1. SNX3-retromer requires an evolutionary conserved MON2:DOPEY2:ATP9A complex to mediate Wntless sorting and Wnt secretion.
- Author
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McGough IJ, de Groot REA, Jellett AP, Betist MC, Varandas KC, Danson CM, Heesom KJ, Korswagen HC, and Cullen PJ
- Subjects
- Animals, Biological Transport, Caenorhabditis elegans, Green Fluorescent Proteins metabolism, HEK293 Cells, HeLa Cells, Humans, Mutation, Phenotype, Protein Binding, Protein Domains, Proteomics, RNA Interference, Transgenes, Adenosine Triphosphatases metabolism, Endosomes metabolism, Golgi Apparatus metabolism, Membrane Transport Proteins metabolism, Phospholipid Transfer Proteins metabolism, Proton-Translocating ATPases metabolism, Sorting Nexins metabolism, Vesicular Transport Proteins metabolism, Wnt Proteins metabolism
- Abstract
Wntless transports Wnt morphogens to the cell surface and is required for Wnt secretion and morphogenic gradients formation. Recycling of endocytosed Wntless requires the sorting nexin-3 (SNX3)-retromer-dependent endosome-to-Golgi transport pathway. Here we demonstrate the essential role of SNX3-retromer assembly for Wntless transport and report that SNX3 associates with an evolutionary conserved endosome-associated membrane re-modelling complex composed of MON2, DOPEY2 and the putative aminophospholipid translocase, ATP9A. In vivo suppression of Ce-mon-2, Ce-pad-1 or Ce-tat-5 (respective MON2, DOPEY2 and ATP9A orthologues) phenocopy a loss of SNX3-retromer function, leading to enhanced lysosomal degradation of Wntless and a Wnt phenotype. Perturbed Wnt signalling is also observed upon overexpression of an ATPase-inhibited TAT-5(E246Q) mutant, suggesting a role for phospholipid flippase activity during SNX3-retromer-mediated Wntless sorting. Together, these findings provide in vitro and in vivo mechanistic details to describe SNX3-retromer-mediated transport during Wnt secretion and the formation of Wnt-morphogenic gradients.
- Published
- 2018
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