The SARS Coronavirus E Protein Interacts with PALS1 and Alters Tight Junction Formation and Epithelial Morphogenesis

Teoh, Kim-Tat; Siu, Yu-Lam; Chan, Wing-Lim; Schlüter, Marc A.; Liu, Chia-Jen; Peiris, J. S. Malik; Bruzzone, Roberto; Margolis, Benjamin; Nal, Béatrice

At all time points and for both cell lines, a significant fraction of eGFP-PALS1 was observed at cell–cell contact, although with different patterns, indicating that either the protein had been retained at cell–cell contacts or had trafficked back to these areas after the calcium switch. As expected, HA-E (wt) partially colocalized with the Golgi markers (Figure 8B, white arrows), whereas HA-E (ΔPBM) did not but was present in the apical region of the cytoplasm. In HA-E (wt), but not HA-E (ΔPBM) MDCKII monolayers, round cells that expressed PALS1 in the cytoplasm and had lost structure of polarized cells were observed at all time points, indicating that proper localization of PALS1 and polarity were specifically affected in these cells (Figure 8B, red arrows). Interestingly, these round cells frequently showed a higher expression of E (wt) and a portion of eGFP-PALS1 colocalized with E (Figure 8B, panel e, white arrowhead).