Open AccessATP‐dependent Ca 2+ transport in vesicles isolated from the bile canalicular region of the hepatocyte plasma membrane
Author(s) -
BACHS Oriol,
FAMULSKI Konrad S.,
MIRABELLI Francesca,
CARAFOLI Ernesto
Publication year - 1985
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1985.tb08710.x
Subject(s) - vanadate , hepatocyte , atpase , membrane , calmodulin , vesicle , biochemistry , chemistry , phosphorylation , biophysics , membrane transport , plasma membrane ca2+ atpase , ion transporter , biology , enzyme , in vitro
Three plasma membrane subfractions have been isolated and characterized from rat liver cells. The high affinity Ca 2+ ‐stimulated ATPase is highly enriched in the bile canalicular subfraction. Taking into account cross‐contamination by the blood sinusoidal and lateral membranes it is suggested that the high‐affinity Ca 2+ ‐ATPase is located exclusively in this fraction. The high‐affinity Ca 2+ ‐ATPase is coupled to Ca 2+ transport, is calmodulin‐insensitive, sensitive to vanadate under appropriate experimental conditions and is strongly inhibited by La 3+ . In the presence of Ca 2+ and ATP the ATPase forms a phosphorylated intermediate of molecular mass about 200 kDa.