Journal article
Assembly of the Epithelial Na+Channel Evaluated Using Sucrose Gradient Sedimentation Analysis
The Journal of biological chemistry, Vol.273(35), pp.22693-22700
08/28/1998
DOI: 10.1074/jbc.273.35.22693
PMID: 9712899
Abstract
Three subunits, alpha, beta, and gamma, contribute to the formation of the epithelial Na+ channel. To investigate the oligomeric assembly of the channel complex, we used sucrose gradient sedimentation analysis to determine the sedimentation properties of individual subunits and heteromultimers comprised of multiple subunits. When the alpha subunit was expressed alone, it first formed an oligomeric complex with a sedimentation coefficient of 11 S, and then generated a higher order multimer of 25 S. In contrast, individual beta and gamma subunits predominately assembled into 11 S complexes. We obtained similar results with expression in cells and in vitro. When we co-expressed beta with alpha or with alpha plus gamma, the beta subunit assembled into a 25 S complex. Glycosylation of the alpha subunit was not required for assembly into a 25 S complex. We found that the alpha subunit formed intra-chain disulfide bonds. Although such bonds were not required to generate an oligomeric complex, under nonreducing conditions the alpha subunit formed a complex that migrated more homogeneously at 25 S. This suggests that intra-chain disulfide bonds may stabilize the complex. These data suggest that the epithelial Na+ channel subunits form high order oligomeric complexes and that the alpha subunit contains the information that facilitates such formation. Interestingly, the ability of the alpha, but not the beta or gamma, subunit to assemble into a 25 S homomeric complex correlates with the ability of these subunits to generate functional channels when expressed alone.
Details
- Title: Subtitle
- Assembly of the Epithelial Na+Channel Evaluated Using Sucrose Gradient Sedimentation Analysis
- Creators
- Chun ChengLawrence S PrincePeter M SnyderMichael J Welsh
- Resource Type
- Journal article
- Publication Details
- The Journal of biological chemistry, Vol.273(35), pp.22693-22700
- DOI
- 10.1074/jbc.273.35.22693
- PMID
- 9712899
- NLM abbreviation
- J Biol Chem
- ISSN
- 0021-9258
- eISSN
- 1083-351X
- Language
- English
- Date published
- 08/28/1998
- Academic Unit
- Neurology; Molecular Physiology and Biophysics; Pulmonary, Critical Care, and Occupational Medicine; Cardiovascular Medicine; Neurosurgery; Medicine Administration; Internal Medicine
- Record Identifier
- 9984020719402771
Metrics
28 Record Views