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P‐type Proton ATPases are Involved in Intracellular Calcium and Proton Uptake in the Plant Parasite Phytomonas francai
Author(s) -
Miranda Kildare,
Vercesi Anibal E.,
Catisti Rosana,
De Souza Wanderley,
Rodrigues Claudia O.,
Docampo Roberto
Publication year - 2005
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/j.1550-7408.2005.3309rr.x
Subject(s) - biology , atpase , parasite hosting , intracellular , calcium , proton , biochemistry , calcium in biology , microbiology and biotechnology , botany , biophysics , enzyme , medicine , physics , quantum mechanics , world wide web , computer science
. The use of digitonin to permeabilize the plasma membrane of promastigotes of Phytomonas francai allowed the identification of two non‐mitochondrial Ca 2+ compartments; one sensitive to ionomycin and vanadate (neutral or alkaline), possibly the endoplasmic reticulum, and another sensitive to the combination of nigericin plus ionomycin (acidic), possibly the acidocalcisomes. A P‐type (phospho‐intermediate form) Ca 2+ ‐ATPase activity was found to be responsible for intracellular Ca 2+ transport in these cells, with no evidence of a mitochondrial Ca 2+ transport activity. ATP‐driven acidification of internal compartments in cell lysates and cells mechanically permeabilized was assayed spectrophotometrically with acridine orange. This activity was inhibited by low concentrations of vanadate and digitonin, was insensitive to bafilomycin A 1 , and stimulated by Na + ions. Taken together, our results indicate that P‐type ATPases are involved in intracellular Ca 2+ and H + transport in promastigotes of P. francai .