
@article {89987,
	title = {Distinct actin-dependent nanoscale assemblies underlie the dynamic and hierarchical organization of E-cadherin.},
	journal = {Curr Biol},
	year = {2021},
	month = {2021 Feb 12},
	abstract = {<p>Cadherins are transmembrane adhesion proteins required for the formation of cohesive tissues. Intracellular interactions of E-cadherin with the Catenin family proteins, α- and β-catenin, facilitate connections with the cortical actomyosin network. This is necessary for maintaining the integrity of cell-cell adhesion in epithelial tissues. The supra-molecular architecture of E-cadherin is an important feature of its adhesion function; cis and trans interactions of E-cadherin are deployed to form clusters, both in cis and trans. Studies in Drosophila embryo have also shown that Drosophila E-cadherin (dE-cad) is organized as finite-sized dynamic clusters that localize with actin patches at cell-cell junctions, in continuous exchange with the extra-junctional pool of dE-cad surrounding the clusters. Here, we use the ectopic expression of dE-cad in larval hemocytes, which lack endogenous dE-cad to recapitulate functional cell-cell junctions in a convenient model system. We find that, while dE-cad at cell-cell junctions in hemocytes exhibits a clustered trans-paired organization similar to that reported previously in embryonic epithelial tissue, extra-junctional dE-cad is also organized as relatively immobile nanoclusters as well as more loosely packed diffusive oligomers. Oligomers are promoted by cis interactions of the ectodomain, and their growth is counteracted by the activity of cortical actomyosin. Oligomers in turn promote assembly of dense nanoclusters that require cortical actomyosin activity. Thus, cortical actin activity remodels oligomers and generates nanoclusters. The requirement for dynamic actin in the organization of dE-cad at the nanoscale may provide a mechanism to dynamically tune junctional strength.</p>
},
	issn = {1879-0445},
	doi = {10.1016/j.cub.2021.01.059},
	author = {Chandran, Rumamol and Kale, Girish and Philippe, Jean-Marc and Lecuit, Thomas and Mayor, Satyajit}
}
@article {34070,
	title = {Quantitative Control of GPCR Organization and Signaling by Endocytosis in Epithelial Morphogenesis.},
	journal = {Curr Biol},
	year = {2018},
	month = {2018 Apr 25},
	abstract = {<p>Tissue morphogenesis arises from controlled cell deformations in response to cellular contractility. During Drosophila gastrulation, apical activation of the actomyosin networks drives apical constriction in the invaginating mesoderm and cell-cell intercalation in the extending ectoderm. Myosin II (MyoII) is activated by cell-surface G protein-coupled receptors (GPCRs), such as Smog and Mist, that activate G proteins, the small GTPase Rho1, and the kinase Rok. Quantitative control over GPCR and Rho1 activation underlies differences in deformation of mesoderm and ectoderm cells. We show that GPCR Smog activity is concentrated on two different apical plasma membrane compartments, i.e., the surface and plasma membrane invaginations. Using fluorescence correlation spectroscopy, we probe the surface of the plasma membrane, and we show that Smog homo-clusters in response to its activating ligand Fog. Endocytosis of Smog is regulated by the kinase Gprk2 and β-arrestin-2 that clears active Smog from the plasma membrane. When Fog concentration is high or endocytosis is low, Smog rearranges in homo-clusters and accumulates in plasma membrane invaginations that are hubs for Rho1 activation. Lastly, we find higher Smog homo-cluster concentration and numerous apical plasma membrane invaginations in the mesoderm compared to the ectoderm, indicative of reduced endocytosis. We identify that dynamic partitioning of active Smog at the surface of the plasma membrane or plasma membrane invaginations has a direct impact on Rho1 signaling. Plasma membrane invaginations accumulate high Rho1-guanosine triphosphate (GTP) suggesting they form signaling centers. Thus, Fog concentration and Smog endocytosis form coupled regulatory processes that regulate differential Rho1 and MyoII activation in the Drosophila embryo.</p>
},
	issn = {1879-0445},
	doi = {10.1016/j.cub.2018.03.068},
	author = {Jha, Ankita and van Zanten, Thomas S and Philippe, Jean-Marc and Mayor, Satyajit and Lecuit, Thomas}
}
