Meshram, C. D. | Search bioRxiv

bioRxiv2025

Tryptophan-aspartic acid containing peptide analog from coronin 1 inhibits model membrane fusion and enveloped viral infection in cells

Membrane fusion is a crucial step in the infection cycle of an enveloped virus, and the development of fusion inhibitors could lead to broad-spectrum antivirals beyond the one-bug-one-drug paradigm. In our continued effort to design peptide-based fusion inhibitors that block fusion by modulating membrane physical properties rather than targeting viral proteins, we have designed a tryptophan-aspartic acid (WD) containing peptide analog, mGG21, from coronin 1. Coronin 1 has been implicated in preventing the fusion of live mycobacteria containing phagosomes with lysosomes. The mGG-21 displays around 60% inhibition in fusion pore formation (complete fusion) in model membranes by increasing the acyl chain ordering of the membrane, regardless of the cholesterol content of the membrane, unlike previously designed predecessors with 20-30 % inhibition activity. Further, we show that mGG-21 inhibits Influenza and Chikungunya virus infection in cellular models without exerting any toxicity. Taken together, our findings underscore the importance of WD repeats in designing broad-range viral fusion inhibitors.

biophysics↗

bioRxiv2021

NAP1L1 and NAP1L4 binding to Hypervariable Domain of Chikungunya Virus nsP3 Protein is bivalent and requires phosphorylation

Chikungunya virus (CHIKV) is one of the most pathogenic members of the Alphavirus genus in the Togaviridae family. Within the last two decades, CHIKV has expanded its presence to both hemispheres and is currently circulating in both Old and New Worlds. Despite the severity and persistence of the arthritis it causes in humans, no approved vaccines or therapeutic means have been developed for CHIKV infection. Replication of alphaviruses, including CHIKV, is determined not only by their nonstructural proteins, but also by a wide range of host factors, which are indispensable components of viral replication complexes (vRCs). Alphavirus nsP3s contain hypervariable domains (HVDs), which encode multiple motifs that drive recruitment of cell- and virus-specific host proteins into vRCs. Our previous data suggested that NAP1 family members are a group of host factors that may interact with CHIKV nsP3 HVD. In this study, we performed a detailed investigation of the NAP1 function in CHIKV replication in vertebrate cells. Our data demonstrate that i) the NAP1-HVD interactions have strong stimulatory effects on CHIKV replication; ii) both NAP1L1 and NAP1L4 interact with the CHIKV HVD; iii) NAP1 family members interact with two motifs, which are located upstream and downstream of the G3BP-binding motifs of CHIKV HVD; iv) NAP1 proteins interact only with a phosphorylated form of CHIKV HVD and HVD phosphorylation is mediated by CK2 kinase; v) NAP1 and other families of host factors redundantly promote CHIKV replication and their bindings have additive stimulatory effects on viral replication. IMPORTANCECellular proteins play critical roles in the assembly of alphavirus replication complexes (vRCs). Their recruitment is determined by the viral nonstructural protein 3 (nsP3). This protein contains a long, disordered hypervariable domain (HVD), which encodes virus-specific combinations of short linear motifs interacting with host factors during vRC assembly. Our study defined the binding mechanism of NAP1 family members to CHIKV HVD and demonstrated a stimulatory effect of this interaction on viral replication. We showed that interaction with NAP1L1 is mediated by two HVD motifs and requires phosphorylation of HVD by CK2 kinase. Based on the accumulated data, we present a map of the binding motifs of the critical host factors currently known to interact with CHIKV HVD. It can be used to manipulate cell specificity of viral replication and pathogenesis, and to develop a new generation of vaccine candidates.

microbiology↗