 271-8510, Japan
- Plant Molecular Science Center, Chiba University, 1-33 Yayoi, Chiba-shi 263-8522, Japan
- Correspondence:
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7
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Biner DW, Grosch JS, Ortoleva PJ. B-cell epitope discovery: The first protein flexibility-based algorithm-Zika virus conserved epitope demonstration. PLoS One 2023; 18:e0262321. [PMID: 36920995 PMCID: PMC10016673 DOI: 10.1371/journal.pone.0262321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 12/22/2021] [Indexed: 03/16/2023] Open
Abstract
Antibody-antigen interaction-at antigenic local environments called B-cell epitopes-is a prominent mechanism for neutralization of infection. Effective mimicry, and display, of B-cell epitopes is key to vaccine design. Here, a physical approach is evaluated for the discovery of epitopes which evolve slowly over closely related pathogens (conserved epitopes). The approach is 1) protein flexibility-based and 2) demonstrated with clinically relevant enveloped viruses, simulated via molecular dynamics. The approach is validated against 1) seven structurally characterized enveloped virus epitopes which evolved the least (out of thirty-nine enveloped virus-antibody structures), 2) two structurally characterized non-enveloped virus epitopes which evolved slowly (out of eight non-enveloped virus-antibody structures), and 3) eight preexisting epitope and peptide discovery algorithms. Rationale for a new benchmarking scheme is presented. A data-driven epitope clustering algorithm is introduced. The prediction of five Zika virus epitopes (for future exploration on recombinant vaccine technologies) is demonstrated. For the first time, protein flexibility is shown to outperform solvent accessible surface area as an epitope discovery metric.
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Affiliation(s)
- Daniel W. Biner
- Department of Chemistry, Indiana University, Bloomington, Indiana, United States of America
| | - Jason S. Grosch
- Department of Chemistry, Indiana University, Bloomington, Indiana, United States of America
| | - Peter J. Ortoleva
- Department of Chemistry, Indiana University, Bloomington, Indiana, United States of America
- * E-mail:
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8
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W B Jr M, A S R, P M, F B. Cellular and Natural Viral Engineering in Cognition-Based Evolution. Commun Integr Biol 2023; 16:2196145. [PMID: 37153718 PMCID: PMC10155641 DOI: 10.1080/19420889.2023.2196145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023] Open
Abstract
Neo-Darwinism conceptualizes evolution as the continuous succession of predominately random genetic variations disciplined by natural selection. In that frame, the primary interaction between cells and the virome is relegated to host-parasite dynamics governed by selective influences. Cognition-Based Evolution regards biological and evolutionary development as a reciprocating cognition-based informational interactome for the protection of self-referential cells. To sustain cellular homeorhesis, cognitive cells collaborate to assess the validity of ambiguous biological information. That collective interaction involves coordinate measurement, communication, and active deployment of resources as Natural Cellular Engineering. These coordinated activities drive multicellularity, biological development, and evolutionary change. The virome participates as the vital intercessory among the cellular domains to ensure their shared permanent perpetuation. The interactions between the virome and the cellular domains represent active virocellular cross-communications for the continual exchange of resources. Modular genetic transfers between viruses and cells carry bioactive potentials. Those exchanges are deployed as nonrandom flexible tools among the domains in their continuous confrontation with environmental stresses. This alternative framework fundamentally shifts our perspective on viral-cellular interactions, strengthening established principles of viral symbiogenesis. Pathogenesis can now be properly appraised as one expression of a range of outcomes between cells and viruses within a larger conceptual framework of Natural Viral Engineering as a co-engineering participant with cells. It is proposed that Natural Viral Engineering should be viewed as a co-existent facet of Natural Cellular Engineering within Cognition-Based Evolution.
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Affiliation(s)
- Miller W B Jr
- Banner Health Systems - Medicine, Paradise Valley, Arizona, AZ, USA
- CONTACT Miller W B Jr Paradise Valley, Arizona, AZ85253, USA
| | - Reber A S
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada
| | - Marshall P
- Department of Engineering, Evolution 2.0, Oak Park, IL, USA
| | - Baluška F
- Institute of Cellular and Molecular Botany, University of Bonn, Bonn, Germany
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9
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Brukman NG, Nakajima KP, Valansi C, Flyak K, Li X, Higashiyama T, Podbilewicz B. A novel function for the sperm adhesion protein IZUMO1 in cell-cell fusion. J Cell Biol 2022; 222:213693. [PMID: 36394541 PMCID: PMC9671554 DOI: 10.1083/jcb.202207147] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 10/11/2022] [Accepted: 11/07/2022] [Indexed: 11/18/2022] Open
Abstract
Mammalian sperm-egg adhesion depends on the trans-interaction between the sperm-specific type I glycoprotein IZUMO1 and its oocyte-specific GPI-anchored receptor JUNO. However, the mechanisms and proteins (fusogens) that mediate the following step of gamete fusion remain unknown. Using live imaging and content mixing assays in a heterologous system and structure-guided mutagenesis, we unveil an unexpected function for IZUMO1 in cell-to-cell fusion. We show that IZUMO1 alone is sufficient to induce fusion, and that this ability is retained in a mutant unable to bind JUNO. On the other hand, a triple mutation in exposed aromatic residues prevents this fusogenic activity without impairing JUNO interaction. Our findings suggest a second function for IZUMO1 as a unilateral mouse gamete fusogen.
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Affiliation(s)
- Nicolas G. Brukman
- Department of Biology, Technion - Israel Institute of Technology, Haifa, Israel
| | - Kohdai P. Nakajima
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi, Japan
| | - Clari Valansi
- Department of Biology, Technion - Israel Institute of Technology, Haifa, Israel
| | - Kateryna Flyak
- Department of Biology, Technion - Israel Institute of Technology, Haifa, Israel
| | - Xiaohui Li
- Department of Biology, Technion - Israel Institute of Technology, Haifa, Israel
| | - Tetsuya Higashiyama
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi, Japan,Institute of Transformative Bio-Molecules, Nagoya University, Nagoya, Aichi, Japan,Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, Japan
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10
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Lu Y, Ikawa M. Eukaryotic fertilization and gamete fusion at a glance. J Cell Sci 2022; 135:jcs260296. [PMID: 36416181 PMCID: PMC10658792 DOI: 10.1242/jcs.260296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
In sexually reproducing organisms, the genetic information is transmitted from one generation to the next via the merger of male and female gametes. Gamete fusion is a two-step process involving membrane recognition and apposition through ligand-receptor interactions and lipid mixing mediated by fusion proteins. HAP2 (also known as GCS1) is a bona fide gamete fusogen in flowering plants and protists. In vertebrates, a multitude of surface proteins have been demonstrated to be pivotal for sperm-egg fusion, yet none of them exhibit typical fusogenic features. In this Cell Science at a Glance article and the accompanying poster, we summarize recent advances in the mechanistic understanding of gamete fusion in eukaryotes, with a particular focus on mammalian species.
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Affiliation(s)
- Yonggang Lu
- Immunology Frontier Research Center, Osaka University, Osaka 565-0871, Japan
- Department of Experimental Genome Research, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Masahito Ikawa
- Immunology Frontier Research Center, Osaka University, Osaka 565-0871, Japan
- Department of Experimental Genome Research, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
- Laboratory of Reproductive Systems Biology, Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
- Center for Infectious Disease Education and Research, Osaka University, Osaka 565-0871, Japan
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11
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DMP8 and 9 regulate HAP2/GCS1 trafficking for the timely acquisition of sperm fusion competence. Proc Natl Acad Sci U S A 2022; 119:e2207608119. [PMID: 36322734 PMCID: PMC9659367 DOI: 10.1073/pnas.2207608119] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Sexual reproduction involves the fusion of two gametes of opposite sex. Although the sperm-expressed fusogen HAPLESS 2 (HAP2) or GENERATIVE CELL SPECIFIC 1 (GCS1) plays a vital role in this process in many eukaryotic organisms and an understanding of its regulation is emerging in unicellular systems [J. Zhang et al., Nat. Commun. 12, 4380 (2021); J. F. Pinello et al. Dev. Cell 56, 3380-3392.e9 (2021)], neither HAP2/GCS1 interactors nor mechanisms for delivery and activation at the fusion site are known in multicellular plants. Here, we show that Arabidopsis thaliana HAP2/GCS1 interacts with two sperm DUF679 membrane proteins (DMP8 and DMP9), which are required for the EGG CELL 1 (EC1)-induced translocation of HAP2/GCS1 from internal storage vesicle to the sperm plasma membrane to ensure successful fertilization. Our studies in Arabidopsis and tobacco provide evidence for a conserved function of DMP8/9-like proteins as HAP2/GCS1 partner in seed plants. Our data suggest that seed plants evolved a DMP8/9-dependent fusogen translocation process to achieve timely acquisition of sperm fusion competence in response to egg cell-derived signals, revealing a previously unknown critical step for successful fertilization.
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12
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Kumar S, Valansi C, Haile MT, Li X, Flyak K, Dwivedy A, Abatiyow BA, Leeb AS, Kennedy SY, Camargo NM, Vaughan AM, Brukman NG, Podbilewicz B, Kappe SHI. Malaria parasites utilize two essential plasma membrane fusogens for gamete fertilization. Cell Mol Life Sci 2022; 79:549. [PMID: 36241929 PMCID: PMC9568910 DOI: 10.1007/s00018-022-04583-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 09/28/2022] [Accepted: 10/01/2022] [Indexed: 11/23/2022]
Abstract
Cell fusion of female and male gametes is the climax of sexual reproduction. In many organisms, the Hapless 2 (HAP2) family of proteins play a critical role in gamete fusion. We find that Plasmodium falciparum, the causative agent of human malaria, expresses two HAP2 proteins: PfHAP2 and PfHAP2p. These proteins are present in stage V gametocytes and localize throughout the flagellum of male gametes. Gene deletion analysis and genetic crosses show that PfHAP2 and PfHAP2p individually are essential for male fertility and thereby, parasite transmission to the mosquito. Using a cell fusion assay, we demonstrate that PfHAP2 and PfHAP2p are both authentic plasma membrane fusogens. Our results establish nonredundant essential roles for PfHAP2 and PfHAP2p in mediating gamete fusion in Plasmodium and suggest avenues in the design of novel strategies to prevent malaria parasite transmission from humans to mosquitoes.
