ERα is poly(ADP-ribosy)lated by PARP1.
A, VSMCs were transfected with PARP1 siRNA (50 nm) or unrelated siRNA (50
nm) for 48 h. The poly(ADP-ribosyl)ation levels in VSMCs were determined by Western
blotting with anti-PAR Ab. GAPDH was used for standardization. B, in a cell-free
system, recombinant ERα protein was incubated with vehicles,
PARP1/NAD+/active DNA, or PARP1/NAD+/active DNA/3AB,
respectively. Poly(ADP-ribosyl)ation levels of recombinant ERα were determined by Western
blotting with anti-PAR Ab. Western blotting with anti-ERα Ab showed the loading control. The
results are from three independent experiments. C, VSMCs were treated with
estradiol (E, 10−8, 10−7,
10−6
m, 24 h), or transfected with PARP1 siRNA (50 nm, 48 h) or unrelated siRNA (50
nm, 48 h). Immunoprecipitation (IP) of ERα from VSMCs treated as indicated, followed
by Western blot assay using anti-PAR antibody. D, VSMCs were treated with estradiol
(E, 10−8, 10−7, 10−6
m, 24 h). PARP activity in VSMCs was assayed as described under “Experimental
Procedures.” The results are from six independent experiments. Data are expressed as the mean
± S.E. #, p < 0.05 is for comparison with control group.