Fig. 4.

E3 down-regulates cytoplasmic and nuclear signaling molecules but not ErbB2 activity in breast tumor cells. Cultures of SKBR3 or MB361 cells were infected with the indicated viruses, and 4 days later, protein lysates were prepared. Fifty micrograms of protein lysates were resolved by SDS/PAGE and transferred onto poly(vinylidene difluoride) membranes. (A) The same membrane was sequentially probed for phospho-ErbB2 (P-ErbB2), ErbB2, and ErbB3. (B) Membranes were probed for phospho-ERK1+2, phospho-PKB, cyclin D3, cyclin A, phospho-pRb, pRb, ERK1+2, and PKB.