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Affiliation(s)
- Sudhir Kumar
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Clari Valansi
- The Technion-Israel Institute of Technology, Haifa, Israel
| | - Meseret T Haile
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Xiaohui Li
- The Technion-Israel Institute of Technology, Haifa, Israel
| | - Kateryna Flyak
- The Technion-Israel Institute of Technology, Haifa, Israel
| | - Abhisek Dwivedy
- Nucleic Acids Programming Laboratory, University of Illinois Urbana Champaign, Urbana, IL, USA
| | - Biley A Abatiyow
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Amanda S Leeb
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Spencer Y Kennedy
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Nelly M Camargo
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Ashley M Vaughan
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA.,Department of Pediatrics, University of Washington, Seattle, USA
| | | | | | - Stefan H I Kappe
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA. .,Department of Pediatrics, University of Washington, Seattle, USA. .,Department of Global Health, University of Washington, Seattle, WA, USA.
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13
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Snell WJ. Uncovering an ancestral green ménage à trois: Contributions of Chlamydomonas to the discovery of a broadly conserved triad of plant fertilization proteins. CURRENT OPINION IN PLANT BIOLOGY 2022; 69:102275. [PMID: 36007296 PMCID: PMC9899528 DOI: 10.1016/j.pbi.2022.102275] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 06/22/2022] [Accepted: 07/04/2022] [Indexed: 05/10/2023]
Abstract
During sexual reproduction in the unicellular green alga Chlamydomonas, gametes undergo the conserved cellular events that define fertilization across the tree of life. After initial ciliary adhesion, plus and minus gametes attach to each other at plasma membrane sites specialized for fusion, their bilayers merge, and cell coalescence into a quadri-ciliated cell signals for nuclear fusion. Recent findings show that these conserved cellular events are driven by 3 conserved protein families, FUS1/GEX2, HAP2/GCS1, and KAR5/GEX1. New results also show that species-specific recognition in Chlamydomonas activates the ancestral, viral-like fusogen HAP2 to drive fusion; that the conserved nuclear envelope fusion protein KAR5/GEX1 is also essential for nuclear fusion in Arabidopsis; and that heterodimerization of BELL-KNOX proteins signals for nuclear fusion in Chlamydomonas through early diverging land plants. This review outlines how Chlamydomonas's Janus-like position in evolution along with the ease of working with its gametes have revealed broadly conserved mechanisms.
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Affiliation(s)
- William J Snell
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA.
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14
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Discovery of archaeal fusexins homologous to eukaryotic HAP2/GCS1 gamete fusion proteins. Nat Commun 2022; 13:3880. [PMID: 35794124 PMCID: PMC9259645 DOI: 10.1038/s41467-022-31564-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 06/22/2022] [Indexed: 12/26/2022] Open
Abstract
AbstractSexual reproduction consists of genome reduction by meiosis and subsequent gamete fusion. The presence of genes homologous to eukaryotic meiotic genes in archaea and bacteria suggests that DNA repair mechanisms evolved towards meiotic recombination. However, fusogenic proteins resembling those found in gamete fusion in eukaryotes have so far not been found in prokaryotes. Here, we identify archaeal proteins that are homologs of fusexins, a superfamily of fusogens that mediate eukaryotic gamete and somatic cell fusion, as well as virus entry. The crystal structure of a trimeric archaeal fusexin (Fusexin1 or Fsx1) reveals an archetypical fusexin architecture with unique features such as a six-helix bundle and an additional globular domain. Ectopically expressed Fusexin1 can fuse mammalian cells, and this process involves the additional globular domain and a conserved fusion loop. Furthermore, archaeal fusexin genes are found within integrated mobile elements, suggesting potential roles in cell-cell fusion and gene exchange in archaea, as well as different scenarios for the evolutionary history of fusexins.
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15
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Brukman NG, Li X, Podbilewicz B. Fusexins, HAP2/GCS1 and Evolution of Gamete Fusion. Front Cell Dev Biol 2022; 9:824024. [PMID: 35083224 PMCID: PMC8784728 DOI: 10.3389/fcell.2021.824024] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 12/21/2021] [Indexed: 12/14/2022] Open
Abstract
Gamete fusion is the climax of fertilization in all sexually reproductive organisms, from unicellular fungi to humans. Similarly to other cell-cell fusion events, gamete fusion is mediated by specialized proteins, named fusogens, that overcome the energetic barriers during this process. In recent years, HAPLESS 2/GENERATIVE CELL-SPECIFIC 1 (HAP2/GCS1) was identified as the fusogen mediating sperm-egg fusion in flowering plants and protists, being both essential and sufficient for the membrane merger in some species. The identification of HAP2/GCS1 in invertebrates, opens the possibility that a similar fusogen may be used in vertebrate fertilization. HAP2/GCS1 proteins share a similar structure with two distinct families of exoplasmic fusogens: the somatic Fusion Family (FF) proteins discovered in nematodes, and class II viral glycoproteins (e.g., rubella and dengue viruses). Altogether, these fusogens form the Fusexin superfamily. While some attributes are shared among fusexins, for example the overall structure and the possibility of assembly into trimers, some other characteristics seem to be specific, such as the presence or not of hydrophobic loops or helices at the distal tip of the protein. Intriguingly, HAP2/GCS1 or other fusexins have neither been identified in vertebrates nor in fungi, raising the question of whether these genes were lost during evolution and were replaced by other fusion machinery or a significant divergence makes their identification difficult. Here, we discuss the biology of HAP2/GCS1, its involvement in gamete fusion and the structural, mechanistic and evolutionary relationships with other fusexins.
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Affiliation(s)
- Nicolas G Brukman
- Department of Biology, Technion- Israel Institute of Technology, Haifa, Israel
| | - Xiaohui Li
- Department of Biology, Technion- Israel Institute of Technology, Haifa, Israel
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16
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Pinello JF, Clark TG. HAP2-Mediated Gamete Fusion: Lessons From the World of Unicellular Eukaryotes. Front Cell Dev Biol 2022; 9:807313. [PMID: 35071241 PMCID: PMC8777248 DOI: 10.3389/fcell.2021.807313] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 11/15/2021] [Indexed: 01/29/2023] Open
Abstract
Most, if not all the cellular requirements for fertilization and sexual reproduction arose early in evolution and are retained in extant lineages of single-celled organisms including a number of important model organism species. In recent years, work in two such species, the green alga, Chlamydomonas reinhardtii, and the free-living ciliate, Tetrahymena thermophila, have lent important new insights into the role of HAP2/GCS1 as a catalyst for gamete fusion in organisms ranging from protists to flowering plants and insects. Here we summarize the current state of knowledge around how mating types from these algal and ciliate systems recognize, adhere and fuse to one another, current gaps in our understanding of HAP2-mediated gamete fusion, and opportunities for applying what we know in practical terms, especially for the control of protozoan parasites.
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Affiliation(s)
- Jennifer F. Pinello
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, United States
| | - Theodore G. Clark
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY, United States
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17
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Pinello JF, Liu Y, Snell WJ. MAR1 links membrane adhesion to membrane merger during cell-cell fusion in Chlamydomonas. Dev Cell 2021; 56:3380-3392.e9. [PMID: 34813735 DOI: 10.1016/j.devcel.2021.10.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 09/22/2021] [Accepted: 10/28/2021] [Indexed: 01/17/2023]
Abstract
Union of two gametes to form a zygote is a defining event in the life of sexual eukaryotes, yet the mechanisms that underlie cell-cell fusion during fertilization remain poorly characterized. Here, in studies of fertilization in the green alga, Chlamydomonas, we report identification of a membrane protein on minus gametes, Minus Adhesion Receptor 1 (MAR1), that is essential for the membrane attachment with plus gametes that immediately precedes lipid bilayer merger. We show that MAR1 forms a receptor pair with previously identified receptor FUS1 on plus gametes, whose ectodomain architecture we find is identical to a sperm adhesion protein conserved throughout plant lineages. Strikingly, before fusion, MAR1 is biochemically and functionally associated with the ancient, evolutionarily conserved eukaryotic Class II fusion protein HAP2 on minus gametes. Thus, the integral membrane protein MAR1 provides a molecular link between membrane adhesion and bilayer merger during fertilization in Chlamydomonas.
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Affiliation(s)
- Jennifer F Pinello
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Yanjie Liu
- Department of Cell Biology, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, Dallas, TX 75390-9039, USA
| | - William J Snell
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA.
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18
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Lai AL, Freed JH. Importance of Negatively Charged Residues in the Membrane Ordering Activity of SARS-CoV-1 and -2 Fusion Peptides. Biophys J 2021; 121:207-227. [PMID: 34929193 PMCID: PMC8683214 DOI: 10.1016/j.bpj.2021.12.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 12/01/2021] [Accepted: 12/16/2021] [Indexed: 11/30/2022] Open
Abstract
Entry of coronaviruses into host cells is mediated by the viral spike (S) protein. Previously, we identified the bona fide FPs for SARS-CoV ("SARS-1") and SARS-CoV-2 ("SARS-2") using ESR spectroscopy. We also found that their FPs induce membrane ordering in a Ca2+-dependent fashion. Here we study which negatively charged residues in SARS-1 FP are involved in this binding, to build a topological model and clarify the role of Ca2+. Our systematic mutation study on the SARS-1 FP shows that all six negatively charged residues contribute to the FP's membrane ordering activity, with D812 the dominant residue. The corresponding SARS-2 residue D830 plays an equivalent role. We provide a topological model of how the FP binds Ca2+ ions: its two segments FP1 and FP2 each bind one Ca2+. The binding of Ca2+, the folding of FP (both studied by ITC experiments), and the ordering activity correlate very well across the mutants, suggesting that the Ca2+ helps the folding of FP in membranes to enhance the ordering activity. Using a novel pseudotyped virus particle (PP)-liposome methodology, we monitored the membrane ordering induced by the FPs in the whole S protein in its trimer form in real time. We found that the SARS-1 and SARS-2 PPs also induce membrane ordering to the extent that separate FPs do, and mutations of the negatively charged residues also significantly suppress the membrane ordering activity. However, the slower kinetics of the FP ordering activity vs. that of the PP suggests the need for initial trimerization of the FPs.
