PRKCA and head and neck squamous cell carcinoma: In head and neck squamous carcinoma (HNSCC), HPV‐induced O‐GlcNAcylation at ULK1 Ser409 antagonises PKCα‐mediated Ser423 phosphorylation, blocks chaperone‐mediated degradation, stabilises ULK1, enhances STX17 binding and ultimately promotes autophagosome–lysosome fusion.75