@entity460 homeostasis in XXXX .

@entity1 @entity11040 @entity1025 @entity1527 @entity8581 @entity3739 @entity598 @entity593 @entity855 @entity1391 @entity1919 @entity460 @entity141 @entity8870 @entity23495
By using the fluorescent @entity141 indicator @entity593 , submicromolar levels of intracellular @entity141 have been detected in @entity1527 different stages. The intracellular transport mechanisms involved in maintaining @entity141 homeostasis in @entity1527 have been characterized by measuring @entity141 transport in @entity11040 -permeabilized cells. Two intracellular @entity460 transport systems have been detected. @entity141 uptake by the mitochondria occurs by an electrophoretic mechanism, is inhibited by @entity8581 , @entity23495 , and @entity3739 red, and stimulated by respiratory substrates, @entity1391 and @entity598 . This pool has a high capacity and low affinity for @entity141 and is able to buffer external @entity141 at concentrations in the range of 0.6-0.7 microM. @entity141 uptake by the endoplasmic reticulum is inhibited by high concentrations of @entity8870 and anticalmodulin agents, and stimulated by @entity855 . This pool has a low capacity and a high affinity for @entity141 and is able to buffer external @entity141 at concentrations in the range of 0.05-1.0 microM. In addition, calmodulin has been purified from @entity1527 epimastigotes and shown to stimulate the homologous plasma membrane @entity141 -ATPase and @entity1919 phosphodiesterase. The gene encoding this protein has been cloned and sequenced and shown to have a great homology to @entity1 calmodulin. The role of the plasma membrane of @entity1527 in the regulation of [ @entity141 ]i has been studied using @entity593 -loaded epimastigotes or plasma membrane vesicles prepared from epimastigotes. Plasma membrane vesicles transport @entity141 in the presence of @entity1025 and have a high affinity, vanadate-sensitive (Ca(2+)-Mg2+)-ATPase with an apparent Km for free @entity141 of 0.3 microM.(ABSTRACT TRUNCATED AT 250 WORDS)
