The plasma membrane Ca2+-ATPase protein from red blood cells is not modified in preeclampsia.
Plasma membrane Ca2+-ATPase activity diminishes by about 50% in red blood cells during preeclampsia. We investigated whether the number of Ca2+-ATPase molecules is modified in red cell membranes from preeclamptic pregnant women by measuring the specific phosphorylated intermediate of this enzyme. Also, we isolated the Ca2+-ATPase protein from both normotensive and preeclamptic pregnant women and estimated its molecular weight, and its cross-reactions with specific polyclonal and monoclonal (5F10) antibodies against it. We measured the Ca2+-ATPase activity in a purified state and the effect of known modulators of this ATPase. It was found that the phosphorylated intermediate associated with PMCA is similar for red cell ghosts from normotensive and preeclamptic women, suggesting a similar number of ATPase molecules in these membranes. The molecular weight of the Ca2+-ATPase is around 140 kDa for both normotensive and preeclamptic membranes, and its cross-reactions with specific antibodies is similar, suggesting that the protein structure remains intact in preeclampsia. Calmodulin, ethanol, or both calmodulin plus ethanol, stimulated the Ca2+-ATPase activity to the same extent for both normotensive and preeclamptic preparations. Our results showed that the reduced Ca2+-ATPase activity of the red cell membranes from preeclamptic women is not associated with a defective enzyme, but rather with a high level of lipid peroxidation.
Oviedo
Néstor J
NJ
Laboratorio de Bioenergética Celular, Centro de Biofísica y Bioquímica (CBB), Instituto Venezolano de Investigaciones Científicas (IVIC), AP 21827, Caracas 1020A, Venezuela.
Benaim
Gustavo
G
Cervino
Vincenza
V
Proverbio
Teresa
T
Proverbio
Fulgencio
F
Marín
Reinaldo
R
D000293:Adolescent; D000328:Adult; D000906:Antibodies / Q000276:immunology; D001794:Blood Pressure / Q000502:physiology; D000252:Calcium-Transporting ATPases / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism; D027682:Cation Transport Proteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D004910:Erythrocyte Membrane / Q000201:enzymology*; D000431:Ethanol / Q000378:metabolism; D005260:Female; D006801:Humans; D015227:Lipid Peroxidation; D008970:Molecular Weight; D010920:Placenta / Q000378:metabolism / Q000473:pathology; D053499:Plasma Membrane Calcium-Transporting ATPases; D011225:Pre-Eclampsia / Q000097:blood / Q000201:enzymology*; D011247:Pregnancy; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
D000906:Antibodies; D002147:Calmodulin; D027682:Cation Transport Proteins; D017392:Thiobarbituric Acid Reactive Substances; D000431:Ethanol; D053499:Plasma Membrane Calcium-Transporting ATPases; D000252:Calcium-Transporting ATPases