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Independent regulation of Ca2+ entry and release from internal stores in activated B cells.
- Source :
- The Journal of Experimental Medicine; July 1989, Vol. 170 Issue: 1 p315-320, 6p
- Publication Year :
- 1989
-
Abstract
- Addition of crosslinking antibody to B lymphocytes results in a rapid rise in cytoplasmic-free Ca2+ ([Ca2+]i) due to release of Ca2+ from internal stores and uptake of Ca2+ across the plasma membrane. Inositol 1,4,5-trisphosphate is believed to mediate the release of internal Ca2+ stores and has also been proposed to mediate extracellular Ca2+ entry. We have compared the properties of these two pathways for Ca2+ mobilization by dissociating the [Ca2+]i changes in ligand-activated human B cells after loading of the cells with the Ca2+ chelator BAPTA. In the present paper we show that: (a) the sustained increase in [Ca2+]i is due to increased unidirectional influx of external [Ca2+]i; (b) entry of extracellular Ca2+, but not release of internal stores, is sensitive to the transmembrane potential; and (c) entry of extracellular Ca2+, but not release of internal stores, is inhibited by increasing [Ca2+]i. These findings suggest that the permeation pathways mediating the translocation of Ca2+ across the plasma membrane and endoplasmic reticulum membrane are not identical.
Details
- Language :
- English
- ISSN :
- 00221007 and 15409538
- Volume :
- 170
- Issue :
- 1
- Database :
- Supplemental Index
- Journal :
- The Journal of Experimental Medicine
- Publication Type :
- Periodical
- Accession number :
- ejs57387099
- Full Text :
- https://doi.org/10.1084/jem.170.1.315