Figure 8

Increased physical associations between wt-rat c-neu protein and mouse erbB3 by HRG treatment. (a) The indicated breast cancer cells were cultured overnight in medium containing 0.5% FBS, and then incubated with or without 2.5 ng/ml HRG for another 2 h. Cell lysates were prepared and 200 μg of total protein was subjected to immunoprecipitation with anti-erbB2 specific antibody (c-neu Ab-4), followed by Western blot analysis for erbB2 (c-neu Ab-3) and erbB3. The bar graph underneath was obtained by densitometry analysis. The relative signal intensities of erbB3 were measured by EAGLE EYE™ II (Stratagene, La Jolla, CA, USA). (b) The same bath of 50 μg total cell lysates was subjected to Western blot analysis with antibodies directed against erbB2 and erbB3.