Reversible translocation and activity-dependent localization of the calcium-myristoyl switch protein VILIP-1 to different membrane compartments in living hippocampal neurons

J Neurosci. 2002 Sep 1;22(17):7331-9. doi: 10.1523/JNEUROSCI.22-17-07331.2002.

Abstract

Visinin-like protein-1 (VILIP-1) belongs to the family of neuronal calcium sensor (NCS) proteins, a neuronal subfamily of EF-hand [corrected] calcium-binding proteins that are myristoylated at their N termini. NCS proteins are discussed to play roles in calcium-dependent signal transduction of physiological and pathological processes in the CNS. The calcium-dependent membrane association, the so-called calcium-myristoyl switch, localizes NCS proteins to a distinct cellular signaling compartment and thus may be a critical mechanism for the coordinated regulation of signaling cascades. To study whether the biochemically defined calcium-myristoyl switch of NCS proteins can occur in living neuronal cells, the reversible and stimulus-dependent translocation of green fluorescent protein (GFP)-tagged VILIP-1 to subcellular targets was examined by fluorescence microscopy in transfected cell lines and hippocampal primary neurons. In transiently transfected NG108-15 and COS-7 cells, a translocation of diffusely distributed VILIP-1-GFP but not of myristoylation-deficient VILIP-1-GFP to the plasma membrane and to intracellular targets, such as Golgi membranes, occurred after raising the intracellular calcium concentration with a calcium ionophore. The observed calcium-dependent localization was completely reversed after depletion of intracellular calcium by EGTA. Interestingly, a fast and reversible translocation of VILIP-1-GFP and translocation of endogenous VILIP-1 to specialized membrane structures was also observed after a depolarizing stimulus or activation of glutamate receptors in hippocampal neurons. These results show for the first time the reversibility and stimulus-dependent occurrence of the calcium-myristoyl switch in living neurons, suggesting a physiological role as a signaling mechanism of NCS proteins, enabling them to activate specific targets localized in distinct membrane compartments.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • COS Cells
  • Calcium / metabolism
  • Calcium-Binding Proteins / genetics
  • Calcium-Binding Proteins / metabolism*
  • Cell Compartmentation / physiology*
  • Cell Line
  • Green Fluorescent Proteins
  • Hippocampus / metabolism*
  • Internet
  • Intracellular Fluid / metabolism
  • Intracellular Membranes / metabolism*
  • Luminescent Proteins / genetics
  • Mice
  • Microscopy, Fluorescence
  • Microscopy, Video
  • Myristates / metabolism
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism*
  • Neurocalcin
  • Neurons / cytology
  • Neurons / metabolism*
  • Protein Transport / physiology
  • Rats
  • Receptors, Calcium-Sensing*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Signal Transduction / physiology
  • Transfection
  • Video Recording

Substances

  • Calcium-Binding Proteins
  • Luminescent Proteins
  • Myristates
  • Nerve Tissue Proteins
  • Neurocalcin
  • Receptors, Calcium-Sensing
  • Recombinant Fusion Proteins
  • Vsnl1 protein, mouse
  • Vsnl1 protein, rat
  • Green Fluorescent Proteins
  • Calcium