Fungal hydrophobins: Proteins that function at an interface

Hydrophobins are small, moderately hydrophobic proteins secreted by fungi and containing eight cysteine residues in a conserved pattern. Most hydrophobins have been discovered as putative products of genes abundantly expressed in development, pathogenesis and symbiosis. Those that have been purified exhibit interfacial self-assembly into amphipathic protein films that can be extremely insoluble. These protein films arise at the surface of emergent structures, such as aerial hyphae, fruit bodies and air-borne spores and they line air channels in tissues, conferring hydrophobicity to these surfaces. Hydrophobins may also be responsible for adherence of hyphae to each other and to hydrophobic surfaces of other organisms, as in pathogenic interactions.