FIG. 5.

Human Bag1 and its longer isoforms similarly inhibit Hsp70 chaperone activity. (A) pCytluc together with an empty vector (control) or p29K, p33K, p46K, or p50K (encoding Bag1 isoforms) was transfected into OT70 cells. After induction of Hsp70 expression, cells were treated as described for Fig. 1B. Luciferase activity was measured directly after heat shock at 45°C for 30 min (HT) or after a subsequent incubation at 37°C for 2 h. All data are the averages of three independent experiments; error bars indicate the standard errors of the means. (B) Cells transfected as described above were analyzed for Bag1 and Hsp70 expression by SDS-PAGE and Western blot analysis with monoclonal antibodies to Hsp70 and human Bag1.