Identification and functional characterization of novel phosphorylation sites in TAK1-binding protein (TAB) 1

• Published in: PloS one Vol. 6; no. 12; p. e29256
• Main Authors: Wolf, Alexander, Beuerlein, Knut, Eckart, Christoph, Weiser, Hendrik, Dickkopf, Beate, Müller, Helmut, Sakurai, Hiroaki, Kracht, Michael
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 22.12.2011; Public Library of Science (PLoS)
• Subjects: Amino Acid Sequence; Amino acids; Anisomycin; Antigens; Apoptosis; Base Sequence; Biology; Calyculin A; Cell Line; Clonal deletion; Cloning; Cytokines; Cytokines - metabolism; Cytoplasm; Cytoplasm - metabolism; DNA Primers; Enzyme-Linked Immunosorbent Assay; Gene expression; Growth factors; Humans; Identification; Immune system; Immunoglobulins; Interleukin 1; Interleukins; Intracellular Signaling Peptides and Proteins - chemistry; Intracellular Signaling Peptides and Proteins - metabolism; Kinases; Localization; MAP kinase; Molecular Sequence Data; Mutation; p38 Mitogen-Activated Protein Kinases - genetics; p38 Mitogen-Activated Protein Kinases - metabolism; Pharmacology; Phosphatases; Phosphorylation; Post-transcription; Protein binding; Protein kinase; Protein kinases; Proteins; Receptors; Reporter gene; RNA Processing, Post-Transcriptional; Rodents; Sequence Homology, Amino Acid; Signal transduction; Sorbitol; Stress, Physiological; TAK1 protein; Toll-like receptors; Tumor necrosis factor; Ubiquitination
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0029256

TAB1 was defined as a regulatory subunit of the protein kinase TAK1, which functions upstream in the pathways activated by interleukin (IL)-1, tumor necrosis factor (TNF), toll-like receptors (TLRs) and stressors. However, TAB1 also functions in the p38 MAPK pathway downstream of TAK1. We identified amino acids (aa) 452/453 and 456/457 of TAB1 as novel sites phosphorylated by TAK1 as well as by p38 MAPK in intact cells as well as in vitro. Serines 452/453 and 456/457 were phosphorylated upon phosphatase blockade by calyculin A, or in response to IL-1 or translational stressors such as anisomycin and sorbitol. Deletion or phospho-mimetic mutations of aa 452-457 of TAB1 retain TAB1 and p38 MAPK in the cytoplasm. The TAB1 mutant lacking aa 452-457 decreases TAB1-dependent phosphorylation of p38 MAPK. It also enhances TAB1-dependent CCL5 secretion in response to IL-1 and increases activity of a post-transcriptional reporter gene, which contains the CCL5 3' untranslated region. These data suggest a complex role of aa 452-457 of TAB1 in controlling p38 MAPK activity and subcellular localization and implicate these residues in TAK1- or p38 MAPK-dependent post-transcriptional control of gene expression.