Which proteins are produced by high-risk HPV types and are known to disrupt cell cycle regulation?

High-risk types of human papillomavirus (HPV), such as HPV 16 and 18, are known to produce specific oncoproteins that play a critical role in the development of cervical and other anogenital cancers. The oncoproteins E6 and E7 are particularly significant because they target key regulatory proteins involved in cell cycle control.

E6 promotes the degradation of the tumor suppressor protein p53, which is crucial for regulating the cell cycle and inducing apoptosis in response to DNA damage. By degrading p53, E6 allows cells with damaged DNA to continue dividing, leading to genomic instability.

Similarly, E7 interferes with the retinoblastoma (Rb) protein, another important regulatory protein that controls the progression of the cell cycle from the G1 phase to the S phase. E7 binding to Rb disrupts its function, leading to unregulated progression through the cell cycle. This further promotes unchecked cellular proliferation.

These interactions between E6, E7, and essential cell cycle regulatory proteins are central to HPV's ability to induce oncogenesis, making this understanding essential for appreciating the pathophysiology of HPV-related cancers.