| Degradation of B Myb by ubiquitin mediated proteolysis : involvement of the Cdc 34 SCF ( p45Skp2 ) pathway . ^^^ Ectopic expression of either Cdc 34 or the F box protein p45Skp2 , respectively the E 2 and E 3 components of a ubiquitination pathway that regulates the G1 / S transition , accelerates degradation of B Myb . ^^^ |