title: The SARS coronavirus E protein interacts with PALS1 and alters tight junction formation and epithelial morphogenesis.
abstract: Intercellular tight junctions define epithelial apicobasal polarity and form a physical fence which protects underlying tissues from pathogen invasions. PALS1, a tight junction-associated protein, is a member of the CRUMBS3-PALS1-PATJ polarity complex, which is crucial for the establishment and maintenance of epithelial polarity in mammals. Here we report that the carboxy-terminal domain of the SARS-CoV E small envelope protein (E) binds to human PALS1. Using coimmunoprecipitation and pull-down assays, we show that E interacts with PALS1 in mammalian cells and further demonstrate that the last four carboxy-terminal amino acids of E form a novel PDZ-binding motif that binds to PALS1 PDZ domain. PALS1 redistributes to the ERGIC/Golgi region, where E accumulates, in SARS-CoV-infected Vero E6 cells. Ectopic expression of E in MDCKII epithelial cells significantly alters cyst morphogenesis and, furthermore, delays formation of tight junctions, affects polarity, and modifies the subcellular distribution of PALS1, in a PDZ-binding motif-dependent manner. We speculate that hijacking of PALS1 by SARS-CoV E plays a determinant role in the disruption of the lung epithelium in SARS patients.
authors.affiliation: HKU-Pasteur Research Centre, Pokfulam, Hong Kong SAR China.
authors.forename: Kim-Tat
authors.initials: KT
authors.lastname: Teoh
authors.forename: Yu-Lam
authors.initials: YL
authors.lastname: Siu
authors.forename: Wing-Lim
authors.initials: WL
authors.lastname: Chan
authors.forename: Marc A
authors.initials: MA
authors.lastname: Schlüter
authors.forename: Chia-Jen
authors.initials: CJ
authors.lastname: Liu
authors.forename: J S Malik
authors.initials: JS
authors.lastname: Peiris
authors.forename: Roberto
authors.initials: R
authors.lastname: Bruzzone
authors.forename: Benjamin
authors.initials: B
authors.lastname: Margolis
authors.forename: Béatrice
authors.initials: B
authors.lastname: Nal
mesh_terms: D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D002522:Chlorocebus aethiops; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism* / Q000821:virology; D004848:Epithelium / Q000254:growth & development / Q000378:metabolism; D005982:Glutathione Transferase; D057809:HEK293 Cells; D054884:Host-Pathogen Interactions; D006801:Humans; D015151:Immunoblotting; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D009024:Morphogenesis; D009703:Nucleoside-Phosphate Kinase / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D045473:Severe acute respiratory syndrome-related coronavirus / Q000378:metabolism / Q000502:physiology; D019108:Tight Junctions / Q000378:metabolism* / Q000821:virology; D020798:Two-Hybrid System Techniques; D014709:Vero Cells; D014759:Viral Envelope Proteins / Q000235:genetics / Q000378:metabolism*; D000086082:Viroporin Proteins
chemical_list: C501689:E protein, SARS coronavirus; D008164:Luminescent Proteins; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; D014759:Viral Envelope Proteins; D000086082:Viroporin Proteins; D005982:Glutathione Transferase; D009703:Nucleoside-Phosphate Kinase; C501307:MPP5 protein, human