Research Information

Cell-cell junctions regulate and maintain the integrity and functionality of epithelial tissues. In this continuum adherens junctions (AJ) attach neighboring cells with each other via their cytoskeleton which also leads to mechanosensitivity. The junctions and their attachment to the cytoskeleton are made up by the junctional core complex, consisting of the transmembrane protein E-Cadherin and catenins. AJ-associated proteins which can bind directly or indirectly to the core complex can strengthen the junction-cytoskeleton binding to ensure junction dynamics and tissue integrity as cells move and change their shape.

My research interest lies in understanding the organization of junctional proteins and AJ-associated proteins and how this organization influences junction dynamics and robustness. Interestingly, some AJ proteins are essential for cell-cell adhesion, while others seem to be dispensable for viability of my model organism Drosophila, although it seems, that they reinforce cell junctions. One example is the mammalian ZO-1 and its Drosophila homolog Polycheatoid (Pyd). Previous work in our lab has revealed that pyd mutant embryos are homozygous viable but show a decreased fertility and viability and tissue rupture at places with increased stress. We hypothesize, that Pyd, together with the AJ-associated protein Canoe (mammalian Afadin) ensures robustness of junctions as part of a dynamic multivalent protein complex, especially at places where AJ experience higher forces. To understand how Pyd and Canoe could organize this complex, I will uncover the substructure of this multivalent protein complex and how it changes with junction maturation and upon increased tissue forces. To do so, I am using cutting-edge microscopy on Drosophila embryos, that undergo a series of morphogenetic movements that lead to increased forces. In a second approach I will understand how the composition and structure of the multivalent protein complex are affected if parts of it are missing and how this could affect the robustness of junctions. Possible binding partners of Pyd and Canoe, that are also dispensable for viability of the flies, could be identified by a BioID assay that was carried out in our lab previously. My goal is to understand how these proteins could substitute to junction robustness and if they are working in the same ore parallel pathways. To do so, I will carefully analyze the phenotypes of embryos lacking these proteins to detect changes in tissue organization during morphogenetic movements in fixed and living embryos.