The calcium pump of the liver nuclear membrane is identical to that of endoplasmic reticulum.

作者：L Lanini, Oriol Bachs, Ernesto Carafoli · 发表于：Journal of Biological Chemistry · 年份：1992 · DOI：10.1016/s0021-9258(19)49945-6 · 被引用次数：145 · 研究领域：Mitochondrial Function and Pathology、Endoplasmic Reticulum Stress and Disease、Trace Elements in Health

The envelope membrane of rat liver nuclei contains a P-type Ca(2+)-transporting pump, revealed by the presence of a Ca(2+)-stimulated phosphoenzyme. The level of the nuclear phosphoenzyme in autoradiographed polyacrylamide gels was decreased by lanthanum, as typically observed in the endoplasmic reticulum Ca2+ pump. It was also decreased by thapsigargin and 2,5-di-(tert-butyl)-1,4-benzohydroquinone, two accepted inhibitors of the endoplasmic reticulum Ca(2+)-ATPase. Comparative proteolysis of the phosphorylated enzyme of liver microsomes (endoplasmic reticulum) and nuclear membranes revealed an identical cleavage pattern. In addition, antibodies raised against the endoplasmic reticulum Ca2+ pump cross-reacted with the pump in the nuclear membranes. The findings show that nuclear membranes contain a Ca(2+)-transporting pump closely related to that of the endoplasmic reticulum, if not identical to it. The pump is likely to be involved in the control of nuclear free calcium.