title: Apico-basal elongation requires a drebrin-E-EB3 complex in columnar human epithelial cells.
abstract: Although columnar epithelial cells are known to acquire an elongated shape, the mechanisms involved in this morphological feature have not yet been completely elucidated. Using columnar human intestinal Caco2 cells, it was established here that the levels of drebrin E, an actin-binding protein, increase in the terminal web both in vitro and in vivo during the formation of the apical domain. Drebrin E depletion was found to impair cell compaction and elongation processes in the monolayer without affecting cell polarity or the formation of tight junctions. Decreasing the drebrin E levels disrupted the normal subapical F-actin-myosin-IIB-βII-spectrin network and the apical accumulation of EB3, a microtubule-plus-end-binding protein. Decreasing the EB3 levels resulted in a similar elongation phenotype to that resulting from depletion of drebrin E, without affecting cell compaction processes or the pattern of distribution of F-actin-myosin-IIB. In addition, EB3, myosin IIB and βII spectrin were found to form a drebrin-E-dependent complex. Taken together, these data suggest that this complex connects the F-actin and microtubule networks apically during epithelial cell morphogenesis, while drebrin E also contributes to stabilizing the actin-based terminal web.
authors.affiliation: CNRS, UMR 6216, Developmental Biology Institute of Marseille Luminy (IBDML), case 907, 13288 Marseille, CEDEX 09,  France.
authors.forename: Elsa
authors.initials: E
authors.lastname: Bazellières
authors.forename: Dominique
authors.initials: D
authors.lastname: Massey-Harroche
authors.forename: Magali
authors.initials: M
authors.lastname: Barthélémy-Requin
authors.forename: Fabrice
authors.initials: F
authors.lastname: Richard
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Arsanto
authors.forename: André
authors.initials: A
authors.lastname: Le Bivic
mesh_terms: D000199:Actins / Q000378:metabolism; D018938:Caco-2 Cells; D016764:Cell Polarity / Q000502:physiology; D048430:Cell Shape / Q000502:physiology*; D004847:Epithelial Cells / Q000166:cytology* / Q000378:metabolism*; D006801:Humans; D008869:Microtubule-Associated Proteins; D009479:Neuropeptides / Q000172:deficiency / Q000378:metabolism*; D024501:Nonmuscle Myosin Type IIB / Q000378:metabolism; D013049:Spectrin / Q000172:deficiency / Q000378:metabolism*; D019108:Tight Junctions
chemical_list: D000199:Actins; C403664:MAPRE3 protein, human; D008869:Microtubule-Associated Proteins; D009479:Neuropeptides; C452439:SPTBN1 protein, human; C083795:drebrin E; D013049:Spectrin; D024501:Nonmuscle Myosin Type IIB