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Affiliation(s)
- Alex L Lai
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, United States
| | - Jack H Freed
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, United States
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19
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Lai AL, Freed JH. Critical Negatively Charged Residues Are Important for the Activity of SARS-CoV-1 and SARS-CoV-2 Fusion Peptides.. [PMID: 34909776 PMCID: PMC8669843 DOI: 10.1101/2021.11.03.467161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Coronaviruses are a major infectious disease threat, and include the human pathogens of zoonotic origin SARS-CoV (“SARS-1”), SARS-CoV-2 (“SARS-2”) and MERS-CoV (“MERS”). Entry of coronaviruses into host cells is mediated by the viral spike (S) protein. Previously, we identified that the domain immediately downstream of the S2’ cleavage site is the bona fide FP (amino acids 798–835) for SARS-1 using ESR spectroscopy technology. We also found that the SARS-1 FP induces membrane ordering in a Ca2+ dependent fashion. In this study, we want to know which residues are involved in this Ca2+ binding, to build a topological model and to understand the role of the Ca2+. We performed a systematic mutation study on the negatively charged residues on the SARS-1 FP. While all six negatively charged residues contributes to the membrane ordering activity of the FP to some extent, D812 is the most important residue. We provided a topological model of how the FP binds Ca2+ ions: both FP1 and FP2 bind one Ca2+ ion, and there are two binding sites in FP1 and three in FP2. We also found that the corresponding residue D830 in the SARS-2 FP plays a similar critical role. ITC experiments show that the binding energies between the FP and Ca2+ as well as between the FP and membranes also decreases for all mutants. The binding of Ca2+, the folding of FP and the ordering activity correlated very well across the mutants, suggesting that the function of the Ca2+ is to help to folding of FP in membranes to enhance its activity. Using a novel pseudotyped virus particle (PP)-liposome methodology, we monitored the membrane ordering induced by the FPs in the whole S proteins in its trimer form in real time. We found that the SARS-1 and SARS-2 PPs also induce membrane ordering as the separate FPs do, and the mutations of the negatively charged residues also greatly reduce the membrane ordering activity. However, the difference in kinetic between the PP and FP indicates a possible role of FP trimerization. This finding could lead to therapeutic solutions that either target the FP-calcium interaction or block the Ca2+ channel to combat the ongoing COVID-19 pandemic.
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20
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Basso LGM, Zeraik AE, Felizatti AP, Costa-Filho AJ. Membranotropic and biological activities of the membrane fusion peptides from SARS-CoV spike glycoprotein: The importance of the complete internal fusion peptide domain. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2021; 1863:183697. [PMID: 34274319 PMCID: PMC8280623 DOI: 10.1016/j.bbamem.2021.183697] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/05/2021] [Accepted: 07/10/2021] [Indexed: 11/28/2022]
Abstract
Fusion peptides (FP) are prominent hydrophobic segments of viral fusion proteins that play critical roles in viral entry. FPs interact with and insert into the host lipid membranes, triggering conformational changes in the viral protein that leads to the viral-cell fusion. Multiple membrane-active domains from the severe acute respiratory syndrome (SARS) coronavirus (CoV) spike protein have been reported to act as the functional fusion peptide such as the peptide sequence located between the S1/S2 and S2' cleavage sites (FP1), the S2'-adjacent fusion peptide domain (FP2), and the internal FP sequence (cIFP). Using a combined biophysical approach, we demonstrated that the α-helical coiled-coil-forming internal cIFP displayed the highest membrane fusion and permeabilizing activities along with membrane ordering effect in phosphatidylcholine (PC)/phosphatidylglycerol (PG) unilamellar vesicles compared to the other two N-proximal fusion peptide counterparts. While the FP1 sequence displayed intermediate membranotropic activities, the well-conserved FP2 peptide was substantially less effective in promoting fusion, leakage, and membrane ordering in PC/PG model membranes. Furthermore, Ca2+ did not enhance the FP2-induced lipid mixing activity in PC/phosphatidylserine/cholesterol lipid membranes, despite its strong erythrocyte membrane perturbation. Nonetheless, we found that the three putative SARS-CoV membrane-active fusion peptide sequences here studied altered the physical properties of model and erythrocyte membranes to different extents. The importance of the distinct membranotropic and biological activities of all SARS-CoV fusion peptide domains and the pronounced effect of the internal fusion peptide sequence to the whole spike-mediated membrane fusion process are discussed.
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Affiliation(s)
- Luis Guilherme Mansor Basso
- Laboratório de Ciências Físicas, Centro de Ciência e Tecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Avenida Alberto Lamego, 2000, 28013-602 Campos dos Goytacazes, RJ, Brazil; Laboratório de Biofísica Molecular, Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes, 3900, 14040-901 Ribeirão Preto, SP, Brazil.
| | - Ana Eliza Zeraik
- Laboratório de Química e Função de Proteínas e Peptídeos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Avenida Alberto Lamego, 2000, 28013-602 Campos dos Goytacazes, RJ, Brazil; Grupo de Biofísica e Biologia Estrutural "Sérgio Mascarenhas", Instituto de Física de São Carlos, Universidade de São Paulo, Avenida Trabalhador São-carlense, 400, Centro, São Carlos, SP, Brazil
| | - Ana Paula Felizatti
- Laboratório de Produtos Naturais, Departamento de Química, Centro de Ciências Exatas e de Tecnologia, Universidade Federal de São Carlos, Rod. Washington Luiz, Km 235, Monjolinho, 13565905, São Carlos, SP, Brazil; Grupo de Biofísica e Biologia Estrutural "Sérgio Mascarenhas", Instituto de Física de São Carlos, Universidade de São Paulo, Avenida Trabalhador São-carlense, 400, Centro, São Carlos, SP, Brazil
| | - Antonio José Costa-Filho
- Laboratório de Biofísica Molecular, Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes, 3900, 14040-901 Ribeirão Preto, SP, Brazil.
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21
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Thorsen MK, Lai A, Lee MW, Hoogerheide DP, Wong GCL, Freed JH, Heldwein EE. Highly Basic Clusters in the Herpes Simplex Virus 1 Nuclear Egress Complex Drive Membrane Budding by Inducing Lipid Ordering. mBio 2021; 12:e0154821. [PMID: 34425706 PMCID: PMC8406295 DOI: 10.1128/mbio.01548-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 07/28/2021] [Indexed: 02/01/2023] Open
Abstract
During replication of herpesviruses, capsids escape from the nucleus into the cytoplasm by budding at the inner nuclear membrane. This unusual process is mediated by the viral nuclear egress complex (NEC) that deforms the membrane around the capsid by oligomerizing into a hexagonal, membrane-bound scaffold. Here, we found that highly basic membrane-proximal regions (MPRs) of the NEC alter lipid order by inserting into the lipid headgroups and promote negative Gaussian curvature. We also find that the electrostatic interactions between the MPRs and the membranes are essential for membrane deformation. One of the MPRs is phosphorylated by a viral kinase during infection, and the corresponding phosphomimicking mutations block capsid nuclear egress. We show that the same phosphomimicking mutations disrupt the NEC-membrane interactions and inhibit NEC-mediated budding in vitro, providing a biophysical explanation for the in vivo phenomenon. Our data suggest that the NEC generates negative membrane curvature by both lipid ordering and protein scaffolding and that phosphorylation acts as an off switch that inhibits the membrane-budding activity of the NEC to prevent capsid-less budding. IMPORTANCE Herpesviruses are large viruses that infect nearly all vertebrates and some invertebrates and cause lifelong infections in most of the world's population. During replication, herpesviruses export their capsids from the nucleus into the cytoplasm by an unusual mechanism in which the viral nuclear egress complex (NEC) deforms the nuclear membrane around the capsid. However, how membrane deformation is achieved is unclear. Here, we show that the NEC from herpes simplex virus 1, a prototypical herpesvirus, uses clusters of positive charges to bind membranes and order membrane lipids. Reducing the positive charge or introducing negative charges weakens the membrane deforming ability of the NEC. We propose that the virus employs electrostatics to deform nuclear membrane around the capsid and can control this process by changing the NEC charge through phosphorylation. Blocking NEC-membrane interactions could be exploited as a therapeutic strategy.
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Affiliation(s)
- Michael K. Thorsen
- Department of Molecular Biology and Microbiology, Graduate Program in Cellular, Molecular and Developmental Biology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Alex Lai
- Department of Chemistry and Chemical Biology and National Biomedical Center for Advanced Electron Spin Resonance Technology, Cornell University, Ithaca, New York, USA
| | - Michelle W. Lee
- Department of Bioengineering, Department of Chemistry and Biochemistry, California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California, USA
| | - David P. Hoogerheide
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland, USA
| | - Gerard C. L. Wong
- Department of Bioengineering, Department of Chemistry and Biochemistry, California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California, USA
| | - Jack H. Freed
- Department of Chemistry and Chemical Biology and National Biomedical Center for Advanced Electron Spin Resonance Technology, Cornell University, Ithaca, New York, USA
| | - Ekaterina E. Heldwein
- Department of Molecular Biology and Microbiology, Graduate Program in Cellular, Molecular and Developmental Biology, Tufts University School of Medicine, Boston, Massachusetts, USA
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22
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Affiliation(s)
- Tyler D R Vance
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Jeffrey E Lee
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada.
