title: The proteome and phosphoproteome of Neurospora crassa in response to cellulose, sucrose and carbon starvation.
abstract: Improving cellulolytic enzyme production by plant biomass degrading fungi holds great potential in reducing costs associated with production of next-generation biofuels generated from lignocellulose. How fungi sense cellulosic materials and respond by secreting enzymes has mainly been examined by assessing function of transcriptional regulators and via transcriptional profiling. Here, we obtained global proteomic and phosphoproteomic profiles of the plant biomass degrading filamentous fungus Neurospora crassa grown on different carbon sources, i.e. sucrose, no carbon, and cellulose, by performing isobaric tags for relative and absolute quantification (iTRAQ)-based LC-MS/MS analyses. A comparison between proteomes and transcriptomes under identical carbon conditions suggests that extensive post-transcriptional regulation occurs in N. crassa in response to exposure to cellulosic material. Several hundred amino acid residues with differential phosphorylation levels on crystalline cellulose (Avicel) or carbon-free medium vs sucrose medium were identified, including phosphorylation sites in a major transcriptional activator for cellulase genes, CLR1, as well as a cellobionic acid transporter, CBT1. Mutation of phosphorylation sites on CLR1 did not have a major effect on transactivation of cellulase production, while mutation of phosphorylation sites in CBT1 increased its transporting capacity. Our data provides rich information at both the protein and phosphorylation levels of the early cellular responses to carbon starvation and cellulosic induction and aids in a greater understanding of the underlying post-transcriptional regulatory mechanisms in filamentous fungi.
authors.affiliation: Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Xiong
authors.affiliation: Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA.
authors.forename: Samuel T
authors.initials: ST
authors.lastname: Coradetti
authors.affiliation: California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA.
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.affiliation: Pacific Northwest National Laboratory, Richland, WA, USA.
authors.forename: Marina A
authors.initials: MA
authors.lastname: Gritsenko
authors.affiliation: Pacific Northwest National Laboratory, Richland, WA, USA.
authors.forename: Therese
authors.initials: T
authors.lastname: Clauss
authors.affiliation: Pacific Northwest National Laboratory, Richland, WA, USA.
authors.forename: Vlad
authors.initials: V
authors.lastname: Petyuk
authors.affiliation: Pacific Northwest National Laboratory, Richland, WA, USA.
authors.forename: David
authors.initials: D
authors.lastname: Camp
authors.affiliation: Pacific Northwest National Laboratory, Richland, WA, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Smith
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA; Department of Chemistry, University of California, Berkeley, CA, USA.
authors.forename: Jamie H D
authors.initials: JHD
authors.lastname: Cate
authors.affiliation: Pacific Northwest National Laboratory, Richland, WA, USA.
authors.forename: Feng
authors.initials: F
authors.lastname: Yang
authors.affiliation: Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA. Electronic address: Lglass@berkeley.edu.
authors.forename: N Louise
authors.initials: NL
authors.lastname: Glass
mesh_terms: D002244:Carbon / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism*; D002853:Chromatography, Liquid; D003470:Culture Media / Q000737:chemistry; D005656:Fungal Proteins / Q000032:analysis; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal; D009492:Neurospora crassa / Q000737:chemistry* / Q000378:metabolism*; D010750:Phosphoproteins / Q000032:analysis*; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D020543:Proteome / Q000032:analysis*; D013395:Sucrose / Q000378:metabolism*; D053719:Tandem Mass Spectrometry
chemical_list: D003470:Culture Media; D005656:Fungal Proteins; D010750:Phosphoproteins; D020543:Proteome; D013395:Sucrose; D002244:Carbon; D002482:Cellulose
keywords: Carbon starvation; Cellulase; Neurospora crassa; Phosphoproteome; Plant biomass; Proteome