Editors' ChoiceCalcium

High Frequency Filter for Ca2+

Science's STKE  07 Jan 2003:
Vol. 2003, Issue 164, pp. tw3-TW3
DOI: 10.1126/stke.2003.164.tw3

Transient changes in intracellular Ca2+ regulate numerous cellular functions including gene expression. Some Ca2+-mediated changes in gene expression are elicited by increases in cytosolic Ca2+ concentration ([Ca2+]c), whereas others require an increase in nuclear Ca2+ concentration ([Ca2+]n). Chamero et al. expressed targeted aequorins in the cytoplasm and nuclei of bovine adrenal chromaffin cells, PC12 cells, and GH3 cells to measure [Ca2+]c and [Ca2+]n and to study the spread of Ca2+ from the cytoplasm to the nucleus following various stimuli. The authors found that stimuli that produced sustained increases in [Ca2+]c, either through Ca2+ entry or through release from intracellular stores, produced similar changes in [Ca2+]n, whereas brief oscillations in [Ca2+]c visualized in individual GH3 cells were dampened during propagation to the nucleus. These data suggest that a kinetic filter limits the effects of high frequency changes in [Ca2+]i on [Ca2+]n but allows sustained Ca2+ signals through. Such a filter could provide a mechanism whereby Ca2+ signals are encoded; this would allow for the differential regulation of processes that depend on increases in either [Ca2+]c or [Ca2+]n.

P. Chamero, C. Villalobos, M. T. Alonso, J. GarcĂ­a-Sancho, Dampening of cytosolic Ca2+ oscillations on propagation to the nucleus. J. Biol. Chem. 277, 50226-50229 (2002). [Abstract] [Full Text]