Membrane insertion of alpha- and beta-subunits of Na+,K+-ATPase.

Details

Serval ID
serval:BIB_BC0D2CF5B951
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Membrane insertion of alpha- and beta-subunits of Na+,K+-ATPase.
Journal
Journal of Biological Chemistry
Author(s)
Geering K., Meyer D.I., Paccolat M.P., Kraehenbühl J.P., Rossier B.C.
ISSN
0021-9258
Publication state
Published
Issued date
04/1985
Peer-reviewed
Oui
Volume
260
Number
8
Pages
5154-5160
Language
english
Abstract
Insertion of the alpha- and beta-subunits of amphibian epithelial Na+,K+-ATPase into pancreatic microsomes in cell-free systems was shown to be the same as into membranes of intact cells. The glycoproteic beta-subunit was observed to be cotranslationally inserted into endoplasmic reticulum membranes and to adopt a different pattern of N-linked core and terminal sugars in two different amphibian species. The beta-subunit lacks a cleavable signal sequence but quantitative membrane integration required membrane addition at the start of synthesis. Proteolysis of beta-subunit assembled in vitro indicated a cleavable cytoplasmic domain of about 2000 daltons. The catalytic 98-kilodalton alpha-subunit was also membrane-associated during its synthesis in an alkali-resistant fashion and independent of newly synthesized beta-subunit. In contrast to the beta-subunit, membrane integration of the alpha-subunit was possible as late as a time point in its synthesis which corresponded to about 1/3-1/2 of completion of the nascent chain. A small 34 kDa trypsin-resistant fragment of the alpha-subunit was produced at an early stage of synthesis both in the intact cell and in the cell-free system. These results suggest that membrane insertion of both alpha- and beta-subunit occurs during their synthesis but with a different time course.
Keywords
Animals, Bufo marinus, Cell Line, Cell Membrane/enzymology, Macromolecular Substances, Molecular Weight, Poly A/metabolism, Protein Biosynthesis, RNA/metabolism, RNA, Messenger, Sodium-Potassium-Exchanging ATPase/metabolism, Time Factors, Xenopus laevis
Pubmed
Web of science
Create date
24/01/2008 13:00
Last modification date
20/08/2019 15:30
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