The present invention relates to the discovery in eukaryotic cells, particularly human cells, of novel protein-protein interactions between certain cellular proteins, referred to herein as "E6AP-binding proteins" or "E6AP-BPs", and the cellular protein E6AP, the latter of which is a component of a ubiquitin-ligase (E3) enzyme. The association of E6AP and the subject E6AP-binding proteins implicates the E6AP-binding proteins in a number of basic cellular functions, such as regulation of gene expression, regulation of the cell-cycle, modification of cell surface receptors, biogenesis of ribosomes, and DNA repair. One of the E6AP-binding proteins shares certain homology with the papillomavirus E6 protein, which also binds E6AP.