title: Quantitative Site-Specific Phosphoproteomics of Trichoderma reesei Signaling Pathways upon Induction of Hydrolytic Enzyme Production.
abstract: The filamentous fungus Trichoderma reesei is used for industrial production of secreted enzymes including carbohydrate active enzymes, such as cellulases and hemicellulases. The production of many of these enzymes by T. reesei is influenced by the carbon source it grows on, where the regulation system controlling hydrolase genes involves various signaling pathways. T. reesei was cultivated in the presence of sorbitol, a carbon source that does not induce the production of cellulases and hemicellulases, and then exposed to either sophorose or spent-grain extract, which are efficient inducers of the enzyme production. Specific changes at phosphorylation sites were investigated in relation to the production of cellulases and hemicellulases using an MS-based framework. Proteome-wide phosphorylation following carbon source exchange was investigated in the early stages of induction: 0, 2, 5, and 10 min. The workflow involved sequential trypsin digestion, TiO2 enrichment, and MS analysis using a Q Exactive mass spectrometer. We report on the identification and quantitation of 1721 phosphorylation sites. Investigation of the data revealed a complex signaling network activated upon induction involving components related to light-mediated cellulase induction, osmoregulation, and carbon sensing. Changes in protein phosphorylation were detected in the glycolytic pathway, suggesting an inhibition of glucose catabolism at 10 min after the addition of sophorose and as early as 2 min after the addition of spent-grain extract. Differential phosphorylation of factors related to carbon storage, intracellular trafficking, cytoskeleton, and cellulase gene regulation were also observed.
authors.affiliation: Turku Centre for Biotechnology, University of Turku and Åbo Akademi University , FI-20520 Turku, Finland.|Biochemistry and Molecular Biology, Monash University , 3861 Victoria, Australia.
authors.forename: Elizabeth V
authors.initials: EV
authors.lastname: Nguyen
authors.affiliation: Turku Centre for Biotechnology, University of Turku and Åbo Akademi University , FI-20520 Turku, Finland.|Faculty of Pharmacy, Meijo University , Nagoya 468-8503, Japan.
authors.forename: Susumu Y
authors.initials: SY
authors.lastname: Imanishi
authors.affiliation: Turku Centre for Biotechnology, University of Turku and Åbo Akademi University , FI-20520 Turku, Finland.
authors.forename: Pekka
authors.initials: P
authors.lastname: Haapaniemi
authors.affiliation: Turku Centre for Biotechnology, University of Turku and Åbo Akademi University , FI-20520 Turku, Finland.
authors.forename: Avinash
authors.initials: A
authors.lastname: Yadav
authors.affiliation: VTT Technical Research Centre of Finland Ltd , P.O. Box 1000, FI-02044 VTT, Finland.
authors.forename: Markku
authors.initials: M
authors.lastname: Saloheimo
authors.affiliation: Turku Centre for Biotechnology, University of Turku and Åbo Akademi University , FI-20520 Turku, Finland.
authors.forename: Garry L
authors.initials: GL
authors.lastname: Corthals
authors.affiliation: VTT Technical Research Centre of Finland Ltd , P.O. Box 1000, FI-02044 VTT, Finland.
authors.forename: Tiina M
authors.initials: TM
authors.lastname: Pakula
mesh_terms: D001665:Binding Sites; D044602:Cellulases / Q000378:metabolism; D002853:Chromatography, Liquid; D005656:Fungal Proteins / Q000378:metabolism*; D005936:Glucans / Q000378:metabolism; D006019:Glycolysis; D006026:Glycoside Hydrolases / Q000378:metabolism; D006868:Hydrolysis; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D020543:Proteome / Q000378:metabolism*; D040901:Proteomics / Q000379:methods*; D015398:Signal Transduction; D013012:Sorbitol / Q000378:metabolism; D053719:Tandem Mass Spectrometry; D014242:Trichoderma / Q000378:metabolism*
chemical_list: D005656:Fungal Proteins; D005936:Glucans; D010750:Phosphoproteins; D020543:Proteome; D013012:Sorbitol; D044602:Cellulases; D006026:Glycoside Hydrolases; C023305:hemicellulase; C003328:sophorose
keywords: MS/MS; TiO2; Trichoderma reesei; cellulase; hemicellulase; mass spectrometry; phosphoenrichment; phosphoproteomics; post-translational modification