Cloning and expression of the cDNA for E6-AP, a protein that mediates the interaction of the human papillomavirus E6 oncoprotein with p53.
The E6 oncoproteins of the cancer-associated or high-risk human papillomaviruses (HPVs) target the cellular p53 protein. The association of E6 with p53 leads to the specific ubiquitination and degradation of p53 in vitro, suggesting a model by which E6 deregulates cell growth control by the elimination of the p53 tumor suppressor protein. Complex formation between E6 and p53 requires an additional cellular factor, designated E6-AP (E6-associated protein), which has a native and subunit molecular mass of approximately 100 kDa. Here we report the purification of E6-AP and the cloning of its corresponding cDNA, which contains a novel open reading frame encoding 865 amino acids. E6-AP, translated in vitro, has the following properties: (i) it associates with wild-type p53 in the presence of the HPV16 E6 protein and simultaneously stimulates the association of E6 with p53, (ii) it associates with the high-risk HPV16 and HPV18 E6 proteins in the absence of p53, and (iii) it induces the E6- and ubiquitin-dependent degradation of p53 in vitro.
Laboratory of Tumor Virus Biology, National Cancer Institute, Bethesda, Maryland 20892.
J M
JM
Huibregtse
M
M
Scheffner
P M
PM
Howley
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004279:DNA, Viral; D006801:Humans; D008969:Molecular Sequence Data; D009856:Oncogene Proteins, Viral / Q000378:metabolism*; D027383:Papillomaviridae / Q000235:genetics* / Q000378:metabolism; D014176:Protein Biosynthesis; D051381:Rats; D012097:Repressor Proteins; D017386:Sequence Homology, Amino Acid; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases; D014764:Viral Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism
D004279:DNA, Viral; C068651:E6 protein, Human papillomavirus type 16; D009856:Oncogene Proteins, Viral; D012097:Repressor Proteins; D016159:Tumor Suppressor Protein p53; D014764:Viral Proteins; C471639:UBE3A protein, human; D044767:Ubiquitin-Protein Ligases