The uptake of divalent cations and the intracellular concentration of calcium in PC12 cells were studied by flow cytometric analysis using the calcium-sensitive dye, Fluo-3, under a variety of conditions. In particular the actions of nerve growth factor were analyzed. The data show that nerve growth
Regulation of intracellular calcium in chick embryo fibroblast: Calcium uptake by the microsomal fraction
✍ Scribed by Leon Moore; Ira Pastan
- Publisher
- John Wiley and Sons
- Year
- 1977
- Tongue
- English
- Weight
- 594 KB
- Volume
- 91
- Category
- Article
- ISSN
- 0021-9541
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
The total membrane fraction of a chick embryo fibroblast (CEF) homogenate accumulates calcium in an energy‐dependent manner. This activity can be dissociated into azide‐sensitive and azide‐insensitive components. The azide‐sensitive component of calcium uptake is believed to represent mitochondrial calcium uptake. The azide‐insensitive component of calcium uptake is enhanced by the presence of a calcium trapping agent such as oxalate, and cannot utilize, ADP, inorganic phosphate and a Krebs cycle substrate to support uptake. The distribution of the azide‐insensitive calcium uptake in subcellular fractions suggests that this uptake occurs in other than mitochondrial membranes. The membranes most likely to contribute to the azide‐insensitive component of calcium uptake are the endoplasmic reticulum and plasma membrane. A microsomal preparation from CEF cells is essentially devoid of the azide‐sensitive calcium uptake activity. This microsomal activity is similar in characteristics to the sarcoplasmic reticulum of skeletal muscle. However the specific activity of CEF microsomal calcium uptake system is much less than that found in the skeletal muscle system. The transport of calcium by these membranes provide a mechanism for the regulation of cytosol calcium levels and may play a role in the control of movement and growth of cultured cells.
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