SLC26A9 interacts with wtCFTR in vivo. Equal amounts of protein (∼500 µg) from HEK 293 cells transiently transfected with wtCFTR alone or with CFTR plus myc-SLC26A9 (myc-A9) were subjected to IP with anti-myc antibodies (left). Of the total protein used for IP (left), 10% was used as input (right); this and coprecipitated CFTR were detected by immunoblot. SLC26A9 was detected by immunoblot with anti-myc; the doublet shown has been previously detected for both myc- and HA-tagged SLC26A9 (Dorwart et al., 2007). An immunoblot of actin was performed as a loading control (separate blot). Representative blots of three experiments are shown.