Drosophila afadin homologue Canoe regulates linkage of the actin cytoskeleton to adherens junctions during apical constriction

• Published in: The Journal of cell biology 2009-07, Vol.186 (1), p.57-73
• Main Authors: Sawyer, Jessica K, Harris, Nathan J, Slep, Kevin C, Gaul, Ulrike, Peifer, Mark
• Format: Article
• Language: English
• Subjects: Actins; Actins - metabolism; Actomyosin - metabolism; Adherens junctions; Adherens Junctions - metabolism; alpha Catenin - metabolism; Animals; Cadherins - metabolism; Canoes; Cell adhesion; Cell adhesion & migration; Cell Polarity; Cell Surface Extensions - metabolism; Cells; Cytoskeleton; Cytoskeleton - metabolism; Drosophila; Drosophila melanogaster - cytology; Drosophila melanogaster - embryology; Drosophila melanogaster - metabolism; Drosophila Proteins - deficiency; Drosophila Proteins - metabolism; Embryos; Epithelial cells; Gene expression regulation; Genetic linkage; Insects; Mesoderm; Mesoderm - metabolism; Microfilament Proteins - chemistry; Morphogenesis; Mutation - genetics; Organ Specificity; Physiological regulation; Protein Binding; Protein Transport; Proteins; Rabbits; rap1 GTP-Binding Proteins - metabolism; Sequence Homology, Amino Acid
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.200904001

Cadherin-based adherens junctions (AJs) mediate cell adhesion and regulate cell shape change. The nectin-afadin complex also localizes to AJs and links to the cytoskeleton. Mammalian afadin has been suggested to be essential for adhesion and polarity establishment, but its mechanism of action is unclear. In contrast, Drosophila melanogaster's afadin homologue Canoe (Cno) has suggested roles in signal transduction during morphogenesis. We completely removed Cno from embryos, testing these hypotheses. Surprisingly, Cno is not essential for AJ assembly or for AJ maintenance in many tissues. However, morphogenesis is impaired from the start. Apical constriction of mesodermal cells initiates but is not completed. The actomyosin cytoskeleton disconnects from AJs, uncoupling actomyosin constriction and cell shape change. Cno has multiple direct interactions with AJ proteins, but is not a core part of the cadherin-catenin complex. Instead, Cno localizes to AJs by a Rap1- and actin-dependent mechanism. These data suggest that Cno regulates linkage between AJs and the actin cytoskeleton during morphogenesis.