Molecular basis of the HPV E7-ZER1 axis reveals a ligandable vulnerability in HPV-positive cancers.

Persistent infection with high-risk human papillomaviruses (HPVs), notably HPV-16 and HPV-18, underlies most cervical cancers and many head and neck cancers. Here, we report the structural and functional basis by which the viral oncoprotein E7 hijacks host CRL2ZER1 to degrade retinoblastoma (Rb) protein and drive E2F-dependent proliferation. Crystal structures reveal that the N-terminal MH/N-degron of E7 engages a defined pocket within the armadillo (ARM)-repeat domain of ZER1. Disruption of this interface abolishes E7-ZER1 binding, prevents Rb degradation, silences E2F transcriptional programs, and impairs proliferation of HPV-positive cancer cells. Guided by these insights, we identify a first-in-class small-molecule inhibitor that blocks E7-ZER1 association, restores Rb stability, and selectively suppresses HPV-positive tumor growth in vivo. These results define a viral mimicry mechanism and nominate the ZER1 degron pocket as a ligandable therapeutic target for HPV-driven malignancies, highlighting translational opportunities for targeted therapy.