The small neurotoxin apamin blocks not only small conductance Ca2+ activated K+ channels (SK type) but also the voltage dependent Kv1.3 channel

Eur Biophys J. 2017 Sep;46(6):517-523. doi: 10.1007/s00249-016-1196-0. Epub 2017 Jan 20.

Abstract

Apamin is frequently used as a specific blocker of small-conductance Ca2+-activated (SK type) K+ channels. Here we show that the small neurotoxin is not as specific as anticipated. It is also a high-affinity inhibitor with an IC50 of 13 nM of the Kv1.3 channel; it blocks the latter with potency similar to the Kv1.3 blocker PAP-1. Since SK type channels and Kv1.3 channels are frequently coexpressed in different tissues such as cells of the immune system, apamin must be used with caution as a pharmacological tool.

Keywords: Apamin block; Jurkat; Kv1.3 channel; Lymphocytes; SK channel.

MeSH terms

  • Apamin / toxicity*
  • Electrophysiological Phenomena / drug effects
  • HEK293 Cells
  • Humans
  • Inhibitory Concentration 50
  • Kv1.3 Potassium Channel / antagonists & inhibitors*
  • Kv1.3 Potassium Channel / metabolism
  • Neurotoxins / toxicity*
  • Pancreatitis-Associated Proteins
  • Potassium Channel Blockers / toxicity*
  • Potassium Channels, Calcium-Activated / antagonists & inhibitors*
  • Potassium Channels, Calcium-Activated / metabolism

Substances

  • Kv1.3 Potassium Channel
  • Neurotoxins
  • Pancreatitis-Associated Proteins
  • Potassium Channel Blockers
  • Potassium Channels, Calcium-Activated
  • REG3A protein, human
  • Apamin