Chimaeric HPV E6 proteins allow dissection of the proteolytic pathways regulating different E6 cellular target...

Area of Science:

• Oncology
• Virology
• Molecular Biology

Background:

• The malignant potential of HPV E6 oncoproteins is linked to their capacity to degrade PDZ domain-containing MAGUK proteins.
• Previous research demonstrated that HPV-6 E6, when engineered with the PDZ-binding domain of HPV-18 E6, could target the Discs Large (Dlg) tumor suppressor for degradation.

Purpose of the Study:

• To investigate the degradation capabilities of E6 proteins from various papillomavirus types against MAGUK proteins.
• To compare the degradation activity of E6 proteins from mucosal versus cutaneous HPV types.

Main Methods:

• Chimeric E6 proteins were engineered by appending PDZ-binding sequences to E6 proteins from low-risk mucosal, and low and high-risk cutaneous HPV types.
• The ability of these chimeric E6 proteins to bind and induce the degradation of Discs Large (Dlg) and MAGI-1 was assessed.

Main Results:

• Chimeric E6 proteins from low-risk mucosal HPV types could degrade Dlg but not MAGI-1.
• E6 proteins from cutaneous HPV types, even when engineered with a PDZ-binding domain, failed to significantly degrade either Dlg or MAGI-1.
• Significant differences were observed in the degradation activities between mucosal and cutaneous HPV E6 proteins.

Conclusions:

• HPV E6 proteins exhibit distinct degradation profiles for MAGUK proteins (Dlg and MAGI-1) depending on their origin (mucosal vs. cutaneous).
• The pathways mediating Dlg and MAGI-1 degradation by HPV E6 proteins differ significantly.