Is phosphorylation of the alpha1 subunit at Ser-16 involved in the control of Na,K-ATPase activity by phorbol ester-activated protein kinase C?
Details
Serval ID
serval:BIB_BA5C1ACD9A29
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Is phosphorylation of the alpha1 subunit at Ser-16 involved in the control of Na,K-ATPase activity by phorbol ester-activated protein kinase C?
Journal
Molecular Biology of the Cell
ISSN
1059-1524 (Print)
Publication state
Published
Issued date
01/2000
Volume
11
Number
1
Pages
39-50
Notes
Journal Article
Research Support, Non-U.S. Gov't --- Old month value: Jan
Research Support, Non-U.S. Gov't --- Old month value: Jan
Abstract
The alpha1 subunit of Na,K-ATPase is phosphorylated at Ser-16 by phorbol ester-sensitive protein kinase(s) C (PKC). The role of Ser-16 phosphorylation was analyzed in COS-7 cells stably expressing wild-type or mutant (T15A/S16A and S16D-E) ouabain-resistant Bufo alpha1 subunits. In cells incubated at 37 degrees C, phorbol 12, 13-dibutyrate (PDBu) inhibited the transport activity and decreased the cell surface expression of wild-type and mutant Na,K-pumps equally ( approximately 20-30%). This effect of PDBu was mimicked by arachidonic acid and was dependent on PKC, phospholipase A(2), and cytochrome P450-dependent monooxygenase. In contrast, incubation of cells at 18 degrees C suppressed the down-regulation of Na,K-pumps and revealed a phosphorylation-dependent stimulation of the transport activity of Na,K-ATPase. Na,K-ATPase from cells expressing alpha1-mutants mimicking Ser-16 phosphorylation (S16D or S16E) exhibited an increase in the apparent Na affinity. This finding was confirmed by the PDBu-induced increase in Na sensitivity of the activity of Na,K-ATPase measured in permeabilized nontransfected COS-7 cells. These results illustrate the complexity of the regulation of Na,K-ATPase alpha1 isozymes by phorbol ester-sensitive PKCs and reveal 1) a phosphorylation-independent decrease in cell surface expression and 2) a phosphorylation-dependent stimulation of the transport activity attributable to an increase in the apparent Na affinity.
Keywords
Animals
Arachidonic Acid/metabolism
Biological Transport
COS Cells
Cell Membrane/metabolism
Cell Membrane Permeability
Down-Regulation
Enzyme Activation
Enzyme Inhibitors/pharmacology
Mutagenesis
Na(+)-K(+)-Exchanging ATPase/genetics/*metabolism
Ouabain/pharmacology
Phorbol 12,13-Dibutyrate/*metabolism/pharmacology
Phosphorylation
Protein Kinase C/*metabolism
Serine/*metabolism
Temperature
Transfection
Pubmed
Web of science
Create date
24/01/2008 12:28
Last modification date
20/08/2019 15:28