The effect of ethanol on the plasma membrane calcium pump is isoform-specific.
The effect of ethanol has been studied on four different isoforms of the plasma membrane Ca2+-ATPase expressed in Sf9 cells with the help of the baculovirus system. The PMCA2CI protein was maximally activated by 0.5% ethanol, a concentration 8-10 times lower than that needed to obtain the same effect on the PMCA4 protein or on the pump of erythrocyte membranes, which is a mixture of isoforms 1 and 4. Experiments performed with truncated pumps indicated that the stimulation by ethanol was lost if the C-terminal region between Lys1065 and Lys1161, encompassing the calmodulin binding domain, was removed. These observations indicate that the stimulation is the result of a direct interaction of ethanol with the C-terminal regulatory domain of the Ca2+ pump.
Cervino
V
V
Laboratory of Biochemistry, Swiss Federal Institute of Technology, CH-8092 Zürich, Switzerland.
Benaim
G
G
Carafoli
E
E
Guerini
D
D
D000818:Animals; D016367:Baculoviridae / Q000235:genetics; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology; D000431:Ethanol / Q000494:pharmacology*; D018411:Spodoptera
D002147:Calmodulin; D000431:Ethanol; D000252:Calcium-Transporting ATPases