CHARACTERIZATION OF CA2-CHABAUDI( TRANSPORT ACTIVITY ASSOCIATED WITH A NONMITOCHONDRIAL CALCIUM POOL IN THE RODENT MALARIA PARASITE P)

Non-mitochondrial calcium deposits were investigated in the intraeryth rocytic malaria parasite Plasmodium chabaudi at the trophozoite stage by means of arsenate III in the presence of ATP and the mitochondrial poisons, antimycin and oligomycin. Addition of vanadate and 2,5-di-(t- butyl)-1,4-hydroquinone (BHQ), both known to interact with SERCA pump, induced calcium release by permeabilized parasites when the medium fr ee calcium concentration was kept at 3.5 mu M. The tumor promoter thap sigargin also caused elevation of the free calcium concentration in pe rmeabilized parasites. Our results support the view that P. chabaudi s equesters calcium in an exchangeable form and maintains its calcium ho meostasis by way of an endoplasmic reticulum Ca2+ pump.