The CD26-related dipeptidyl aminopeptidase-like protein DPPX is a critical component of neuronal A-type K+ channels

Neuron. 2003 Feb 6;37(3):449-61. doi: 10.1016/s0896-6273(02)01185-6.


Subthreshold-activating somatodendritic A-type potassium channels have fundamental roles in neuronal signaling and plasticity which depend on their unique cellular localization, voltage dependence, and kinetic properties. Some of the components of A-type K(+) channels have been identified; however, these do not reproduce the properties of the native channels, indicating that key molecular factors have yet to be unveiled. We purified A-type K(+) channel complexes from rat brain membranes and found that DPPX, a protein of unknown function that is structurally related to the dipeptidyl aminopeptidase and cell adhesion protein CD26, is a novel component of A-type K(+) channels. DPPX associates with the channels' pore-forming subunits, facilitates their trafficking and membrane targeting, reconstitutes the properties of the native channels in heterologous expression systems, and is coexpressed with the pore-forming subunits in the somatodendritic compartment of CNS neurons.

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.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cell Adhesion / physiology
  • Cerebellum / cytology
  • Dendrites / enzymology
  • Dipeptidyl Peptidase 4 / genetics
  • Dipeptidyl-Peptidases and Tripeptidyl-Peptidases
  • Extracellular Matrix / metabolism
  • Membrane Proteins / chemistry
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Molecular Sequence Data
  • Nerve Tissue Proteins / chemistry
  • Nerve Tissue Proteins / genetics*
  • Nerve Tissue Proteins / metabolism*
  • Neurons / enzymology*
  • Neurons / ultrastructure
  • Oocytes / physiology
  • Potassium Channels / chemistry
  • Potassium Channels / genetics*
  • Potassium Channels / metabolism*
  • Potassium Channels, Voltage-Gated*
  • Precipitin Tests
  • Protein Transport / physiology
  • Rats
  • Rats, Sprague-Dawley
  • Shal Potassium Channels
  • Xenopus


  • Membrane Proteins
  • Nerve Tissue Proteins
  • Potassium Channels
  • Potassium Channels, Voltage-Gated
  • Shal Potassium Channels
  • DPP6 protein, rat
  • Dipeptidyl-Peptidases and Tripeptidyl-Peptidases
  • Dipeptidyl Peptidase 4