TI - Down-regulation of CFTR currents in trp4-deficient MAEC . AB - The PHOSphorylating cocktail failed to activate a similar current in trp4-deficient MAEC . Figure 4 shows an example for stimulating wild-type and Trp4 - deficient MAEC . On the other hand , the CaCC current activated by loading MAEC with 1 muM [Ca2+] i was not significantly different from that in wild type MAEC , i.e. 16 + - 4 pA/pF in WT ( n = 11 ) compared to 24 + - 6 pA/pF ( n = 8 ) in trp4 -/- cells at +100 mV . Also VRAC was not significantly different in both cell types ( peak currents at +100 mV : 58 + - 8 pA/pF , n = 7 , in WT cells ; 55 + - 11 pA/pF , n = 6 in trp4 -/- MAEC ) .