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Volume 4

Full article

In silico reconstruction of nutrient-sensing signal transduction pathways in Aspergillus nidulans

Vignesh Muthuvijayan and Mark R. Marten*

University of Maryland, Baltimore County (UMBC), Department of Chemical and Biochemical Engineering, 1000 Hilltop Circle, Baltimore, MD 21250, USA

^* Corresponding author; Phone: +1-410-455 3439; Fax: +1-410-455 1049; Email: marten@umbc.edu


Edited by E. Wingender; received August 05, 2004; revised October 29, 2004; accepted October 31, 2004; published November 12, 2004

Abstract

We report here probable nutrient-sensing signal transduction pathways in Aspergillus nidulans, a model filamentous fungus, based on sequence homology studies with known Saccharomyces cerevisiae and Schizosaccharomyces pombe proteins. Specifically, we identified A. nidulans homologs for yeast proteins involved in (1) filamentation-invasion, (2) cAMP-PKA, (3) pheromone response, (4) cell integrity and (5) TOR signaling pathways. We have also studied autophagy, one of the most important cellular responses regulated by TOR signaling. The Basic Local Alignment Search Tool program "blastp" was used to assess the homology of proteins. We note that by using a highly conservative approach, 70% of the S. cerevisiae signal transduction proteins (107 proteins out of 153 proteins studied) have significant homologs in A. nidulans. Using a slightly less conservative approach, we are able to identify homologs for as high as 91% of the S. cerevisiae signal transduction proteins (139 proteins out of 153 proteins studied). The filamentation-invasion, cell integrity and TOR signaling pathways showed greatest similarity with S. cerevisiae, while the cAMP-PKA and pheromone response pathways showed greater similarity with S. pombe. Based on these results, probable pathways in A. nidulans were constructed using well-established S. cerevisiae and S. pombe models.

Key words: BLAST, signal transduction, bioinformatics, nutrient sensing, Aspergillus nidulans, comparative genomics