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Proc Natl Acad Sci U S A. 2009 Mar 3;106(9):3573-8. doi: 10.1073/pnas.0813402106. Epub 2009 Feb 13.

Oxidant regulated inter-subunit disulfide bond formation between ASIC1a subunits.

Author information

1
Howard Hughes Medical Institute and Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.

Abstract

The acid-sensing ion channel-1a (ASIC1a) is composed of 3 subunits and is activated by a decrease in extracellular pH. It plays an important role in diseases associated with a reduced pH and production of oxidants. Previous work showed that oxidants reduce ASIC1a currents. However, the effects on channel structure and composition are unknown. We found that ASIC1a formed inter-subunit disulfide bonds and the oxidant H(2)O(2) increased this link between subunits. Cys-495 in the ASIC1a C terminus was particularly important for inter-subunit disulfide bond formation, although other C-terminal cysteines contributed. Inter-subunit disulfide bonds also produced some ASIC1a complexes larger than trimers. Inter-subunit disulfide bond formation reduced the proportion of ASIC1a located on the cell surface and contributed to the H(2)O(2)-induced decrease in H(+)-gated current. These results indicate that channel function is controlled by disulfide bond formation between intracellular residues on distinct ASIC1a subunits. They also suggest a mechanism by which the redox state can dynamically regulate membrane protein activity by forming intracellular bridges.

PMID:
19218436
PMCID:
PMC2642663
DOI:
10.1073/pnas.0813402106
[Indexed for MEDLINE]
Free PMC Article
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