Neurexin IV, caspr and paranodin--novel members of the neurexin family: encounters of axons and glia

Trends Neurosci. 1998 Oct;21(10):444-9. doi: 10.1016/s0166-2236(98)01267-3.


Axonal insulation is of key importance for the proper propagation of action potentials. In Drosophila and other invertebrates, it has recently been demonstrated that septate junctions play an essential role in axonal insulation or blood-brain-barrier formation. Neurexin IV, a molecular component of Drosophila septate junctions, has been shown to be essential for axonal insulation in the PNS in embryos and larvae. Interestingly, a vertebrate homolog of Neurexin IV, caspr--also named paranodin--has been shown to localize to septate-like junctional structures. These vertebrate junctions are localized to the paranodal region of the nodes of Ranvier, between axons and Schwann cells. Caspr/paranodin might play an important role in barrier formation, and link neuronal membrane components with the axonal cytoskeletal network.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Action Potentials / physiology
  • Animals
  • Axons / metabolism*
  • Axons / ultrastructure
  • Blood-Brain Barrier / physiology*
  • Cell Adhesion Molecules, Neuronal*
  • Drosophila / physiology
  • Drosophila Proteins*
  • Insect Proteins / physiology*
  • Membrane Glycoproteins / physiology*
  • Membrane Proteins / physiology*
  • Molecular Structure
  • Myelin Sheath / physiology
  • Nerve Tissue Proteins / physiology*
  • Neuroglia / metabolism*
  • Neuroglia / ultrastructure
  • Neuropeptides / physiology*
  • Neurotransmitter Agents / metabolism
  • Ranvier's Nodes / ultrastructure
  • Receptors, Cell Surface / physiology*
  • Synaptic Membranes / ultrastructure


  • Cell Adhesion Molecules, Neuronal
  • Drosophila Proteins
  • Insect Proteins
  • Membrane Glycoproteins
  • Membrane Proteins
  • Nerve Tissue Proteins
  • Neuropeptides
  • Neurotransmitter Agents
  • Nrx protein, Drosophila
  • Receptors, Cell Surface