TABLE 2.

Regulation of JNK activity by Src, Ras, aPKC, and PI3K^a

Treatment	JNK activity (fold stimulation)
PC12 control	1
PC12 + NGF	2.8 ± 0.4
Ras− + NGF	1.5 ± 0.3
Src− + NGF	1.2 ± 0.4
v-Src	4.2 ± 0.6
PC12 + Wort + NGF	1.1 ± 0.3
PC12 + LY + NGF	1.3 ± 0.4
PC12 + CH + NGF	1.1 ± 0.3

^aCell lysates were prepared from the indicated PC12 cell cultures that had been treated with NGF (100 ng/ml) for 15 min. Alternatively, cells were treated with either wortmannin (Wort; 100 nM), LY294002 (LY; 50 μM), or chelerythrine chloride (CH; 6 μM) for 1 h prior to addition of NGF. PC12 cells expressing a temperature-sensitive v-Src were shifted to 37°C for 4 days to activate Src. JNK activity was measured using 400 μg of total protein in an immune complex kinase assay (17) with GST-cJun(1-79) as substrate. Data are means ± standard error of the means of three independent experiments.