ERp29 enhances functional expression of ΔF508-CFTR in Xenopus oocytes. X. laevis oocytes were injected with cRNA for ΔF508-CFTR (10 ng) or ERp29 alone (10 ng) or co-injected with cRNAs for ΔF508-CFTR (10 ng) and either 1, 10, or 30 ng of ERp29. A, I/V relationship (adjusted for resting transmembrane potential) of whole-cell current was determined by TEV for oocytes co-injected with 10 ng of ΔF508-CFTR cRNA and 1 ng of ERp29 cRNA before (closed circles) and after (open circles) stimulation with forskolin/IBMX. Data are presented as mean ± S.E. for n = 22 oocytes. B, forskolin/IBMX-stimulated current at −100-mV holding potential (adjusted for resting transmembrane potential) of oocytes injected with ΔF508-CFTR alone (10 ng; closed bar) or ERp29 alone (10 ng; open bar) or co-injected with ΔF508-CFTR and either 1, 10, or 30 ng of ERp29 cRNA (gray bars). Data are presented as mean ± S.E. for the indicated numbers of oocytes, and the significance of differences from oocytes injected with ΔF508-CFTR alone was determined by ANOVA.