Coexpression of USP18 increases electrogenic peptide transport in PEPT2-expressing <i>Xenopus laevis</i> oocytes.

<p><b>A:</b> Representative original tracings showing I_gly-gly in <i>Xenopus laevis</i> oocytes injected with water (a) or expressing USP18 alone (b) or expressing PEPT2 without (c) or with additional coexpression of wild type USP18 (d). <b>B:</b> Arithmetic means ± SEM (n = 8–9) of I_gly-gly in <i>Xenopus</i> oocytes injected with water (striped bar), expressing USP18 alone (grey bar), or expressing PEPT2 without (white bar) or with (black bar) wild type USP18. **(p<0.01) indicates statistically significant difference from the absence of USP18.