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Title: | Function of ArhGAP12 in the assembly and regulation of epithelial tight junctions | Authors: | Tambrin, Hana Maldivita | Keywords: | Medicine, Health and Life Sciences | Issue Date: | 2024 | Publisher: | Nanyang Technological University | Source: | Tambrin, H. M. (2024). Function of ArhGAP12 in the assembly and regulation of epithelial tight junctions. Doctoral thesis, Nanyang Technological University, Singapore. https://hdl.handle.net/10356/179880 | Abstract: | In epithelia cells, tight junctions (TJ) form selective gates that control the paracellular diffusion of ions and solutes, and they act as a border between the apical and basolateral plasma-membrane domains. TJ formation and function are regulated by Rho-GTPases, whose activities are controlled by guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). We have identified ArhGAP12, a specific GAP for Rac1/Cdc42, as a novel TJ component recruited via ZO-2. Additionally, ArhGAP12 interacts with N-WASP and WAVE2, linking it to Arp2/3-driven actin polymerization at TJs. Our 3D cysts showed that the absence of ArhGAP12 impairs lumen formation. While our calcium-switch assay revealed that MDCK-II cells depleted of ArhGAP12 exhibited delayed TJ formation, accompanied by a delayed onset of TEER peaks. Permeability assays utilizing 4kDa FITC-dextran underscored ArhGAP12's critical role in regulating TJ permeability, as deletion of ArhGAP12 led to more restrictive leak pathways. Laser ablation experiments further revealed increased tension in ArhGAP12-deficient cells. Notably, both the restrictive leak pathways and heightened junctional tension in these cells were rescued upon inhibition of Arp2/3 activity. Together, these findings suggest that ArhGAP12 coordinates TJ formation and permeability, potentially by regulating N-WASP and WAVE2-mediated actin assembly. | URI: | https://hdl.handle.net/10356/179880 | DOI: | 10.32657/10356/179880 | Schools: | School of Biological Sciences | Rights: | This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0). | Fulltext Permission: | open | Fulltext Availability: | With Fulltext |
Appears in Collections: | SBS Theses |
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Hana_Thesis_Final.pdf | 5.01 MB | Adobe PDF | View/Open |
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