Fig. 2. GroA reduces ErbB2-mediated signaling in vivo through disruption of ErbB2–nucleolin complexes in ErbB2-positive breast tumors.

a Phosphorylation levels of Erk in dissected GFP or NCL tumors were determined by immunostaining using anti-phopsho-Erk antibodies (means ± SE). b Co-immunoprecipitation (co-IP) analysis of ErbB2 and nucleolin in dissected GFP tumors following GroA treatment. Left, representative blots are presented. Right, quantification of the results (means ± SE); ErbB2 background levels, obtained from control pulldowns (right lane), were subtracted from ErbB2 levels, obtained through nucleolin pulldown (left and middle lanes); the resulting ErbB2 protein levels were normalized to nucleolin pulldown levels in each sample. *p < 0.05, ***p < 0.005, n = 5