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Titolo:
ACTIVATION OF PROTEIN-KINASE-A ACUTELY INHIBITS AND PHOSPHORYLATES NAH EXCHANGER NHE-3/
Autore:
MOE OW; AMEMIYA M; YAMAJI Y;
Indirizzi:
UNIV TEXAS,SW MED CTR,DEPT INTERNAL MED,5323 HARRY HINES BLVD DALLAS TX 75235 DEPT VET AFFAIRS MED CTR,DEPT INTERNAL MED DALLAS TX 75235
Titolo Testata:
The Journal of clinical investigation
fascicolo: 5, volume: 96, anno: 1995,
pagine: 2187 - 2194
SICI:
0021-9738(1995)96:5<2187:AOPAIA>2.0.ZU;2-N
Fonte:
ISI
Lingua:
ENG
Soggetto:
NA+-H+ EXCHANGER; CYCLIC ADENOSINE-MONOPHOSPHATE; PROXIMAL CONVOLUTED TUBULE; RENAL EPITHELIAL-CELLS; CFTR CHLORIDE CHANNEL; ANGIOTENSIN-II; CYTOPLASMIC DOMAIN; GROWTH-FACTOR; BICARBONATE ABSORPTION; FUNCTIONAL EXPRESSION;
Keywords:
NA TRANSPORT; HYDROGEN ION TRANSPORT; HORMONAL REGULATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
61
Recensione:
Indirizzi per estratti:
Citazione:
O.W. Moe et al., "ACTIVATION OF PROTEIN-KINASE-A ACUTELY INHIBITS AND PHOSPHORYLATES NAH EXCHANGER NHE-3/", The Journal of clinical investigation, 96(5), 1995, pp. 2187-2194

Abstract

In the mammalian renal proximal tubule, protein kinase A (PKA) plays an important role in mediating hormonal regulation of apical membrane Na/H exchanger activity, This exchanger is likely encoded by NHE-3. The present studies examined regulation of NHE-3 by PKA. NHE-3 was stably expressed in Na/H exchanger-deficient fibroblasts (AP-1/NHE-3 cells). PKA activation (0.1 mM 8-BrcAMP x 20 min) inhibited NHE-3 activity by 39% (P < 0.01) with no change in NHE-3 protein abundance in the plasma membrane. To define the structural requirements for PKA-mediated inhibition, full-length NHE-3 and a cytoplasmic domain-truncated mutant (NHE-3(Delta cyto)) were expressed in Xenopus laevis oocytes. 8-BrcAMPinhibited NHE-3 activity by 27% (P < 0.05), an effect that was blocked by 10(-7) M PKA inhibitor peptide, NHE-3(Delta cyto) had baseline activity similar to that of full-length NHE-3 but its activity was not regulated by 8-BrcAMP. The purified recombinant cytoplasmic domain of NHE-3 was phosphorylated in vitro by the catalytic subunit of PKA on serine residues, In AP-1/NHE-3 cells, NHE-3 was immunoprecipitated as a similar to 87-kD phosphoprotein. Addition of 0.1 mM 8-BrcAMP increasedthe phosphocontent of NHE-3 by threefold. In summary, acute activation of PKA inhibits NHE-3 activity, an effect that is likely mediated byphosphorylation of its cytoplasmic domain.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 06/04/20 alle ore 08:38:05