FIG. 1.

Oligomer formation of onco-Dbl. (A) GST-Dbl forms a stable complex with HA-Dbl expressed in Cos-7 cells. HA-Dbl was transiently expressed in Cos-7 cells for 48 h before cells were lysed and analyzed by GST-glutathione affinity precipitation with GST, GST-Dbl, or GST-N17Cdc42. After three washes with ice-cold cell lysis buffer, the coprecipitates were visualized by anti-HA Western blotting. (B) Oligomerization of onco-Dbl is mediated through direct interaction between Dbl molecules. Purified His₆-Dbl was incubated with glutathione-agarose-immobilized GST, GST-Dbl, or GST-N17Cdc42 for 30 min before separation by centrifugation. The coprecipitates were detected by Western blotting with anti-Dbl antibody. (C) The oligomerization of onco-Dbl occurs in cells. The Flag-tagged onco-Dbl protein was transiently expressed in Cos-7 cells with or without HA-Dbl, and the cell lysates were subjected to anti-Flag immunoprecipitation followed by anti-HA Western blotting.