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23
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Zhang J, Pinello JF, Fernández I, Baquero E, Fedry J, Rey FA, Snell WJ. Species-specific gamete recognition initiates fusion-driving trimer formation by conserved fusogen HAP2. Nat Commun 2021; 12:4380. [PMID: 34282138 PMCID: PMC8289870 DOI: 10.1038/s41467-021-24613-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 06/15/2021] [Indexed: 12/02/2022] Open
Abstract
Recognition and fusion between gametes during fertilization is an ancient process. Protein HAP2, recognized as the primordial eukaryotic gamete fusogen, is a structural homolog of viral class II fusion proteins. The mechanisms that regulate HAP2 function, and whether virus-fusion-like conformational changes are involved, however, have not been investigated. We report here that fusion between plus and minus gametes of the green alga Chlamydomonas indeed requires an obligate conformational rearrangement of HAP2 on minus gametes from a labile, prefusion form into the stable homotrimers observed in structural studies. Activation of HAP2 to undergo its fusogenic conformational change occurs only upon species-specific adhesion between the two gamete membranes. Following a molecular mechanism akin to fusion of enveloped viruses, the membrane insertion capacity of the fusion loop is required to couple formation of trimers to gamete fusion. Thus, species-specific membrane attachment is the gateway to fusion-driving HAP2 rearrangement into stable trimers. HAP2 is essential for gamete fusion during fertilization and is conserved among eukaryotes. Here the authors show that species-specific adhesion between Chlamydomonas plus and minus gametes initiates HAP2 to undergo a fusogenic conformational change into homotrimers via a molecular mechanism akin to that of enveloped viruses.
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Affiliation(s)
- Jun Zhang
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
| | - Jennifer F Pinello
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
| | - Ignacio Fernández
- Unité de Virologie Structurale, Virology Department and CNRS UMR 3569, Institut Pasteur, Paris, France
| | - Eduard Baquero
- Unité de Virologie Structurale, Virology Department and CNRS UMR 3569, Institut Pasteur, Paris, France
| | - Juliette Fedry
- Unité de Virologie Structurale, Virology Department and CNRS UMR 3569, Institut Pasteur, Paris, France
| | - Félix A Rey
- Unité de Virologie Structurale, Virology Department and CNRS UMR 3569, Institut Pasteur, Paris, France
| | - William J Snell
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA.
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24
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Lai AL, Freed JH. SARS-CoV-2 Fusion Peptide has a Greater Membrane Perturbating Effect than SARS-CoV with Highly Specific Dependence on Ca 2. J Mol Biol 2021; 433:166946. [PMID: 33744314 PMCID: PMC7969826 DOI: 10.1016/j.jmb.2021.166946] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 03/11/2021] [Accepted: 03/11/2021] [Indexed: 11/03/2022]
Abstract
Coronaviruses are a major infectious disease threat, and include the zoonotic-origin human pathogens SARS-CoV-2, SARS-CoV, and MERS-CoV (SARS-2, SARS-1, and MERS). Entry of coronaviruses into host cells is mediated by the spike (S) protein. In our previous ESR studies, the local membrane ordering effect of the fusion peptide (FP) of various viral glycoproteins including the S of SARS-1 and MERS has been consistently observed. We previously determined that the sequence immediately downstream from the S2′ cleavage site is the bona fide SARS-1 FP. In this study, we used sequence alignment to identify the SARS-2 FP, and studied its membrane ordering effect. Although there are only three residue differences, SARS-2 FP induces even greater membrane ordering than SARS-1 FP, possibly due to its greater hydrophobicity. This may be a reason that SARS-2 is better able to infect host cells. In addition, the membrane binding enthalpy for SARS-2 is greater. Both the membrane ordering of SARS-2 and SARS-1 FPs are dependent on Ca2+, but that of SARS-2 shows a greater response to the presence of Ca2+. Both FPs bind two Ca2+ ions as does SARS-1 FP, but the two Ca2+ binding sites of SARS-2 exhibit greater cooperativity. This Ca2+ dependence by the SARS-2 FP is very ion-specific. These results show that Ca2+ is an important regulator that interacts with the SARS-2 FP and thus plays a significant role in SARS-2 viral entry. This could lead to therapeutic solutions that either target the FP-calcium interaction or block the Ca2+ channel.
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Affiliation(s)
- Alex L Lai
- ACERT, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, United States
| | - Jack H Freed
- ACERT, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, United States.
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Wenzhong L, Hualan L. COVID-19: the CaMKII-like system of S protein drives membrane fusion and induces syncytial multinucleated giant cells. Immunol Res 2021; 69:496-519. [PMID: 34410575 PMCID: PMC8374125 DOI: 10.1007/s12026-021-09224-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 07/24/2021] [Indexed: 02/07/2023]
Abstract
The SARS-CoV-2 S protein on the membrane of infected cells can promote receptor-dependent syncytia formation, relating to extensive tissue damage and lymphocyte elimination. In this case, it is challenging to obtain neutralizing antibodies and prevent them through antibodies effectively. Considering that, in the current study, structural domain search methods are adopted to analyze the SARS-CoV-2 S protein to find the fusion mechanism. The results show that after the EF-hand domain of S protein bound to calcium ions, S2 protein had CaMKII protein activities. Besides, the CaMKII_AD domain of S2 changed S2 conformation, facilitating the formation of HR1-HR2 six-helix bundles. Apart from that, the Ca2+-ATPase of S2 pumped calcium ions from the virus cytoplasm to help membrane fusion, while motor structures of S drove the CaATP_NAI and CaMKII_AD domains to extend to the outside and combined the viral membrane and the cell membrane, thus forming a calcium bridge. Furthermore, the phospholipid-flipping-ATPase released water, triggering lipid mixing and fusion and generating fusion pores. Then, motor structures promoted fusion pore extension, followed by the cytoplasmic contents of the virus being discharged into the cell cytoplasm. After that, the membrane of the virus slid onto the cell membrane along the flowing membrane on the gap of the three CaATP_NAI. At last, the HR1-HR2 hexamer would fall into the cytoplasm or stay on the cell membrane. Therefore, the CaMKII_like system of S protein facilitated membrane fusion for further inducing syncytial multinucleated giant cells.
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Affiliation(s)
- Liu Wenzhong
- grid.412605.40000 0004 1798 1351School of Computer Science and Engineering, Sichuan University of Science & Engineering, Zigong, 643002 China ,grid.413041.30000 0004 1808 3369School of Life Science and Food Engineering, Yibin University, Yibin, 644000 China
| | - Li Hualan
- grid.413041.30000 0004 1808 3369School of Life Science and Food Engineering, Yibin University, Yibin, 644000 China
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Straus MR, Tang T, Lai AL, Flegel A, Bidon M, Freed JH, Daniel S, Whittaker GR. Ca 2+ Ions Promote Fusion of Middle East Respiratory Syndrome Coronavirus with Host Cells and Increase Infectivity. J Virol 2020. [PMID: 32295925 DOI: 10.1101/2019.12.18.881391] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023] Open
Abstract
Fusion with, and subsequent entry into, the host cell is one of the critical steps in the life cycle of enveloped viruses. For Middle East respiratory syndrome coronavirus (MERS-CoV), the spike (S) protein is the main determinant of viral entry. Proteolytic cleavage of the S protein exposes its fusion peptide (FP), which initiates the process of membrane fusion. Previous studies on the related severe acute respiratory syndrome coronavirus (SARS-CoV) FP have shown that calcium ions (Ca2+) play an important role in fusogenic activity via a Ca2+ binding pocket with conserved glutamic acid (E) and aspartic acid (D) residues. SARS-CoV and MERS-CoV FPs share a high sequence homology, and here, we investigated whether Ca2+ is required for MERS-CoV fusion by screening a mutant array in which E and D residues in the MERS-CoV FP were substituted with neutrally charged alanines (A). Upon verifying mutant cell surface expression and proteolytic cleavage, we tested their ability to mediate pseudoparticle (PP) infection of host cells in modulating Ca2+ environments. Our results demonstrate that intracellular Ca2+ enhances MERS-CoV wild-type (WT) PP infection by approximately 2-fold and that E891 is a crucial residue for Ca2+ interaction. Subsequent electron spin resonance (ESR) experiments revealed that this enhancement could be attributed to Ca2+ increasing MERS-CoV FP fusion-relevant membrane ordering. Intriguingly, isothermal calorimetry showed an approximate 1:1 MERS-CoV FP to Ca2+ ratio, as opposed to an 1:2 SARS-CoV FP to Ca2+ ratio, suggesting significant differences in FP Ca2+ interactions of MERS-CoV and SARS-CoV FP despite their high sequence similarity.IMPORTANCE Middle East respiratory syndrome coronavirus (MERS-CoV) is a major emerging infectious disease with zoonotic potential and has reservoirs in dromedary camels and bats. Since its first outbreak in 2012, the virus has repeatedly transmitted from camels to humans, with 2,468 confirmed cases causing 851 deaths. To date, there are no efficacious drugs and vaccines against MERS-CoV, increasing its potential to cause a public health emergency. In order to develop novel drugs and vaccines, it is important to understand the molecular mechanisms that enable the virus to infect host cells. Our data have found that calcium is an important regulator of viral fusion by interacting with negatively charged residues in the MERS-CoV FP region. This information can guide therapeutic solutions to block this calcium interaction and also repurpose already approved drugs for this use for a fast response to MERS-CoV outbreaks.
