Figure 15. BAG3 is essential for drug-induced degradation of GRP78. (A–C) HCN2 cells were transfected with a scrambled siRNA or with an siRNA to knock down BAG3 expression. After 24h, cells were treated with vehicle control, AR12 (2 μM), neratinib (50 nM) or the drugs in combination for 6h. Cells were fixed in place and immunostaining performed to determine the expression of GRP78 (total and cell surface), HDAC6, HSP90, p62, LAMP2, PERK, P-PERK T980, eIF2α and P-eIF2α S51 and ERK2. (n = 3 +/-SD) * p < 0.05 less than vehicle control; ** p < 0.05 less than corresponding AR12 value; # p < 0.05 greater than vehicle control.