TABLE II.

Response of System A to Hypertonicity and Amino Acid Starvation in a JNK1 Negative Dominant

	Vector	JNK	APF
No treatment	3.35 ± 0.43	3.76 ± 0.34	3.01 ± 0.28
200 mM sucrose	8.69 ± 0.55***	7.99 ± 0.44***	7.06 ± 0.65**
Amino acid deprivation	6.89 ± 1.14**	7.15 ± 0.92**	3.76 ± 0.67†

CHO-K1 cells were transfected with vector alone (pCDNA3), the wild-type JNK1 (Thr183/Tyr185), and the mutated JNK1 (Ala183/Phe185, APF). Cells were incubated in EMEM (no treatment group) or in EMEM supplemented with 200 mM sucrose or in amino acid–free medium for 12 h and system A transport activity was measured (nmol ala/2 min/mg protein). Results are the mean ± SEM of triplicate measurements made on seven independent cell cultures. Statistical significance using Student's t test: **, P < 0.01; ***, P < 0.001, respectively, versus no treatment; ^†, P < 0.05 versus vector.