{"id":{"repo_id":"utswmed","oai_identifier":"oai:utswmed-ir.tdl.org:2152.5/10592"},"canonical_url":"https://search.dev.ndltd.org/etd/utswmed/oai:utswmed-ir.tdl.org:2152.5/10592","repository":{"repo_id":"utswmed","name":"University of Texas Southwestern Medical Center","base_url":"https://utswmed-ir.tdl.org/server/oai/request"},"display":{"title":"Structural Investigations of Porcupine and Dispatched-1 in Wnt and Hedgehog Morphogen Biogenesis","abstract":"Here, I present the cryo-EM studies in two key developmental signaling pathways, Hedgehog (HH) and Wnt signaling pathways. HH signaling is vital for metazoan development, and its ligand is secreted by a cell surface protein named Dispatched-1 (DISP1). I report the cryo-EM structure of the DISP1 in complex with dual lipid-modified HH ligand, suggesting how DISP1 engages with HH ligand. DISP1 contains 12 transmembrane helices and two extracellular domains (ECDs) in an open state, unlike its structural homologues PTCH1 and NPC1, whose extracellular/luminal domains adopt a closed state. Wnt signaling is essential for embryonic development and adult tissue homeostasis, and aberrant Wnt signaling is frequently associated with cancer. Palmitoleoylation on the hairpin 2 motif by the endoplasmic reticulum-resident membrane-bound O-acyltransferase Porcupine (PORCN) is indispensable for Wnt binding to its receptor Frizzled, which triggers signaling. I report four cryo-EM structures of human PORCN: the complex with its substrate palmitoleoyl-coenzyme A, the complex with the PORCN inhibitor LGK974, the ternary complex with LGK974 and WNT3A hairpin 2 (WNT3Ap), and the complex with its product - a synthetic palmitoleoylated WNT3Ap analogue. These structures reveal that hairpin 2 of WNT3A inserts into PORCN from the lumenal side, and the palmitoleoyl-CoA accesses the enzyme from the cytosolic side. The catalytic histidine triggers the transfer of the unsaturated palmitoleoyl group to the target serine on the Wnt hairpin 2, facilitated by the proximity of the two substrates. The inhibitor LGK974 occupies the palmitoleoyl-CoA binding site to prevent the reaction. In summary, my studies provide insights into the structure and function of human DISP1, which is involved in HH signaling, and PORCN, which plays a crucial role in Wnt signaling. These findings shed light on the mechanism of morphogen biogenesis in Hedgehog and Wnt signaling pathways and could pave the way for the development of new therapeutics to target these pathways.","abstract_html":"Here, I present the cryo-EM studies in two key developmental signaling pathways, Hedgehog (HH) and Wnt signaling pathways. HH signaling is vital for metazoan development, and its ligand is secreted by a cell surface protein named Dispatched-1 (DISP1). I report the cryo-EM structure of the DISP1 in complex with dual lipid-modified HH ligand, suggesting how DISP1 engages with HH ligand. DISP1 contains 12 transmembrane helices and two extracellular domains (ECDs) in an open state, unlike its structural homologues PTCH1 and NPC1, whose extracellular/luminal domains adopt a closed state. Wnt signaling is essential for embryonic development and adult tissue homeostasis, and aberrant Wnt signaling is frequently associated with cancer. Palmitoleoylation on the hairpin 2 motif by the endoplasmic reticulum-resident membrane-bound O-acyltransferase Porcupine (PORCN) is indispensable for Wnt binding to its receptor Frizzled, which triggers signaling. I report four cryo-EM structures of human PORCN: the complex with its substrate palmitoleoyl-coenzyme A, the complex with the PORCN inhibitor LGK974, the ternary complex with LGK974 and WNT3A hairpin 2 (WNT3Ap), and the complex with its product - a synthetic palmitoleoylated WNT3Ap analogue. These structures reveal that hairpin 2 of WNT3A inserts into PORCN from the lumenal side, and the palmitoleoyl-CoA accesses the enzyme from the cytosolic side. The catalytic histidine triggers the transfer of the unsaturated palmitoleoyl group to the target serine on the Wnt hairpin 2, facilitated by the proximity of the two substrates. The inhibitor LGK974 occupies the palmitoleoyl-CoA binding site to prevent the reaction. In summary, my studies provide insights into the structure and function of human DISP1, which is involved in HH signaling, and PORCN, which plays a crucial role in Wnt signaling. These findings shed light on the mechanism of morphogen biogenesis in Hedgehog and Wnt signaling pathways and could pave the way for the development of new therapeutics to target these pathways.","abstract_has_math":false,"creators":["Liu, Yang"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Nam, Yunsun","Li, Xiaochun","Radhakrishnan, Arun","Wang, Weiwei"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2025,"date_issued":"2025-06-03T19:48:58Z","date_published":"2025-06-03T19:48:58Z","updated_at":"2026-07-24T05:52:08Z","subjects":["Acyltransferases","Membrane Proteins","Membrane Transport Proteins","Wnt Signaling Pathway"],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["1522122363"],"render_values":[{"text":"1522122363","href":null,"code":true}]}]},"links":{"outbound_url":"https://hdl.handle.net/2152.5/10592","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Nam, Yunsun","Li, Xiaochun","Radhakrishnan, Arun","Wang, Weiwei"]},{"key":"dc:creator","label":"Author","values":["Liu, Yang"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2025-06-03T19:48:58Z","2023-05","May 