Cell Biology

Calcium and the Nucleoplasmic Reticulum

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Science  09 May 2003:
Vol. 300, Issue 5621, pp. 869
DOI: 10.1126/science.300.5621.869a

Calcium is used in multiple signal transduction events within cells to control multiple cellular activities involved in locomotion, morphogenesis, and secretion. In the nucleus, calcium signals regulate gene transcription and cell growth independently of their effects in the cytosol. In trying to visualize and understand nuclear calcium signals, Echevarria et al. revealed the presence of an intranucleoplasmic reticulum. This reticular network of calcium stores was physically connected to the nuclear envelope and to the endoplasmic reticulum. The nucleoplasmic reticulum was enriched in inositol 1,4,5-trisphophate (InsP3) receptors. Under limited localized stimulation, these InsP3 receptors generated local intra-nuclear calcium signals and stimulated nuclear protein kinase C to translocate to the same specific region of the nuclear envelope. Thus, the nucleoplasmic reticulum may represent a specialized cellular compartment involved in regulating in time and space specific intranuclear signalling events.—SMH

Nature Cell Biol. 5, 440 (2003).

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