Physical and functional association of a serine-threonine protein kinase to the cytoplasmic domain of the p80 form of the human tumor necrosis factor receptor in human histiocytic lymphoma U-937 cells.
Tumor necrosis factor (TNF) binds two distinct cell surface receptors designated p60 and p80. Our previous studies indicate that a protein kinase from U-937 cells binds to and phosphorylates the p60 receptor. While the p80 receptor is phosphorylated in vivo, no association of a protein kinase has been described. We employed a fusion protein comprising of glutathione S-transferase and the cytoplasmic domain of the p80 receptor (GST-p80CD) to identify cellular proteins that might associate with this receptor. From 35S- and 32P-labeled cells, a protein of 59 kDa bound specifically to GST-p80CD. In vitro kinase reactions indicated that serine/threonine protein kinase activity associated with GST-p80CD and causes its phosphorylation. Additionally, a 59-kDa phosphoprotein was also identified after kinase reactions of proteins bound to GST-p80CD. This kinase activity required either Mg2+ or Mn2+ for optimal activity, and it phosphorylated myelin basic protein, histone H2B, and also the cytoplasmic domain of the p60 receptor. Treatment of cells with TNF increased the p80 receptor-associated kinase activity by 200%. In summary, our results provide evidence of a novel ligand-activated serine/threonine protein kinase that associates with the cytoplasmic domain of the p80 receptor and causes the phosphorylation of both forms of the TNF receptor. This p80 TNF receptor-associated protein and the associated kinase described here are referred to as p80-TRAP and p80-TRAK, respectively.
Darnay
B G
BG
Department of Clinical Immunology and Biological Therapy, University of Texas M. D. Anderson Cancer Center, Houston 77030.
Reddy
S A
SA
Aggarwal
B B
BB
D001483:Base Sequence; D003593:Cytoplasm / Q000378:metabolism; D017931:DNA Primers; D006801:Humans; D016403:Lymphoma, Large B-Cell, Diffuse; D008969:Molecular Sequence Data; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D018124:Receptors, Tumor Necrosis Factor / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D017931:DNA Primers; D018124:Receptors, Tumor Necrosis Factor; D017346:Protein Serine-Threonine Kinases