Tracking autophagy during proliferation and differentiation of trypanosoma brucei

Proto, W. R., Jones, N. G., Coombs, G. H. and Mottram, J. C. (2014) Tracking autophagy during proliferation and differentiation of trypanosoma brucei. Microbial Cell, 1(1), pp. 9-20. (doi: 10.15698/mic2014.01.120)

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Abstract

Autophagy is a lysosome-dependent degradation mechanism that sequesters target cargo into autophagosomal vesicles. The Trypanosoma brucei genome contains apparent orthologues of several autophagy-related proteins including an ATG8 family. These ubiquitin-like proteins are required for autophagosome membrane formation, but our studies show that ATG8.3 is atypical. To investigate the function of other ATG proteins, RNAi compatible T. brucei were modified to function as autophagy reporter lines by expressing only either YFP-ATG8.1 or YFP-ATG8.2. In the insect procyclic lifecycle stage, independent RNAi down-regulation of ATG3 or ATG7 generated autophagy-defective mutants and confirmed a pro-survival role for autophagy in the procyclic form nutrient starvation response. Similarly, RNAi depletion of ATG5 or ATG7 in the bloodstream form disrupted autophagy, but did not impede proliferation. Further characterisation showed bloodstream form autophagy mutants retain the capacity to undergo the complex cellular remodelling that occurs during differentiation to the procyclic form and are equally susceptible to dihydroxyacetone-induced cell death as wild type parasites, not supporting a role for autophagy in this cell death mechanism. The RNAi reporter system developed, which also identified TOR1 as a negative regulator controlling YFP-ATG8.2 but not YFP-ATG8.1 autophagosome formation, will enable further targeted analysis of the mechanisms and function of autophagy in the medically relevant bloodstream form of T. brucei.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Proto, Mr William and Coombs, Professor Graham and Mottram, Professor Jeremy
Authors: Proto, W. R., Jones, N. G., Coombs, G. H., and Mottram, J. C.
College/School:College of Medical Veterinary and Life Sciences
College of Medical Veterinary and Life Sciences > Institute of Infection Immunity and Inflammation
Journal Name:Microbial Cell
Publisher:Shared Science Publishers OG
ISSN:2311-2638
ISSN (Online):2311-2638
Copyright Holders:Copyright © 2014 The Authors
First Published:First published in Microbial Cell 1(1):9-20
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
371796The Wellcome Centre for Molecular Parasitology ( Core Support )Andrew WatersWellcome Trust (WELLCOME)085349/Z/08/ZIII - PARASITOLOGY
611411Proteolysis and life cycle progression in LeishmaniaJeremy MottramMedical Research Council (MRC)MR/K019384/1III - PARASITOLOGY