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Affiliation(s)
- Marco R Straus
- Department of Microbiology and Immunology, Cornell University, Ithaca, New York, USA
| | - Tiffany Tang
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York, USA
| | - Alex L Lai
- ACERT, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, USA
| | - Annkatrin Flegel
- Department of Microbiology and Immunology, Cornell University, Ithaca, New York, USA
- Institute of Veterinary Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Miya Bidon
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York, USA
| | - Jack H Freed
- ACERT, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, USA
| | - Susan Daniel
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York, USA
| | - Gary R Whittaker
- Department of Microbiology and Immunology, Cornell University, Ithaca, New York, USA
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Ca 2+ Ions Promote Fusion of Middle East Respiratory Syndrome Coronavirus with Host Cells and Increase Infectivity. J Virol 2020; 94:JVI.00426-20. [PMID: 32295925 DOI: 10.1128/jvi.00426-20] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 04/07/2020] [Indexed: 12/12/2022] Open
Abstract
Fusion with, and subsequent entry into, the host cell is one of the critical steps in the life cycle of enveloped viruses. For Middle East respiratory syndrome coronavirus (MERS-CoV), the spike (S) protein is the main determinant of viral entry. Proteolytic cleavage of the S protein exposes its fusion peptide (FP), which initiates the process of membrane fusion. Previous studies on the related severe acute respiratory syndrome coronavirus (SARS-CoV) FP have shown that calcium ions (Ca2+) play an important role in fusogenic activity via a Ca2+ binding pocket with conserved glutamic acid (E) and aspartic acid (D) residues. SARS-CoV and MERS-CoV FPs share a high sequence homology, and here, we investigated whether Ca2+ is required for MERS-CoV fusion by screening a mutant array in which E and D residues in the MERS-CoV FP were substituted with neutrally charged alanines (A). Upon verifying mutant cell surface expression and proteolytic cleavage, we tested their ability to mediate pseudoparticle (PP) infection of host cells in modulating Ca2+ environments. Our results demonstrate that intracellular Ca2+ enhances MERS-CoV wild-type (WT) PP infection by approximately 2-fold and that E891 is a crucial residue for Ca2+ interaction. Subsequent electron spin resonance (ESR) experiments revealed that this enhancement could be attributed to Ca2+ increasing MERS-CoV FP fusion-relevant membrane ordering. Intriguingly, isothermal calorimetry showed an approximate 1:1 MERS-CoV FP to Ca2+ ratio, as opposed to an 1:2 SARS-CoV FP to Ca2+ ratio, suggesting significant differences in FP Ca2+ interactions of MERS-CoV and SARS-CoV FP despite their high sequence similarity.IMPORTANCE Middle East respiratory syndrome coronavirus (MERS-CoV) is a major emerging infectious disease with zoonotic potential and has reservoirs in dromedary camels and bats. Since its first outbreak in 2012, the virus has repeatedly transmitted from camels to humans, with 2,468 confirmed cases causing 851 deaths. To date, there are no efficacious drugs and vaccines against MERS-CoV, increasing its potential to cause a public health emergency. In order to develop novel drugs and vaccines, it is important to understand the molecular mechanisms that enable the virus to infect host cells. Our data have found that calcium is an important regulator of viral fusion by interacting with negatively charged residues in the MERS-CoV FP region. This information can guide therapeutic solutions to block this calcium interaction and also repurpose already approved drugs for this use for a fast response to MERS-CoV outbreaks.
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Li D, Yu C, Guo J, Wang Y, Zhao Y, Wang L, Soe MT, Feng H, Kyaw MP, Sattabongkot J, Jiang L, Cui L, Zhu X, Cao Y. Plasmodium vivax HAP2/GCS1 gene exhibits limited genetic diversity among parasite isolates from the Greater Mekong Subregion. Parasit Vectors 2020; 13:175. [PMID: 32264948 PMCID: PMC7137254 DOI: 10.1186/s13071-020-04050-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 03/28/2020] [Indexed: 12/02/2022] Open
Abstract
Background Antigens expressed in sexual stages of the malaria parasites are targets of transmission-blocking vaccines (TBVs). HAP2/GCS1, a TBV candidate, is critical for fertilization in Plasmodium. Here, the genetic diversity of PvHAP2 was studied in Plasmodium vivax parasite populations from the Greater Mekong Subregion (GMS). Methods Plasmodium vivax clinical isolates were collected in clinics from the China-Myanmar border region (135 samples), western Thailand (41 samples) and western Myanmar (51 samples). Near full-length Pvhap2 (nucleotides 13–2574) was amplified and sequenced from these isolates. Molecular evolution studies were conducted to evaluate the genetic diversity, selection and population differentiation. Results Sequencing of the pvhap2 gene for a total of 227 samples from the three P. vivax populations revealed limited genetic diversity of this gene in the GMS (π = 0.00036 ± 0.00003), with the highest π value observed in Myanmar (0.00053 ± 0.00009). Y133S was the dominant mutation in the China-Myanmar border (99.26%), Myanmar (100%) and Thailand (95.12%). Results of all neutrality tests were negative for all the three populations, suggesting the possible action of purifying selection. Codon-based tests identified specific codons which are under purifying or positive selections. Wright’s fixation index showed low to moderate genetic differentiation of P. vivax populations in the GMS, with FST ranging from 0.04077 to 0.24833, whereas high levels of genetic differentiation were detected between the China-Myanmar border and Iran populations (FST = 0.60266), and between Thailand and Iran populations (FST = 0.44161). A total of 20 haplotypes were identified, with H2 being the abundant haplotype in China-Myanmar border, Myanmar and Thailand populations. Epitope mapping prediction of Pvhap2 antigen showed that high-score B-cell epitopes are located in the S307-G324, L429-P453 and V623-D637 regions. The E317K and D637N mutations located within S307-G324 and V623-D637 epitopes slightly reduced the predicted score for potential epitopes. Conclusions The present study showed a very low level of genetic diversity of pvhap2 gene among P. vivax populations in the Greater Mekong Subregion. The relative conservation of pvhap2 supports further evaluation of a Pvhap2-based TBV.![]()
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Affiliation(s)
- Danni Li
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110122, Liaoning Province, People's Republic of China
| | - Chunyun Yu
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110122, Liaoning Province, People's Republic of China
| | - Jian Guo
- Department of Laboratory Medicine, Shanghai East Hospital, Tongji School of Medicine, Shanghai, People's Republic of China
| | - Yazhou Wang
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, 110122, Liaoning Province, People's Republic of China
| | - Yan Zhao
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110122, Liaoning Province, People's Republic of China
| | - Lin Wang
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110122, Liaoning Province, People's Republic of China
| | - Myat Thu Soe
- Myanmar Health Network Organization, Yangon, Myanmar
| | - Hui Feng
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110122, Liaoning Province, People's Republic of China
| | | | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Lubin Jiang
- Unit of Human Parasite Molecular and Cell Biology, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Suite 304, Tampa, FL, 33612, USA
| | - Xiaotong Zhu
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110122, Liaoning Province, People's Republic of China.
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110122, Liaoning Province, People's Republic of China.
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Ma Y, Yan G, Han X, Zhang J, Xiong J, Miao W. Sexual cell cycle initiation is regulated by CDK19 and CYC9 in Tetrahymena thermophila. J Cell Sci 2020; 133:jcs235721. [PMID: 32041901 DOI: 10.1242/jcs.235721] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 01/27/2020] [Indexed: 01/31/2023] Open
Abstract
To investigate the mechanisms underlying initiation of the sexual cell cycle in eukaryotes, we have focused on cyclins and cyclin-dependent kinases (CDKs) in the well-studied model ciliate, Tetrahymena thermophila We identified two genes, CDK19 and CYC9, which are highly co-expressed with the mating-associated factors MTA, MTB and HAP2. Both CDK19 and CYC9 were found to be essential for mating in T. thermophila Subcellular localization experiments suggested that these proteins are located at the oral area, including the conjugation junction area, and that CDK19 or CYC9 knockout prevents mating. We found that CDK19 and CYC9 form a complex, and also identified several additional subunits, which may have regulatory or constitutive functions. RNA sequencing analyses and cytological experiments showed that mating is abnormal in both ΔCDK19 and ΔCYC9, mainly at the entry to the co-stimulation stage. These results indicate that the CDK19-CYC9 complex initiates the sexual cell cycle in T. thermophila.
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Affiliation(s)
- Yang Ma
- State Key Laboratory of Freshwater Ecology and Biotechnology, Wuhan 430072, China
- Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guanxiong Yan
- State Key Laboratory of Freshwater Ecology and Biotechnology, Wuhan 430072, China
- Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaojie Han
- Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
- College of Fisheries and Life Science, Dalian Ocean University, Dalian 116023, China
| | - Jing Zhang
- Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Jie Xiong
- Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Wei Miao
- State Key Laboratory of Freshwater Ecology and Biotechnology, Wuhan 430072, China
- Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- CAS Center for Excellence in Animal Evolution and Genetics, Kunming 650223, China
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30
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Abstract
Viruses are ubiquitous parasites of cellular life and the most abundant biological entities on Earth. It is widely accepted that viruses are polyphyletic, but a consensus scenario for their ultimate origin is still lacking. Traditionally, three scenarios for the origin of viruses have been considered: descent from primordial, precellular genetic elements, reductive evolution from cellular ancestors and escape of genes from cellular hosts, achieving partial replicative autonomy and becoming parasitic genetic elements. These classical scenarios give different timelines for the origin(s) of viruses and do not explain the provenance of the two key functional modules that are responsible, respectively, for viral genome replication and virion morphogenesis. Here, we outline a 'chimeric' scenario under which different types of primordial, selfish replicons gave rise to viruses by recruiting host proteins for virion formation. We also propose that new groups of viruses have repeatedly emerged at all stages of the evolution of life, often through the displacement of ancestral structural and genome replication genes.
