Xenbase Image ID: 121210

Figure 1. . AE2-mediated Cl− transport is regulated by varying pHo independent of pHi. (A) pHi measured by pH-sensitive microelectrode in an AE2-expressing oocyte during the indicated changes in pHo. (B) pHi measured by pH-sensitive microelectrode in an AE2-expressing oocyte during the same pHo changes in the presence of the indicated butyrate concentrations, resulting in nominal “pHi clamp.” Initial condition for both A and B was pHo 7.4 in absence of butyrate. (C) Summary of pHo versus pHi relationship in the presence (filled circles) and absence (open squares) of nominal “pHi clamp.” Initial resting pHi is indicated by the asterisk. (D) Representative 36Cl− efflux timecourse for wild-type AE2 oocyte measured during sequential increases in pHo under pHi clamp conditions. D = 200 μM DIDS. (E) Representative 36Cl− efflux timecourse for wild-type AE2 oocyte measured during sequential decreases in pHo under pHi clamp conditions. (F) Representative 36Cl− efflux timecourse for wild-type AE2-expressing oocytes measured during nonsequential order of pHo changes under pHi clamp conditions. (G) pHo versus activity profile for oocytes expressing wild-type AE2 under pHi clamp conditions when pHo is changed from 5.0 to 8.5 (filled circles), from 8.5 to 5.0 (filled squares), and in nonsequential order (open squares). (H) pHo(50) values exhibited by wild-type AE2 where pHo has been changed under conditions of unclamped pHi and under the pHi clamp conditions indicated, calculated from fits of pHo versus 36Cl− efflux activity plots as in G for n individual oocytes (means ± SEM). pH nonseq. = nonsequential order of bath pH changes. The pHo(50) values did not differ as assessed by ANOVA. Image published in: Stewart AK et al. (2002) Copyright © 2002, The Rockefeller University Press. Creative Commons Attribution-NonCommercial-ShareAlike license Larger Image Printer Friendly View

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