Ca(2+)-transporting ATPase(s) of the reticulum type in intracellular membranes of Saccharomyces cerevisiae: biochemical identification.
Several lines of evidence are presented to show that the Ca(2+)-ATPase activity of total yeast membranes is due to the reticulum (R) type of Ca(2+)-ATPase: (1) Neither calmodulin nor low concentrations of calmodulin antagonists change Ca2+ uptake; (2) removal of plasma membranes (PM) following Con A treatment of spheroplasts (SP) does not significantly alter Ca2+ uptake by the remaining membranes, but increases its specific activity 3.5-fold; (3) after incubation of membranes with [gamma-32P]ATP, SDS-PAGE shows the formation of acyl phosphate intermediates with molecular masses of around 100, 180-190 and 205 kDa; formation of these acyl phosphates requires Ca2+ and is blocked by cyclopiazonic acid, La3+ ions and in the absence of Ca2+. The data on fractionation of yeast membranes are consistent with the suggestion that both the ER and the Golgi are equipped with Ca(2+)-ATPase(s).
Okorokov
L A
LA
Departamento de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Brazil.
Kuranov AJu
Kuranova
E V
EV
Silva
R dos S
Rdos S
D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000302:isolation & purification / Q000378:metabolism*; D002147:Calmodulin / Q000037:antagonists & inhibitors / Q000378:metabolism; D002458:Cell Fractionation; D004721:Endoplasmic Reticulum / Q000201:enzymology; D006056:Golgi Apparatus / Q000201:enzymology; D007425:Intracellular Membranes / Q000201:enzymology / Q000378:metabolism; D017136:Ion Transport; D010766:Phosphorylation; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000378:metabolism; D013104:Spheroplasts / Q000201:enzymology
D002147:Calmodulin; D000252:Calcium-Transporting ATPases; D002118:Calcium