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

Autor: Alexander Wolf, Knut Beuerlein, Christoph Eckart, Hendrik Weiser, Beate Dickkopf, Helmut Müller, Hiroaki Sakurai, Michael Kracht
Jazyk: angličtina
Rok vydání: 2011
Předmět:
Zdroj: PLoS ONE, Vol 6, Iss 12, p e29256 (2011)
Druh dokumentu: article
ISSN: 1932-6203
DOI: 10.1371/journal.pone.0029256
Popis: 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.
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