title: FAPP2, cilium formation, and compartmentalization of the apical membrane in polarized Madin-Darby canine kidney (MDCK) cells.
abstract: We have analyzed the role of the phosphatidylinositol-4-phosphate adaptor protein-2 (FAPP2), a component of the apical transport machinery, in cilium formation in polarized Madin-Darby canine kidney (MDCK) cells. We show that ciliogenesis is defective in FAPP2 knockdown cells. Furthermore, by using fluorescence recovery after photobleaching studies of domain connectivity and the generalized polarization spectra of Laurdan, we demonstrate that FAPP2 depletion impairs the formation of condensed apical membrane domains. Laurdan staining also revealed that the ciliary membrane has a highly condensed bilayer domain at its base that could function as a fence to separate the ciliary membrane from the surrounding apical membrane. These results indicate that the compartmentalization of the apical membrane in MDCK cells into the ciliary membrane and the surrounding membrane depends on the balance of raft and nonraft domains.
authors.affiliation: Max Planck Institute for Molecular Cell Biology and Genetics, D-01307 Dresden, Germany.
authors.forename: Otilia V
authors.initials: OV
authors.lastname: Vieira
authors.forename: Katharina
authors.initials: K
authors.lastname: Gaus
authors.forename: Paul
authors.initials: P
authors.lastname: Verkade
authors.forename: Joachim
authors.initials: J
authors.lastname: Fullekrug
authors.forename: Winchil L C
authors.initials: WL
authors.lastname: Vaz
authors.forename: Kai
authors.initials: K
authors.lastname: Simons
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001693:Biological Transport, Active / Q000502:physiology; D002352:Carrier Proteins; D002451:Cell Compartmentation / Q000502:physiology*; D002460:Cell Line; D002462:Cell Membrane / Q000502:physiology*; D016764:Cell Polarity / Q000502:physiology*; D002923:Cilia / Q000502:physiology; D022162:Cytoplasmic Vesicles / Q000502:physiology*; D004285:Dogs; D021962:Membrane Microdomains / Q000502:physiology; D026901:Membrane Transport Proteins / Q000502:physiology*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D026901:Membrane Transport Proteins; C487038:PLEKHA8 protein, human