Scavenger receptor-C acts as a receptor for Bacillus thuringiensis vegetative insecticidal protein Vip3Aa and mediates the internalization of Vip3Aa via endocytosis

Autor: Zhanglei Cao, Tong-tong Tan, Jin Chang, Jun Cai, Dan Zhao, Bing Yan, Xiao-yue Hou, Lu Han, Kun Jiang, Si-qi Mei
Jazyk: angličtina
Rok vydání: 2018
Předmět:
0301 basic medicine
Life Cycles
Molecular biology
Cell Membranes
Sf9
Toxicology
Pathology and Laboratory Medicine
Larvae
Bacillus thuringiensis
Medicine and Health Sciences
Toxins
Drosophila Proteins
Biology (General)
Secretory Pathway
biology
Virulence
Chemistry
Drosophila Melanogaster
Eukaryota
Animal Models
Scavenger Receptors
Class C
Endocytosis
Cell biology
Insects
Experimental Organism Systems
Cell Processes
Drosophila
Cellular Structures and Organelles
Research Article
Arthropoda
QH301-705.5
030106 microbiology
Immunology
Toxic Agents
Spodoptera
DNA construction
Research and Analysis Methods
Microbiology
03 medical and health sciences
Model Organisms
Downregulation and upregulation
Bacterial Proteins
Virology
Genetics
Animals
Scavenger receptor
Pest Control
Biological
Toxicity
fungi
Organisms
Biology and Life Sciences
Membrane Proteins
Biological Transport
Cell Biology
RC581-607
biology.organism_classification
Invertebrates
030104 developmental biology
Molecular biology techniques
Membrane protein
Plasmid Construction
biology.protein
Animal Studies
Parasitology
Immunologic diseases. Allergy
Complement control protein
Developmental Biology
Zdroj: PLoS Pathogens, Vol 14, Iss 10, p e1007347 (2018)
PLoS Pathogens
ISSN: 1553-7374
1553-7366
Popis: The vegetative insecticidal proteins (Vip), secreted by many Bacillus thuringiensis strains during their vegetative growth stage, are genetically distinct from known insecticidal crystal proteins (ICPs) and represent the second-generation insecticidal toxins. Compared with ICPs, the insecticidal mechanisms of Vip toxins are poorly understood. In particular, there has been no report of a definite receptor of Vip toxins to date. In the present study, we identified the scavenger receptor class C like protein (Sf-SR-C) from the Spodoptera frugiperda (Sf9) cells membrane proteins that bind to the biotin labeled Vip3Aa, via the affinity magnetic bead method coupled with HPLC-MS/MS. We then certified Vip3Aa protoxin could interact with Sf-SR-C in vitro and ex vivo. In addition, downregulation of SR-C expression in Sf9 cells and Spodoptera exigua larvae midgut reduced the toxicity of Vip3Aa to them. Coincidently, heterologous expression of Sf-SR-C in transgenic Drosophila midgut significantly enhanced the virulence of Vip3Aa to the Drosophila larvae. Moreover, the complement control protein domain and MAM domain of Sf-SR-C are involved in the interaction with Vip3Aa protoxin. Furthermore, endocytosis of Vip3Aa mediated by Sf-SR-C correlates with its insecticidal activity. Our results confirmed for the first time that Sf-SR-C acts as a receptor for Vip3Aa protoxin and provides an insight into the mode of action of Vip3Aa that will significantly facilitate the study of its insecticidal mechanism and application.
Author summary Bacillus thuringiensis Vip3A has potential in control of Lepidopteran pest and has been used in transgenic plants. However, studies of the insecticidal mechanisms of Vip3A are rare, and none of their definite receptors have been reported so far, which seriously restricts the study of its insecticidal mechanism and application. This work identified and confirmed the scavenger receptor class C like protein (Sf-SR-C) acts as the receptor of Vip3Aa protoxin, demonstrated that Sf-SR-C mediates the toxicity of Vip3Aa to Sf9 cells in an internalized manner. These results extend our understanding of SR-C proteins in insects and explain the specificity of Vip3Aa insecticidal activity, which strongly support it as a safe biopesticide. More importantly, it suggests the insecticidal mechanism of Vip3Aa different from the well-known “pore formation” model, “signal transduction” model, as well as newly found “necrosis” model of Cry toxins, which will significantly promote the relevant study of Vip3Aa. Last but not least, because scavenger receptors play a crucial role in innate immunity, our results provide relevant insights into host-pathogen interactions.
Databáze: OpenAIRE
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