Diverse Chemical Scaffolds Support Direct Inhibition of the Membrane-bound O-Acyltransferase Porcupine

• Published in: The Journal of biological chemistry 2012-06, Vol.287 (27), p.23246-23254
• Main Authors: Dodge, Michael E., Moon, Jesung, Tuladhar, Rubina, Lu, Jianming, Jacob, Leni S., Zhang, Li-shu, Shi, Heping, Wang, Xiaolei, Moro, Enrico, Mongera, Alessandro, Argenton, Francesco, Karner, Courtney M., Carroll, Thomas J., Chen, Chuo, Amatruda, James F., Lum, Lawrence
• Format: Article
• Language: English
• Subjects: Acyltransferases; Animals; Animals, Genetically Modified; Antineoplastic Agents - pharmacology; beta Catenin - metabolism; Cell Biology; Cell Membrane - enzymology; Chemical Biology; Chlorocebus aethiops; COS Cells; Development; Drug Design; Enzyme Inhibitors - pharmacology; Guided Tissue Regeneration - methods; HEK293 Cells; HeLa Cells; Humans; Kidney - cytology; Kidney - embryology; Kidney - enzymology; Membrane Proteins - antagonists & inhibitors; Membrane Proteins - metabolism; Organ Culture Techniques; Protein Palmitoylation; Signal Transduction; Tissue Scaffolds; Wnt Signaling; Wnt Signaling Pathway - drug effects; Wnt Signaling Pathway - physiology; Zebrafish
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M112.372029

Secreted Wnt proteins constitute one of the largest families of intercellular signaling molecules in vertebrates with essential roles in embryonic development and adult tissue homeostasis. The functional redundancy of Wnt genes and the many forms of cellular responses they elicit, including some utilizing the transcriptional co-activator β-catenin, has limited the ability of classical genetic strategies to uncover their roles in vivo. We had previously identified a chemical compound class termed Inhibitor of Wnt Production (or IWP) that targets Porcupine (Porcn), an acyltransferase catalyzing the addition of fatty acid adducts onto Wnt proteins. Here we demonstrate that diverse chemical structures are able to inhibit Porcn by targeting its putative active site. When deployed in concert with small molecules that modulate the activity of Tankyrase enzymes and glycogen synthase kinase 3 β (GSK3β), additional transducers of Wnt/β-catenin signaling, the IWP compounds reveal an essential role for Wnt protein fatty acylation in eliciting β-catenin-dependent and -independent forms of Wnt signaling during zebrafish development. This collection of small molecules facilitates rapid dissection of Wnt gene function in vivo by limiting the influence of redundant Wnt gene functions on phenotypic outcomes and enables temporal manipulation of Wnt-mediated signaling in vertebrates. Background: The acyltransferase Porcupine (Porcn) is essential for active Wnt ligand production and is chemically tractable. Results: Novel small molecules targeting Porcn enables interrogation of Wnt signaling in vitro and in vivo. Conclusion: Porcn is highly druggable and supports diverse cellular responses in embryonic development and regeneration. Significance: Porcn inhibitors represent versatile chemical probes for Wnt signaling in vivo and are potential anti-cancer therapeutic agents.