title: Extracellular proteinase formation in carbon starving Aspergillus nidulans cultures--physiological function and regulation.
abstract: Extracellular proteinase formation in carbon depleted cultures of the model filamentous fungus Aspergillus nidulans was studied to elucidate its regulation and possible physiological function. As demonstrated by gene deletion, culture optimization, microbial physiological and enzymological experiments, the PrtA and PepJ proteinases of A. nidulans did not appear to play a decisive role in the autolytic decomposition of fungal cells under the conditions we tested. However, carbon starvation induced formation of the proteinases observable in autolytic cultures. Similar to other degradative enzymes, production of proteinase was regulated by FluG-BrlA asexual developmental signaling and modulated by PacC-dependent pH-responsive signaling. Under the same carbon starved culture conditions, alterations of CreA, MeaB or heterotrimeric G protein mediated signaling pathways caused less significant changes in the formation of extracellular proteinases. Taken together, these results indicate that while the accumulation of PrtA and PepJ is tightly coupled to the initiation of autolysis, they are not essential for autolytic cell wall degradation in A. nidulans. Thus, as Aspergillus genomes contain a large group of genes encoding proteinases with versatile physiological functions, selective control of proteinase production in fungal cells is needed for the improved industrial use of fungi.
authors.affiliation: Department of Microbial Biotechnology and Cell Biology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary.
authors.forename: Melinda
authors.initials: M
authors.lastname: Szilágyi
authors.forename: Nak-Jung
authors.initials: NJ
authors.lastname: Kwon
authors.forename: Fruzsina
authors.initials: F
authors.lastname: Bakti
authors.forename: Márta
authors.initials: M
authors.lastname: M-Hamvas
authors.forename: Katalin
authors.initials: K
authors.lastname: Jámbrik
authors.forename: HeeSoo
authors.initials: H
authors.lastname: Park
authors.forename: István
authors.initials: I
authors.lastname: Pócsi
authors.forename: Jae-Hyuk
authors.initials: JH
authors.lastname: Yu
authors.forename: Tamás
authors.initials: T
authors.lastname: Emri
mesh_terms: D001233:Aspergillus nidulans / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D001329:Autolysis; D002244:Carbon / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D010447:Peptide Hydrolases / Q000378:metabolism*
chemical_list: D003470:Culture Media; D002244:Carbon; D010447:Peptide Hydrolases