The role of protein kinases in Aspergillus fumigatus hypoxia adaptation and virulence

Ref ID: 19536

Author:

SR Beattie1*, C Harty-French1, L Losada2, W Nierman2, RA Cramer1

Author address:

1Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH,
USA
2J. Craig Venter Institute, Rockville, MD, USA

Full conference title:

6th Advances Against Aspergillosis 2014

Abstract:

Purpose:
Fungi encounter a broad range of conditions in their natural environment as well as in a host during
infection. The ability to adapt to a variety of conditions has contributed to the ubiquitous nature
of Aspergillus fumigatus in the environment and to the success of this fungus as a pathogen. One
condition that Aspergillus faces in the environment and within the host is rapidly changing oxygen
tension. Recently, it has been shown that fungal lesions in murine lungs are characterized in part
by hypoxic regions (with oxygen tension 8804;1%). Intriguingly, the ability of Aspergillus fumigatus
to cause disease in a murine model of invasive pulmonary aspergillosis depends on the presence
of the master regulator of the hypoxia response, SrbA. Here we aim to identify protein kinases that
are crucial for this adaptation to hypoxia with hopes of identifying fungal-specific kinases that are
required for virulence of Aspergillus fumigatus.
Methods:
We have used two methods to identify candidate protein kinases that are essential for Aspergillus
fumigatus hypoxia adaptation. First, an Aspergillus nidulans kinase deletion collection has been
screened under ambient air (~20% oxygen) and hypoxic (1% oxygen) conditions to find kinases that
are required for growth in hypoxia. Additionally, protein kinases that are transcriptionally induced
in response to hypoxia, based on an RNA-sequencing data set of wild type A. fumigatus shifted from
ambient air to hypoxic conditions, will be chosen as candidates. Null mutants of candidate kinases
identified in these 2 screens will be generated in Aspergillus fumigatus, and growth in hypoxia and
virulence will be assessed.
Results:
Screening of the A. nidulans kinase knockout revealed 10 kinases that have a 20% or greater defect
in hypoxic growth compared to wild type. The kinases identified include: Stk47, PtkA, NikA, SepH,
Ssn3, Plk1, CmkA, MpkA, Snf1 and Stk19. Orthologs of these kinases in Aspergillus fumigatus
are mostly uncharacterized, and generation and characterization of the null mutants is ongoing in
our laboratory. From the RNA-sequencing data set, 23 kinases were identified as being induced in
response to hypoxia. These include many uncharacterized serine/threonine kinases and histidine
kinases, including one putative histidine kinase, AFUB_101210, which is an ortholog of MpkA in
A. nidulans, which was identified in our initial screen.
Conclusions:
Our preliminary results show that promising candidates for kinases required for adaptation to hypoxic
conditions are present in the A. fumigatus genome. In our ongoing work, we hope to characterize
these kinases mutants in Aspergillus fumigatus to better understand their role in this organism
and their relationship to the master hypoxia transcriptional regulator, SrbA. Full characterization
of the protein kinases involved in hypoxia signaling in A. fumigatus is expected to enhance our
understanding of hypoxia’s impact on IPA outcomes.

Abstract Number: 63

Conference Year: 2014

Link to conference website: http://www.AAA2014.org

New link: NULL

Conference abstracts, posters & presentations

Showing 10 posts of 17325 posts found.

  • Title

    Author

    Year

    Number

    Poster