Cellulase expression analysis of serine/threonine kinase gene deletion mutants of Neurospora crassa

Abstract:

[Objective] Protein phosphorylation plays an important role in many important cellular processes, such as the extracellular cellulase induction signal sensing and intracellular signal transduction processes in filamentous fungi. The protein phosphorylation is controlled by protein kinases. [Methods] to discover the roles of protein kinases in cellulase induction signaling pathway, we analyzed cellulase expression levels of 61 kinase mutants using 2% crystalline cellulose as the sole carbon source. Compared with the wild type, cellulase productions in 7 mutants were significantly changed. Then, we did the SDS-PAGE analysis and measured the endo-beta-1,4-glucanase activity, beta-glucosidase activity, cellobiohydrolase activity, xylansae activity of these 7 mutants. [Results] We found that extracellular proteins of mutants W14, W38, W87 and W40 increased more than 30%, and their endo-beta-1,4-glucanase activities increased by 62%, 42% and 42% respectively, except for mutant W14. Moreover, the extracellular proteins of mutants W85, W26 and W46 decreased over 50%, and their endo-beta-1,4-glucanase activities were also reduced by 86%, 75% and 84% respectively. [Conclusion] These observations about serine/threonine protein kinase genes in Neurospora crassa could be helpful to better understand the roles of protein kinases in cellulase induction pathway.