Figure 5.

Basal Amounts of Active Lck Are Regulated by Its Own Kinase Activity and Binding to the HsP90-CDC37 Chaperone Complex

(A) Jurkat cells were treated with different concentrations of PP2 or its inactive analog PP3. The amount of pY394-Lck was quantitated by anti-pY416 immunoblotting at the indicated times. Error bars represent standard deviation from three independent experiments.

(B) Jurkat cells were treated with 5 μM Geldanamycin, or DMSO as control, for 3 hr at 37°C. Cell lysates were probed with anti-pY416 and anti-Lck, and GAPDH was used as a loading control. The histogram on the right represents data collected from three independent experiments.

(C) Jurkat cells preincubated with 50 μM PP2 or its inactive analog PP3, or J45 cells, were treated with 5 μM Geldanamycin or DMSO, as in (B). The amount of Lck was determined by anti-Lck immunoblotting and protein loading by GAPDH (not shown). Error bars represent standard deviation from three independent experiments