eLife Assessment
This important paper presents a rigorous and comprehensive deep mutational analysis of the kinase TYK2, revealing how single amino acid substitutions influence protein abundance, signaling activity, and responses to pharmacological inhibitors. By combining high‑quality experimental design with dose‑response signaling assays and multiple inhibitor conditions, the authors generate a robust dataset that identifies variants across all domains of TYK2, including clusters at functionally critical sites and protein-protein interfaces. The study highlights mutations that drive drug resistance or potentiation and shows that reduced TYK2 abundance aligns with protective autoimmune‑associated variants, underscoring the therapeutic relevance of modulating TYK2 stability. Overall, the work provides compelling insights with clear implications for biochemistry, immunology, clinical genetics, and drug discovery.