Assembly of the extracellular domain of the Na,K-ATPase beta subunit with the alpha subunit. Analysis of beta subunit chimeras and carboxyl-terminal deletions.

Hamrick, M.; Renaud, K J; Fambrough, Douglas M.

doi:10.1016/s0021-9258(20)80535-3

Cited by 45 publications

(1 citation statement)

References 40 publications

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“…The specificity of cross-linking in forming the 31 kDa product and the location of the cross-link in a short segment of the R subunit near M8 (between Tyr895 and Tyr901) fit very well with the finding that the sequence 894 SYGQ 897 represents the major site of R-β subunit interactions at the extracellular surface. Residues in the β subunit which interact with the R subunit have not been mapped in detail, although work with truncated β subunits and mutations of the cysteines suggested that a region up to and including the first S-S bridge could be involved (40,41). The twohybrid work restricts the location further to residues between Ser61 after the transmembrane segment and Cys125 before the first S-S bridge (36).…”

Section: Discussionmentioning

confidence: 99%

Specific Cross-Links between Fragments of Proteolyzed Na,K-ATPase Induced by o-Phthalaldehyde

Or¹,

Goldshleger²,

Shainskaya³

et al. 1998

Biochemistry

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We have used o-phthalaldehyde (OPA) to cross-link adjacent fragments of "19 kDa membranes", a tryptic preparation of Na,K-ATPase lacking the ATP site but retaining cation occlusion sites. Treatment with OPA of "19 kDa membranes" or detergent-solubilized membranes containing occluded Rb ions [Or, E., Goldshleger, R., Tal, D. M., and Karlish, S. J. D. (1996) Biochemistry 35, 6853-6864] yielded cross-linked products of 25 and 31 kDa. Both species contained the 19 kDa fragment of the alpha subunit (transmembrane segments M7-M10). In addition, the 25 kDa product contained the fragment including M5-M6, while the 31 kDa product contained a 16 kDa fragment of the beta subunit. Cross-linking was unaffected by the absence or presence of ligands (Na, Rb, or Mg and ouabain). Cross-linking was largely abolished in thermally inactivated "19 kDa membranes". When proteolytic digestion of the 25 and 31 kDa products was combined with antibody binding, PKA-dependent phosphorylation, and sequencing of fragments, approximate positions of the cross-links were established. In the 25 kDa product, the cross-link was located within the short cytoplasmic segment Asn831-Arg841 of the 19 kDa fragment preceding M7 and within Ala749-Ala770 preceding M5. Thus, M7 and M5 are likely to be in close proximity. In the 31 kDa product, the cross-link was located in the extracellular loop of the alpha subunit between M7 and M8, close to residues which are known to interact with the beta subunit. Functional implications of the interactions between the fragments of the alpha (M5-M6 and M7-M10) and beta subunits are discussed.

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Section: Discussionmentioning

confidence: 99%

Specific Cross-Links between Fragments of Proteolyzed Na,K-ATPase Induced by o-Phthalaldehyde

Or¹,

Goldshleger²,

Shainskaya³

et al. 1998

Biochemistry

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The Extracellular Domain of the Sodium Pump β Isoforms Determines Complex Stability with α1

Pontiggia

Gloor

1997

Biochemical and Biophysical Research Communications

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Effect of antidigoxin monoclonal antibodies on cardiac disturbances caused by high concentrations of digoxin

et al. 1998

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Effect of high-affinity mouse monoclonal antidigoxin antibodies D22 on digoxin-induced cardiac disturbances is studied in guinea pigs injected with 0.5 mg/kg digoxin. Five minutes after digoxin injection, bradycardia, isolated extrasystoles, conduction disturbances, and changes in the ST segment and QRS complex appear; digoxin concentration attains 0.2-0.4 gg/ml. Antidigoxin monoclonal antibodies injected 10 min after digoxin slightly reduce heart rate, prevent isolated extrasystoles, improve atrioventricular conduction, and normalize the amplitude of the ST segment and the shape of the QRS complex. Serum digoxin concentration decreases to 0.015-0.03 gg/ml. These data suggest that monoclonal antidigoxin antibodies can be effectively used in acute digoxin intoxication.

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Assembly of the extracellular domain of the Na,K-ATPase beta subunit with the alpha subunit. Analysis of beta subunit chimeras and carboxyl-terminal deletions.

Cited by 45 publications

References 40 publications

Specific Cross-Links between Fragments of Proteolyzed Na,K-ATPase Induced by o-Phthalaldehyde

Specific Cross-Links between Fragments of Proteolyzed Na,K-ATPase Induced by o-Phthalaldehyde

The Extracellular Domain of the Sodium Pump β Isoforms Determines Complex Stability with α1

Effect of antidigoxin monoclonal antibodies on cardiac disturbances caused by high concentrations of digoxin

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