PMID: 6108951Jan 10, 1981Paper

The regulation of endoplasmic reticulum calcium uptake of adipocytes by cytoplasmic calcium.

The Journal of Biological Chemistry
B L BlackJ M McDonald

Abstract

The endoplasmic reticulum of adipocytes can accumulate calcium by an active transport system linked to (Ca2+ + Mg2+)-ATPase activity (Black, B. L., Jarett, L., and McDonald, J. M. (1980) Biochim. Biophys. Acta 596, 359-371). The ability of this transport system to regulate intracellular calcium levels was tested by incubating adipocytes with various concentrations of calcium and measuring the calcium transport activity in subsequently isolated endoplasmic reticulum vesicles (microsomes). The calcium transport system responded to changes in extracellular calcium concentration; 2.5 mM calcium elicited a transport rate 21 to 34% greater than that of microsomes from cells incubated in the absence of calcium. The stimulatory effect of extracellular calcium was maximum at 2.5 mM, was reduced in magnitude at higher calcium concentrations, was demonstrable after a cell incubation period as short as 5 min, and was maintained for an additional 60 min. The transport system also could be modulated by preincubating isolated microsomes in calcium-containing medium prior to assay of calcium transport. Preincubation with low calcium concentrations elicited a 22 to 33% stimulation of subsequent calcium uptake with half-maximal stimulation at 0....Continue Reading

Related Concepts

Related Feeds

ASBMB Publications

The American Society for Biochemistry and Molecular Biology (ASBMB) includes the Journal of Biological Chemistry, Molecular & Cellular Proteomics, and the Journal of Lipid Research. Discover the latest research from ASBMB here.