The malaria parasite mitochondrion senses cytosolic Ca2+ fluctuations.
By using the fluorescent dye Rhod-2, we have investigated the ability of Plasmodium mitochondria to participate in cellular Ca2+ homeostasis. To this end, isolated parasites were simultaneously loaded with the mitochondrial Ca2+ probe Rhod-2 and the cytosolic Ca2+ dye Fluo-3 and their fluorescent intensities were monitored in the same cells by confocal microscopy. We here demonstrate that Ca2+ increases, as elicited by treatment of parasites with sarco-endoplasmic reticulum Ca2+ ATPase inhibitors or the hormone melatonin, induce rapid and reversible increases of the Ca2+ concentration in the mitochondria of both human and murine parasites. Pre-treatment of parasites with the mitochondrial uncoupler, FCCP, suppresses mitochondrial Ca2+ accumulation. Our data demonstrate that mitochondria of malaria parasites are able to reversibly accumulate part of the Ca2+ released in the cytoplasm by pharmacological and physiological agents and thus suggest that this organelle participate in the maintenance of Ca2+ homeostasis of Plasmodia.
Gazarini
Marcos L
ML
Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo. Av. Lineu Prestes 1374, Brazil.
Garcia
Célia R S
CR
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D003600:Cytosol / Q000378:metabolism; D004912:Erythrocytes / Q000469:parasitology; D006801:Humans; D008550:Melatonin / Q000494:pharmacology; D051379:Mice; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000502:physiology*; D016788:Plasmodium chabaudi / Q000502:physiology*; D010963:Plasmodium falciparum / Q000502:physiology*
D000252:Calcium-Transporting ATPases; D008550:Melatonin; D002118:Calcium