Herpesvirus lytic infection-induced mitophagy via viral interferon regulatory factor 1

Abstract

ABSTRACTViral control of mitochondria via mitophagy has a dampening effect on mitochondrion-mediated innate immune responses. We previously found that human herpesvirus 8 (HHV-8) could activate mitophagy via its lytic gene product vIRF-1 (viral interferon regulatory factor 1). Mechanistically, we previously demonstrated that vIRF-1 interacts with the mitophagic proteins BNIP3L (BCL2 interacting protein 3 like) and TUFM (Tu translation elongation factor, mitochondrial). Despite these significant findings, however, the precise molecular mechanisms underlying vIRF-1-activated mitophagy, particularly with core components of the autophagy machinery, remained to be fully elucidated. We recently reported that vIRF-1 binds preferentially and directly to GABARAPL1 (GABA type A receptor associated protein like 1) in a noncanonical manner, and this interaction is essential for virus-productive replication. Furthermore, we found that BNIP3L is a crucial factor that promotes vIRF-1 oligomerization and associated mitophagy activation, including GABARAPL1 interaction with vIRF-1 and TUFM dimerization. Together, our findings deepen our understanding of lytic infection-induced mitophagy and provide the key protein-protein interactions involved in vIRF-1-mediated mitophagy.Abbreviations: ATG8, autophagy-related gene 8; BNIP3L, BCL2 interacting protein 3 like; HHV-8, human herpesvirus 8; GABARAP, GABA type A receptor associated protein; GABARAPL1, GABARAP-like 1; LC3, microtubule-associated protein 1 light chain 3; LIR, LC3-interacting region; Nix, NIP3-like protein X; TUFM, Tu translation elongation factor, mitochondria; vIRF-1, viral interferon regulatory factor 1; UIM, ubiquitin-interacting motif; VIR, vIRF-1-interacting region.

Keywords

• BNIP3L
• Human herpesvirus 8
• GABARAPL1
• Mitochondria
• Mitophagy
• Nix