Villarroel Campos, David;
(2020)
Regulation of intracellular traffic by TBK1 and its relevance to ALS.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Neurons are highly polarised cells, typically comprising a somatodendritic compartment and an axon that can extend for a meter or more. Their extreme morphology challenges neurons to establish an efficient communication system between the axonal terminal and the soma, a mechanism known as axonal transport. Axonal transport is required for the maintenance of neuronal homeostasis, and is impaired in many neurodegenerative diseases, such as Amyotrophic Lateral Sclerosis (ALS). Mutations in TANK-binding kinase-1 (TBK1) have been described as causative for familial ALS. TBK1 phosphorylates Rab7, a small GTPase regulating the endolysosomal pathway. We have previously shown that the retrograde transport of signalling endosomes carrying neurotrophic receptors relies on Rab7, and that deficits in retrograde axonal transport can be detected at early symptomatic stages during ALS pathogenesis. In this work, we address whether TBK1 loss-of-function or Rab7-S72 phosphorylation alters the retrograde transport of signalling endosomes. We transfected Rab7 WT, S72A (phospho-deficient) and S72E (phospho-mimetic) in primary motor neurons and assessed the trafficking of signalling endosomes. Our results show that the directionality of transport is affected upon transfection of Rab7-S72E, whilst neuronal polarity remains unaltered. Axonal microtubule polarity also remains unchanged. We then characterised a set of shRNAs against TBK1 and showed that reduced TBK1 expression phenocopies the S72E condition. This alteration in transport is specific for signalling endosomes, as lysosomes and mitochondria were not affected. Altogether, these results suggest an involvement of TBK1 in the regulation of axonal transport of signalling endosomes and suggest that deficits in TBK1 activity determines retrograde transport dysfunction, which may be causative in ALS pathogenesis.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Regulation of intracellular traffic by TBK1 and its relevance to ALS |
| Event: | UCL (University College London) |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2020. Original content in this thesis is licensed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) Licence (https://creativecommons.org/licenses/by/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 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 Brain Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology > Department of Neuromuscular Diseases |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10097189 |
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