The Skp2 locus encodes two proteins, Skp2 and Skp2B. The role of Skp2 in the ubiquitin-dependent degradation of key regulators of the retinoblastoma protein pathway has been well established. More recent work from the McCormick's group suggested that Skp2 has an ubiquitin-independent function in the regulation of the p53 pathway. Adding to this observation, we reported that Skp2B also regulates the activity of p53 by degrading a distinct substrate, prohibitin. Since prohibitin has been implicated in the regulation of the Rb pathway, collectively, these observations suggest that Skp2 and Skp2B team up against p53 and Rb.