Skip to main content
PMC home page
Genetics logoLink to Genetics
. 2001 Feb;157(2):591–600. doi: 10.1093/genetics/157.2.591

Genetic involvement of a cAMP-dependent protein kinase in a G protein signaling pathway regulating morphological and chemical transitions in Aspergillus nidulans.

K Shimizu 1, N P Keller 1
PMCID: PMC1461531  PMID: 11156981

Abstract

In the filamentous fungus Aspergillus nidulans, a heterotrimeric G protein alpha-subunit and an RGS domain protein, encoded by fadA and flbA, respectively, regulate production of the carcinogenic metabolite sterigmatocystin (ST) and asexual spores (i.e., conidia). We investigated the genetic involvement of the cAMP-dependent protein kinase catalytic subunit (PkaA), a potential downstream target of FadA activity, in ST production and conidiation. Relative to wild type, sporulation was decreased in the pkaA overexpression strain but was not totally absent, as occurs in DeltaflbA or fadA(G42R) (fadA-dominant active) strains. Deletion of pkaA resulted in a hyper-conidiating strain with limited radial growth. This phenotype was epistatic to mutation in flbA or fadA; the double mutants DeltapkaA; DeltaflbA and DeltapkaA; fadA(G42R) recovered sporulation and their radial growth was severely restricted. PkaA overexpression also negatively regulated AflR, the ST biosynthesis-specific transcription factor, both transcriptionally and post-transcriptionally. Deletion of pkaA restored ST production in the DeltaflbA background but not in the fadA(G42R) background. These data provide genetic evidence that the FlbA/FadA signaling pathway regulating ST production and morphological development is partially mediated through PkaA.

