Lipids driving protein structure? Evolutionary adaptations in Kir channels

Channels (Austin). May-Jun 2010;4(3):139-41. doi: 10.4161/chan.4.3.12129. Epub 2010 May 1.

Abstract

Many eukaryotic channels, transporters and receptors are activated by phosphatidyl inositol bisphosphate (PIP(2)) in the membrane, and every member of the eukaryotic inward rectifier potassium (Kir) channel family requires membrane PIP(2) for activity. In contrast, a bacterial homolog (KirBac1.1) is specifically inhibited by PIP(2). We speculate that a key evolutionary adaptation in eukaryotic channels is the insertion of additional linkers between transmembrane and cytoplasmic domains, revealed by new crystal structures, that convert PIP(2) inhibition to activation. Such an adaptation may reflect a novel evolutionary drive to protein structure, and that was necessary to permit channel function within the highly negatively charged membranes that evolved in the eukaryotic lineage.

Publication types

  • Review

MeSH terms

  • Bacterial Proteins / chemistry
  • Eukaryota / chemistry
  • Evolution, Molecular*
  • Membrane Lipids / physiology*
  • Potassium Channels, Inwardly Rectifying / chemistry*
  • Potassium Channels, Inwardly Rectifying / genetics

Substances

  • Bacterial Proteins
  • Membrane Lipids
  • Potassium Channels, Inwardly Rectifying