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

Overview of attention for article published in Biotechnology for Biofuels, December 2015
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Title
Aspergillus nidulans protein kinase A plays an important role in cellulase production
Published in
Biotechnology for Biofuels, December 2015
DOI 10.1186/s13068-015-0401-1
Pubmed ID
Authors

Leandro José de Assis, Laure Nicolas Annick Ries, Marcela Savoldi, Thaila Fernanda dos Reis, Neil Andrew Brown, Gustavo Henrique Goldman

Abstract

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. 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 ΔpkaA 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 ΔpkaA 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. 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.

Mendeley readers

The data shown below were compiled from readership statistics for 38 Mendeley readers of this research output. Click here to see the associated Mendeley record.

Geographical breakdown

Country Count As %
Germany 1 3%
Unknown 37 97%

Demographic breakdown

Readers by professional status Count As %
Researcher 10 26%
Student > Master 7 18%
Student > Ph. D. Student 3 8%
Student > Bachelor 3 8%
Unspecified 3 8%
Other 12 32%
Readers by discipline Count As %
Biochemistry, Genetics and Molecular Biology 13 34%
Agricultural and Biological Sciences 12 32%
Unspecified 5 13%
Chemistry 4 11%
Engineering 2 5%
Other 2 5%