Understanding the structure and functional role of the hydrophobin protein RodA from <em>Aspergillus fumigatus</em> — ASN Events
  1. Schedule
  2. Session Ten - Poster Session C including Refreshments
  3. Understanding the structure and functional role of the hydrophobin protein RodA from Aspergillus fumigatus

Understanding the structure and functional role of the hydrophobin protein RodA from Aspergillus fumigatus (#357)

Jennifer I-Chun Lai 1 , Jake A. Campbell 1 , Victor Lo 1 , Ann H. Kwan 1 , Ivan Cheung 1 , Matthew Hampsey 1 , Ariane Pille 2 , Iñaki Guijarro 2 , Margaret Sunde 1
  1. The University of Sydney, Sydney, NSW, Australia
  2. Institut Pasteur, Paris, France

Hydrophobins are small proteins produced by filamentous fungi which self-assemble into amphipathic monolayers at hydrophobic:hydrophilic interfaces. They are characterised by the pattern of eight conserved cysteine residues bridging four disulphide bonds and these proteins play a number of different functional roles, including reducing surface tension, facilitating attachment to surfaces and mediating fungal-host interactions. RodA has been shown to form a robust, protein monolayer on the surface of the Aspergillus fumigatus conidia. This layer provides as a mechanism for evasion of host innate immune response through masking of the pathogen-associated molecular patterns (PAMPs) expressed on the fungal cell wall [1]. RodB is expressed in the mycelium when A. fumigatus is grown under aerial static conditions, such as those in vivo under conditions of invasive aspergillosis [2]. RodA and RodB both form filamentous structures known as rodlets, which share many structural characteristics with amyloid fibrils.

Previous work on a different hydrophobin suggests that only one region of the protein (bound by Cys7-Cys8) is critically involved in hydrophobin self-assembly [3]. However, more recently another region bound by Cys4-Cys5 has emerged as a secondary point of contact for self-assembly of RodA. We have carried out a program of mutagenesis in RodA to identify residues in these two regions, which are critical for self-assembly into rodlets and formation of the amphipathic monolayers. Four single-glycine mutations were successfully produced and compared to the wild-type for changes in kinetics and morphology of self-assembly. In the kinetics assay all mutants displayed a general trend of increase in lag phase, implicating the involvement of these residues in self-assembly. A clear picture of the structure of the monomeric and polymeric forms of this hydrophobin will lead to an understanding of the specific functional roles played by the different hydrophobin proteins in A. fumigatus during normal growth and host infection.

  1. Aimanianda, V., Bayry, J., Bozza, S., Kniemeyer, O,. Perruccio, K., Elluru, S.R., Clavaud, C., Paris, S., Brakhage, A.A., Kaveri, S.V., Romani, L., and Latgé, J.P. (2009) Surface hydrophobin prevents immune recognition of airborne fungal spores. Nature 460, 1117-1121.
  2. Beauvais, A., Schmidt, C., Guadagnini, S., Roux, P., Perret, E., Henry, C., Paris, S., Mallet, A., Prévost, M., and Latgé, J.P. (2007) An extracellular matrix glues together the aerial-grown hyphae of Aspergillus fumigatus. Cellular Microbiology 9, 1588-1600.
  3. Macindoe, I., Kwan A.H., Ren, Q., Morris, V.K., Yang, W., Mackay, J.P., and Sunde, M. (2012) Self-assembly of functional, amphipathic amyloid monolayers by the fungal hydrophobin EAS. Proceedings of the National Academy of Sciences of the United States of America 109, 6951-6956.