Timimi, Lewis John;
(2024)
Recruitment of ATG16L1 in response to dissipated proton gradients.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Intracellular proton gradients are essential for eukaryotic life. Disruption of these gradients can signify the presence of damaged or infected compartments, requiring effective detection mechanisms. In response to proton gradient dissipation, cells rapidly target neutralised organelles with ubiquitin-like molecules, called ATG8s. This pathway – termed Conjugation of ATG8s to Single Membranes or CASM – depends on the recruitment of the key upstream regulator ATG16L1 to perturbed compartments, but the mechanism by which this occurs is unclear. In this thesis, ATG16L1 is shown to bind directly to an intracellular proton pump, called the vacuolar-type ATPase (V-ATPase). The interaction between the V-ATPase and ATG16L1 is regulated by changes in V- ATPase assembly and activity that occur in response to the disruption of transmembrane proton gradients. ATG16L1 recruitment was found to be mediated by the V1H V-ATPase subunit, and absence of this subunit abolishes CASM following ionophore drug treatment, influenza A virus infection and activation of the immune receptor STING. Unexpectedly, a neuronal isoform of V1H lacks a crucial component of the ATG16L1 binding site and was found to be associated with attenuated CASM in neurons. Finally, the V- ATPase/ATG16L1 complex was targeted pharmacologically using compounds designed to bind a key pocket of a V-ATPase-interacting domain of ATG16L1, illustrating how these new insights into CASM initiation can be harnessed experimentally. This thesis argues that the V-ATPase complex acts as an intracellular damage sensor, directly recruiting ATG16L1 through changes in assembly and state that are coupled to proton gradient integrity. This model of CASM initiation provides new mechanistic insight and uncovers new modes of spatiotemporal CASM regulation.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Recruitment of ATG16L1 in response to dissipated proton gradients |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2024. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Div of Biosciences |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10195437 |
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