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Published December 12, 2022 | Published + Supplemental Material
Journal Article Open

Temporal changes in plasma membrane lipid content induce endocytosis to regulate developmental epithelial-to-mesenchymal transition


Epithelial-to-mesenchymal transition (EMT) is a dramatic change in cellular physiology during development and metastasis, which requires coordination between cell signaling, adhesion, and membrane protrusions. These processes all involve dynamic changes in the plasma membrane; yet, how membrane lipid content regulates membrane function during EMT remains incompletely understood. By screening for differential expression of lipid-modifying genes over the course of EMT in the avian neural crest, we have identified the ceramide-producing enzyme neutral sphingomyelinase 2 (nSMase2) as a critical regulator of a developmental EMT. nSMase2 expression begins at the onset of EMT, and in vivo knockdown experiments demonstrate that nSMase2 is necessary for neural crest migration. We find that nSMase2 promotes Wnt and BMP signaling and is required to activate the mesenchymal gene expression program. Mechanistically, we show that nSMase2-dependent ceramide production is necessary for and sufficient to up-regulate endocytosis and is required for Wnt co-receptor internalization. Finally, inhibition of endocytosis in the neural crest mimics the loss of migration and Wnt signaling observed following nSMase2 knockdown. Our results support a model in which nSMase2 is expressed at the onset of neural crest EMT to produce ceramide and facilitate receptor-mediated endocytosis of Wnt and BMP signaling complexes, thereby activating promigratory gene expression. These results highlight the critical role of plasma membrane lipid metabolism in regulating transcriptional changes during developmental EMT programs.

Additional Information

© 2022 the Author(s). Published by PNAS. This article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND). Funding for this work comes from the NIH grants K99DE029240 to M.L.P., K99DE028592 to E.J.H., R01DE027538 and R01DE027568 to M.E.B., and from the Caltech Summer Undergraduate Research Fellowship (SURF) to C.J.A. Author Contributions. M.L.P. and M.E.B. designed research; M.L.P., E.J.H., and C.J.A. performed research; M.L.P. contributed new reagents/analytic tools; M.L.P., E.J.H., and C.J.A. analyzed data; M.L.P. wrote the manuscript; and E.J.H. and M.E.B. edited the manuscript. Data, Materials, and Software Availability. All study data are included in the main text and/or supporting information. Source data can also be found with data analysis codes on GitHub at https://github.com/PiacentinoLab/2022_PNAS_nSMase2_Endocytosis. The Smpd3 mRNA sequence has been submitted to GenBank (Accession #MW142015). The authors declare no competing interest.

Attached Files

Published - pnas.202212879.pdf

Supplemental Material - pnas.2212879119.sapp.pdf


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August 22, 2023
December 22, 2023