TY - JOUR
T1 - Sequential and compartmentalized action of Rabs, SNAREs, and MAL in the apical delivery of fusiform vesicles in urothelial umbrella cells
AU - Wankel, Bret
AU - Ouyang, Jiangyong
AU - Guo, Xuemei
AU - Hadjiolova, Krassimira
AU - Miller, Jeremy
AU - Liao, Yi
AU - Tham, Daniel Kai Long
AU - Romih, Rok
AU - Andrade, Leonardo R.
AU - Gumper, Iwona
AU - Simon, Jean Pierre
AU - Sachdeva, Rakhee
AU - Tolmachova, Tanya
AU - Seabra, Miguel C.
AU - Fukuda, Mitsunori
AU - Schaeren-Wiemers, Nicole
AU - Hong, Wanjin
AU - Sabatini, David D.
AU - Wu, Xue Ru
AU - Kong, Xiangpeng
AU - Kreibich, Gert
AU - Rindler, Michael J.
AU - Sun, Tung Tien
N1 - Funding Information:
We dedicate this article to Herbert Lepor to gratefully acknowledge his steadfast support of urological research at the New York University Langone Medical Center. We thank Melanie Pearson and Nicole Bornkamp for reading the manuscript and Robert Boyd for technical assistance. This work was supported by National Institutes of Health Grants DK-52206 (G.K., X.P.K., X.R.W., M.R., and T.-T.S.) and DK- 39753 (T.-T.S.), the New York University Langone Medical Center Center of Excellence for Urological Diseases, the Goldstein Fund for Urological Research (X.R.W. and T.-T.S.), and Swiss National Science Foundation Grant 31003A-12510 (N.S.-W.). The New York University Langone Medical Center Microscopy Core is supported in part by NCRR RR023704 and RR024708 from the National Institutes of Health.
Publisher Copyright:
© 2016 Wankel et al.
PY - 2016/5/15
Y1 - 2016/5/15
N2 - 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.
AB - 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.
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U2 - 10.1091/mbc.E15-04-0230
DO - 10.1091/mbc.E15-04-0230
M3 - Article
C2 - 27009205
AN - SCOPUS:84968611325
VL - 27
SP - 1621
EP - 1634
JO - Molecular Biology of the Cell
JF - Molecular Biology of the Cell
SN - 1059-1524
IS - 10
ER -