HYDROPHOBINS AND REPELLENTS - PROTEINS WITH FUNDAMENTAL ROLES IN FUNGAL MORPHOGENESIS

Fungal hydrophobins are secreted proteins which react to interfaces be tween fungal cell walls and the air or between fungal cell walls and s olid surfaces, They have been shown to be important in many morphogene tic processes, including sporulation, fruit body development, and infe ction structure formation, Hydrophobins form hydrophobic surface layer s by self-assembly of secreted protein monomers in response to the env ironment, This process results in amphipathic polymers of interwoven r odlets on surfaces of fungal aerial structures and hyphal aggregations , Hydrophobin self-assembly is also involved in attachment of hyphae t o hydrophobic surfaces and this may act as a conformational cue for ce rtain developmental processes, Although hydrophobins appear to be ubiq uitous among fungal taxa, a second class of fungal protein with very d ifferent biochemical characteristics could fulfill a similar role, The se proteins, called repellents, have been identified in only one funga l species so far, but clearly help to make aerial hyphae hydrophobic, The functional similarities between hydrophobins and repellents highli ght the importance of aerial development to the fungal lifestyle. (C) 1998 Academic Press.