Membrane binding of zebrafish actinoporin-like protein: AF domains, a novel superfamily of cell membrane binding domains

Ion Gutiérrez-Aguirre , Peter Trontelj , Peter Macek , Jeremy H. Lakey , Gregor Anderluh (1)

1 Department of Biology

Actinoporins are potent eukaryotic pore-forming toxins specific for sphingomyelin-containing membranes. They are structurally similar to members of the fungal fruit-body lectin family that bind cell-surface exposed Thomson-Friedenreich antigen. In this study we found a number of sequences in public databases similar to actinoporins. They originate from three animal and two plant phyla and can be classified in three families according to phylogenetic analysis. The sequence similarity is confined to a region from the C-terminal half of the actinoporin molecule and comprises the membrane binding site with a highly conserved P-[WYF]-D pattern. A member of this novel actinoporin-like protein family from zebrafish was cloned and expressed in E. coli. It displays membrane-binding behaviour, but does not have permeabilising activity nor sphingomyelin specificity, two properties typical of actinoporins. We propose that the three families of actinoporin-like proteins and the fungal fruit body lectin family comprise a novel superfamily of membrane binding proteins, tentatively called AF domains (abbreviated from actinoporin-like proteins and fungal fruit-body lectins).

Mots clés: Life Sciences

Ion Gutiérrez-Aguirre, Peter Trontelj, Peter Macek, Jeremy H. Lakey, Gregor Anderluh. Membrane binding of zebrafish actinoporin-like protein: AF domains, a novel superfamily of cell membrane binding domains. Biochemical Journal, 2006, 398 (3), pp.381-392. ⟨10.1042/BJ20060206⟩. ⟨hal-00478529⟩