Direct visualization of the trimeric structure of the ASIC1a channel, using AFM imaging

Biochem Biophys Res Commun. 2008 Aug 8;372(4):752-5. doi: 10.1016/j.bbrc.2008.05.100. Epub 2008 Jun 2.


There has been confusion about the subunit stoichiometry of the degenerin family of ion channels. Recently, a crystal structure of acid-sensing ion channel (ASIC) 1a revealed that it assembles as a trimer. Here, we used atomic force microscopy (AFM) to image unprocessed ASIC1a bound to mica. We detected a mixture of subunit monomers, dimers and trimers. In some cases, triple-subunit clusters were clearly visible, confirming the trimeric structure of the channel, and indicating that the trimer sometimes disaggregated after adhesion to the mica surface. This AFM-based technique will now enable us to determine the subunit arrangement within heteromeric ASICs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acid Sensing Ion Channels
  • Aluminum Silicates / chemistry
  • Humans
  • Microscopy, Atomic Force*
  • Nerve Tissue Proteins / chemistry*
  • Nerve Tissue Proteins / ultrastructure*
  • Protein Subunits / chemistry
  • Sodium Channels / chemistry*
  • Sodium Channels / ultrastructure*


  • ASIC1 protein, human
  • Acid Sensing Ion Channels
  • Aluminum Silicates
  • Nerve Tissue Proteins
  • Protein Subunits
  • Sodium Channels
  • mica