Interfacial self-assembly of a hydrophobin into an amphipathic protein membrane mediates fungal attachment to hydrophobic surfaces.

The SC3p hydrophobin of Schizophyllum commune is a small hydrophobic protein (100-101 amino acids with eight cysteine residues) that self-assembles at a water/air interface and coats aerial hyphae with an SDS-insoluble protein membrane, at the outer side highly hydrophobic and with a typical rodlet pattern. SC3p monomers in water also self-assemble at the interfaces between water and oils or hydrophobic solids. These materials are then coated with a 10 nm thick SDS-insoluble assemblage of SC3p making their surfaces hydrophilic. Hyphae of S. commune growing on a Teflon surface became firmly attached and SC3p was shown to be present between the fungal cell wall and the Teflon. Decreased attachment of hyphae to Teflon was observed in strains not expressing SC3, i.e. a strain containing a targeted mutation in this gene and a regulatory mutant thn. These findings indicate that hydrophobins, in addition to forming hydrophobic wall coatings, play a role in adherence of fungal hyphae to hydrophobic surfaces.