title: Phosphoproteome dynamics reveal novel ERK1/2 MAP kinase substrates with broad spectrum of functions.
abstract: The ERK1/2 MAP kinase pathway is an evolutionarily conserved signaling module that controls many fundamental physiological processes. Deregulated activity of ERK1/2 MAP kinases is associated with developmental syndromes and several human diseases. Despite the importance of this pathway, a comprehensive picture of the natural substrate repertoire and biochemical mechanisms regulated by ERK1/2 is still lacking. In this study, we used large-scale quantitative phosphoproteomics and bioinformatics analyses to identify novel candidate ERK1/2 substrates based on their phosphorylation signature and kinetic profiles in epithelial cells. We identified a total of 7936 phosphorylation sites within 1861 proteins, of which 155 classify as candidate ERK1/2 substrates, including 128 new targets. Candidate ERK1/2 substrates are involved in diverse cellular processes including transcriptional regulation, chromatin remodeling, RNA splicing, cytoskeleton dynamics, cellular junctions and cell signaling. Detailed characterization of one newly identified substrate, the transcriptional regulator JunB, revealed that ERK1/2 phosphorylate JunB on a serine adjacent to the DNA-binding domain, resulting in increased DNA-binding affinity and transcriptional activity. Our study expands the spectrum of cellular functions controlled by ERK1/2 kinases.
authors.affiliation: Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, Quebec, Canada.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Courcelles
authors.forename: Christophe
authors.initials: C
authors.lastname: Frémin
authors.forename: Laure
authors.initials: L
authors.lastname: Voisin
authors.forename: Sébastien
authors.initials: S
authors.lastname: Lemieux
authors.forename: Sylvain
authors.initials: S
authors.lastname: Meloche
authors.forename: Pierre
authors.initials: P
authors.lastname: Thibault
mesh_terms: D000818:Animals; D002460:Cell Line; D042002:Chromatin Assembly and Disassembly; D003599:Cytoskeleton / Q000235:genetics / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000201:enzymology*; D005786:Gene Expression Regulation; D006801:Humans; D007365:Intercellular Junctions / Q000235:genetics / Q000378:metabolism; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000378:metabolism*; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D020543:Proteome; D016755:Proto-Oncogene Proteins c-jun / Q000235:genetics / Q000378:metabolism; D012326:RNA Splicing; D051381:Rats; D015398:Signal Transduction; D013045:Species Specificity; D013379:Substrate Specificity; D014158:Transcription, Genetic
chemical_list: D010750:Phosphoproteins; D020543:Proteome; D016755:Proto-Oncogene Proteins c-jun; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3