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Isoform-specific interactions of Na,K-ATPase subunits are mediated via extracellular domains and carbohydrates
- Publication Year :
- 1997
- Publisher :
- The National Academy of Sciences of the USA, 1997.
-
Abstract
- The functional unit of the Na,K-ATPase consists of a catalytic α subunit noncovalently linked with a glycoprotein subunit, β. Using ouabain binding assays and immunoprecipitation of rodent α/β complexes, we show here that all six possible isozymes between three α and two β isoforms can be formed inXenopusoocytes. Two isoform-specific differences in α/β interactions are observed: (i) α1/β1 and α2/β2 complexes, in contrast to α1/β2 complexes, are stable against Triton X-100-mediated dissociation, and (ii) β2 subunits must carryN-glycans to combine with α1 but not with α2. The interacting surfaces are mainly exposed to the extracellular side because coexpression of a truncated β1 subunit comprising the ectodomain results in assembly with α1 and α2, but not with α3; the β2 ectodomain combines with α2 only. A chimera consisting of 81% and 19% of the α1 N terminus and α2 C terminus, respectively, behaves like α2 and coprecipitates with the β2 ectodomain. In contrast, the reciprocal chimera does not coprecipitate with the β2 ectodomain. These results provide evidence for a selective interaction of Na,K-ATPase α and β subunits.
- Subjects :
- Gene isoform
Models, Molecular
Immunoprecipitation
Protein Conformation
Protein subunit
Xenopus
Plasma protein binding
Mice
Protein structure
Enzyme Stability
Animals
Enzyme Inhibitors
Ouabain
G alpha subunit
Glycoproteins
Multidisciplinary
biology
Cell Polarity
Biological Sciences
biology.organism_classification
Rats
Isoenzymes
Ectodomain
Biochemistry
Sodium-Potassium-Exchanging ATPase
Protein Binding
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....8fc8eba1a33336bad1644fbefb62e76b