title: Cargo-selective apical exocytosis in epithelial cells is conducted by Myo5B, Slp4a, Vamp7, and Syntaxin 3.
abstract: Mutations in the motor protein Myosin Vb (Myo5B) or the soluble NSF attachment protein receptor Syntaxin 3 (Stx3) disturb epithelial polarity and cause microvillus inclusion disease (MVID), a lethal hereditary enteropathy affecting neonates. To understand the molecular mechanism of Myo5B and Stx3 interplay, we used genome editing to introduce a defined Myo5B patient mutation in a human epithelial cell line. Our results demonstrate a selective role of Myo5B and Stx3 for apical cargo exocytosis in polarized epithelial cells. Apical exocytosis of NHE3, CFTR (cystic fibrosis transmembrane conductance regulator), and GLUT5 required an interaction cascade of Rab11, Myo5B, Slp4a, Munc18-2, and Vamp7 with Stx3, which cooperate in the final steps of this selective apical traffic pathway. The brush border enzymes DPPIV and sucrase-isomaltase still correctly localize at the apical plasma membrane independent of this pathway. Hence, our work demonstrates how Myo5B, Stx3, Slp4a, Vamp7, Munc18-2, and Rab8/11 cooperate during selective apical cargo trafficking and exocytosis in epithelial cells and thereby provides further insight into MVID pathophysiology.
authors.affiliation: Division of Cell Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria Division of Histology and Embryology, Medical University of Innsbruck, 6020 Innsbruck, Austria.
authors.forename: Georg F
authors.initials: GF
authors.lastname: Vogel
authors.affiliation: Division of Cell Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria Institute of Molecular Biology, University of Innsbruck, 6020 Innsbruck, Austria Center for Molecular Biosciences Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria.
authors.forename: Katharina M C
authors.initials: KM
authors.lastname: Klee
authors.affiliation: Department of Paediatrics I, Medical University of Innsbruck, 6020 Innsbruck, Austria.
authors.forename: Andreas R
authors.initials: AR
authors.lastname: Janecke
authors.affiliation: Department of Paediatrics I, Medical University of Innsbruck, 6020 Innsbruck, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Müller
authors.affiliation: Division of Histology and Embryology, Medical University of Innsbruck, 6020 Innsbruck, Austria lukas.a.huber@i-med.ac.at michael.hess@i-med.ac.at.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Hess
authors.affiliation: Division of Cell Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria lukas.a.huber@i-med.ac.at michael.hess@i-med.ac.at.
authors.forename: Lukas A
authors.initials: LA
authors.lastname: Huber
mesh_terms: D018938:Caco-2 Cells; D002460:Cell Line; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D016764:Cell Polarity / Q000502:physiology; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism* / Q000502:physiology*; D005089:Exocytosis / Q000502:physiology*; D051296:Glucose Transporter Type 5 / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D008286:Malabsorption Syndromes / Q000378:metabolism; D008871:Microvilli / Q000378:metabolism / Q000473:pathology; D009081:Mucolipidoses / Q000378:metabolism; D051938:Munc18 Proteins / Q000378:metabolism; D009154:Mutation / Q000502:physiology; D018995:Myosin Heavy Chains / Q000378:metabolism*; D024701:Myosin Type V / Q000378:metabolism*; D050765:Qa-SNARE Proteins / Q000378:metabolism*; D050683:R-SNARE Proteins / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D000074083:Sodium-Hydrogen Exchanger 3; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000378:metabolism*; D020691:rab GTP-Binding Proteins / Q000378:metabolism; D000099193:rab11 GTP-Binding Proteins
chemical_list: D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D051296:Glucose Transporter Type 5; D051938:Munc18 Proteins; D018995:Myosin Heavy Chains; D024701:Myosin Type V; D050765:Qa-SNARE Proteins; D050683:R-SNARE Proteins; D000074083:Sodium-Hydrogen Exchanger 3; D017923:Sodium-Hydrogen Exchangers; D033921:Vesicular Transport Proteins; D020691:rab GTP-Binding Proteins; D000099193:rab11 GTP-Binding Proteins; C505832:MYO5B protein, human; C495726:SLC2A5 protein, human; C000613385:SLC9A3 protein, human; C512779:SYTL4 protein, human; C121241:VAMP7 protein, human