Aspergillus fumigatus RasA regulates asexual development and cell wall integrity

Jarrod Fortwendel, Kevin K. Fuller, Timothy J. Stephens, W. Clark Bacon, David S. Askew, Judith C. Rhodes

Research output: Contribution to journalArticle

44 Citations (Scopus)

Abstract

The Ras family of proteins is a large group of monomeric GTPases. Members of the fungal Ras family act as molecular switches that transduce signals from the outside of the cell to signaling cascades inside the cell. A. fumigatus RasA is 94% identical to the essential RasA gene of Aspergillus nidulans and is the Ras family member sharing the highest identity to Ras homologs studied in many other fungi. In this study, we report that rasA is not essential in A. fumigatus, but its absence is associated with slowed germination and a severe defect in radial growth. The ΔrasA hyphae were more than two times the diameter of wild-type hyphae, and they displayed repeated changes in the axis of polarity during hyphal growth. The deformed hyphae accumulated numerous nuclei within each hyphal compartment. The ΔrasA mutant conidiated poorly, but this phenotype could be ameliorated by growth on osmotically stabilized media. The ΔrasA mutant also showed increased susceptibility to cell wall stressors, stained more intensely with calcofluor white, and was refractory to lysing enzymes used to make protoplasts, suggesting an alteration of the cell wall. All phenotypes associated with deletion of rasA could be corrected by reinsertion of the wild-type gene. These data demonstrate a crucial role for RasA in both hyphal growth and asexual development in A. fumigatus and provide evidence that RasA function is linked to cell wall integrity.

Original languageEnglish (US)
Pages (from-to)1530-1539
Number of pages10
JournalEukaryotic Cell
Volume7
Issue number9
DOIs
StatePublished - Sep 1 2008

Fingerprint

Aspergillus fumigatus
Hyphae
Cell Wall
hyphae
cell walls
Growth
Phenotype
phenotype
ras Proteins
Aspergillus nidulans
mutants
Protoplasts
GTP Phosphohydrolases
Essential Genes
guanosinetriphosphatase
Germination
Growth and Development
protoplasts
Fungi
genes

All Science Journal Classification (ASJC) codes

  • Microbiology
  • Molecular Biology

Cite this

Fortwendel, J., Fuller, K. K., Stephens, T. J., Bacon, W. C., Askew, D. S., & Rhodes, J. C. (2008). Aspergillus fumigatus RasA regulates asexual development and cell wall integrity. Eukaryotic Cell, 7(9), 1530-1539. https://doi.org/10.1128/EC.00080-08

Aspergillus fumigatus RasA regulates asexual development and cell wall integrity. / Fortwendel, Jarrod; Fuller, Kevin K.; Stephens, Timothy J.; Bacon, W. Clark; Askew, David S.; Rhodes, Judith C.

In: Eukaryotic Cell, Vol. 7, No. 9, 01.09.2008, p. 1530-1539.

Research output: Contribution to journalArticle

Fortwendel, J, Fuller, KK, Stephens, TJ, Bacon, WC, Askew, DS & Rhodes, JC 2008, 'Aspergillus fumigatus RasA regulates asexual development and cell wall integrity', Eukaryotic Cell, vol. 7, no. 9, pp. 1530-1539. https://doi.org/10.1128/EC.00080-08
Fortwendel, Jarrod ; Fuller, Kevin K. ; Stephens, Timothy J. ; Bacon, W. Clark ; Askew, David S. ; Rhodes, Judith C. / Aspergillus fumigatus RasA regulates asexual development and cell wall integrity. In: Eukaryotic Cell. 2008 ; Vol. 7, No. 9. pp. 1530-1539.
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