Full Text

The Full Text of this article is available as a PDF (319.5 KB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Adachi K., Hamer J. E. Divergent cAMP signaling pathways regulate growth and pathogenesis in the rice blast fungus Magnaporthe grisea. Plant Cell. 1998 Aug;10(8):1361–1374. doi: 10.1105/tpc.10.8.1361. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Alspaugh J. A., Perfect J. R., Heitman J. Cryptococcus neoformans mating and virulence are regulated by the G-protein alpha subunit GPA1 and cAMP. Genes Dev. 1997 Dec 1;11(23):3206–3217. doi: 10.1101/gad.11.23.3206. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Banuett F. Signalling in the yeasts: an informational cascade with links to the filamentous fungi. Microbiol Mol Biol Rev. 1998 Jun;62(2):249–274. doi: 10.1128/mmbr.62.2.249-274.1998. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Brown D. W., Yu J. H., Kelkar H. S., Fernandes M., Nesbitt T. C., Keller N. P., Adams T. H., Leonard T. J. Twenty-five coregulated transcripts define a sterigmatocystin gene cluster in Aspergillus nidulans. Proc Natl Acad Sci U S A. 1996 Feb 20;93(4):1418–1422. doi: 10.1073/pnas.93.4.1418. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Butchko R. A., Adams T. H., Keller N. P. Aspergillus nidulans mutants defective in stc gene cluster regulation. Genetics. 1999 Oct;153(2):715–720. doi: 10.1093/genetics/153.2.715. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Chen B., Gao S., Choi G. H., Nuss D. L. Extensive alteration of fungal gene transcript accumulation and elevation of G-protein-regulated cAMP levels by a virulence-attenuating hypovirus. Proc Natl Acad Sci U S A. 1996 Jul 23;93(15):7996–8000. doi: 10.1073/pnas.93.15.7996. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Choi W., Dean R. A. The adenylate cyclase gene MAC1 of Magnaporthe grisea controls appressorium formation and other aspects of growth and development. Plant Cell. 1997 Nov;9(11):1973–1983. doi: 10.1105/tpc.9.11.1973. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. De Vries L., Gist Farquhar M. RGS proteins: more than just GAPs for heterotrimeric G proteins. Trends Cell Biol. 1999 Apr;9(4):138–144. doi: 10.1016/s0962-8924(99)01515-9. [DOI] [PubMed] [Google Scholar]
  9. Dohlman H. G., Thorner J., Caron M. G., Lefkowitz R. J. Model systems for the study of seven-transmembrane-segment receptors. Annu Rev Biochem. 1991;60:653–688. doi: 10.1146/annurev.bi.60.070191.003253. [DOI] [PubMed] [Google Scholar]
  10. Dürrenberger F., Wong K., Kronstad J. W. Identification of a cAMP-dependent protein kinase catalytic subunit required for virulence and morphogenesis in Ustilago maydis. Proc Natl Acad Sci U S A. 1998 May 12;95(10):5684–5689. doi: 10.1073/pnas.95.10.5684. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Etchebehere L. C., Van Bemmelen M. X., Anjard C., Traincard F., Assemat K., Reymond C., Véron M. The catalytic subunit of Dictyostelium cAMP-dependent protein kinase -- role of the N-terminal domain and of the C-terminal residues in catalytic activity and stability. Eur J Biochem. 1997 Sep 15;248(3):820–826. doi: 10.1111/j.1432-1033.1997.t01-2-00820.x. [DOI] [PubMed] [Google Scholar]
  12. Fernandes M., Keller N. P., Adams T. H. Sequence-specific binding by Aspergillus nidulans AflR, a C6 zinc cluster protein regulating mycotoxin biosynthesis. Mol Microbiol. 1998 Jun;28(6):1355–1365. doi: 10.1046/j.1365-2958.1998.00907.x. [DOI] [PubMed] [Google Scholar]
  13. Gold S., Duncan G., Barrett K., Kronstad J. cAMP regulates morphogenesis in the fungal pathogen Ustilago maydis. Genes Dev. 1994 Dec 1;8(23):2805–2816. doi: 10.1101/gad.8.23.2805. [DOI] [PubMed] [Google Scholar]
  14. Hicks J. K., Yu J. H., Keller N. P., Adams T. H. Aspergillus sporulation and mycotoxin production both require inactivation of the FadA G alpha protein-dependent signaling pathway. EMBO J. 1997 Aug 15;16(16):4916–4923. doi: 10.1093/emboj/16.16.4916. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Hunter T., Cooper J. A. Protein-tyrosine kinases. Annu Rev Biochem. 1985;54:897–930. doi: 10.1146/annurev.bi.54.070185.004341. [DOI] [PubMed] [Google Scholar]
  16. Isshiki T., Mochizuki N., Maeda T., Yamamoto M. Characterization of a fission yeast gene, gpa2, that encodes a G alpha subunit involved in the monitoring of nutrition. Genes Dev. 1992 Dec;6(12B):2455–2462. doi: 10.1101/gad.6.12b.2455. [DOI] [PubMed] [Google Scholar]
  17. Ivey F. D., Yang Q., Borkovich K. A. Positive regulation of adenylyl cyclase activity by a galphai homolog in Neurospora crassa. Fungal Genet Biol. 1999 Feb;26(1):48–61. doi: 10.1006/fgbi.1998.1101. [DOI] [PubMed] [Google Scholar]
