View the Current Issue

Article

  • The EMBO Journal (2003) 22, 4646 - 4655
  • doi:10.1093/emboj/cdg449

Crystal structure of the M1 protein-binding domain of the influenza A virus nuclear export protein (NEP/NS2)

Hatice Akarsu1,2,4, Wilhelm P. Burmeister1,2,4, Carlo Petosa1,4, Isabelle Petit1, Christoph W. Müller1, Rob W.H. Ruigrok1,2 and Florence Baudin1,2,3

  1. EMBL Grenoble Outstation, BP 181, 38042 Grenoble cedex 9, France
  2. Laboratoire de Virologie Moléculaire et Structurale, EA 2939,Faculté de Médecine, Université Joseph Fourier, 38706 La Tronche, France
  3. Institut de Biologie Structurale, UMR 5075 CEA-CNRS-UJF, 41 rue Jules Horowitz, 38027 Grenoble cedex 1, France
  4. H.Akarsu, W.P.Burmeister and C.Petosa contributed equally to this work

Correspondence to:

Florence Baudin, E-mail: baudin@embl-grenoble.fr

Received 25 April 2003; Accepted 23 July 2003; Revised 9 July 2003

During influenza virus infection, viral ribonucleoproteins (vRNPs) are replicated in the nucleus and must be exported to the cytoplasm before assembling into mature viral particles. Nuclear export is mediated by the cellular protein Crm1 and putatively by the viral protein NEP/NS2. Proteolytic cleavage of NEP defines an N-terminal domain which mediates RanGTP-dependent binding to Crm1 and a C- terminal domain which binds to the viral matrix protein M1. The 2.6 Å crystal structure of the C-terminal domain reveals an amphipathic helical hairpin which dimerizes as a four-helix bundle. The NEP–M1 interaction involves two critical epitopes: an exposed tryptophan (Trp78) surrounded by a cluster of glutamate residues on NEP, and the basic nuclear localization signal (NLS) of M1. Implications for vRNP export are discussed.

  • Keywords:

    • Crm1 RanGTP,
    • influenza A virus,
    • M1 protein,
    • NEP (NS2) protein,
    • nuclear export