Linked Life Data

2556932

Source:http://linkedlifedata.com/resource/pubmed/id/2556932

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5 Pt 1
pubmed:dateCreated
1990-1-12
pubmed:abstractText
In all cellular systems studied so far, the catalytic alpha- and the glycosylated beta-subunit of Na+-K+-ATPase are coordinately synthesized and are assembled into stoichiometric alpha, beta-complexes. In contrast to these data, in this study we show that the fully grown oocyte of Xenopus laevis synthesizes much less beta-subunit than alpha-subunit. The alpha-subunit produced in excess over the beta-subunit is membrane associated but highly trypsin sensitive and can be compared with the immature alpha-subunit population identified in epithelial cells immediately after synthesis (K. Geering, J. P. Kraehenbuhl, and B.C. Rossier, J. Cell Biol. 105: 2613-2619, 1987). The Xenopus oocyte thus turns out to be a unique system to study the functional role of the beta-subunit. Injection of beta-subunit-specific mRNA transcribed in vitro from a beta-cDNA clone (derived from Xenopus kidney, A6 cells) into oocytes results in translation of a glycosylated beta-subunit. The synthesis of this exogenous beta-subunit increases significantly the proportion of trypsin-resistant oocyte alpha-subunits able to perform cation-dependent conformational changes. In addition, 25-65% more ouabian binding sites are expressed at the plasma membrane in beta-mRNA-injected oocytes. In contrast, newly synthesized alpha-subunit translated after injection of size-fractionated mRNA enriched in alpha-mRNA remains trypsin sensitive as the oocyte alpha-subunit. These data suggest that association of the beta-subunit to the alpha-subunit provokes a structural rearrangement of the alpha-subunit that might be a first step toward the functional maturation of the Na+-K+-ATPase and its expression at the plasma membrane.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0002-9513
pubmed:author
pubmed:issnType
Print
pubmed:volume
257
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
C851-8
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
A role for the beta-subunit in the expression of functional Na+-K+-ATPase in Xenopus oocytes.
pubmed:affiliation
Institut de Pharmacologie de l'Université de Lausanne, Switzerland.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't