1. Chaperone-Mediated Autophagy Protein BAG3 Negatively Regulates Ebola and Marburg VP40-Mediated Egress
- Author
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Mark T. Bedford, Marius Sudol, Cari A. Sagum, Jingjing Liang, Sachdev S. Sidhu, Ziying Han, and Ronald N. Harty
- Subjects
0301 basic medicine ,Physiology ,Protein Extraction ,Nedd4 Ubiquitin Protein Ligases ,viruses ,Cell Membranes ,Filoviridae ,Pathogenesis ,Pathology and Laboratory Medicine ,medicine.disease_cause ,Biochemistry ,Chaperone-mediated autophagy ,Cricetinae ,Medicine and Health Sciences ,Chemical Precipitation ,Marburg Virus Disease ,RNA, Small Interfering ,lcsh:QH301-705.5 ,Virus Release ,Extraction Techniques ,biology ,Chromatographic Techniques ,Chemical Reactions ,Hematology ,Ebolavirus ,Body Fluids ,3. Good health ,Transport protein ,Cell biology ,Chemistry ,Protein Transport ,Blood ,Amino Acid Specific Chromatography ,Host-Pathogen Interactions ,Physical Sciences ,RNA Interference ,Anatomy ,Cellular Structures and Organelles ,Research Article ,lcsh:Immunologic diseases. Allergy ,Proline ,Cell Survival ,Ubiquitin-Protein Ligases ,Immunology ,Research and Analysis Methods ,BAG3 ,Precipitates ,Microbiology ,Viral Matrix Proteins ,03 medical and health sciences ,VP40 ,Protein Domains ,Cell Line, Tumor ,Virology ,Glutathione Chromatography ,Autophagy ,Genetics ,medicine ,Animals ,Humans ,Molecular Biology ,Adaptor Proteins, Signal Transducing ,Ebola virus ,Endosomal Sorting Complexes Required for Transport ,030102 biochemistry & molecular biology ,Affinity Chromatography ,Biology and Life Sciences ,Membrane Proteins ,Proteins ,Correction ,Cell Biology ,Blood Serum ,Hemorrhagic Fever, Ebola ,biology.organism_classification ,Marburgvirus ,Protein Structure, Tertiary ,Repressor Proteins ,HEK293 Cells ,030104 developmental biology ,lcsh:Biology (General) ,Parasitology ,Apoptosis Regulatory Proteins ,lcsh:RC581-607 ,Immune Serum ,HeLa Cells - Abstract
Ebola (EBOV) and Marburg (MARV) viruses are members of the Filoviridae family which cause outbreaks of hemorrhagic fever. The filovirus VP40 matrix protein is essential for virus assembly and budding, and its PPxY L-domain motif interacts with WW-domains of specific host proteins, such as Nedd4 and ITCH, to facilitate the late stage of virus-cell separation. To identify additional WW-domain-bearing host proteins that interact with VP40, we used an EBOV PPxY-containing peptide to screen an array of 115 mammalian WW-domain-bearing proteins. Using this unbiased approach, we identified BCL2 Associated Athanogene 3 (BAG3), a member of the BAG family of molecular chaperone proteins, as a specific VP40 PPxY interactor. Here, we demonstrate that the WW-domain of BAG3 interacts with the PPxY motif of both EBOV and MARV VP40 and, unexpectedly, inhibits budding of both eVP40 and mVP40 virus-like particles (VLPs), as well as infectious VSV-EBOV recombinants. BAG3 is a stress induced protein that regulates cellular protein homeostasis and cell survival through chaperone-mediated autophagy (CMA). Interestingly, our results show that BAG3 alters the intracellular localization of VP40 by sequestering VP40 away from the plasma membrane. As BAG3 is the first WW-domain interactor identified that negatively regulates budding of VP40 VLPs and infectious virus, we propose that the chaperone-mediated autophagy function of BAG3 represents a specific host defense strategy to counteract the function of VP40 in promoting efficient egress and spread of virus particles., Author Summary The unprecedented magnitude and scope of the catastrophic 2014–2015 EBOV outbreak in West Africa, and its continued global emergence underscores the urgent need to better understand the biology and pathogenesis of this zoonotic pathogen. We have identified BAG3 as a novel and functional host VP40 interactor that negatively regulates VP40 VLP and virus egress in a PPxY/WW-domain dependent manner. As a cell survival protein and key regulator of chaperone-mediated autophagy (CMA), BAG3 sequesters EBOV and MARV VP40 away from the site of budding at the plasma membrane, and thus may represent a novel host defense strategy to combat filovirus VP40-mediated egress and spread.
- Published
- 2017