  18. Korswagen H. C., van der Linden A. M., Plasterk R. H. G protein hyperactivation of the Caenorhabditis elegans adenylyl cyclase SGS-1 induces neuronal degeneration. EMBO J. 1998 Sep 1;17(17):5059–5065. doi: 10.1093/emboj/17.17.5059. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Kronstad J., De Maria A. D., Funnell D., Laidlaw R. D., Lee N., de Sá M. M., Ramesh M. Signaling via cAMP in fungi: interconnections with mitogen-activated protein kinase pathways. Arch Microbiol. 1998 Nov;170(6):395–404. doi: 10.1007/s002030050659. [DOI] [PubMed] [Google Scholar]
  20. Krüger J., Loubradou G., Regenfelder E., Hartmann A., Kahmann R. Crosstalk between cAMP and pheromone signalling pathways in Ustilago maydis. Mol Gen Genet. 1998 Nov;260(2-3):193–198. doi: 10.1007/s004380050885. [DOI] [PubMed] [Google Scholar]
  21. Lee B. N., Adams T. H. Overexpression of flbA, an early regulator of Aspergillus asexual sporulation, leads to activation of brlA and premature initiation of development. Mol Microbiol. 1994 Oct;14(2):323–334. doi: 10.1111/j.1365-2958.1994.tb01293.x. [DOI] [PubMed] [Google Scholar]
  22. Mitchell T. K., Dean R. A. The cAMP-dependent protein kinase catalytic subunit is required for appressorium formation and pathogenesis by the rice blast pathogen Magnaporthe grisea. Plant Cell. 1995 Nov;7(11):1869–1878. doi: 10.1105/tpc.7.11.1869. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Quan F., Thomas L., Forte M. Drosophila stimulatory G protein alpha subunit activates mammalian adenylyl cyclase but interacts poorly with mammalian receptors: implications for receptor-G protein interaction. Proc Natl Acad Sci U S A. 1991 Mar 1;88(5):1898–1902. doi: 10.1073/pnas.88.5.1898. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Regenfelder E., Spellig T., Hartmann A., Lauenstein S., Bölker M., Kahmann R. G proteins in Ustilago maydis: transmission of multiple signals? EMBO J. 1997 Apr 15;16(8):1934–1942. doi: 10.1093/emboj/16.8.1934. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Robertson L. S., Causton H. C., Young R. A., Fink G. R. The yeast A kinases differentially regulate iron uptake and respiratory function. Proc Natl Acad Sci U S A. 2000 May 23;97(11):5984–5988. doi: 10.1073/pnas.100113397. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Robertson L. S., Fink G. R. The three yeast A kinases have specific signaling functions in pseudohyphal growth. Proc Natl Acad Sci U S A. 1998 Nov 10;95(23):13783–13787. doi: 10.1073/pnas.95.23.13783. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Rosén S., Yu J. H., Adams T. H. The Aspergillus nidulans sfaD gene encodes a G protein beta subunit that is required for normal growth and repression of sporulation. EMBO J. 1999 Oct 15;18(20):5592–5600. doi: 10.1093/emboj/18.20.5592. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Rupp S., Summers E., Lo H. J., Madhani H., Fink G. MAP kinase and cAMP filamentation signaling pathways converge on the unusually large promoter of the yeast FLO11 gene. EMBO J. 1999 Mar 1;18(5):1257–1269. doi: 10.1093/emboj/18.5.1257. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Sanger F., Nicklen S., Coulson A. R. DNA sequencing with chain-terminating inhibitors. Proc Natl Acad Sci U S A. 1977 Dec;74(12):5463–5467. doi: 10.1073/pnas.74.12.5463. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Saviñn-Tejeda A. L., Ongay-Larios L., Ramírez J., Coria R. Isolation of a gene encoding a G protein alpha subunit involved in the regulation of cAMP levels in the yeast Kluyveromyces lactis. Yeast. 1996 Sep 15;12(11):1125–1133. doi: 10.1002/(SICI)1097-0061(19960915)12:11%3C1125::AID-YEA7%3E3.0.CO;2-2. [DOI] [PubMed] [Google Scholar]
  31. Som T., Kolaparthi V. S. Developmental decisions in Aspergillus nidulans are modulated by Ras activity. Mol Cell Biol. 1994 Aug;14(8):5333–5348. doi: 10.1128/mcb.14.8.5333. [DOI] [PMC free article] [PubMed] [Google Scholar]
  32. Toda T., Cameron S., Sass P., Zoller M., Wigler M. Three different genes in S. cerevisiae encode the catalytic subunits of the cAMP-dependent protein kinase. Cell. 1987 Jul 17;50(2):277–287. doi: 10.1016/0092-8674(87)90223-6. [DOI] [PubMed] [Google Scholar]
  33. Yu J. H., Butchko R. A., Fernandes M., Keller N. P., Leonard T. J., Adams T. H. Conservation of structure and function of the aflatoxin regulatory gene aflR from Aspergillus nidulans and A. flavus. Curr Genet. 1996 May;29(6):549–555. doi: 10.1007/BF02426959. [DOI] [PubMed] [Google Scholar]
  34. Yu J. H., Wieser J., Adams T. H. The Aspergillus FlbA RGS domain protein antagonizes G protein signaling to block proliferation and allow development. EMBO J. 1996 Oct 1;15(19):5184–5190. [PMC free article] [PubMed] [Google Scholar]

Articles from Genetics are provided here courtesy of Oxford University Press

RESOURCES