Fig. 1. CBP mediates the interaction of SRC-1 with HIF-1
. (A) Interaction of HIF-1
with endogenous CBP is dependent on the integrity of both HIF-1
transactivation domains. Cells were transfected with 1 µg pFlag-mHIF-1
(Flag-HIF-1
) or pFlag-mHIF1
(532
583)(L808A/L809A) [Flag-HIF-1
(532
583)LL808AA] and kept at normoxia (N) or treated with 100 µM CoCl2 (C) for 3 hours. 3 mg protein from HEK 293 whole cell extracts was incubated with anti-CBP antibody (
-CBP), and precipitated complexes were separated by SDS-PAGE followed by immunoblotting using anti-CBP and anti-Flag (
-Flag) antibodies. (B) CBP immunodepletion abolishes interaction between HIF-1
and SRC-1. HEK 293 cells were transfected with 1 µg of pFlag-mHIF-1
and kept at normoxia (N) or treated with 100 µM CoCl2 for 3 hours (C). CBP immunodepletion (CBP ID) was performed by incubating whole cell extracts with either IgG (-) or anti-CBP antibodies (+) for 2 hours at room temperature. Following immunodepletion whole cell extracts were recovered and incubated with anti-SRC-1 antibody (
-SRC-1) for an additional 2 hours. Precipitated complexes were separated by SDS-PAGE and analyzed by immunoblotting using anti-Flag, anti-CBP and anti-SRC-1 antibodies. *Non-specific band. Input gels were loaded with 50 µg protein of each whole cell extract.