title: The F-BAR protein Cip4/Toca-1 antagonizes the formin Diaphanous in membrane stabilization and compartmentalization.
abstract: During Drosophila embryogenesis, the first epithelium with defined cortical compartments is established during cellularization. Actin polymerization is required for the separation of lateral and basal domains as well as suppression of tubular extensions in the basal domain. The actin nucleator mediating this function is unknown. We found that the formin Diaphanous (Dia) is required for establishing and maintaining distinct lateral and basal domains during cellularization. In dia mutant embryos lateral marker proteins, such as Discs-large and Armadillo/β-Catenin spread into the basal compartment. Furthermore, high-resolution and live-imaging analysis of dia mutant embryos revealed an increased number of membrane extensions and endocytic activity at the basal domain, indicating a suppressing function of dia on membrane invaginations. Dia function might be based on an antagonistic interaction with the F-BAR protein Cip4/Toca-1, a known activator of the WASP/WAVE-Arp2/3 pathway. Dia and Cip4 physically and functionally interact and overexpression of Cip4 phenocopies dia loss-of-function. In vitro, Cip4 inhibits mainly actin nucleation by Dia. Thus, our data support a model in which linear actin filaments induced by Dia stabilize cortical compartmentalization by antagonizing membrane turnover induced by WASP/WAVE-Arp2/3.
authors: Institut für Biochemie, Universitätsmedizin, Universität Göttingen, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany.
authors: Shuling
authors: S
authors: Yan
authors: Zhiyi
authors: Z
authors: Lv
authors: Moritz
authors: M
authors: Winterhoff
authors: Christian
authors: C
authors: Wenzl
authors: Thomas
authors: T
authors: Zobel
authors: Jan
authors: J
authors: Faix
authors: Sven
authors: S
authors: Bogdan
authors: Jörg
authors: J
authors: Grosshans
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D000080865:Formins; D011485:Protein Binding; D051316:Wiskott-Aldrich Syndrome Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; C534739:Cip4 protein, Drosophila; D029721:Drosophila Proteins; D000080865:Formins; C477859:WASp protein, Drosophila; D051316:Wiskott-Aldrich Syndrome Protein; C106890:diaphanous protein, Drosophila
keywords: Drosophila; Embryogenesis; F-BAR; Formin; Membrane compartment