title: On the evolution of programmed cell death: apoptosis of the unicellular eukaryote Leishmania major involves cysteine proteinase activation and mitochondrion permeabilization.
abstract: Leishmania major is a protozoan parasite from one of the most ancient phylogenic branches of unicellular eukaryotes, and containing only one giant mitochondrion. Here we report that staurosporine, that induces apoptosis in all mammalian nucleated cells, also induces in L. major a death process with several cytoplasmic and nuclear features of apoptosis, including cell shrinkage, phosphatidyl serine exposure, maintenance of plasma membrane integrity, mitochondrial transmembrane potential (DeltaPsim) loss and cytochrome c release, nuclear chromatin condensation and fragmentation, and DNA degradation. Nuclear apoptosis-like features were prevented by cysteine proteinase inhibitors, and cell free assays using dying L. major cytoplasmic extracts indicated that the cysteine proteinases involved (i) also induced nuclear apoptosis-like features in isolated mammalian nuclei, and (ii) shared at least two nuclear substrates, but no cleavage site preference, with human effector caspases. Finally, isolated L. major mitochondria released cytochrome c and cysteine proteinases with nuclear pro-apoptotic activity when incubated with human recombinant Bax, even (although much less efficiently) when Bax was deleted of its transmembrane domain required for insertion in mitochondrial outermembranes, implying that L. major mitochondrion may express proteins able to interact with Bax. The recruitment of cysteine proteinases and mitochondria to the cell death machinery may be of very ancient evolutionary origin. Alternately, host/parasite interactions may have exerted selective pressures on the cell death phenotype of kinetoplastid parasites, resulting in the more recent emergence of an apoptotic machinery through a process of convergent evolution.
authors.affiliation: EMI-U 9922 INSERM-Universite Paris 7, IFR 02, AP-HP, Hopital Bichat-Claude Bernard, 46, rue Henri Huchard, 75877 Paris cedex 18, France.
authors.forename: D
authors.initials: D
authors.lastname: Arnoult
authors.forename: K
authors.initials: K
authors.lastname: Akarid
authors.forename: A
authors.initials: A
authors.lastname: Grodet
authors.forename: P X
authors.initials: PX
authors.lastname: Petit
authors.forename: J
authors.initials: J
authors.lastname: Estaquier
authors.forename: J C
authors.initials: JC
authors.lastname: Ameisen
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D051017:Apoptosis Regulatory Proteins; D005075:Biological Evolution; D002352:Carrier Proteins / Q000494:pharmacology; D002467:Cell Nucleus / Q000187:drug effects / Q000502:physiology*; D002843:Chromatin / Q000187:drug effects; D003546:Cysteine Endopeptidases / Q000187:drug effects / Q000378:metabolism*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D003574:Cytochrome c Group / Q000378:metabolism; D053938:DNA Fragmentation / Q000187:drug effects / Q000502:physiology; D004789:Enzyme Activation; D006023:Glycoproteins / Q000494:pharmacology; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D019169:Jurkat Cells; D018320:Leishmania major / Q000187:drug effects / Q000502:physiology*; D008928:Mitochondria / Q000502:physiology; D010539:Permeability / Q000187:drug effects; D011065:Poly(ADP-ribose) Polymerases / Q000187:drug effects / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000494:pharmacology; D019253:Proto-Oncogene Proteins c-bcl-2; D019311:Staurosporine / Q000494:pharmacology*; D051028:bcl-2-Associated X Protein
chemical_list: D051017:Apoptosis Regulatory Proteins; C494826:BAX protein, human; D002352:Carrier Proteins; D002843:Chromatin; D015853:Cysteine Proteinase Inhibitors; D003574:Cytochrome c Group; D006023:Glycoproteins; D047908:Intracellular Signaling Peptides and Proteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; C039304:calpain inhibitors; C109664:caspase-activated DNase inhibitor; C015482:protein kinase modulator; D011065:Poly(ADP-ribose) Polymerases; D003546:Cysteine Endopeptidases; D019311:Staurosporine