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31
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Qiu Y, Zhao Y, Liu F, Ye B, Zhao Z, Thongpoon S, Roobsoong W, Sattabongkot J, Cui L, Fan Q, Cao Y. Evaluation of Plasmodium vivax HAP2 as a transmission-blocking vaccine candidate. Vaccine 2020; 38:2841-2848. [PMID: 32093983 DOI: 10.1016/j.vaccine.2020.02.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 01/31/2020] [Accepted: 02/05/2020] [Indexed: 12/23/2022]
Abstract
Transmission-blocking vaccine (TBV) is a promising strategy to interfere with the transmission of malaria. To date, only limited TBV candidate antigens have been identified for Plasmodium vivax. HAP2 is a gamete membrane fusion protein, with homology to the class II viral fusion proteins. Herein we reported the characterization of the PvHAP2 for its potential as a TBV candidate for P. vivax. The HAP2/GCS1 domain of PvHAP2 was expressed in the baculovirus expression system and the recombinant protein was used to raise antibodies in rabbits. Indirect immunofluorescence assays showed that anti-PvHAP2 antibodies reacted only with the male gametocytes on blood smears. Direct membrane feeding assays were conducted using four field P. vivax isolates in Anopheles dirus. At a mean infection intensity of 72.4, 70.7, 51.3, and 15.6 oocysts/midgut with the control antibodies, anti-PvHAP2 antibodies significantly reduced the midgut oocyst intensity by 40.3, 44.4, 61.9, and 89.7%. Whereas the anti-PvHAP2 antibodies were not effective in reducing the infection prevalence at higher parasite exposure (51.3-72.4 oocysts/midgut in the control group), the anti-PvHAP2 antibodies reduced infection prevalence by 50% at a low challenge (15.6 oocysts/midgut). Multiple sequence alignment showed 100% identity among these Thai P. vivax isolates, suggesting that polymorphism may not be an impediment for the utilization of PvHAP2 as a TBV antigen. In conclusion, our results suggest that PvHAP2 could serve as a TBV candidate for P. vivax, and further optimization and evaluation are warranted.
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Affiliation(s)
- Yue Qiu
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning 110122, China
| | - Yan Zhao
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning 110122, China
| | - Fei Liu
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning 110122, China
| | - Bo Ye
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Zhenjun Zhao
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Sataporn Thongpoon
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Thailand
| | - Wanlapa Roobsoong
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Thailand
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Thailand
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Suite 304, Tampa, FL 33612, USA
| | - Qi Fan
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning 110122, China.
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Nathan L, Lai AL, Millet JK, Straus MR, Freed JH, Whittaker GR, Daniel S. Calcium Ions Directly Interact with the Ebola Virus Fusion Peptide To Promote Structure-Function Changes That Enhance Infection. ACS Infect Dis 2020; 6:250-260. [PMID: 31746195 DOI: 10.1021/acsinfecdis.9b00296] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ebola virus disease is a serious global health concern given its periodic occurrence, high lethality, and the lack of approved therapeutics. Certain drugs that alter intracellular calcium, particularly in endolysosomes, have been shown to inhibit Ebola virus infection; however, the underlying mechanism is unknown. Here, we provide evidence that Zaire ebolavirus (EBOV) infection is promoted in the presence of calcium as a result of the direct interaction of calcium with the EBOV fusion peptide (FP). We identify the glycoprotein residues D522 and E540 in the FP as functionally critical to EBOV's interaction with calcium. We show using spectroscopic and biophysical assays that interactions of the fusion peptide with Ca2+ ions lead to lipid ordering in the host membrane during membrane fusion, and these changes are promoted at low pH and can be correlated with infectivity. We further demonstrate using circular dichroism spectroscopy that calcium interaction with the fusion peptide promotes α-helical structure of the fusion peptide, a conformational change that enhances membrane fusion, as validated using functional assays of membrane fusion. This study shows that calcium directly targets the Ebola virus fusion peptide and influences its conformation. As these residues are highly conserved across the Filoviridae, calcium's impact on fusion, and subsequently infectivity, is a key interaction that can be leveraged for developing strategies to defend against Ebola infection. This mechanistic insight provides a rationale for the use of calcium-interfering drugs already approved by the FDA as therapeutics against Ebola and enables further development of novel drugs to combat the virus.
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Affiliation(s)
- Lakshmi Nathan
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, 120 Olin Hall, Ithaca, New York 14853, United States
| | - Alex L. Lai
- Baker Laboratory, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Jean Kaoru Millet
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, United States
| | - Marco R. Straus
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, United States
| | - Jack H. Freed
- Baker Laboratory, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Gary R. Whittaker
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, United States
| | - Susan Daniel
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, 120 Olin Hall, Ithaca, New York 14853, United States
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33
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Sprunck S. Twice the fun, double the trouble: gamete interactions in flowering plants. CURRENT OPINION IN PLANT BIOLOGY 2020; 53:106-116. [PMID: 31841779 DOI: 10.1016/j.pbi.2019.11.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 11/14/2019] [Accepted: 11/17/2019] [Indexed: 05/13/2023]
Abstract
During sexual reproduction two gametes of opposite sex unite to produce a zygote. Gamete fusion is a highly controlled process and it has become evident that, across species, common concepts apply to this ancient and fundamental event. Sexual reproduction in flowering plants is even more complex in that two sperm cells fertilize two female reproductive cells (egg and central cell) in a process called double fertilization. Due to the coordinated developmental progression and mutual dependency of the two fertilization products (embryo and endosperm), the success and timing of the two fusion events substantially affects seed set. So far, four proteins are known to act on the surfaces of Arabidopsis gametes to accomplish double fertilization. The molecular and evolutionary characteristics of these players prove that flowering plants integrate plant-specific and widely conserved mechanisms to accomplish the timely fusion of each sperm cell with one female reproductive cell.
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Affiliation(s)
- Stefanie Sprunck
- Cell Biology and Plant Biochemistry, University of Regensburg, Universitätsstr. 31, 93053 Regensburg, Germany.
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34
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Bloomfield G. The molecular foundations of zygosis. Cell Mol Life Sci 2020; 77:323-330. [PMID: 31203379 PMCID: PMC11105095 DOI: 10.1007/s00018-019-03187-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 05/27/2019] [Accepted: 06/06/2019] [Indexed: 10/26/2022]
Abstract
Zygosis is the generation of new biological individuals by the sexual fusion of gamete cells. Our current understanding of eukaryotic phylogeny indicates that sex is ancestral to all extant eukaryotes. Although sexual development is extremely diverse, common molecular elements have been retained. HAP2-GCS1, a protein that promotes the fusion of gamete cell membranes that is related in structure to certain viral fusogens, is conserved in many eukaryotic lineages, even though gametes vary considerably in form and behaviour between species. Similarly, although zygotes have dramatically different forms and fates in different organisms, diverse eukaryotes share a common developmental programme in which homeodomain-containing transcription factors play a central role. These common mechanistic elements suggest possible common evolutionary histories that, if correct, would have profound implications for our understanding of eukaryogenesis.
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35
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Angrisano F, Sala KA, Tapanelli S, Christophides GK, Blagborough AM. Male-Specific Protein Disulphide Isomerase Function is Essential for Plasmodium Transmission and a Vulnerable Target for Intervention. Sci Rep 2019; 9:18300. [PMID: 31797966 PMCID: PMC6892906 DOI: 10.1038/s41598-019-54613-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 11/11/2019] [Indexed: 11/10/2022] Open
Abstract
Inhibiting transmission of Plasmodium is an essential strategy in malaria eradication, and the biological process of gamete fusion during fertilization is a proven target for this approach. Lack of knowledge of the mechanisms underlying fertilization have been a hindrance in the development of transmission-blocking interventions. Here we describe a protein disulphide isomerase essential for malarial transmission (PDI-Trans/PBANKA_0820300) to the mosquito. We show that PDI-Trans activity is male-specific, surface-expressed, essential for fertilization/transmission, and exhibits disulphide isomerase activity which is up-regulated post-gamete activation. We demonstrate that PDI-Trans is a viable anti-malarial drug and vaccine target blocking malarial transmission with the use of PDI inhibitor bacitracin (98.21%/92.48% reduction in intensity/prevalence), and anti-PDI-Trans antibodies (66.22%/33.16% reduction in intensity/prevalence). To our knowledge, these results provide the first evidence that PDI function is essential for malarial transmission, and emphasize the potential of anti-PDI agents to act as anti-malarials, facilitating the future development of novel transmission-blocking interventions.
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Affiliation(s)
- Fiona Angrisano
- Division of Microbiology and Parasitology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, United Kingdom
| | - Katarzyna A Sala
- Department of Life Sciences, Imperial College of Science, Technology and Medicine, London, SW7 2AZ, United Kingdom
| | - Sofia Tapanelli
- Department of Life Sciences, Imperial College of Science, Technology and Medicine, London, SW7 2AZ, United Kingdom
| | - George K Christophides
- Department of Life Sciences, Imperial College of Science, Technology and Medicine, London, SW7 2AZ, United Kingdom
| | - Andrew M Blagborough
- Division of Microbiology and Parasitology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, United Kingdom. .,Department of Life Sciences, Imperial College of Science, Technology and Medicine, London, SW7 2AZ, United Kingdom.
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36
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Petrany MJ, Millay DP. Cell Fusion: Merging Membranes and Making Muscle. Trends Cell Biol 2019; 29:964-973. [PMID: 31648852 PMCID: PMC7849503 DOI: 10.1016/j.tcb.2019.09.002] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 09/10/2019] [Accepted: 09/11/2019] [Indexed: 12/12/2022]
Abstract
Cell fusion is essential for the development of multicellular organisms, and plays a key role in the formation of various cell types and tissues. Recent findings have highlighted the varied protein machinery that drives plasma-membrane merger in different systems, which is characterized by diverse structural and functional elements. We highlight the discovery and activities of several key sets of fusion proteins that together offer an evolving perspective on cell membrane fusion. We also emphasize recent discoveries in vertebrate myoblast fusion in skeletal muscle, which is composed of numerous multinucleated myofibers formed by the fusion of progenitor cells during development.
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Affiliation(s)
- Michael J Petrany
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Douglas P Millay
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA.
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37
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Akematsu T, Sánchez-Fernández R, Kosta F, Holzer E, Loidl J. The Transmembrane Protein Semi1 Positions Gamete Nuclei for Reciprocal Fertilization in Tetrahymena. iScience 2019; 23:100749. [PMID: 31884169 PMCID: PMC6941865 DOI: 10.1016/j.isci.2019.100749] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 11/01/2019] [Accepted: 11/25/2019] [Indexed: 11/01/2022] Open
Abstract
During sexual reproduction in the ciliate, Tetrahymena thermophila, cells of complementary mating type pair ("conjugate") undergo simultaneous meiosis and fertilize each other. In both mating partners only one of the four meiotic products is "selected" to escape autophagy, and this nucleus divides mitotically to produce two pronuclei. The migrating pronucleus of one cell translocates to the mating partner and fuses with its stationary pronucleus and vice versa. Selection of the designated gametic nucleus was thought to depend on its position within the cell because it always attaches to the junction with the partner cell. Here we show that a transmembrane protein, Semi1, is crucial for attachment. Loss of Semi1 causes failure to attach and consequent infertility. However, a nucleus is selected and gives rise to pronuclei regardless of Semi1 expression, indicating that attachment of a nucleus to the junction is not a precondition for selection but follows the selection process.
