TY - JOUR
T1 - Dimerization Controls Marburg Virus VP24-dependent Modulation of Host Antioxidative Stress Responses
AU - Johnson, Britney
AU - Li, Jing
AU - Adhikari, Jagat
AU - Edwards, Megan R.
AU - Zhang, Hao
AU - Schwarz, Toni
AU - Leung, Daisy W.
AU - Basler, Christopher F.
AU - Gross, Michael L.
AU - Amarasinghe, Gaya K.
N1 - Publisher Copyright:
© 2016 Elsevier Ltd
PY - 2016/8/28
Y1 - 2016/8/28
N2 - Marburg virus (MARV), a member of the Filoviridae family that also includes Ebola virus (EBOV), causes lethal hemorrhagic fever with case fatality rates that have exceeded 50% in some outbreaks. Within an infected cell, there are numerous host-viral interactions that contribute to the outcome of infection. Recent studies identified MARV protein 24 (mVP24) as a modulator of the host antioxidative responses, but the molecular mechanism remains unclear. Using a combination of biochemical and mass spectrometry studies, we show that mVP24 is a dimer in solution that directly binds to the Kelch domain of Kelch-like ECH-associated protein 1 (Keap1) to regulate nuclear factor (erythroid-derived 2)-like 2 (Nrf2). This interaction between Keap1 and mVP24 occurs through the Kelch interaction loop (K-Loop) of mVP24 leading to upregulation of antioxidant response element transcription, which is distinct from other Kelch binders that regulate Nrf2 activity. N-terminal truncations disrupt mVP24 dimerization, allowing monomeric mVP24 to bind Kelch with higher affinity and stimulate higher antioxidative stress response element (ARE) reporter activity. Mass spectrometry-based mapping of the interface revealed overlapping binding sites on Kelch for mVP24 and the Nrf2 proteins. Substitution of conserved cysteines, C209 and C210, to alanine in the mVP24 K-Loop abrogates Kelch binding and ARE activation. Our studies identify a shift in the monomer-dimer equilibrium of MARV VP24, driven by its interaction with Keap1 Kelch domain, as a critical determinant that modulates host responses to pathogenic Marburg viral infections.
AB - Marburg virus (MARV), a member of the Filoviridae family that also includes Ebola virus (EBOV), causes lethal hemorrhagic fever with case fatality rates that have exceeded 50% in some outbreaks. Within an infected cell, there are numerous host-viral interactions that contribute to the outcome of infection. Recent studies identified MARV protein 24 (mVP24) as a modulator of the host antioxidative responses, but the molecular mechanism remains unclear. Using a combination of biochemical and mass spectrometry studies, we show that mVP24 is a dimer in solution that directly binds to the Kelch domain of Kelch-like ECH-associated protein 1 (Keap1) to regulate nuclear factor (erythroid-derived 2)-like 2 (Nrf2). This interaction between Keap1 and mVP24 occurs through the Kelch interaction loop (K-Loop) of mVP24 leading to upregulation of antioxidant response element transcription, which is distinct from other Kelch binders that regulate Nrf2 activity. N-terminal truncations disrupt mVP24 dimerization, allowing monomeric mVP24 to bind Kelch with higher affinity and stimulate higher antioxidative stress response element (ARE) reporter activity. Mass spectrometry-based mapping of the interface revealed overlapping binding sites on Kelch for mVP24 and the Nrf2 proteins. Substitution of conserved cysteines, C209 and C210, to alanine in the mVP24 K-Loop abrogates Kelch binding and ARE activation. Our studies identify a shift in the monomer-dimer equilibrium of MARV VP24, driven by its interaction with Keap1 Kelch domain, as a critical determinant that modulates host responses to pathogenic Marburg viral infections.
KW - Marburg virus
KW - VP24
KW - antioxidative stress
KW - hydrogen deuterium exchange mass spectrometry
KW - viral subversion
UR - http://www.scopus.com/inward/record.url?scp=84984580469&partnerID=8YFLogxK
U2 - 10.1016/j.jmb.2016.07.020
DO - 10.1016/j.jmb.2016.07.020
M3 - Article
C2 - 27497688
AN - SCOPUS:84984580469
SN - 0022-2836
VL - 428
SP - 3483
EP - 3494
JO - Journal of Molecular Biology
JF - Journal of Molecular Biology
IS - 17
ER -