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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
30
pubmed:dateCreated
1995-9-5
pubmed:abstractText
We have characterized the regulation of the endogenous Na+/H+ exchanger in Xenopus laevis oocytes by G proteins and protein kinases by measuring the ethylisopropylamiloride-sensitive Li+ uptake. Injection of oocytes with the stable GTP analog GTP gamma S stimulated Li+ uptake up to almost 4-fold, an effect blocked by coinjection with the GDP analog, guanyl-5'-yl thiophosphate. Injection into oocytes of beta gamma subunits of the heterotrimeric G protein transducin enhanced Li+ uptake by about 3-fold. This stimulation was blocked by transducin alpha subunits, which by themselves did not influence Li+ uptake. Using various activators and inhibitors of protein kinases, it is demonstrated that the X. laevis oocyte Na+/H+ antiporter can be stimulated by activation of both protein kinase A and C. Stimulation of Na+/H+ exchanger activity by GTP gamma S but not that induced by transducin beta gamma subunits was blocked by the protein kinase A inhibitor H-89. On the other hand, transducin beta gamma subunit-stimulated activity was prevented by the protein kinase C inhibitor, calphostin C. The non-selective protein kinase inhibitor H-7 blocked both GTP gamma S- and transducin beta gamma subunit-stimulated Na+/H+ exchanger activity. The results suggest that the Na+/H+ exchanger of X. laevis oocytes can be activated by G proteins and that this activation is not direct but mediated by protein kinase A- and/or protein kinase C-dependent pathways.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
28
pubmed:volume
270
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
17898-901
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
G protein regulation of the Na+/H+ antiporter in Xenopus laevis oocytes. Involvement of protein kinases A and C.
pubmed:affiliation
Institut für Pharmakologie, Universität GH Essen, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't