Session topic

Title: Deciphering the role of Nicastrin in the assembly/budding of influenza A virus
ID: P 48
Type: ePoster self study
Session: ePoster self study
Assembly, egress and structure

Speaker: Swathi Sukumar (Münster/DE)

Abstract - Text

Abstract text (incl. references and figure legends)

Introduction: Influenza A virus (IAV) continues to pose a huge threat to humans due to its zoonotic potential. The IAV matrix protein 1 (M1) is a highly abundant and conserved protein that regulates the viral replication cycle at several stages mediated by a diverse interplay with host cellular machineries. Identification of potential host factors that interact with M1 might open the door for antiviral interventions to fight the virus and is needed for a better understanding of the virus life cycle. 

Objectives: The aim of the study is to identify the role of Nicastrin, a host cell interaction partner of M1, in the regulation of the IAV life cycle.

Methods: siRNA-mediated knockdown and molecular virology based studies were used to analyse the role of Nicastrin in IAV life cycle regulation including membrane flotation assay, immunoprecipitation, etc,.

Results: In a previous study based on immuno-competitive capture mass spectrometry, we identified cellular protein Nicastrin, an essential component of the gamma secretase complex (GSC), as an interaction partner of M1. The interaction was also confirmed by immunoprecipitation. siRNA-mediated knockdown of Nicastrin induced a significant increase in viral titers by one order of magnitude that was independent of its function in GSC activity as confirmed by using the GSC inhibitor DAPT. Interestingly, there was no effect on viral protein production, indicating a possible role in later stages of the viral replication cycle.  Furthermore, less non-infectious viral particles were produced after infection of Nicastrin knock down cells and the released viral progeny were structurally more stable. Consistently, membrane flotation assay also indicated an increased detergent resistance of viral proteins M1 and HA in detergent resistant membranes in Nicastrin deficient cells.

Conclusions:  Our data suggest antiviral properties of Nicastrin that are independent of its function in the gamma secretase complex. Furthermore, Nicastrin seems to affect influenza virus replication in the assembly/budding stages potentially mediated by its interaction with the viral M1 protein.