FIG. 8.

The wild-type and K298R HSF1 rescue the heat shock response equally well in hsf1^−/− MEFs. (A) Gel mobility shift assay (upper panel) was performed on hsf1^−/− MEFs transfected with the wild-type or K298R mutant HSF1 and left untreated (C) or subjected to a 1-h heat shock (HS). The input lysates were resolved by SDS-PAGE and blotted with anti-HSF1 and anti-Hsc70 antibodies (lower panels). (B) hsf1^−/− MEFs were transfected with empty vector (mock) or the wild-type or K298R mutant HSF1 and left untreated (C) or subjected to a 1-h heat shock (HS) or a 1-h heat shock followed by a 3-h recovery (R). Induction of the heat shock response was analyzed by Western blotting with anti-HSF1 and anti-Hsp70 antibodies. Anti-Hsc70 antibodies were used for loading control. Lack of Hsp70 induction in the absence of HSF1 (mock) is shown in the right panel. WT, wild type; WB, Western blot; CHBA, constitutive HSE-binding activity.