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Affiliation(s)
- Takahiko Akematsu
- Department of Chromosome Biology, University of Vienna, Dr. Bohr-Gasse 9, Vienna 1030, Austria.
| | | | - Felix Kosta
- Department of Chromosome Biology, University of Vienna, Dr. Bohr-Gasse 9, Vienna 1030, Austria
| | - Elisabeth Holzer
- Department of Chromosome Biology, University of Vienna, Dr. Bohr-Gasse 9, Vienna 1030, Austria
| | - Josef Loidl
- Department of Chromosome Biology, University of Vienna, Dr. Bohr-Gasse 9, Vienna 1030, Austria
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38
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Abstract
Cell-cell fusion is a fundamental process underlying fertilization, development, regeneration and physiology of metazoans. It is a multi-step process involving cell recognition and adhesion, actin cytoskeletal rearrangements, fusogen engagement, lipid mixing and fusion pore formation, ultimately resulting in the integration of two fusion partners. Here, we focus on the asymmetric actin cytoskeletal rearrangements at the site of fusion, known as the fusogenic synapse, which was first discovered during myoblast fusion in Drosophila embryos and later also found in mammalian muscle and non-muscle cells. At the asymmetric fusogenic synapse, actin-propelled invasive membrane protrusions from an attacking fusion partner trigger actomyosin-based mechanosensory responses in the receiving cell. The interplay between the invasive and resisting forces generated by the two fusion partners puts the fusogenic synapse under high mechanical tension and brings the two cell membranes into close proximity, promoting the engagement of fusogens to initiate fusion pore formation. In this Cell Science at a Glance article and the accompanying poster, we highlight the molecular, cellular and biophysical events at the asymmetric fusogenic synapse using Drosophila myoblast fusion as a model.
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Affiliation(s)
- Ji Hoon Kim
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Elizabeth H Chen
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA .,Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
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39
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Genetic and genomic evolution of sexual reproduction: echoes from LECA to the fungal kingdom. Curr Opin Genet Dev 2019; 58-59:70-75. [PMID: 31473482 DOI: 10.1016/j.gde.2019.07.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/28/2019] [Accepted: 07/16/2019] [Indexed: 12/30/2022]
Abstract
Sexual reproduction is vastly diverse and yet highly conserved across the eukaryotic domain. This ubiquity suggests that the last eukaryotic common ancestor (LECA) was sexual. It is hypothesized that several critical processes in sexual reproduction, including cell fusion and meiosis, were acquired during the evolution from the first eukaryotic common ancestor (FECA) to the sexual LECA. However, it is challenging to delineate the exact origin and evolution of sexual reproduction given that both FECA and LECA are extinct. Studies of diverse eukaryotes have helped to shed light on this sexual evolutionary trajectory, revealing that a primordial sexual ploidy cycle likely involved endoreplication followed by concerted chromosome loss and that cell-cell fusion, meiosis, and sex determination later arose to shape modern sexual reproduction. Despite the general conservation of sexual reproduction processes throughout eukaryotes, modern sexual cycles are immensely diverse and complex. This diversity and complexity has become readily apparent in the fungal kingdom with the recent rapid expansion of whole-genome sequencing. This abundance of data, the variety of genetic tools available to manipulate and characterize fungi, and the thorough characterization of many fungal sexual cycles make the fungal kingdom an excellent forum, in which to study the conservation and diversification of sexual reproduction.
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40
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Meirovitch E, Freed JH. Local ordering and dynamics in anisotropic media by magnetic resonance: from liquid crystals to proteins. LIQUID CRYSTALS 2019; 47:1926-1954. [PMID: 32435078 PMCID: PMC7239324 DOI: 10.1080/02678292.2019.1622158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Indexed: 06/11/2023]
Abstract
Magnetic resonance methods have been used extensively for over 50 years to elucidate molecular structure and dynamics of liquid crystals (LCs), providing information quite unique in its rigour and extent. The ESR- or NMR-active probe is often a solute molecule reporting on characteristics associated with the surrounding (LC) medium, which exerts the spatial restrictions on the probe. The theoretical approaches developed for LCs are applicable to anisotropic media in general. Of particular interest is the interior space of a globular protein labelled, e.g. with a nitroxide moiety or a 15N-1H bond. The ESR or NMR label plays the role of the probe and the internal protein surroundings the role of the anisotropic medium. A general feature of the restricted motions is the local ordering, i.e. the nature, magnitude and symmetry of the spatial restraints exerted at the site of the moving probe. This property is the main theme of the present review article. We outline its treatment in our work from both the theoretical and the experimental points of view, highlighting the new physical insights gained. Our illustrations include studies on thermotropic (nematic and smectic) and lyotropic liquid crystals formed by phospholipids, in addition to studies of proteins.
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Affiliation(s)
- Eva Meirovitch
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Jack H Freed
- Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
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41
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Brukman NG, Uygur B, Podbilewicz B, Chernomordik LV. How cells fuse. J Cell Biol 2019; 218:1436-1451. [PMID: 30936162 PMCID: PMC6504885 DOI: 10.1083/jcb.201901017] [Citation(s) in RCA: 113] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 03/05/2019] [Accepted: 03/08/2019] [Indexed: 12/11/2022] Open
Abstract
Brukman et al. review cell–cell fusion mechanisms, focusing on the identity of the fusogens that mediate these processes and the regulation of their activities. Cell–cell fusion remains the least understood type of membrane fusion process. However, the last few years have brought about major advances in understanding fusion between gametes, myoblasts, macrophages, trophoblasts, epithelial, cancer, and other cells in normal development and in diseases. While different cell fusion processes appear to proceed via similar membrane rearrangements, proteins that have been identified as necessary and sufficient for cell fusion (fusogens) use diverse mechanisms. Some fusions are controlled by a single fusogen; other fusions depend on several proteins that either work together throughout the fusion pathway or drive distinct stages. Furthermore, some fusions require fusogens to be present on both fusing membranes, and in other fusions, fusogens have to be on only one of the membranes. Remarkably, some of the proteins that fuse cells also sculpt single cells, repair neurons, promote scission of endocytic vesicles, and seal phagosomes. In this review, we discuss the properties and diversity of the known proteins mediating cell–cell fusion and highlight their different working mechanisms in various contexts.
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Affiliation(s)
- Nicolas G Brukman
- Department of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Berna Uygur
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | | | - Leonid V Chernomordik
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
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42
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Abstract
Fusion of lipid bilayers to deliver genetic information is a process common to both viral infection and fertilization, and the two share common molecular mechanisms. Now, identification of fusion-facilitators shows that plants have their own unique slant on the fusion process.
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Affiliation(s)
- Jun Zhang
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
| | - Jennifer F Pinello
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
| | - William J Snell
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA.
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43
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Baquero E, Fedry J, Legrand P, Krey T, Rey FA. Species-Specific Functional Regions of the Green Alga Gamete Fusion Protein HAP2 Revealed by Structural Studies. Structure 2018; 27:113-124.e4. [PMID: 30416037 PMCID: PMC6327110 DOI: 10.1016/j.str.2018.09.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 08/28/2018] [Accepted: 09/28/2018] [Indexed: 12/25/2022]
Abstract
The cellular fusion protein HAP2, which is structurally homologous to viral class II fusion proteins, drives gamete fusion across several eukaryotic kingdoms. Gamete fusion is a highly controlled process in eukaryotes, and is allowed only between same species gametes. In spite of a conserved architecture, HAP2 displays several species-specific functional regions that were not resolved in the available X-ray structure of the green alga Chlamydomonas reinhardtii HAP2 ectodomain. Here we present an X-ray structure resolving these regions, showing a target membrane interaction surface made by three amphipathic helices in a horseshoe-shaped arrangement. HAP2 from green algae also features additional species-specific motifs inserted in regions that in viral class II proteins are critical for the fusogenic conformational change. Such insertions include a cystine ladder-like module evocative of EGF-like motifs responsible for extracellular protein-protein interactions in animals, and a mucin-like region. These features suggest potential HAP2 interaction sites involved in gamete fusion control. Unprecedented organization of amphipathic α helices in the algal HAP2 fusion loops An inserted EGF-like motif suggests a potential algal-specific fusion control site An adjacent mucin-like region potentially modulates algal-specific interactions Inter-chain stem/domain II interactions stabilize the post-fusion hairpin conformation
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Affiliation(s)
- Eduard Baquero
- Institut Pasteur, Unité de Virologie Structurale, 25-28 Rue du Docteur Roux, 75724 Paris Cedex 15, France; CNRS UMR 3569, 25-28 Rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Juliette Fedry
- Institut Pasteur, Unité de Virologie Structurale, 25-28 Rue du Docteur Roux, 75724 Paris Cedex 15, France; CNRS UMR 3569, 25-28 Rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Pierre Legrand
- Synchrotron SOLEIL, L'Orme des Merisiers, 91192 Gif-sur-Yvette, France
| | - Thomas Krey
- Institut Pasteur, Unité de Virologie Structurale, 25-28 Rue du Docteur Roux, 75724 Paris Cedex 15, France; CNRS UMR 3569, 25-28 Rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Felix A Rey
- Institut Pasteur, Unité de Virologie Structurale, 25-28 Rue du Docteur Roux, 75724 Paris Cedex 15, France; CNRS UMR 3569, 25-28 Rue du Docteur Roux, 75724 Paris Cedex 15, France.
