Expression of C/EBPα-ER and mutant variants.

(A) Diagram of C/EBPα-ER (αER), the ER segment alone, and the Leu12Val (L12V), BR3, Δ3-8, and GZ C/EBPα-ER mutant variants. In Leu12Val, the first 2 leucines of the leucine zipper (LZ) are changed to valines (V). In BR3, 4 residues on the basic region (BR) are altered. Δ3-8 deletes C/EBPα's transactivation domains (TAD1, TAD2). In GZ, the GCN4 LZ replaces the C/EBPα LZ. (B) Western blot of PKCδ cell lines stably expressing the indicated proteins. The blot was probed sequentially using an ER antiserum and β-actin antibody.