title: Sequential and compartmentalized action of Rabs, SNAREs, and MAL in the apical delivery of fusiform vesicles in urothelial umbrella cells.
abstract: Uroplakins (UPs) are major differentiation products of urothelial umbrella cells and play important roles in forming the permeability barrier and in the expansion/stabilization of the apical membrane. Further, UPIa serves as a uropathogenic Escherichia coli receptor. Although it is understood that UPs are delivered to the apical membrane via fusiform vesicles (FVs), the mechanisms that regulate this exocytic pathway remain poorly understood. Immunomicroscopy of normal and mutant mouse urothelia show that the UP-delivering FVs contained Rab8/11 and Rab27b/Slac2-a, which mediate apical transport along actin filaments. Subsequently a Rab27b/Slp2-a complex mediated FV-membrane anchorage before SNARE-mediated and MAL-facilitated apical fusion. We also show that keratin 20 (K20), which forms a chicken-wire network ∼200 nm below the apical membrane and has hole sizes allowing FV passage, defines a subapical compartment containing FVs primed and strategically located for fusion. Finally, we show that Rab8/11 and Rab27b function in the same pathway, Rab27b knockout leads to uroplakin and Slp2-a destabilization, and Rab27b works upstream from MAL. These data support a unifying model in which UP cargoes are targeted for apical insertion via sequential interactions with Rabs and their effectors, SNAREs and MAL, and in which K20 plays a key role in regulating vesicular trafficking.
authors.affiliation: Department of Cell Biology, New York University School of Medicine, New York, NY10016.
authors.forename: Bret
authors.initials: B
authors.lastname: Wankel
authors.affiliation: Department of Cell Biology, New York University School of Medicine, New York, NY10016.
authors.forename: Jiangyong
authors.initials: J
authors.lastname: Ouyang
authors.affiliation: Department of Cell Biology, New York University School of Medicine, New York, NY10016.
authors.forename: Xuemei
authors.initials: X
authors.lastname: Guo
authors.affiliation: Department of Cell Biology, New York University School of Medicine, New York, NY10016.
authors.forename: Krassimira
authors.initials: K
authors.lastname: Hadjiolova
authors.affiliation: Department of Cell Biology, New York University School of Medicine, New York, NY10016.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Miller
authors.affiliation: Department of Cell Biology, New York University School of Medicine, New York, NY10016.
authors.forename: Yi
authors.initials: Y
authors.lastname: Liao
authors.affiliation: Department of Cell Biology, New York University School of Medicine, New York, NY10016.
authors.forename: Daniel Kai Long
authors.initials: DK
authors.lastname: Tham
authors.affiliation: Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, SI-1000 Ljubljana, Slovenia.
authors.forename: Rok
authors.initials: R
authors.lastname: Romih
authors.affiliation: Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil.
authors.forename: Leonardo R
authors.initials: LR
authors.lastname: Andrade
authors.affiliation: Department of Cell Biology, New York University School of Medicine, New York, NY10016.
authors.forename: Iwona
authors.initials: I
authors.lastname: Gumper
authors.affiliation: Department of Cell Biology, New York University School of Medicine, New York, NY10016.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Simon
authors.affiliation: Department of Cell Biology, New York University School of Medicine, New York, NY10016.
authors.forename: Rakhee
authors.initials: R
authors.lastname: Sachdeva
authors.affiliation: Molecular and Cellular Medicine, Imperial College, London SW7 2AZ, United Kingdom.
authors.forename: Tanya
authors.initials: T
authors.lastname: Tolmachova
authors.affiliation: Molecular and Cellular Medicine, Imperial College, London SW7 2AZ, United Kingdom.
authors.forename: Miguel C
authors.initials: MC
authors.lastname: Seabra
authors.affiliation: Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai 980-8578, Japan.
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Fukuda
authors.affiliation: Neurobiology Laboratory, Department of Biomedicine, University Hospital Basel, University of Basel, CH-4031 Basel, Switzerland.
authors.forename: Nicole
authors.initials: N
authors.lastname: Schaeren-Wiemers
authors.affiliation: Cancer and Developmental Cell Biology Division, Institute of Molecular and Cell Biology, A*STAR, Biopolis, Singapore 138673.
authors.forename: Wan Jin
authors.initials: WJ
authors.lastname: Hong
authors.affiliation: Department of Cell Biology, New York University School of Medicine, New York, NY10016.
authors.forename: David D
authors.initials: DD
authors.lastname: Sabatini
authors.affiliation: Department of Urology, New York University School of Medicine, New York, NY10016.
authors.forename: Xue-Ru
authors.initials: XR
authors.lastname: Wu
authors.affiliation: Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY10016.
authors.forename: Xiangpeng
authors.initials: X
authors.lastname: Kong
authors.affiliation: Department of Cell Biology, New York University School of Medicine, New York, NY10016.
authors.forename: Gert
authors.initials: G
authors.lastname: Kreibich
authors.affiliation: Department of Cell Biology, New York University School of Medicine, New York, NY10016 sunt01@nyumc.org Michael.Rindler@nyumc.org.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Rindler
authors.affiliation: Department of Cell Biology, New York University School of Medicine, New York, NY10016 Department of Urology, New York University School of Medicine, New York, NY10016 Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY10016 Department of Dermatology, New York University School of Medicine, New York, NY10016 sunt01@nyumc.org Michael.Rindler@nyumc.org.
authors.forename: Tung-Tien
authors.initials: TT
authors.lastname: Sun
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000378:metabolism; D053554:Keratin-20 / Q000378:metabolism*; D062792:MARVEL Domain-Containing Proteins / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D009130:Muscle, Smooth / Q000378:metabolism; D021381:Protein Transport; D050600:SNARE Proteins / Q000378:metabolism*; D060165:Uroplakins / Q000235:genetics / Q000378:metabolism; D019459:Urothelium / Q000166:cytology* / Q000378:metabolism*; D020691:rab GTP-Binding Proteins / Q000378:metabolism
chemical_list: D053554:Keratin-20; C489975:Krt20 protein, mouse; D062792:MARVEL Domain-Containing Proteins; C521976:Rab8 protein, mouse; D050600:SNARE Proteins; D060165:Uroplakins; C512958:Rab27b protein, mouse; D020691:rab GTP-Binding Proteins