title: Inhibition of protein tyrosine phosphatases causes phosphorylation of tyrosine-331 in the p60 TNF receptor and inactivates the receptor-associated kinase.
abstract: Inhibition of protein tyrosine phosphatases blocks tumor necrosis factor (TNF)-induced growth modulation and NF-kappaB activation, both mediated primarily through the p60 TNF receptor. How inhibition of the phosphatases affects the p60 TNF receptor or the recently described receptor-associated serine/threonine kinase (p60TRAK) is not known. In this report, we show that this inhibition, when induced by pervanadate, caused the tyrosine phosphorylation of the cytoplasmic domain (CD) of the p60 receptor, as revealed by phosphoamino acid analysis. Furthermore, site-directed mutagenesis indicated that pervanadate specifically induced the phosphorylation of tyrosine-331, which is located in the death domain of the TNF receptor, a domain to which p60TRAK binds. This tyrosine residue was also phosphorylated by purified, recombinant pp60Src in vitro. Inhibition of protein tyrosine phosphatases by pervanadate also led to the inactivation of p60TRAK. In contrast, okadaic acid, a specific inhibitor of protein serine/threonine phosphatase, increased p60TRAK activity. Taken together, these results suggest that protein tyrosine phosphatases play an essential role in phosphorylation of the cytoplasmic domain of the TNF receptor and in regulation of the receptor-associated kinase, and this in turn may play a role in TNF-mediated growth modulation and NF-kappaB activation.
authors.affiliation: Department of Molecular Oncology, The University of Texas M.D. Anderson Cancer Center, Houston 77030, USA.
authors.forename: B G
authors.initials: BG
authors.lastname: Darnay
authors.forename: B B
authors.initials: BB
authors.lastname: Aggarwal
mesh_terms: D000595:Amino Acid Sequence; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D003593:Cytoplasm; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D019319:Okadaic Acid / Q000494:pharmacology; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors*; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors*; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000494:pharmacology; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics / Q000378:metabolism*; D047888:Receptors, Tumor Necrosis Factor, Type I; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014443:Tyrosine / Q000378:metabolism*; D014638:Vanadates / Q000494:pharmacology*
chemical_list: D015703:Antigens, CD; D004791:Enzyme Inhibitors; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; D011993:Recombinant Fusion Proteins; D014409:Tumor Necrosis Factor-alpha; C076715:pervanadate; D019319:Okadaic Acid; D014638:Vanadates; D014443:Tyrosine; C094313:p60 tumor necrosis factor receptor-associated kinase; D016392:Proto-Oncogene Proteins pp60(c-src); D017346:Protein Serine-Threonine Kinases; D017027:Protein Tyrosine Phosphatases