Journal of Cell Science 116, e1303 (2003)
Copyright © 2003 The Company of Biologists Limited
Calcium signalling and cell polarity
Generation of complex spatiotemporal Ca2+ signals is critical
for numerous physiological processes. Cells achieve this by localizing
Ca2+ pumps and channels to specific subcellular regions. Inositol
1,4,5-trisphosphate receptors (IP3Rs) that release Ca2+
from the ER, for example, are often concentrated at one pole but this depends
on the cell type. So how are these patterns of receptor localization
established and maintained? Jean-Pierre Mauger and co-workers have used
immunofluoresence confocal microscopy and immunogold EM analysis to probe the
relationship between IP3Rs and polarity in MDCK cells. They observe
that, in non-polarized cells, IP3Rs are present throughout the ER
but that as the cells polarize IP3Rs become concentrated around
tight junctions at the apical region of the lateral membrane (see
p. 2791). The authors go on to
show that culturing cells in Ca2+-depleted medium, which disrupts
polarity, rapidly abolishes the pattern of IP3R localization and
that this slowly returns following restoration of Ca2+, which
repolarizes cells. They conclude that receptor localization is intricately
linked to cell polarization, suggesting that IP3Rs are recruited to
forming tight junctions, where local Ca2+ release could have
numerous roles.
Related articles in JCS:
- The type 3 inositol 1,4,5-trisphosphate receptor is concentrated at the tight junction level in polarized MDCK cells
- Pascal Colosetti, Richard E. A. Tunwell, Caroline Cruttwell, Jean-Pierre Arsanto, Jean-Pierre Mauger, and Doris Cassio
JCS 2003 116: 2791-2803.
[Abstract]
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