Schistosoma mansoni Ca2+-ATPase SMA2 restores viability to yeast Ca2+-ATPase-deficient strains and functions in calcineurin-mediated Ca2+ tolerance.
The sarco(endo)plasmic reticulum of animal cells contains an ATP-powered Ca2+ pump that belongs to the P-type family of membrane-bound cation-translocating enzymes. In Schistosoma mansoni, the sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) is encoded by the SMA1 and SMA2 genes. A full-length SMA2 cDNA clone was isolated, sequenced, and expressed into a yeast Ca2+-ATPase-deficient strain requiring plasmid-borne rabbit SERCA1a for viability. The S. mansoni Ca2+-ATPase supports growth of mutant cells lacking SERCA1a, indicating functional expression in yeast and a role in calcium sequestration. Subcellular fractionation showed that the SMA2 ATPase is localized in yeast internal membranes. SMA2 expression was found to be associated with thapsigargin-sensitive, Ca2+-dependent ATPase activity. The activity increased 2-fold upon calcineurin inactivation, which correlates with in vivo stimulated contribution of SMA2 in calcium tolerance. These results suggest that calcineurin controls calcium homeostasis by inhibiting Ca2+-ATPase activity in an internal compartment.
Unité de Biochimie Physiologique, Université Catholique de Louvain, Place Croix du Sud 2-20, B-1348 Louvain-la-Neuve, Belgium.
E
E
Talla
R L
RL
de Mendonça
I
I
Degand
A
A
Goffeau
M
M
Ghislain
D000595:Amino Acid Sequence; D000818:Animals; D019703:Calcineurin / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology*; D000252:Calcium-Transporting ATPases / Q000235:genetics / Q000378:metabolism*; D002451:Cell Compartmentation; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004351:Drug Resistance; D017238:Genes, Helminth; D005816:Genetic Complementation Test; D007425:Intracellular Membranes / Q000201:enzymology; D007527:Isoenzymes; D008969:Molecular Sequence Data; D011817:Rabbits; D012441:Saccharomyces cerevisiae / Q000235:genetics; D012519:Sarcoplasmic Reticulum / Q000201:enzymology*; D012550:Schistosoma mansoni / Q000201:enzymology*; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D007527:Isoenzymes; D019703:Calcineurin; D000252:Calcium-Transporting ATPases; D002118:Calcium