Distinct sites in E-cadherin regulate different steps in Drosophila tracheal tube fusion.
We have investigated how E-cadherin controls the elaboration of adherens junction associated cytoskeletal structures crucial for assembling tubular networks. During Drosophila development, tracheal branches are joined at branch tips through lumens that traverse doughnut-shaped fusion cells. Fusion cells form E-cadherin contacts associated with a track that contains F-actin, microtubules, and Shot, a plakin that binds F-actin and microtubules. Live imaging reveals that fusion occurs as the fusion cell apical surfaces meet after invaginating along the track. Initial track assembly requires E-cadherin binding to beta-catenin. Surprisingly, E-cadherin also controls track maturation via a juxtamembrane site in the cytoplasmic domain. Fusion cells expressing an E-cadherin mutant in this site form incomplete tracks that contain F-actin and Shot, but lack microtubules. These results indicate that E-cadherin controls track initiation and maturation using distinct, evolutionarily conserved signals to F-actin and microtubules, and employs Shot to promote adherens junction-associated cytoskeletal assembly.
Department of Cell and Developmental Biology, Center for Molecular Neuroscience, Program in Developmental Biology, Vanderbilt University Medical Center, Nashville TN 37232-2175, USA.
Mihye
M
Lee
Seungbok
S
Lee
Alireza Dehghani
AD
Zadeh
Peter A
PA
Kolodziej
D000199:Actins / Q000378:metabolism; D022005:Adherens Junctions / Q000378:metabolism; D000818:Animals; D015820:Cadherins / Q000235:genetics / Q000378:metabolism*; D002459:Cell Fusion; D003598:Cytoskeletal Proteins / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism; D004330:Drosophila / Q000033:anatomy & histology / Q000196:embryology* / Q000502:physiology; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism; D009024:Morphogenesis / Q000502:physiology*; D009154:Mutation; D017434:Protein Structure, Tertiary; D015398:Signal Transduction; D015534:Trans-Activators / Q000378:metabolism; D051176:beta Catenin
D000199:Actins; D015820:Cadherins; D003598:Cytoskeletal Proteins; D029721:Drosophila Proteins; D008840:Microfilament Proteins; D015534:Trans-Activators; D051176:beta Catenin; C450828:shot protein, Drosophila