Fig. 1
TNF70–80 activates p38 via the TNFRI. Neutrophils were treated with the indicated concentrations of either TNF or TNF70–80 and then incubated for 15 min before examining for p38 activation (a) or measuring chemiluminescence (b) over the 45-min period. The TNF70–80 induced chemiluminescence is inhibited by the p38 pharmacological inhibitor, SB203580. The neutrophils were pre-incubated with SB203580 for 10 min before the addition of TNF70–80. c TNF70–80 stimulates p38 activity in 70Z/3 pre-B cells, transfected with hTNFR1 (solid bars). Open bars represent mock-transfected cells. d Inhibition of biotin-labelled TNF70–80 binding to immobilised TNFR1 by unlabelled TNF70–80. e Peptide-TNFR1 binding was conducted as described under 'Methods'. Four-parameter curve fit yielded an IC50 value of 55 μM. (Inset) Lack of binding of scrambled peptide. The scrambled peptide and unlabelled TNF70–80 were both tested at 1 mM in the presence of 10 μM biotinylated TNF70–80. f TNF70–80 (10 μM) stimulated p38 activity in HEK 293T cells stably transfected with either wild-type TNF receptor-associated factor 2 (TRAF2) or an empty vector, but not in those transfected with a dominant-negative TRAF2 (∆TRAF2). Results are mean ± s.e.m. of four experiments. Significance of difference (two-tailed Mann–Whitney U test): *p < 0.05; **p < 0.01, ***p < 0.001
