Cross-linking disrupts pH regulation. (A) Representative current traces in Xenopus oocytes (voltage clamped to −60 mV) expressing α_K477Cβ_V85CγENaC before (black, −MTS-14) and after (blue, +MTS-14) treatment with MTS-14-O4-MTS. Extracellular pH was shifted from 7.4 to 5.25, as indicated. The two traces were obtained from different cells and are scaled to facilitate comparisons. (B) Percent change in ENaC current (relative to current at pH 7.4) in response to changes in extracellular pH before (black) and after treatment with MTS-14-O4-MTS (blue) or MTS-2-MTS (green). Mean ± SEM is shown (n = 3–6; some data symbols and error bars are hidden by other data symbols).