title: SARS-CoV accessory protein 7a directly interacts with human LFA-1.
abstract: The SARS-CoV accessory protein 7a is a type I membrane protein with an extracellular domain of 81 amino acid residues. It is described to be expressed during infection and to be a component of the virus particle surface. In this study, we demonstrate that protein 7a binds directly and specifically to human lymphocyte function-associated antigen 1 (LFA-1) on the cell surface of Jurkat cells. The binding is increased upon artificial cell activation with phorbol ester. These observations are confirmed by direct in vitro binding of recombinant protein 7a to the wild type and mutant K287C/K294C I domain showing that the I domain is the 7a binding site in the alpha(L) chain of LFA-1. Consequences of the LFA-1 interaction with 7a are discussed. In particular, our data suggest LFA-1 to be an attachment factor or the receptor for SARS-CoV on human leukocytes.
authors.affiliation: Forschungszentrum Jülich, INB-2, D-52425 Jülich, Germany.
authors.forename: Karen
authors.initials: K
authors.lastname: Hänel
authors.forename: Dieter
authors.initials: D
authors.lastname: Willbold
mesh_terms: D015153:Blotting, Western; D002273:Carcinogens / Q000494:pharmacology; D003001:Cloning, Molecular; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D019169:Jurkat Cells; D016169:Lymphocyte Function-Associated Antigen-1 / Q000737:chemistry*; D009154:Mutation; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D011485:Protein Binding; D011487:Protein Conformation; D011956:Receptors, Cell Surface / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry; D014763:Viral Matrix Proteins / Q000737:chemistry* / Q000235:genetics; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics
chemical_list: D002273:Carcinogens; D016169:Lymphocyte Function-Associated Antigen-1; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; D014763:Viral Matrix Proteins; D014764:Viral Proteins; C488151:sars7a protein, SARS virus; D018799:Intercellular Adhesion Molecule-1; D015240:Phorbol 12,13-Dibutyrate