Extracellular ATP triggers proteolysis and cytosolic Ca2+ rise in Plasmodium berghei and Plasmodium yoelii malaria parasites

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Date
2012-03-15Author
Cruz, Laura Nogueira
Juliano, Maria Aparecida [UNIFESP]
Budu, Alexandre
Juliano, Luiz [UNIFESP]
Holder, Anthony A.
Blackman, Michael J.
Garcia, Celia R. S.
Type
ArtigoISSN
1475-2875Is part of
Malaria JournalDOI
10.1186/1475-2875-11-69Metadata
Show full item recordAbstract
Background: Plasmodium has a complex cell biology and it is essential to dissect the cell-signalling pathways underlying its survival within the host.Methods: Using the fluorescence resonance energy transfer (FRET) peptide substrate Abz-AIKFFARQ-EDDnp and Fluo4/AM, the effects of extracellular ATP on triggering proteolysis and Ca2+ signalling in Plasmodium berghei and Plasmodium yoelii malaria parasites were investigated.Results: the protease activity was blocked in the presence of the purinergic receptor blockers suramin (50 mu M) and PPADS (50 mu M) or the extracellular and intracellular calcium chelators EGTA (5 mM) and BAPTA/AM (25, 100, 200 and 500 mu M), respectively for P. yoelii and P. berghei. Addition of ATP (50, 70, 200 and 250 mu M) to isolated parasites previously loaded with Fluo4/AM in a Ca2+-containing medium led to an increase in cytosolic calcium. This rise was blocked by pre-incubating the parasites with either purinergic antagonists PPADS (50 mu M), TNP-ATP (50 mu M) or the purinergic blockers KN-62 (10 mu M) and Ip5I (10 mu M). Incubating P. berghei infected cells with KN-62 (200 mu M) resulted in a changed profile of merozoite surface protein 1 (MSP1) processing as revealed by western blot assays. Moreover incubating P. berghei for 17 h with KN-62 (10 mu M) led to an increase in rings forms (82% +/- 4, n = 11) and a decrease in trophozoite forms (18% +/- 4, n = 11).Conclusions: the data clearly show that purinergic signalling modulates P. berghei protease(s) activity and that MSP1 is one target in this pathway.
Citation
Malaria Journal. London: Biomed Central Ltd, v. 11, 11 p., 2012.Keywords
ATPPurinergic receptor
Malaria
Plasmodium berghei
Plasmodium yoelii
Protease activity
Calcium modulation
Merozoite surface protein 1
Sponsorship
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
UK Medical Research Council
EU through the Network of Excellence EviMalaR
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