The E3 Ubiquitin Ligase Siah-1 Suppresses Avian Reovirus Infection by Targeting p10 for Degradation

Abstract

Avian reovirus (ARV) causes viral arthritis, chronic respiratory diseases, retarded growth, and malabsorption syndrome. The ARV p10 protein, a viroporin responsible for the induction of cell syncytium formation and apoptosis, is rapidly degraded in host cells. Our previous report demonstrated that cellular lysosome-associated membrane protein 1 (LAMP-1) interacted with p10 and was involved in its degradation. However, the molecular mechanism underlying LAMP-1-mediated p10 degradation remains elusive. We report here that the E3 ubiquitin ligase seven in absentia homolog 1 (Siah-1) is critical for p10 ubiquitylation. Our data show that Siah-1 ubiquitylated p10 and targeted it for proteasome degradation. Furthermore, the ubiquitylation of p10 by Siah-1 required the participation of LAMP-1 by forming a multicomponent complex. Thus, LAMP-1 promotes the proteasomal degradation of p10 via interacting with both p10 and the E3 ligase Siah-1. These data establish a novel host defense mechanism where LAMP-1 serves as a scaffold for both Siah-1 and p10 that allows the E3 ligase targeting p10 for ubiquitylation and degradation to suppress ARV infection. Avian reovirus (ARV) is an important poultry pathogen causing viral arthritis, chronic respiratory diseases, retarded growth, and malabsorption syndrome, leading to considerable economic losses to the poultry industry across the globe. The ARV p10 protein is a virulence factor responsible for the induction of cell syncytium formation and apoptosis and is rapidly degraded in host cells. We previously found that cellular lysosome-associated membrane protein 1 (LAMP-1) interacts with p10 and is involved in its degradation. Here we report that the E3 ubiquitin ligase seven in absentia homolog 1 (Siah-1) ubiquitylated p10 and targeted it for proteasomal degradation. Furthermore, the ubiquitylation of p10 by Siah-1 required the participation of LAMP-1 by forming a multicomponent complex. Thus, LAMP-1 serves as an adaptor to allow Siah-1 to target p10 for degradation, thereby suppressing ARV growth in host cells.

De Novo Cholesterol Biosynthesis and Its Trafficking in LAMP-1-Positive Vesicles Are Involved in Replication and Spread of Marek’s Disease Virus

“…RNA interference with LAMP-1 reduced MDV titers and plaque sizes, highlighting the importance of LAMP-1 and MVBs in MDV replication and cell-to-cell spread. It has been suggested that avian LAMP-1 is involved in the degradation of the avian reovirus nonstructural p10 protein, involved in the induction of cell syncytium formation and apoptosis, through interacting with both p10 and the E3 ligase Siah-1 ( 31 , 32 ). We are currently examining whether LAMP-1 is also involved in the degradation of MDV viral proteins, which are required for the generation of infectious cell-free MDV.…”

Real-Time Dissecting the Entry and Intracellular Dynamics of Single Reovirus Particle

“…These results suggested that SMReV particles were sorted through early endosome to late endosome, finally disseminated to lysosome, in which the outer capsids of virus particles were disassembled by proteolytic cleavage. This disassembly may be significant for yielding metastable infectious subviral particle (ISVP) for productive infection (Zhang et al, 2006 ; Mainou and Dermody, 2011 ), otherwise may be due to the novel host defense mechanism of host to suppress virus infection through degradation to lead invalid infection (Chen et al, 2018 ).…”

Susceptibility to South African cassava mosaic virus is Associated with a RING Finger E3 Ubiquitin Ligase

“…The concurrent CRISPR-mediated gene editing of MeE3L and infection with SACMV appears to induce increased expression of the MeE3L, suggesting that the interaction between the virus and MeE3L is based on recognition of the MeE3L's speci c base sequence. Previously, plant E3 ligases have been shown to be induced by viral infection (Lai et al, 2009;Czosnek et al, 2013;Chen et al, 2018) and plant defence elicitors (Libault et al, 2007;Sadanandom et al, 2012). The muted response of the T200 MeE3L to all treatments was expected given its nonsense mutation which silences the RING domain responsible for E3 ligase activity.…”

“…Several viral proteins reportedly hinder E3 ligase function by encoding these E3 ligases in their viral genomes (Lai et al, 2009;Rosa-Diaz et al, 2013;Wang et al, 2013;Chen et al, 2018;Lozano-Duran and Bejarano, 2018). However, a blastn search for MeE3L homologs in the SACMV genome did not return any hits, thus ruling out the possibility that SACMV encodes a protein with E3 ligase activity as a strategy to target host proteins for degradation via the RNA silencing pathway.…”