title: Analysis of the Bile Salt Export Pump (ABCB11) Interactome Employing Complementary Approaches.
abstract: The bile salt export pump (BSEP, ABCB11) plays an essential role in the formation of bile. In hepatocytes, BSEP is localized within the apical (canalicular) membrane and a deficiency of canalicular BSEP function is associated with severe forms of cholestasis. Regulation of correct trafficking to the canalicular membrane and of activity is essential to ensure BSEP functionality and thus normal bile flow. However, little is known about the identity of interaction partners regulating function and localization of BSEP. In our study, interaction partners of BSEP were identified in a complementary approach: Firstly, BSEP interaction partners were co-immunoprecipitated from human liver samples and identified by mass spectrometry (MS). Secondly, a membrane yeast two-hybrid (MYTH) assay was used to determine protein interaction partners using a human liver cDNA library. A selection of interaction partners identified both by MYTH and MS were verified by in vitro interaction studies using purified proteins. By these complementary approaches, a set of ten novel BSEP interaction partners was identified. With the exception of radixin, all other interaction partners were integral or membrane-associated proteins including proteins of the early secretory pathway and the bile acyl-CoA synthetase, the second to last, ER-associated enzyme of bile salt synthesis.
authors.affiliation: Institute of Biochemistry, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Przybylla
authors.affiliation: Department of Gastroenterology, Hepatology and Infectious Diseases, University Hospital, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Stindt
authors.affiliation: Institute of Biochemistry, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany.
authors.forename: Diana
authors.initials: D
authors.lastname: Kleinschrodt
authors.affiliation: Department of General, Visceral and Pediatric Surgery, University Hospital, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Schulte Am Esch
authors.affiliation: Department of Gastroenterology, Hepatology and Infectious Diseases, University Hospital, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany.
authors.forename: Dieter
authors.initials: D
authors.lastname: Häussinger
authors.affiliation: Department of Gastroenterology, Hepatology and Infectious Diseases, University Hospital, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany.
authors.forename: Verena
authors.initials: V
authors.lastname: Keitel
authors.affiliation: Institute of Biochemistry, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany.
authors.forename: Sander H
authors.initials: SH
authors.lastname: Smits
authors.affiliation: Institute of Biochemistry, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany.
authors.forename: Lutz
authors.initials: L
authors.lastname: Schmitt
mesh_terms: D000074020:ATP Binding Cassette Transporter, Subfamily B, Member 11; D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D018076:DNA, Complementary / Q000235:genetics; D006801:Humans; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000235:genetics; D020798:Two-Hybrid System Techniques
chemical_list: C093491:ABCB11 protein, human; D000074020:ATP Binding Cassette Transporter, Subfamily B, Member 11; D018528:ATP-Binding Cassette Transporters; D018076:DNA, Complementary