FIG. 5.

Binding and destabilization of p130 in PHKs expressing wild-type or mutated HPV E7 or E7-ER fusion proteins. PHKs were acutely transduced with a retrovirus which expressed the wild-type or mutated E7 (A and B) or E7-ER (C and D) or a control vector (empty or encoding the ER moiety) as indicated. (A and B) Lysates from subconfluent, proliferating PHK cultures (top panels) or 2 mM CaCl₂-treated, confluent cultures (bottom panels) were Western blotted to reveal relative p130 levels. Actin or GAPDH was detected as a loading reference. Cultures in panel B were treated with 250 μM CHX for 6 h prior to harvest. (C and D) Western blot analyses of p130, E7-ER, and actin. The cultures were induced with 5 μM β-estradiol for 24 h prior to harvest and were further treated for 6 h with 250 μM CHX in the absence (top panels) or in the presence (bottom panels) of 50 μM MG132.