Selective Transfer of Calcium from an Acidic Compartment to the Mitochondrion of Trypanosoma brucei

Xiong, Zhaohui; Ridgley, Evelyn L.; Enis, David R.; Olness, Fred; Ruben, Larry

doi:10.1074/jbc.272.49.31022

Cited by 40 publications

(52 citation statements)

References 47 publications

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“…As the second rapid deactivation mechanism, one now may consider uptake into mitochondria (Xu et al, 1997;Nguyen et al, 1998;Csordas et al, 1999;Duchen, 1999) by a Ca 2 + uniporter (depending on inner membrane potential), followed by the slower release of Ca 2 +via a Na +/Ca 2 +exchanger (Duchen et al, 1998;Rutter et al, 1998). Some nonciliate protozoa (Trypanosoma) possess acidic Ca 2 + stores with a Ca 2 +/H+ antiporter (Xiong et al, 1997), which may be assumed to work fast. Much more time is required for Ca 2 +sequestration into SR or ER (endoplasmic reticulum) or equivalent stores by a universal Ca 2 + pump (SERCA-type Ca 2 + pump, from SR/ER/ Ca 2 +-ATPase).…”

Section: Regulation Of Ca 2 + Dynamicsmentioning

confidence: 99%

Calcium in ciliated protozoa: Sources, regulation, and calcium-regulated cell functions

Plattner

Klauke²

2001

International Review of Cytology

105

121

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In ciliates, a variety of processes are regulated by Ca 2 ', e.g., exocytosis, endocytosis, ciliary beat, cell contraction, and nuclear migration. Differential microdomain regulation may occur by activation of specific channels in different cell regions (e.g., voltagedependent Ca 2 ' channels in cilia), by local, nonpropagated activation of subplasmalemmal Ca stores (alveolar sacs), by different sensitivity thresholds, and eventually by interplay with additional second messengers (cilia). During stimulus-secretion coupling, Ca 2 ' as the only known second messenger operates at -5 f.tM, whereby mobilization from alveolar sacs is superimposed by "store-operated Ca

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Section: Regulation Of Ca 2 + Dynamicsmentioning

confidence: 99%

Calcium in ciliated protozoa: Sources, regulation, and calcium-regulated cell functions

Plattner

Klauke²

2001

International Review of Cytology

105

121

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“…Notably, seminal work described Ca 2ϩ influx into the trypanosome mitochondrion in a ruthenium red-sensitive fashion (23,24). These data became critical for the algorithm to identify conserved proteins responsible for Ca 2ϩ uptake, by testing a pool of mt proteins shared by kinetoplastids and vertebrates but absent in yeast, which lack this activity.…”

mentioning

confidence: 99%

Trypanosome Letm1 Protein Is Essential for Mitochondrial Potassium Homeostasis

Hashimi

McDonald

Stříbrná

et al. 2013

Journal of Biological Chemistry

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Background: Letm1 is a mitochondrial protein attributed disparate roles, including cation/proton antiport and translation. Results: Letm1 RNAi silencing in Trypanosoma brucei triggers swelling mitochondria and translation arrest that is ameliorated by chemical potassium/proton exchangers. Conclusion:The ancestral function of Letm1, to maintain mitochondrial potassium homeostasis, shows remarkable conservation. Significance: Results from diverged T. brucei provide a better understanding of Letm1 function throughout eukaryotes.

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“…Recombinant Bcl-2 was detected with the rabbit anti-Bcl-2 polyclonal antibody bcl-2(Ab-2) (Calbiochem) diluted 1 : 350. Duplicate blots were also incubated with rabbit anti-(cytochrome c " ) [ Procyclic cells were stably transformed with different aequorin constructs, as described previously [26][27][28]. The night before each experiment, aequorin transformants were diluted to (2-5)i10' cells\ml.…”

Section: Immunoblotsmentioning

confidence: 99%

“…The targeted [26][27][28]. Aequorin was reconstituted with coelenterazine in i o for 3.5 h in SDM-79 containing 10 % (v\v) fetal bovine serum, as described previously [26].…”

Section: Ca 2 + Homeostasis In Ros-treated Cellsmentioning

confidence: 99%

“…Targeted aequorins have been used to study the dynamic interactions of Ca# + between these compartments [26][27][28]. The trypanosome mitochondrion maintains a low resting level of Ca# + , but transiently accumulates large quantities of Ca# + from the cytosol after influx across the plasma membrane [27], or after release from the acidocalcisome [27,28].…”

Section: Introductionmentioning

confidence: 99%

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Reactive oxygen species activate a Ca2+-dependent cell death pathway in the unicellular organism Trypanosoma brucei brucei

Ridgley

Xiong²,

Ruben³

1999

Biochemical Journal

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Here we examine a cell death process induced by reactive oxygen species (ROS) in the haemoflagellate Trypanosoma brucei brucei. Ca# + distribution in cellular compartments was measured with stable transformants expressing aequorin targeted to the cytosol, nucleus or mitochondrion. Within 1.5 h of ROS production, mitochondrial Ca# + transport was impaired and the Ca# + barrier between the nuclear envelope and cytosol was disrupted. Consequently the mitochondrion did not accumulate Ca# + efficiently in response to an extracellular stimulus, and excess Ca# + accumulated in the nucleus. The terminal transferase deoxytidyl uridine end labelling assay revealed that, 5 h after treatment with ROS, extensive fragmentation of nuclear DNA occurred in over 90 % of the cells. Permeability changes in the plasma membrane did not occur until an additional 2 h had elapsed. The intracellular

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Selective Transfer of Calcium from an Acidic Compartment to the Mitochondrion of Trypanosoma brucei

Cited by 40 publications

References 47 publications

Calcium in ciliated protozoa: Sources, regulation, and calcium-regulated cell functions

Calcium in ciliated protozoa: Sources, regulation, and calcium-regulated cell functions

Trypanosome Letm1 Protein Is Essential for Mitochondrial Potassium Homeostasis

Reactive oxygen species activate a Ca2+-dependent cell death pathway in the unicellular organism Trypanosoma brucei brucei

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