Pharmacoproteomics pinpoints HSP70 interaction for correction of the most frequent Wilson disease-causing mutant of ATP7B

• Published in: Proceedings of the National Academy of Sciences - PNAS 2020-12, Vol.117 (51), p.32453-32463
• Main Authors: Concilli, Mafalda, Petruzzelli, Raffaella, Parisi, Silvia, Catalano, Federico, Sirci, Francesco, Napolitano, Francesco, Renda, Mario, Galietta, Luis J. V., Di Bernardo, Diego, Polishchuk, Roman S.
• Format: Article
• Language: English
• Subjects: Baits; Benzimidazoles - chemistry; Benzimidazoles - pharmacology; Bioinformatics; Biological Sciences; Cells, Cultured; Copper; Copper - metabolism; Copper-Transporting ATPases - genetics; Copper-Transporting ATPases - metabolism; Degradation; Domperidone - chemistry; Domperidone - pharmacology; Endoplasmic reticulum; Endoplasmic Reticulum - drug effects; Endoplasmic Reticulum - metabolism; Hep G2 Cells; Hepatocytes - metabolism; Hepatolenticular Degeneration - drug therapy; Hepatolenticular Degeneration - genetics; Hepatolenticular Degeneration - metabolism; Hepatolenticular Degeneration - pathology; HSP70 Heat-Shock Proteins - antagonists & inhibitors; HSP70 Heat-Shock Proteins - metabolism; Hsp70 protein; Humans; Mutants; Mutation; Mutation, Missense; Nipecotic Acids - chemistry; Nipecotic Acids - pharmacology; Protein Transport - drug effects; Protein Transport - genetics; Proteins; Proteomics; Proteomics - methods; Toxicosis; Wilson's disease
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.2006648117

Pathogenic mutations in the copper transporter ATP7B have been hypothesized to affect its protein interaction landscape contributing to loss of function and, thereby, to hepatic copper toxicosis in Wilson disease. Although targeting mutant interactomes was proposed as a therapeutic strategy, druggable interactors for rescue of ATP7B mutants remain elusive. Using proteomics, we found that the frequent H1069Q substitution promotes ATP7B interaction with HSP70, thus accelerating endoplasmic reticulum (ER) degradation of the mutant protein and consequent copper accumulation in hepatic cells. This prompted us to use an HSP70 inhibitor as bait in a bioinformatics search for structurally similar Food and Drug Administration-approved drugs. Among the hits, domperidone emerged as an effective corrector that recovered trafficking and function of ATP7B-H1069Q by impairing its exposure to the HSP70 proteostatic network. Our findings suggest that HSP70-mediated degradation can be safely targeted with domperidone to rescue ER-retained ATP7B mutants and, hence, to counter the onset of Wilson disease.