Fig. 5. Securin is ubiquitylated by SCFβTrCP. (A) COS-7 cells were transfected with the indicated plasmids, and treated with LLnL for 4 hours before harvesting. Extracts were prepared as indicated in the Materials and Methods. Proteins were separated by SDS-PAGE, electroblotted and probed with anti-HA and anti-GFP antibodies. (B) Transfected cells were left untreated (C) or irradiated (UV) 1 hour 30 minutes before harvesting.