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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Calmidazolium evokes high calcium fluctuations in Plasmodium falciparum

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Budu, Alexandre [1] ; Gomes, Mayrim M. [2] ; Melo, Pollyana M. [1] ; Maluf, Sarah El Chamy [1] ; Bagnaresi, Piero [1] ; Azevedo, Mauro F. [3] ; Carmona, Adriana K. [1] ; Gazarini, Marcos L. [2]
Total Authors: 8
[1] Univ Fed Sao Paulo, Dept Biofis, Sao Paulo, SP - Brazil
[2] Univ Fed Sao Paulo, Dept Biociencias, Santos, SP - Brazil
[3] Univ Sao Paulo, Inst Ciencias Biomed, BR-05508 Sao Paulo, SP - Brazil
Total Affiliations: 3
Document type: Journal article
Source: CELLULAR SIGNALLING; v. 28, n. 3, p. 125-135, MAR 2016.
Web of Science Citations: 2

Calcium and calmodulin (CaM) are important players in eukaryote cell signaling. In the present study, by using a knockin approach, we demonstrated the expression and localization of CaM in all erythrocytic stages of Plasmodium falciparum. Under extracellular Ca2+-free conditions, calmidazolium (CZ), a potent CaM inhibitor, promoted a transient cytosolic calcium ({[}Ca2+](cyt)) increase in isolated trophozoites, indicating that CZ mobilizes intracellular sources of calcium. In the same extracellular Ca2+-free conditions, the {[}Ca2+](cyt) rise elicited by CZ treatment was similar to 3.5 fold higher when the endoplasmic reticulum (ER) calcium store was previously depleted ruling out the mobilization of calcium from the ER by CZ. The effects of the Ca2+/H+ ionophore ionomycin (ION) and the Na+/H+ ionophore monensin (MON) suggest that the {[}Ca2+](cyt)-increasing effect of CZ is driven by the removal of Ca2+ from at least one Ca2+-CaM-related (CaMR) protein as well as by the mobilization of Ca2+ from intracellular acidic calcium stores. Moreover, we showed that the mitochondrion participates in the sequestration of the cytosolic Ca2+ elicited by CZ. Finally, the modulation of membrane Ca2+ channels by CZ and thapsigargin (THG) was demonstrated. The opened channels were blocked by the unspecific calcium channel blocker Co2+ but not by 2-APB (capacitative calcium entry inhibitor) or nifedipine (L-type Ca2+ channel inhibitor). Taken together, the results suggested that one CaMR protein is an important modulator of calcium signaling and homeostasis during the Plasmodium intraerythrocytic cell cycle, working as a relevant intracellular Ca2+ reservoir in the parasite. (C) 2015 Elsevier Inc. All rights reserved. (AU)

FAPESP's process: 11/14403-4 - Processment of plasmatic proteins by Plasmodium
Grantee:Pollyana Maria Saud Melo
Support type: Scholarships in Brazil - Doctorate
FAPESP's process: 13/12913-0 - Calcium-calmodulin of Plasmodium falciparum: identification of ligands and participation in the host-parasite signalling
Grantee:Alexandre Budu
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 15/07182-2 - Investigation of HINT-1 involvement in calcium cellular signaling in Plasmodium falciparum
Grantee:Mayrim Machado Gomes Smaul
Support type: Scholarships in Brazil - Doctorate