Distinct roles in autophagy and importance in infectivity of the two ATG4 cysteine peptidases of leishmania major

Williams, R.A.M., Mottram, J.C. and Coombs, G.H. (2013) Distinct roles in autophagy and importance in infectivity of the two ATG4 cysteine peptidases of leishmania major. Journal of Biological Chemistry, 288(5), pp. 3678-3690. (doi:10.1074/jbc.M112.415372)

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Publisher's URL: http://dx.doi.org/10.1074/jbc.M112.415372

Abstract

Macroautophagy in Leishmania, which is important for the cellular remodeling required during differentiation, relies upon the hydrolytic activity of two ATG4 cysteine peptidases (ATG4.1 and ATG4.2). We have investigated the individual contributions of each ATG4 to Leishmania major by generating individual gene deletion mutants (Δatg4.1 and Δatg4.2); double mutants could not be generated, indicating that ATG4 activity is required for parasite viability. Both mutants were viable as promastigotes and infected macrophages in vitro and mice, but Δatg4.2 survived poorly irrespective of infection with promastigotes or amastigotes, whereas this was the case only when promastigotes of Δatg4.1 were used. Promastigotes of Δatg4.2 but not Δatg4.1 were more susceptible than wild type promastigotes to starvation and oxidative stresses, which correlated with increased reactive oxygen species levels and oxidatively damaged proteins in the cells as well as impaired mitochondrial function. The antioxidant N-acetylcysteine reversed this phenotype, reducing both basal and induced autophagy and restoring mitochondrial function, indicating a relationship between reactive oxygen species levels and autophagy. Deletion of ATG4.2 had a more dramatic effect upon autophagy than did deletion of ATG4.1. This phenotype is consistent with a reduced efficiency in the autophagic process in Δatg4.2, possibly due to ATG4.2 having a key role in removal of ATG8 from mature autophagosomes and thus facilitating delivery to the lysosomal network. These findings show that there is a level of functional redundancy between the two ATG4s, and that ATG4.2 appears to be the more important. Moreover, the low infectivity of Δatg4.2 demonstrates that autophagy is important for the virulence of the parasite.

Item Type:Articles
Additional Information:This research was originally published in Journal of Biological Chemistry. Williams, R.A.M, Mottram, J.C., and Coombs, G.H., Distinct roles in autophagy and importance in infectivity of the two ATG4 cysteine peptidases of leishmania major. Journal of Biological Chemistry. 2013; Vol. 288(5).pp. 3678-3690. 2013 © the American Society for Biochemistry and Molecular Biology.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Coombs, Professor Graham and Mottram, Professor Jeremy
Authors: Williams, R.A.M., Mottram, J.C., and Coombs, G.H.
College/School:College of Medical Veterinary and Life Sciences > Institute of Infection Immunity and Inflammation
College of Medical Veterinary and Life Sciences > School of Life Sciences
Journal Name:Journal of Biological Chemistry
Publisher:American Society for Biochemistry and Molecular Biology, Inc.
ISSN:0021-9258
Published Online:19 November 2012
Copyright Holders:Copyright © 2013 The American Society for Biochemistry and Molecular Biology, Inc.
First Published:First published in Journal of Biological Chemistry 288(5):3678-3690
Publisher Policy:Reproduced under a Creative Commons License
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