title: α-Spectrin and integrins act together to regulate actomyosin and columnarization, and to maintain a monolayered follicular epithelium.
abstract: The spectrin cytoskeleton crosslinks actin to the membrane, and although it has been greatly studied in erythrocytes, much is unknown about its function in epithelia. We have studied the role of spectrins during epithelia morphogenesis using the Drosophila follicular epithelium (FE). As previously described, we show that α-Spectrin and β-Spectrin are essential to maintain a monolayered FE, but, contrary to previous work, spectrins are not required to control proliferation. Furthermore, spectrin mutant cells show differentiation and polarity defects only in the ectopic layers of stratified epithelia, similar to integrin mutants. Our results identify α-Spectrin and integrins as novel regulators of apical constriction-independent cell elongation, as α-Spectrin and integrin mutant cells fail to columnarize. Finally, we show that increasing and reducing the activity of the Rho1-Myosin II pathway enhances and decreases multilayering of α-Spectrin cells, respectively. Similarly, higher Myosin II activity enhances the integrin multilayering phenotype. This work identifies a primary role for α-Spectrin in controlling cell shape, perhaps by modulating actomyosin. In summary, we suggest that a functional spectrin-integrin complex is essential to balance adequate forces, in order to maintain a monolayered epithelium.
authors.affiliation: Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK.
authors.forename: Bing Fu
authors.initials: BF
authors.lastname: Ng
authors.affiliation: Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK.
authors.forename: Gokul Kannan
authors.initials: GK
authors.lastname: Selvaraj
authors.affiliation: Centro Andaluz de Biología del Desarrollo CSIC-Univ. Pablo de Olavide, Sevilla 41013, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Santa-Cruz Mateos
authors.affiliation: Centro Andaluz de Biología del Desarrollo CSIC-Univ. Pablo de Olavide, Sevilla 41013, Spain.
authors.forename: Inna
authors.initials: I
authors.lastname: Grosheva
authors.affiliation: Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK.
authors.forename: Ines
authors.initials: I
authors.lastname: Alvarez-Garcia
authors.affiliation: Centro Andaluz de Biología del Desarrollo CSIC-Univ. Pablo de Olavide, Sevilla 41013, Spain.
authors.forename: María Dolores
authors.initials: MD
authors.lastname: Martín-Bermudo
authors.affiliation: Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK mip22@cam.ac.uk.
authors.forename: Isabel M
authors.initials: IM
authors.lastname: Palacios
mesh_terms: D000205:Actomyosin / Q000502:physiology*; D000818:Animals; D002454:Cell Differentiation; D016764:Cell Polarity; D048430:Cell Shape; D003599:Cytoskeleton / Q000502:physiology; D004330:Drosophila; D029721:Drosophila Proteins / Q000502:physiology*; D004848:Epithelium / Q000033:anatomy & histology*; D005260:Female; D016023:Integrins / Q000502:physiology*; D008938:Mitosis; D009154:Mutation; D009865:Oocytes / Q000166:cytology; D006080:Ovarian Follicle / Q000166:cytology*; D013049:Spectrin / Q000502:physiology*
chemical_list: D029721:Drosophila Proteins; D016023:Integrins; D013049:Spectrin; D000205:Actomyosin
keywords: Cell shape; Epithelium; Monolayer; Proliferation; Tissue architecture; Tumor-like mass