Inositol 1,4,5-trisphosphate binding sites copurify with the putative Ca-storage protein calreticulin in rat liver
|Published in||Cell Calcium. 1993, vol. 14, no. 6, p. 485-492|
|Abstract||Rat liver was homogenized and subjected to differential centrifugation. When the low speed nuclear pellet was processed on a Percoll gradient, plasma membrane markers and Ins(1,4,5)P3 binding activity purified together. The high speed (microsomal) fraction was subfractionated by sucrose density gradient centrifugation, resulting in 10-fold enrichment of [32P]-Ins(1,4,5)P3 binding. In the sucrose density gradient fractions there was an inverse relationship between the enrichment of plasma membrane markers and Ins(1,4,5)P3 binding sites. Endoplasmic reticulum markers showed a moderate enrichment in the fractions displaying high Ins(1,4,5)P3 binding activity. Calcium binding proteins in the homogenate and in the microsomal subfractions were separated by SDS/PAGE. A 60 kD protein, stained metachromatically with Stains-All was identified as calreticulin with immunoblotting. Its enrichment pattern was similar to that of Ins(1,4,5)P3 binding sites, indicating the co-existence of these two elements of Ca(2+)-metabolism in the same intracellular compartment in the liver.|
|Keywords||Animals — Biological Markers — Calcium Channels — Calcium-Binding Proteins/ isolation & purification — Calreticulin — Cell Compartmentation — Cell Fractionation — Cell Membrane/chemistry — Centrifugation, Density Gradient — Electrophoresis, Polyacrylamide Gel — Endoplasmic Reticulum/chemistry — Female — Immunoblotting — Inositol 1,4,5-Trisphosphate/metabolism — Inositol 1,4,5-Trisphosphate Receptors — Liver/ chemistry/ultrastructure — Microsomes, Liver/chemistry — Molecular Weight — Rats — Rats, Wistar — Receptors, Cell Surface/ isolation & purification — Receptors, Cytoplasmic and Nuclear — Ribonucleoproteins/ isolation & purification — Subcellular Fractions/ chemistry|
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|ENYEDI, P. et al. Inositol 1,4,5-trisphosphate binding sites copurify with the putative Ca-storage protein calreticulin in rat liver. In: Cell Calcium, 1993, vol. 14, n° 6, p. 485-492. https://archive-ouverte.unige.ch/unige:9317|