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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Aspergillus nidulans protein kinase A plays an important role in cellulase production

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de Assis, Leandro Jose [1] ; Ries, Laure Nicolas Annick [1] ; Savoldi, Marcela [1] ; dos Reis, Thaila Fernanda [1] ; Brown, Neil Andrew [2] ; Goldman, Gustavo Henrique [1]
Número total de Autores: 6
Afiliação do(s) autor(es):
[1] Univ Sao Paulo, Fac Ciencias Farmaceut Ribeirao Preto, Dept Ciencias Farmaceut, BR-14040903 Ribeirao Preto, SP - Brazil
[2] Rothamsted Res, Plant Biol & Crop Sci, Harpenden AL5 2JQ, Herts - England
Número total de Afiliações: 2
Tipo de documento: Artigo Científico
Citações Web of Science: 14
Assunto(s):Aspergillus nidulans   Proteínas quinases   Celulose

Background: The production of bioethanol from lignocellulosic feedstocks is dependent on lignocellulosic biomass degradation by hydrolytic enzymes. The main component of lignocellulose is cellulose and different types of organisms are able to secrete cellulases. The filamentous fungus Aspergillus nidulans serves as a model organism to study cellulase production and the available tools allow exploring more in depth the mechanisms governing cellulase production and carbon catabolite repression. Results: In A. nidulans, microarray data identified the cAMP-dependent protein kinase A (PkaA) as being involved in the transcriptional modulation and the production of lignocellulolytic enzymes in the presence of cellulose. Deletion of pkaA resulted in increased hydrolytic enzyme secretion, but reduced growth in the presence of lignocellulosic components and various other carbon sources. Furthermore, genes involved in fungal development were increased in the Delta pkaA strain, probably leading to the increased hyphal branching as was observed in this strain. This would allow the secretion of higher amounts of proteins. In addition, the expression of SynA, encoding a V-SNARE synaptobrevin protein involved in secretion, was increased in the Delta pkaA mutant. Deletion of pkaA also resulted in the reduced nuclear localization of the carbon catabolite repressor CreA in the presence of glucose and in partial de-repression when grown on cellulose. PkaA is involved in the glucose signaling pathway as the absence of this protein resulted in reduced glucose uptake and lower hexokinase/glucokinase activity, directing the cell to starvation conditions. Genome-wide transcriptomics showed that the expression of genes encoding proteins involved in fatty acid metabolism, mitochondrial function and in the use of cell storages was increased. Conclusions: This study shows that PkaA is involved in hydrolytic enzyme production in A. nidulans. It appears that this protein kinase blocks the glucose pathway, hence forcing the cell to change to starvation conditions, increasing hydrolytic enzyme secretion and inducing the usage of cellular storages. This work uncovered new regulatory avenues governing the tight interplay between the metabolic states of the cell, which are important for the production of hydrolytic enzymes targeting lignocellulosic biomass. Deletion of pkaA resulted in a strain with increased hydrolytic enzyme secretion and reduced biomass formation. (AU)

Processo FAPESP: 14/00789-6 - Caracterização funcional de fosfatases de Aspergillus nidulans envolvidas no metabolismo da glicose
Beneficiário:Leandro Jose de Assis
Linha de fomento: Bolsas no Brasil - Pós-Doutorado