title: Retromer regulates apical-basal polarity through recycling Crumbs.
abstract: Epithelial cells are characterized by an "apical-basal" polarization. The transmembrane protein Crumbs (Crb) is an essential apical determinant which confers apical membrane identity. Previous studies indicated that Crb did not constantly reside on the apical membrane, but was actively recycled. However, the cellular mechanism(s) underlying this process was unclear. Here we showed that in Drosophila, retromer, which was a retrograde complex recycling certain transmembrane proteins from endosomes to trans-Golgi network (TGN), regulated Crb in epithelial cells. In the absence of retromer, Crb was mis-targeted into lysosomes and degraded, causing a disruption of the apical-basal polarity. We further showed that Crb co-localized and interacted with retromer, suggesting that retromer regulated the retrograde recycling of Crb. Our data presented here uncover the role of retromer in regulating apical-basal polarity in epithelial cells and identify retromer as a novel regulator of Crb recycling.
authors.affiliation: Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, and the Graduate Program in Molecular and Developmental Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhou
authors.forename: Yihui
authors.initials: Y
authors.lastname: Wu
authors.forename: Xinhua
authors.initials: X
authors.lastname: Lin
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D016764:Cell Polarity / Q000235:genetics / Q000502:physiology*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004331:Drosophila melanogaster / Q000166:cytology* / Q000196:embryology / Q000235:genetics / Q000502:physiology*; D056827:Endosomal Sorting Complexes Required for Transport / Q000378:metabolism; D004847:Epithelial Cells / Q000502:physiology; D005260:Female; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D009154:Mutation; D055550:Protein Stability; D058305:Sorting Nexins / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; D056827:Endosomal Sorting Complexes Required for Transport; D008565:Membrane Proteins; D058305:Sorting Nexins; D033921:Vesicular Transport Proteins; C527271:Vps35 protein, Drosophila; C064360:crb protein, Drosophila