Fig 9.

Schematic model for NiV entry, spread, and release and envelope protein distribution in polarized epithelial cells. (A) NiV can enter the epithelium from either the luminal (apical) or basolateral side. (B) Early in infection, viral G and F proteins are localized basolaterally, while the M protein is still localized in the cytoplasm. Basolaterally expressed viral glycoproteins lead to cell-to-cell fusion, facilitating lateral spread of infection. (C) Later in infection, all three envelope proteins (M, G, and F) concentrate at apical plasma membranes, leading to apical virus release. (D) Virus replication and cell-to-cell fusion finally disrupt epithelial cell integrity and allow subsequent spread of apical virus through the partly disrupted epithelial barrier.