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Cell death in parasitic protozoa: regulated or incidental?

Abstract

Apoptosis and other types of regulated cell death have been defined as fundamental processes in plant and animal development, but the occurrence of, and possible roles for, regulated cell death in parasitic protozoa remain controversial. A key problem has been the difficulty in reconciling the presence of apparent morphological markers of apoptosis and the notable absence of some of the key executioners functioning in higher eukaryotes. Here, we review the evidence for regulated cell death pathways in selected parasitic protozoa and propose that cell death in these organisms be classified into just two primary types: necrosis and incidental death. It is our opinion that dedicated molecular machinery required for the initiation and execution of regulated cell death has yet to be convincingly identified.

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Figure 1: Major cell death modalities in eukaryotes.
Figure 2: Life cycles and cell death of parasitic protozoa.
Figure 3: Autophagy in Leishmania spp.

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Acknowledgements

The authors are grateful to N. Fasel for insightful comments on the manuscript and K. McLuskey for help with preparing the figure in box 2. J.C.M. and G.H.C. are supported by the UK Medical Research Council (grant 0700127). The Wellcome Trust Centre for Molecular Parasitology is supported by core funding from the Wellcome Trust (grant 085349).

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Proto, W., Coombs, G. & Mottram, J. Cell death in parasitic protozoa: regulated or incidental?. Nat Rev Microbiol 11, 58–66 (2013). https://doi.org/10.1038/nrmicro2929

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