Regulation of AE2-mediated Cl- transport by intracellular or by extracellular pH requires highly conserved amino acid residues of the AE2 NH2-terminal cytoplasmic domain.

ABSTRACT: We reported recently that regulation by intracellular pH (pH(i)) of the murine Cl-/HCO(3)(-) exchanger AE2 requires amino acid residues 310-347 of the polypeptide's NH(2)-terminal cytoplasmic domain. We have now identified individual amino acid residues within this region whose integrity is required for regulation of AE2 by pH. 36Cl- efflux from AE2-expressing Xenopus oocytes was monitored during variation of extracellular pH (pH(o)) with unclamped or clamped pH(i), or during variation of pH(i) at constant pH(o). Wild-type AE2-mediated 36Cl- efflux was profoundly inhibited by acid pH(o), with a value of pH(o50) = 6.87 +/- 0.05, and was stimulated up to 10-fold by the intracellular alkalinization produced by bath removal of the preequilibrated weak acid, butyrate. Systematic hexa-alanine [(

SUBMITTER: Stewart AK 

PROVIDER: S-EPMC2229549 | biostudies-literature | 2002 Nov

REPOSITORIES: biostudies-literature