The ankyrin repeats of TRPV1 bind multiple ligands and modulate channel sensitivity

Neuron. 2007 Jun 21;54(6):905-18. doi: 10.1016/j.neuron.2007.05.027.

Abstract

TRPV1 plays a key role in nociception, as it is activated by heat, low pH, and ligands such as capsaicin, leading to a burning pain sensation. We describe the structure of the cytosolic ankyrin repeat domain (ARD) of TRPV1 and identify a multiligand-binding site important in regulating channel sensitivity within the TRPV1-ARD. The structure reveals a binding site that accommodates triphosphate nucleotides such as ATP, and biochemical studies demonstrate that calmodulin binds the same site. Electrophysiology experiments show that either ATP or PIP2 prevent desensitization to repeated applications of capsaicin, i.e., tachyphylaxis, while calmodulin plays an opposing role and is necessary for tachyphylaxis. Mutations in the TRPV1-ARD binding site eliminate tachyphylaxis. We present a model for the calcium-dependent regulation of TRPV1 via competitive interactions of ATP and calmodulin at the TRPV1-ARD-binding site and discuss its relationship to the C-terminal region previously implicated in interactions with PIP2 and calmodulin.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adenosine Triphosphate / pharmacokinetics
  • Adenosine Triphosphate / pharmacology
  • Analgesics, Non-Narcotic / pharmacology
  • Animals
  • Ankyrin Repeat*
  • Binding Sites / drug effects
  • Capsaicin / pharmacology
  • Cell Line, Transformed
  • Cloning, Molecular / methods
  • Humans
  • Insecta / cytology
  • Ion Channel Gating*
  • Membrane Potentials / drug effects
  • Membrane Potentials / physiology
  • Models, Biological
  • Models, Molecular
  • Mutagenesis, Site-Directed
  • Patch-Clamp Techniques
  • Protein Binding / drug effects
  • Protein Binding / physiology
  • Protein Structure, Tertiary
  • Rats
  • Receptors, Drug / drug effects
  • Receptors, Drug / physiology
  • TRPV Cation Channels / chemistry*
  • TRPV Cation Channels / genetics*
  • Transfection

Substances

  • Analgesics, Non-Narcotic
  • Receptors, Drug
  • TRPV Cation Channels
  • Trpv1 protein, rat
  • Adenosine Triphosphate
  • Capsaicin