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(Referência obtida automaticamente do SciELO, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Physiological implications of the regulation of vacuolar H+-ATPase by chloride ions

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Autor(es):
L.R. Carraro-Lacroix [1] ; L.M.A. Lessa [2] ; R. Fernandez [3] ; G. Malnic [4]
Número total de Autores: 4
Afiliação do(s) autor(es):
[1] Universidade de São Paulo. Instituto de Ciências Biomédicas. Departamento de Fisiologia e Biofísica - Brasil
[2] Universidade de São Paulo. Instituto de Ciências Biomédicas. Departamento de Fisiologia e Biofísica - Brasil
[3] Universidade Federal do Paraná. Setor de Ciências Biológicas. Departamento de Fisiologia - Brasil
[4] Universidade de São Paulo. Instituto de Ciências Biomédicas. Departamento de Fisiologia e Biofísica - Brasil
Número total de Afiliações: 4
Tipo de documento: Artigo Científico
Fonte: Brazilian Journal of Medical and Biological Research; v. 42, n. 2, p. 155-163, 2009-02-00.
Assunto(s):Angiotensinas
Resumo

Vacuolar H+-ATPase is a large multi-subunit protein that mediates ATP-driven vectorial H+ transport across the membranes. It is widely distributed and present in virtually all eukaryotic cells in intracellular membranes or in the plasma membrane of specialized cells. In subcellular organelles, ATPase is responsible for the acidification of the vesicular interior, which requires an intraorganellar acidic pH to maintain optimal enzyme activity. Control of vacuolar H+-ATPase depends on the potential difference across the membrane in which the proton ATPase is inserted. Since the transport performed by H+-ATPase is electrogenic, translocation of H+-ions across the membranes by the pump creates a lumen-positive voltage in the absence of a neutralizing current, generating an electrochemical potential gradient that limits the activity of H+-ATPase. In many intracellular organelles and cell plasma membranes, this potential difference established by the ATPase gradient is normally dissipated by a parallel and passive Cl- movement, which provides an electric shunt compensating for the positive charge transferred by the pump. The underlying mechanisms for the differences in the requirement for chloride by different tissues have not yet been adequately identified, and there is still some controversy as to the molecular identity of the associated Cl--conducting proteins. Several candidates have been identified: the ClC family members, which may or may not mediate nCl-/H+ exchange, and the cystic fibrosis transmembrane conductance regulator. In this review, we discuss some tissues where the association between H+-ATPase and chloride channels has been demonstrated and plays a relevant physiologic role. (AU)

Processo FAPESP: 06/50828-1 - Regulacao da h+atpase vacuolar de celulas de tubulos proximais de ratos por canais de cloreto.
Beneficiário:Luciene Regina Carraro-Lacroix
Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
Processo FAPESP: 04/01683-5 - Estudo molecular e funcional de transportadores de íons em membranas
Beneficiário:Gerhard Malnic
Modalidade de apoio: Auxílio à Pesquisa - Temático
Processo FAPESP: 05/60491-1 - Acao da guanilina e uroguanilina no transporte ionico em tubulos renais.
Beneficiário:Lucília Maria Abreu Lessa Leite Lima
Modalidade de apoio: Bolsas no Brasil - Doutorado