FIG. 5.

E1B-156R binds to a p53 form. (A) H1299 cells were transfected with plasmids expressing p53 (3 μg pC53-SN3), E1B-55K (7 μg pE1B-55K ΔSD #1415), and E1B-156R (7 μg pE1B-156R #1326), and total cell extracts were prepared. A plus sign indicates the use of a given plasmid in the corresponding lane. p53 and the E1B proteins were detected by immunoblotting. A Western blot assay of β-actin was included as a loading control. (B) The same lysates were used to immunoprecipitate (IP) the E1B proteins with the 2A6 antibody. The proteins could be detected by Western blot assays using 7C11. p53 was specifically coprecipitated with E1B-156R as well as E1B-55K and detected with the FL-393 antibody in Western blot assays.