Cell cycle-related changes in the conducting properties of r-eag K+ channels

J Cell Biol. 1998 Nov 2;143(3):767-75. doi: 10.1083/jcb.143.3.767.


Release from arrest in G2 phase of the cell cycle causes profound changes in rat ether-à-go-go (r-eag) K+ channels heterologously expressed in Xenopus oocytes. The most evident consequence of the onset of maturation is the appearance of rectification in the r-eag current. The trigger for these changes is located downstream of the activation of mitosis-promoting factor (MPF). We demonstrate here that the rectification is due to a voltage-dependent block by intracellular Na+ ions. Manipulation of the intracellular Na+ concentration indicates that the site of Na+ block is located approximately 45% into the electrical distance of the pore and is only present in oocytes undergoing maturation. Since the currents through excised patches from immature oocytes exhibited a fast rundown, we studied CHO-K1 cells permanently transfected with r-eag. These cells displayed currents with a variable degree of block by Na+ and variable permeability to Cs+. Partial synchronization of the cultures in G0/G1 or M phases of the cell cycle greatly reduced the variability. The combined data obtained from mammalian cells and oocytes strongly suggest that the permeability properties of r-eag K+ channels are modulated during cell cycle-related processes.

MeSH terms

  • Animals
  • CHO Cells
  • Cell Cycle / physiology*
  • Cell Membrane Permeability
  • Cesium / metabolism
  • Cricetinae
  • Enzyme Activation
  • Ether-A-Go-Go Potassium Channels
  • Intracellular Fluid / physiology
  • Ions
  • Maturation-Promoting Factor / metabolism
  • Potassium Channels / physiology*
  • Sodium / metabolism


  • Ether-A-Go-Go Potassium Channels
  • Ions
  • Potassium Channels
  • Cesium
  • Sodium
  • Maturation-Promoting Factor