Pharmacological inhibition of cell cycle progression (flavopiridol) versus Wlds: opposing changes in cell cycle proteins. (a) Bar chart showing protein expression assayed by quantitative fluorescent western blots in HEK293 cells transfected with Wlds(black bars) or treated with exogenous flavopiridol (10 μmol/l; cell cycle inhibitor). Whereas Wldsinduced increases in all cell cycle proteins, flavopiridol treatment led to decreased expression of the majority of proteins examined. (b) Representative Western blots showing pituitary tumor transforming gene 1 (Pttg1) protein levels in HEK293 cells comparing control versus Wldstransfected cells (top panel) and control versus flavopiridol treated cells (bottom panel). Note how Pttg1 protein levels are increased by Wldsexpression and decreased by flavopiridol treatment.