Human papillomavirus oncoprotein E6 inactivates the transcriptional coactivator human ADA3.
High-risk human papillomaviruses (HPVs) are associated with carcinomas of the cervix and other genital tumors. The HPV oncoprotein E6 is essential for oncogenic transformation. We identify here hADA3, human homologue of the yeast transcriptional coactivator yADA3, as a novel E6-interacting protein and a target of E6-induced degradation. hADA3 binds selectively to the high-risk HPV E6 proteins and only to immortalization-competent E6 mutants. hADA3 functions as a coactivator for p53-mediated transactivation by stabilizing p53 protein. Notably, three immortalizing E6 mutants that do not induce direct p53 degradation but do interact with hADA3 induced the abrogation of p53-mediated transactivation and G(1) cell cycle arrest after DNA damage, comparable to wild-type E6. These findings reveal a novel strategy of HPV E6-induced loss of p53 function that is independent of direct p53 degradation. Given the likely role of the evolutionarily conserved hADA3 in multiple coactivator complexes, inactivation of its function may allow E6 to perturb numerous cellular pathways during HPV oncogenesis.
Kumar
Ajay
A
Division of Radiation and Cancer Biology, Department of Radiation Oncology, New England Medical Center, Boston, Massachusetts 02111, USA.
Zhao
Yongtong
Y
Meng
Gaoyuan
G
Zeng
Musheng
M
Srinivasan
Seetha
S
Delmolino
Laurie M
LM
Gao
Qingshen
Q
Dimri
Goberdhan
G
Weber
Georg F
GF
Wazer
David E
DE
Band
Hamid
H
Band
Vimla
V
D000970:Antineoplastic Agents / Q000494:pharmacology; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D004317:Doxorubicin / Q000494:pharmacology; D017930:Genes, Reporter; D006801:Humans; D009856:Oncogene Proteins, Viral / Q000235:genetics / Q000378:metabolism*; D027383:Papillomaviridae / Q000378:metabolism*; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D014018:Tissue Distribution; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism; D020798:Two-Hybrid System Techniques
D000970:Antineoplastic Agents; C068651:E6 protein, Human papillomavirus type 16; D009856:Oncogene Proteins, Viral; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; C444103:TADA3 protein, human; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D004317:Doxorubicin