Table 1.

Cell death and activation of SAPK by TNF and TNF-R1-associated proteins in HeLa cells. For apoptosis assays, HeLa cells were transiently transfected with a β-galactosidase expression vector (pCDNA HislacZ, 1 μg) in the presence or absence of 5 μg of the indicated expression constructs encoding TRAF1, TRAF2, TRAF2(87–501), or FADD(80–205), respectively (5, 9). Forty-eight hours after transfection, the cells were treated with TNF in the presence or absence of ActD as indicated. After 12 hours the cells were fixed and stained with X-Gal. The data are expressed as the mean percentage (±SEM) of blue cells exhibiting signs of apoptosis (that is, intensely staining, shrunken blue cells showing loss of adherence) as a fraction of the total number of cells counted (shown in parentheses) (25). SAPK activation assays were performed as described (14). The data are from three independent experiments.

Expression vectorTreatmentPercent dead cells + SEMSAPK activity
Vector15.3 ± 1.2 (876)1
VectorTNF-α14.6 ± 1.7 (830)4.2 ± 0.5
VectorActD24.5 ± 1.2 (780)0.9 ± 0.2
VectorTNF-α + ActD96.2 ± 0.4 (143)4.5 ± 0.8
TRAF113.8 ± 1.2 (910)0.9 ± 0.3
TRAF212.7 ± 1.1 (935)7.3 ± 1.2
TRAF2(87–501)14.3 ± 1.3 (883)1.3 ± 0.2
TRAF2(87–501)TNF-α41.0 ± 0.8 (462)1.2 ± 0.4
TRAF2(87–501)TNF-α + ActD95.1 ± 0.3 (162)1.1 ± 0.4
FADD(80–205)13.7 ± 1.2 (897)1.2 ± 0.2
FADD(80–205)TNF-α14.2 ± 1.1 (923)4.5 ± 0.4
FADD(80–205)TNF-α + ActD18.3 ± 0.9 (753)4.3 ± 0.5