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J Biol Chem. 2018 Mar 2;293(9):3335-3349. doi: 10.1074/jbc.M117.816280. Epub 2018 Jan 18.

A cationic, C-terminal patch and structural rearrangements in Ebola virus matrix VP40 protein control its interactions with phosphatidylserine.

Author information

1
From the Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556.
2
the Department of Physics and.
3
the Department of Immunology and Microbiology and.
4
The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, and.
5
Biomolecular Sciences Institute, Florida International University, Miami, Florida 33199.
6
From the Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, rstaheli@purdue.edu.
7
the Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907.

Abstract

Ebola virus (EBOV) is a filamentous lipid-enveloped virus that causes hemorrhagic fever with a high fatality rate. Viral protein 40 (VP40) is the major EBOV matrix protein and regulates viral budding from the plasma membrane. VP40 is a transformer/morpheein that can structurally rearrange its native homodimer into either a hexameric filament that facilitates viral budding or an RNA-binding octameric ring that regulates viral transcription. VP40 associates with plasma-membrane lipids such as phosphatidylserine (PS), and this association is critical to budding from the host cell. However, it is poorly understood how different VP40 structures interact with PS, what essential residues are involved in this association, and whether VP40 has true selectivity for PS among different glycerophospholipid headgroups. In this study, we used lipid-binding assays, MD simulations, and cellular imaging to investigate the molecular basis of VP40-PS interactions and to determine whether different VP40 structures (i.e. monomer, dimer, and octamer) can interact with PS-containing membranes. Results from quantitative analysis indicated that VP40 associates with PS vesicles via a cationic patch in the C-terminal domain (Lys224, 225 and Lys274, 275). Substitutions of these residues with alanine reduced PS-vesicle binding by >40-fold and abrogated VP40 localization to the plasma membrane. Dimeric VP40 had 2-fold greater affinity for PS-containing membranes than the monomer, whereas binding of the VP40 octameric ring was reduced by nearly 10-fold. Taken together, these results suggest the different VP40 structures known to form in the viral life cycle harbor different affinities for PS-containing membranes.

KEYWORDS:

Ebola virus; VP40; filovirus; lipid-binding protein; oligomerization; phosphatidylserine; plasma membrane; viral budding

PMID:
29348171
PMCID:
PMC5836117
[Available on 2019-03-02]
DOI:
10.1074/jbc.M117.816280
[Indexed for MEDLINE]

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