2023"]},{"key":"dc:type","label":"Dc Type","values":["Thesis","text"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Acyltransferases","Membrane Proteins","Membrane Transport Proteins","Wnt Signaling Pathway"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/2152.5/10592","1522122363"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Here, I present the cryo-EM studies in two key developmental signaling pathways, Hedgehog (HH) and Wnt signaling pathways. HH signaling is vital for metazoan development, and its ligand is secreted by a cell surface protein named Dispatched-1 (DISP1). I report the cryo-EM structure of the DISP1 in complex with dual lipid-modified HH ligand, suggesting how DISP1 engages with HH ligand. DISP1 contains 12 transmembrane helices and two extracellular domains (ECDs) in an open state, unlike its structural homologues PTCH1 and NPC1, whose extracellular/luminal domains adopt a closed state. Wnt signaling is essential for embryonic development and adult tissue homeostasis, and aberrant Wnt signaling is frequently associated with cancer. Palmitoleoylation on the hairpin 2 motif by the endoplasmic reticulum-resident membrane-bound O-acyltransferase Porcupine (PORCN) is indispensable for Wnt binding to its receptor Frizzled, which triggers signaling. I report four cryo-EM structures of human PORCN: the complex with its substrate palmitoleoyl-coenzyme A, the complex with the PORCN inhibitor LGK974, the ternary complex with LGK974 and WNT3A hairpin 2 (WNT3Ap), and the complex with its product - a synthetic palmitoleoylated WNT3Ap analogue. These structures reveal that hairpin 2 of WNT3A inserts into PORCN from the lumenal side, and the palmitoleoyl-CoA accesses the enzyme from the cytosolic side. The catalytic histidine triggers the transfer of the unsaturated palmitoleoyl group to the target serine on the Wnt hairpin 2, facilitated by the proximity of the two substrates. The inhibitor LGK974 occupies the palmitoleoyl-CoA binding site to prevent the reaction. In summary, my studies provide insights into the structure and function of human DISP1, which is involved in HH signaling, and PORCN, which plays a crucial role in Wnt signaling. These findings shed light on the mechanism of morphogen biogenesis in Hedgehog and Wnt signaling pathways and could pave the way for the development of new therapeutics to target these pathways."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Structural Investigations of Porcupine and Dispatched-1 in Wnt and Hedgehog Morphogen Biogenesis"]}]}],"canonical_facts":{"dc:contributor":["Nam, Yunsun","Li, Xiaochun","Radhakrishnan, Arun","Wang, Weiwei"],"dc:creator":["Liu, Yang"],"dc:date":["2025-06-03T19:48:58Z","2023-05","May 2023"],"dc:description":["Here, I present the cryo-EM studies in two key developmental signaling pathways, Hedgehog (HH) and Wnt signaling pathways. HH signaling is vital for metazoan development, and its ligand is secreted by a cell surface protein named Dispatched-1 (DISP1). I report the cryo-EM structure of the DISP1 in complex with dual lipid-modified HH ligand, suggesting how DISP1 engages with HH ligand. DISP1 contains 12 transmembrane helices and two extracellular domains (ECDs) in an open state, unlike its structural homologues PTCH1 and NPC1, whose extracellular/luminal domains adopt a closed state. Wnt signaling is essential for embryonic development and adult tissue homeostasis, and aberrant Wnt signaling is frequently associated with cancer. Palmitoleoylation on the hairpin 2 motif by the endoplasmic reticulum-resident membrane-bound O-acyltransferase Porcupine (PORCN) is indispensable for Wnt binding to its receptor Frizzled, which triggers signaling. I report four cryo-EM structures of human PORCN: the complex with its substrate palmitoleoyl-coenzyme A, the complex with the PORCN inhibitor LGK974, the ternary complex with LGK974 and WNT3A hairpin 2 (WNT3Ap), and the complex with its product - a synthetic palmitoleoylated WNT3Ap analogue. These structures reveal that hairpin 2 of WNT3A inserts into PORCN from the lumenal side, and the palmitoleoyl-CoA accesses the enzyme from the cytosolic side. The catalytic histidine triggers the transfer of the unsaturated palmitoleoyl group to the target serine on the Wnt hairpin 2, facilitated by the proximity of the two substrates. The inhibitor LGK974 occupies the palmitoleoyl-CoA binding site to prevent the reaction. In summary, my studies provide insights into the structure and function of human DISP1, which is involved in HH signaling, and PORCN, which plays a crucial role in Wnt signaling. These findings shed light on the mechanism of morphogen biogenesis in Hedgehog and Wnt signaling pathways and could pave the way for the development of new therapeutics to target these pathways."],"dc:format":["application/pdf"],"dc:identifier":["https://hdl.handle.net/2152.5/10592","1522122363"],"dc:language":["en"],"dc:subject":["Acyltransferases","Membrane Proteins","Membrane Transport Proteins","Wnt Signaling Pathway"],"dc:title":["Structural Investigations of Porcupine and Dispatched-1 in Wnt and Hedgehog Morphogen Biogenesis"],"dc:type":["Thesis","text"]},"updated_at":"2026-07-24T05:52:08Z"}