Dolata, K. M. | Search bioRxiv

bioRxiv2024

Exploring virus-host interactions through combined proteomic approaches identifies BANF1 as a new essential factor for African Swine Fever Virus.

African swine fever virus (ASFV) causes a highly lethal disease in pigs and represents a significant threat to the global pork industry due to the lack of effective vaccines or treatments. Despite intensive research, many ASFV proteins remain uncharacterized. This study aimed to elucidate the functions of two ASFV proteins, MGF360-21R and A151R, through comprehensive analysis of their interactions with host proteins. Using affinity purification-mass spectrometry and yeast two-hybrid screening approaches, we identified the host protein barrier- to-autointegration factor 1 (BANF1) as a key interactor of both viral proteins. Biochemical and colocalization assays confirmed these interactions and demonstrated that MGF360-21R and A151R expression leads to cytoplasmic relocalization of BANF1. Functionally, BANF1 silencing significantly reduced ASFV replication, indicating its proviral role. Given BANF1s established function in regulating the cGAS/STING-dependent type I interferon (IFN-I) response, we postulated that A151R and MGF360-21R could inhibit this pathway. Using different strategies, we showed that both A151R and MGF360-21R did indeed inhibit IFN-I induction. Generation of ASFV deficient of A151R or MGF360-21R showed that both mutant viruses enhanced the host IFN response in primary porcine macrophages compared to wild-type virus. However, their capacity to inhibit this pathway could occur through mechanisms independent of BANF1. Proteomic analysis of BANF1 interactors during ASFV infection highlighted potentially roles in chromatin remodeling, nuclear transport, and innate immune response pathways. Altogether, our data provide new insights into ASFV-host interactions, identifying BANF1 as an important new host factor required for replication and uncovering novel functions for A151R and MGF360-21R. Author SummaryAfrican swine fever virus (ASFV) is a highly contagious and deadly disease affecting pigs worldwide, for which there are currently no effective vaccines or treatments. Despite extensive research, many ASFV proteins remain poorly understood. Our study investigated two ASFV proteins, MGF360-21R and A151R, to better understand their functions and interactions with host proteins. Using proteomic approaches, we found both these viral proteins interact with a host protein called barrier-to-autointegration factor 1 (BANF1). Importantly, BANF1 silencing significantly reduced ASFV replication, indicating its important role in the viral life cycle. We also showed that MGF360-21R and A151R help the virus evade the immune system by blocking the production of interferons, which are key defensive molecules against viral infections. However, this immune evasion does not seem to depend on their interaction with BANF1. Additionally, our analysis of BANF1s interactions during ASFV infection revealed potential roles in chromatin remodeling, nuclear transport, and the innate immune response. These findings provide new insights into how ASFV interacts with its host and highlight BANF1 as a critical factor in viral replication and immune evasion. Our work contributes to a better understanding of ASFV and could pave the way for developing more effective strategies to fight this virus.

microbiology↗

bioRxiv2022

CP204L Is a Multifunctional Protein of African Swine Fever Virus That Interacts with The VPS39 Subunit of HOPS Complex and Promotes Lysosome Clustering

Virus replication depends on a complex interplay between viral and host proteins. In the case of African swine fever virus (ASFV), a large DNA virus, only few virus-host protein-protein interactions have been identified to date. In this study, we demonstrate that the ASFV protein CP204L directly interacts with the cellular homotypic fusion and protein sorting (HOPS) protein VPS39, blocking its association with the lysosomal HOPS complex, that modulates endolysosomal trafficking and promotes lysosome clustering. Instead, VPS39 is targeted to the sites of virus replication termed virus factories. Furthermore, we show that loss of VPS39 reduces the levels of virus proteins synthesized in the early phase of infection and delays ASFV replication but does not completely inhibit it. Collectively, these results identify a novel virus-host protein interaction that modulates host membrane rearrangement during infection and provide evidence that CP204L is a multifunctional protein engaged in distinct steps of the ASFV life cycle. ImportanceAfrican swine fever virus (ASFV) was first identified over a hundred years ago. Since then, much effort has been made to understand the pathogenesis of ASFV. Yet, the specific roles of many individual ASFV proteins during the infection remain enigmatic. This study provides evidence that CP204L, one of the most abundant ASFV proteins, modulates endosomal trafficking during virus infection. Through direct protein-protein interaction, CP204L prevents the recruitment of VPS39 to the endosomal and lysosomal membranes, resulting in their accumulation. Consequently, CP204L and VPS39 become sequestered to the ASFV replication site. These results uncover a novel function of viral protein CP204L and extend our understanding of complex interaction between virus and host.

microbiology↗