title: Changes in Gab2 phosphorylation and interaction partners in response to interleukin (IL)-2 stimulation in T-lymphocytes.
abstract: Interleukin-2 (IL-2) stimulation results in T-cell growth as a consequence of activation of highly sophisticated and fine-tuned signaling pathways. Despite lacking intrinsic enzymatic activity, scaffold proteins such as Gab2, play a pivotal role in IL-2-triggered signal transduction integrating, diversifying and amplifying the signal by serving as a platform for the assembly of effectors proteins. Traditionally, Gab2-mediated protein recruitment was believed to solely depend on cytokine-induced phosphotyrosine moieties. At present, phosphorylation on serine/threonine residues is also emerging as a key mediator of Gab2-dependent signal regulation. Despite its relevance, IL-2-triggered regulation on Gab2 phosphorylation is yet poorly understood. Combining antibody- and TiO2-based enrichment of the scaffold protein with SILAC quantitative mass spectrometry we disclose the prominent regulation IL-2 exerts on Gab2 serine/threonine phosphorylation by showing that at least 18 serines and 1 threonine, including previously non-reported ones, become phosphorylated in response to cytokine stimulation. Additionally, we decipher the interactome of the docking protein in resting and cytokine-treated T-lymphocytes and besides well-known Gab2 interactors we discover three novel cytokine-inducible Gab2-binding proteins. Thus, our data provide novel insights and a wealth of candidates for future studies that will shed light into the role of Gab2 in IL-2-initiated signal transduction.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark.
authors.forename: Nerea
authors.initials: N
authors.lastname: Osinalde
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark.
authors.forename: Virginia
authors.initials: V
authors.lastname: Sánchez-Quiles
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark.
authors.forename: Blagoy
authors.initials: B
authors.lastname: Blagoev
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark.
authors.forename: Irina
authors.initials: I
authors.lastname: Kratchmarova
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D015153:Blotting, Western; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D058543:Class Ia Phosphatidylinositol 3-Kinase; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology*; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11 / Q000235:genetics / Q000378:metabolism; D040901:Proteomics / Q000379:methods; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D013601:T-Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D053719:Tandem Mass Spectrometry
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D058543:Class Ia Phosphatidylinositol 3-Kinase; D004268:DNA-Binding Proteins; D007376:Interleukin-2; D019869:Phosphatidylinositol 3-Kinases; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; C120893:ARID3B protein, human; C490895:GAB2 protein, human; C443673:GAB3 protein, human; C588001:PIK3R1 protein, human; C516724:PTPN11 protein, human