Background: Influenza virus NA is transported to the host cell surface. Results: Cdc42 promotes the transport of NA to the plasma membranes, whereas ARHGAP21 inhibits this process. Conclusion: Cdc42 positively and ARHGAP21 negatively regulate NA transport to the cell surface and virus replication. Significance: Identification of host factors involved in regulating NA transport is critical for understanding influenza virus replication. Influenza virus neuraminidase (NA) is transported to the virus assembly site at the plasma membrane and is a major viral envelope component that plays a critical role in the release of progeny virions and in determination of host range restriction. However, little is known about the host factors that are involved in regulating the intracellular and cell surface transport of NA. Here we identified the Cdc42-specific GAP, ARHGAP21 differentially expressed in host cells infected with influenza A virus using cDNA microarray analysis. Furthermore, we have investigated the involvement of Rho family GTPases in NA transport to the cell surface. We found that expression of constitutively active or inactive mutants of RhoA or Rac1 did not significantly affect the amount of NA that reached the cell surface. However, expression of constitutively active Cdc42 or depletion of ARHGAP21 promoted the transport of NA to the plasma membranes. By contrast, cells expressing shRNA targeting Cdc42 or overexpressing ARHGAP21 exhibited a significant decrease in the amount of cell surface-localized NA. Importantly, silencing Cdc42 reduced influenza A virus replication, whereas silencing ARHGAP21 increased the virus replication. Together, our results reveal that ARHGAP21- and Cdc42-based signaling regulates the NA transport and thereby impacts virus replication.
【저자키워드】 Influenza virus, Viral protein, GTPase, Actin, Cdc42, neuraminidase, membrane transport, ARHGAP21, Protein Transport,