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44
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Feng J, Dong X, Pinello J, Zhang J, Lu C, Iacob RE, Engen JR, Snell WJ, Springer TA. Fusion surface structure, function, and dynamics of gamete fusogen HAP2. eLife 2018; 7:39772. [PMID: 30281023 PMCID: PMC6170185 DOI: 10.7554/elife.39772] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 09/02/2018] [Indexed: 01/16/2023] Open
Abstract
HAP2 is a class II gamete fusogen in many eukaryotic kingdoms. A crystal structure of Chlamydomonas HAP2 shows a trimeric fusion state. Domains D1, D2.1 and D2.2 line the 3-fold axis; D3 and a stem pack against the outer surface. Surprisingly, hydrogen-deuterium exchange shows that surfaces of D1, D2.2 and D3 closest to the 3-fold axis are more dynamic than exposed surfaces. Three fusion helices in the fusion loops of each monomer expose hydrophobic residues at the trimer apex that are splayed from the 3-fold axis, leaving a solvent-filled cavity between the fusion loops in each monomer. At the base of the two fusion loops, Arg185 docks in a carbonyl cage. Comparisons to other structures, dynamics, and the greater effect on Chlamydomonas gamete fusion of mutation of axis-proximal than axis-distal fusion helices suggest that the apical portion of each monomer could tilt toward the 3-fold axis with merger of the fusion helices into a common fusion surface.
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Affiliation(s)
- Juan Feng
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States.,Program in Cellular and Molecular Medicine, Children's Hospital Boston, Boston, United States
| | - Xianchi Dong
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States.,Program in Cellular and Molecular Medicine, Children's Hospital Boston, Boston, United States
| | - Jennifer Pinello
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, United States
| | - Jun Zhang
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, United States
| | - Chafen Lu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States.,Program in Cellular and Molecular Medicine, Children's Hospital Boston, Boston, United States
| | - Roxana E Iacob
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, United States
| | - John R Engen
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, United States
| | - William J Snell
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, United States
| | - Timothy A Springer
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States.,Program in Cellular and Molecular Medicine, Children's Hospital Boston, Boston, United States
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45
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Koonin EV, Krupovic M. The depths of virus exaptation. Curr Opin Virol 2018; 31:1-8. [PMID: 30071360 DOI: 10.1016/j.coviro.2018.07.011] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 07/13/2018] [Accepted: 07/19/2018] [Indexed: 02/07/2023]
Abstract
Viruses are ubiquitous parasites of cellular life forms and the most abundant biological entities on earth. The relationships between viruses and their hosts involve the continuous arms race but are by no account limited to it. Growing evidence shows that, in the course of evolution, viruses and their components are repeatedly recruited (exapted) for host functions. The functions of exapted viruses typically involve either defense from other viruses or cellular competitors or transfer of nucleic acids between cells, or storage functions. Virus exaptation can reach different depths, from recruitment of a fully functional virus to exploitation of defective, partially degraded viruses, to utilization of individual virus proteins.
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Affiliation(s)
- Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, United States.
| | - Mart Krupovic
- Unité Biologie Moléculaire du Gène chez les Extrêmophiles, Department of Microbiology, Institut Pasteur, 25 rue du Docteur Roux, Paris 75015, France.
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46
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Targeting the Conserved Fusion Loop of HAP2 Inhibits the Transmission of Plasmodium berghei and falciparum. Cell Rep 2018; 21:2868-2878. [PMID: 29212032 PMCID: PMC5732318 DOI: 10.1016/j.celrep.2017.11.024] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 10/05/2017] [Accepted: 11/02/2017] [Indexed: 01/01/2023] Open
Abstract
Inhibiting transmission of Plasmodium is a central strategy in malarial eradication, and the biological process of gamete fusion during fertilization is a proven target for this approach. The lack of a structure or known molecular function of current anti-malarial vaccine targets has previously been a hindrance in the development of transmission-blocking vaccines. Structure/function studies have indicated that the conserved gamete membrane fusion protein HAP2 is a class II viral fusion protein. Here, we demonstrate that targeting a function-critical site of the fusion/cd loop with species-specific antibodies reduces Plasmodium berghei transmission in vivo by 58.9% and in vitro fertilization by up to 89.9%. A corresponding reduction in P. falciparum transmission (75.5%/36.4% reductions in intensity/prevalence) is observed in complimentary field studies. These results emphasize conserved mechanisms of fusion in Apicomplexa, while highlighting an approach to design future anti-malarial transmission-blocking vaccines. Plasmodium HAP2 is a class II fusion protein Class II proteins are targetable to inhibit fertilization/transmission A short synthetically generated peptide can induce transmission-blocking immunity
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47
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Abstract
Sex in social amoebae (or dictyostelids) has a number of striking features. Dictyostelid zygotes do not proliferate but grow to a large size by feeding on other cells of the same species, each zygote ultimately forming a walled structure called a macrocyst. The diploid macrocyst nucleus undergoes meiosis, after which a single meiotic product survives to restart haploid vegetative growth. Meiotic recombination is generally initiated by the Spo11 enzyme, which introduces DNA double-strand breaks. Uniquely, as far as is known among sexual eukaryotes, dictyostelids lack a SPO11 gene. Despite this, recombination occurs at high frequencies during meiosis in dictyostelids, through unknown mechanisms. The molecular processes underlying these events, and the evolutionary drivers that brought them into being, may shed light on the genetic conflicts that occur within and between genomes, and how they can be resolved.
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48
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The AFF-1 exoplasmic fusogen is required for endocytic scission and seamless tube elongation. Nat Commun 2018; 9:1741. [PMID: 29717108 PMCID: PMC5931541 DOI: 10.1038/s41467-018-04091-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 04/03/2018] [Indexed: 12/28/2022] Open
Abstract
Many membranes must merge during cellular trafficking, but fusion and fission events initiating at exoplasmic (non-cytosolic) membrane surfaces are not well understood. Here we show that the C. elegans cell-cell fusogen anchor-cell fusion failure 1 (AFF-1) is required for membrane trafficking events during development of a seamless unicellular tube. EGF-Ras-ERK signaling upregulates AFF-1 expression in the excretory duct tube to promote tube auto-fusion and subsequent lumen elongation. AFF-1 is required for scission of basal endocytic compartments and for apically directed exocytosis to extend the apical membrane. Lumen elongation also requires the transcytosis factor Rab11, but occurs independently of dynamin and clathrin. These results support a transcytosis model of seamless tube lumen growth and show that cell-cell fusogens also can play roles in intracellular membrane trafficking events.
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49
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Helenius A. Virus Entry: Looking Back and Moving Forward. J Mol Biol 2018; 430:1853-1862. [PMID: 29709571 PMCID: PMC7094621 DOI: 10.1016/j.jmb.2018.03.034] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 03/15/2018] [Accepted: 03/16/2018] [Indexed: 12/29/2022]
Abstract
Research over a period of more than half a century has provided a reasonably accurate picture of mechanisms involved in animal virus entry into their host cells. Successive steps in entry include binding to receptors, endocytosis, passage through one or more membranes, targeting to specific sites within the cell, and uncoating of the genome. For some viruses, the molecular interactions are known in great detail. However, as more viruses are analyzed, and as the focus shifts from tissue culture to in vivo experiments, it is evident that viruses display considerable redundancy and flexibility in receptor usage, endocytic mechanism, location of penetration, and uncoating mechanism. For many viruses, the picture is still elusive because the interactions that they engage in rely on sophisticated adaptation to complex cellular functions and defense mechanisms. Studies using a broad combination of technologies have provided detailed information on the entry and uncoating of many animal viruses. Not only the identity of cell surface receptors but their distribution in plasma membrane and in microdomains defines cell tropism and infection efficiency. The majority of viruses enter by endocytic mechanisms and penetrate into the cytosol intracellularly from a variety of different organelles. The picture is often elusive because many viruses display redundancy in receptor choice and entry strategy.
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Affiliation(s)
- Ari Helenius
- ETH Zurich, Institute of Biochemistry, Otto-Stern-Weg 3, Zurich 8093, Switzerland.
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50
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Wood FC, Heidari A, Tekle YI. Genetic Evidence for Sexuality in Cochliopodium (Amoebozoa). J Hered 2018; 108:769-779. [PMID: 29036297 PMCID: PMC5892394 DOI: 10.1093/jhered/esx078] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Accepted: 09/18/2017] [Indexed: 12/18/2022] Open
Abstract
Microbial eukaryotes, including amoeboids, display diverse and complex life cycles that may or may not involve sexual reproduction. A recent comprehensive gene inventory study concluded that the Amoebozoa are ancestrally sexual. However, the detection of sex genes in some lineages known for their potentially sexual life cycle was very low. Particularly, the genus Cochliopodium, known to undergo a process of cell fusion, karyogamy, and subsequent fission previously described as parasexual, had no meiosis genes detected. This is likely due to low data representation, given the extensive nuclear fusion observed in the genus. In this study, we generate large amounts of transcriptome data for 2 species of Cochliopodium, known for their high frequency of cellular and nuclear fusion, in order to study the genetic basis of the complex life cycle observed in the genus. We inventory 60 sex-related genes, including 11 meiosis-specific genes, and 31 genes involved in fusion and karyogamy. We find a much higher detection of sex-related genes, including 5 meiosis-specific genes not previously detected in Cochliopodium, in this large transcriptome data. The expressed genes form a near-complete recombination machinery, indicating that Cochliopodium is an actively recombining sexual lineage. We also find 9 fusion-related genes in Cochliopodium, although no conserved fusion-specific genes were detected in the transcriptomes. Cochliopodium thus likely uses lineage specific genes for the fusion and depolyploidization processes. Our results demonstrate that Cochliopodium possess the genetic toolkit for recombination, while the mechanism involving fusion and genome reduction remains to be elucidated.
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Affiliation(s)
- Fiona C Wood
- Department of Biology, Spelman College, 350 Spelman Lane Southwest, Atlanta, GA 30314
| | - Alireza Heidari
- Department of Biology, Spelman College, 350 Spelman Lane Southwest, Atlanta, GA 30314
| | - Yonas I Tekle
- Department of Biology, Spelman College, 350 Spelman Lane Southwest, Atlanta, GA 30314
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