Mtap2 is a constituent of the protein network that regulates twik-related K+ channel expression and trafficking

J Neurosci. 2008 Aug 20;28(34):8545-52. doi: 10.1523/JNEUROSCI.1962-08.2008.

Abstract

Twik-related K+ (TREK) channels produce background currents that regulate cell excitability. In vivo, TREK-1 is involved in neuronal processes including neuroprotection against ischemia, general anesthesia, pain perception, and mood. Recently, we demonstrated that A-kinase anchoring protein AKAP150 binds to a major regulatory domain of TREK-1, promoting drastic changes in channel regulation by polyunsaturated fatty acids, pH, and stretch, and by G-protein-coupled receptors to neurotransmitters and hormones. Here, we show that the microtubule-associated protein Mtap2 is another constituent of native TREK channels in the brain. Mtap2 binding to TREK-1 and TREK-2 does not affect directly channel properties but enhances channel surface expression and current density. This effect relies on Mtap2 binding to microtubules. Mtap2 and AKAP150 interacting sites in TREK-1 are distinct and both proteins can dock simultaneously. Their effects on TREK-1 surface expression and activation are cumulative. In neurons, the three proteins are simultaneously detected in postsynaptic dense bodies. AKAP150 and Mtap2 put TREK channels at the center of a complex protein network that finely tunes channel trafficking, addressing, and regulation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • A Kinase Anchor Proteins / metabolism*
  • Animals
  • Binding Sites
  • Brain / metabolism
  • COS Cells
  • Cells, Cultured
  • Chlorocebus aethiops
  • Dogs
  • Female
  • Immunoprecipitation
  • Mice
  • Microtubule-Associated Proteins / genetics
  • Microtubule-Associated Proteins / metabolism*
  • Microtubules / metabolism
  • Mutation
  • Oocytes / metabolism
  • Potassium Channels, Tandem Pore Domain / metabolism*
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism
  • Protein Transport / physiology
  • Tissue Distribution
  • Transfection
  • Xenopus

Substances

  • A Kinase Anchor Proteins
  • Akap5 protein, mouse
  • Microtubule-Associated Proteins
  • Mtap2 protein, mouse
  • Potassium Channels, Tandem Pore Domain
  • Protein Isoforms