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

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 dete...

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Bibliographic Details
Published in:Biochemical and biophysical research communications 2008-08, Vol.372 (4), p.752-755
Main Authors: Carnally, Stewart M., Dev, Harveer S., Stewart, Andrew P., Barrera, Nelson P., Van Bemmelen, Miguel X., Schild, Laurent, Henderson, Robert M., Edwardson, J.Michael
Format: Article
Language:English
Subjects:
60 APPLIED LIFE SCIENCES
Acid Sensing Ion Channels
Aluminum Silicates - chemistry
ATOMIC FORCE MICROSCOPY
Channel assembly
CRYSTAL STRUCTURE
DIMERS
Humans
MICA
Microscopy, Atomic Force
MONOMERS
Nerve Tissue Proteins - chemistry
Nerve Tissue Proteins - ultrastructure
Protein Subunits - chemistry
Sodium Channels - chemistry
Sodium Channels - ultrastructure
STOICHIOMETRY
Subunit stoichiometry
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Summary: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.
ISSN:0006-291X
1090-2104
DOI:10.1016/j.bbrc.2008.05.100