Characterization of the plasma-membrane calcium pump from Trypanosoma cruzi.
Despite previous reports [McLaughlin (1985) Mol. Biochem. Parasitol. 15, 189-201; Ghosh, Ray, Sarkar and Bhaduri (1990) J. Biol. Chem. 265, 11345-11351; Mazumder, Mukherjee, Ghosh, Ray and Bhaduri (1992) J. Biol. Chem. 267, 18440-18446] suggesting that the plasma-membrane Ca(2+)-ATPases of different trypanosomatids differ from the Ca2+ pumps present in mammalian cells, Trypanosoma cruzi plasma-membrane Ca(2+)-ATPase shares several characteristics with the Ca2+ pumps present in other systems. This enzyme could be partially purified from epimastigote plasma-membrane vesicles using calmodulin-agarose affinity chromatography. The activity of the partially purified enzyme was stimulated by T. cruzi or bovine brain calmodulin. In addition, the enzyme cross-reacted with antiserum and monoclonal antibody 5F10 raised against human red-blood-cell Ca(2+)-ATPase, has a molecular mass of 140 kDa and forms Ca(2+)-dependent hydroxylamine-sensitive phosphorylated intermediates. These results, together with its high sensitivity to vanadate, indicate that this enzyme belongs to the P-type class of ionic pumps.
Benaim
G
G
Department of Veterinary Pathobiology, University of Illinois at Urbana-Champaign 61801.
Moreno
S N
SN
Hutchinson
G
G
Cervino
V
V
Hermoso
T
T
Romero
P J
PJ
Ruiz
F
F
de Souza
W
W
Docampo
R
R
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000252:Calcium-Transporting ATPases / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D002147:Calmodulin / Q000494:pharmacology; D002417:Cattle; D002462:Cell Membrane / Q000201:enzymology*; D002846:Chromatography, Affinity; D000939:Epitopes / Q000276:immunology; D004912:Erythrocytes / Q000201:enzymology; D006801:Humans; D008854:Microscopy, Electron; D013552:Swine; D014349:Trypanosoma cruzi / Q000201:enzymology*
D000911:Antibodies, Monoclonal; D002147:Calmodulin; D000939:Epitopes; D000252:Calcium-Transporting ATPases