Rabies virus phosphoprotein P5 binding to BECN1 regulates self-replication by BECN1-mediated autophagy signaling pathway

Juan Liu,Jiyong Zhou,Min Liao,Hailong Wang,Yan Yan,Hui Yang

doi:10.1186/s12964-020-00644-4

Juan Liu, Jiyong Zhou + Show 4 more

Open Access

https://doi.org/10.1186/s12964-020-00644-4

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Abstract

BackgroundRabies virus (RABV) is reported to encode five phosphoproteins (P), which are involved in viral genomic replication, axonal transport, oxidative stress, interferon antagonism, and autophagy induction. However, the functions of the different P proteins are poorly understood.MethodsImmunofluorescence staining and western blot were performed to detect the autophagy activity, the form of ring-like structure, and the colocalization of BECN1 and P. Co-immunoprecipitation was performed to detect the interaction between P and BECN1. QRT-PCR and TCID50 assay were performed to detect the replication level of RABV. Small interfering RNA was used to detect the autophagy signaling pathway.ResultsWe found that P5 attaches to N-terminal residues 1–139 of BECN1 (beclin1) on the BECN1 ring-like structure through amino acid residues 173–222 of P5. Subsequently, we found that P5-induced autophagosomes did not fuse with lysosomes. Becn1 silencing did not recover P5 overexpression-induced promotion of RABV replication. Mechanistically, RABV protein PΔN82 (P5) induced incomplete autophagy via the BECN1-mediated signaling pathway.ConclusionsOur data indicate that P5 binding to the BECN1 ring benefits RABV replication by inducing BECN1 signaling pathway-dependent incomplete autophagy, which provides a potential target for antiviral drugs against RABV.1BoHPEPoc4wqHnwcyFSWMbVideo abstractGraphical abstract

Highlights

Rabies virus (RABV) is reported to encode five phosphoproteins (P), which are involved in viral genomic replication, axonal transport, oxidative stress, interferon antagonism, and autophagy induction
Residues 173–222 of the RABV P protein form an autophagy-inducing domain Our previous report discovers that the RABV P protein induces incomplete autophagy [10], the domain responsible for this incomplete autophagy induction is unknown
Western blotting assay revealed that the level of endogenous LC3-phosphatidylethanolamine conjugate (LC3-II) was dramatically increased in cells transfected with all truncated P mutants except for those transfected with PΔC125 compared with the empty vector transfected cells, and chloroquine (CQ), a lysosomal proteolysis inhibitor, as a control for autophagic flux (Fig. 1b; P < 0.05, P < 0.001)

Summary

Introduction

Rabies virus (RABV) is reported to encode five phosphoproteins (P), which are involved in viral genomic replication, axonal transport, oxidative stress, interferon antagonism, and autophagy induction. Rabies virus (RABV), belonging to the Rhabdoviridae family, is a single nonsegmented negative-stranded RNA virus with genome of 12 kb. The RABV genome encodes a nucleoprotein (N), phosphoprotein (P), matrix protein (M), glycoprotein (G), and RNA polymerase (L) [2]. Liu et al Cell Communication and Signaling (2020) 18:153 which inhibits viral replication [8]. RABV P binding to beclin (BECN1) can induce incomplete autophagy through the caspase (CASP2)-mediated signaling pathways to promote viral genome replication [10]. RABV P protein, via an interferon antagonist interaction with activated STAT3, inhibits membrane glycoprotein 130 (GP130) receptor signaling to generate optimal cellular conditions for viral replication and spread [12]

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