11
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: not found

      Regulation of calcium signals in the nucleus by a nucleoplasmic reticulum.

      Nature cell biology
      Active Transport, Cell Nucleus, physiology, Calcium, metabolism, Calcium Channels, Calcium Signaling, genetics, Cell Membrane, Cell Nucleus Structures, ultrastructure, Cytosol, Endoplasmic Reticulum, Eukaryotic Cells, cytology, Humans, Inositol 1,4,5-Trisphosphate, pharmacology, Inositol 1,4,5-Trisphosphate Receptors, Microscopy, Confocal, Nuclear Envelope, Photochemistry, Protein Kinase C, Protein Transport, Receptors, Cytoplasmic and Nuclear, agonists, Tumor Cells, Cultured

      Read this article at

      ScienceOpenPublisherPMC
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Calcium is a second messenger in virtually all cells and tissues. Calcium signals in the nucleus have effects on gene transcription and cell growth that are distinct from those of cytosolic calcium signals; however, it is unknown how nuclear calcium signals are regulated. Here we identify a reticular network of nuclear calcium stores that is continuous with the endoplasmic reticulum and the nuclear envelope. This network expresses inositol 1,4,5-trisphosphate (InsP3) receptors, and the nuclear component of InsP3-mediated calcium signals begins in its locality. Stimulation of these receptors with a little InsP3 results in small calcium signals that are initiated in this region of the nucleus. Localized release of calcium in the nucleus causes nuclear protein kinase C (PKC) to translocate to the region of the nuclear envelope, whereas release of calcium in the cytosol induces translocation of cytosolic PKC to the plasma membrane. Our findings show that the nucleus contains a nucleoplasmic reticulum with the capacity to regulate calcium signals in localized subnuclear regions. The presence of such machinery provides a potential mechanism by which calcium can simultaneously regulate many independent processes in the nucleus.

          Related collections

          Most cited references30

          • Record: found
          • Abstract: not found
          • Article: not found

          Two-photon laser scanning fluorescence microscopy

            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Range of messenger action of calcium ion and inositol 1,4,5-trisphosphate.

            The range of messenger action of a point source of Ca2+ or inositol 1,4,5-trisphosphate (IP3) was determined from measurements of their diffusion coefficients in a cytosolic extract from Xenopus laevis oocytes. The diffusion coefficient (D) of [3H]IP3 injected into an extract was 283 microns 2/s. D for Ca2+ increased from 13 to 65 microns 2/s when the free calcium concentration was raised from about 90 nM to 1 microM. The slow diffusion of Ca2+ in the physiologic concentration range results from its binding to slowly mobile or immobile buffers. The calculated effective ranges of free Ca2+ before it is buffered, buffered Ca2+, and IP3 determined from their diffusion coefficients and lifetimes were 0.1 micron, 5 microns, and 24 microns, respectively. Thus, for a transient point source of messenger in cells smaller than 20 microns, IP3 is a global messenger, whereas Ca2+ acts in restricted domains.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Distinct functions of nuclear and cytoplasmic calcium in the control of gene expression.

              Calcium entry into neuronal cells through voltage or ligand-gated ion channels triggers neuronal activity-dependent gene expression critical for adaptive changes in the nervous system. Cytoplasmic calcium transients are often accompanied by an increase in the concentration of nuclear calcium, but the functional significance of such spatially distinct calcium signals is unknown. Here we show that gene expression is differentially controlled by nuclear and cytoplasmic calcium signals which enable a single second messenger to generate diverse transcriptional responses. We used nuclear microinjection of a non-diffusible calcium chelator to block increases in nuclear, but not cytoplasmic, calcium concentrations following activation of L-type voltage-gated calcium channels. We showed that increases in nuclear calcium concentration control calcium-activated gene expression mediated by the cyclic-AMP-response element (CRE), and demonstrated that the CRE-binding protein CREB can function as a nuclear calcium-responsive transcription factor. A second signalling pathway, activating transcription through the serum-response element (SRE), is triggered by a rise in cytoplasmic calcium and does not require an increase in nuclear calcium.
                Bookmark

                Author and article information

                Comments

                Comment on this article