| A yeast two hybrid screen identified HAX 1 as a binding partner for BSEP , MDR 1 , and MDR 2 . ^^^ BSEP and HAX 1 were over represented in rat liver subcellular fractions enriched for canalicular membrane vesicles , microsomes , and clathrin coated vesicles . ^^^ HAX 1 was bound to BSEP , MDR 1 , and MDR 2 in canalicular membrane vesicles and co localized with BSEP and MDR 1 in the apical membrane of Madin Darby canine kidney ( MDCK ) cells . ^^^ RNA interference of HAX 1 increased BSEP levels in the apical membrane of MDCK cells by 71 % . ^^^ Pulse chase studies indicated that HAX 1 depletion did not affect BSEP translation , post translational modification , delivery to the plasma membrane , or half life . ^^^ |