Identification of HAX-1 as a Protein That Binds Bile Salt Export Protein and Regulates Its Abundance in the Apical Membrane of Madin-Darby Canine Kidney Cells

Ortiz, Daniel; Moseley, James B.; Calderón, Germán; Swift, Amy L.; Li, Shaohua; Arias, Irwin M.

doi:10.1074/jbc.m404337200

Cited by 105 publications

(120 citation statements)

References 54 publications

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“…In addition to these pathways, the mitogenactivated kinase cascades are also involved in the posttranscriptional regulation of Bsep expression: Induction of choleresis by tauroursodeoxycholic acid or alteration of bile flow by anisosomolarity leads to canalicular insertion/ retrieval of Bsep, a process that is critically dependent on mitogen-activated kinases [83]. In addition, studies in polarized cell lines expressing Bsep revealed that HAX-1 and myosin II regulatory light chain are required for the trafficking of Bsep to the apical membrane as well as in the regulation of its abundance in the apical plasma membrane of MDCK cells [12,73]. Studies in the polarized hepatic WIF-B9 cell line indicated that Bsep undergoes a constitutive cycling between a rab11 positive compartment and the canalicular plasma membrane domain [95].…”

Section: Ontogenesis and Regulationmentioning

confidence: 99%

The bile salt export pump

Stieger

Meier

2006

Pflugers Arch - Eur J Physiol

209

137

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Section: Ontogenesis and Regulationmentioning

confidence: 99%

The bile salt export pump

Stieger

Meier

2006

Pflugers Arch - Eur J Physiol

209

137

View full text Add to dashboard Cite

“…Indeed, Ortiz et al (22) showed presence of HAX-1 in clathrin-coated vesicles and HAX-1 participation in clathrin-mediated endocytosis, which itself depends on the functionality of cortactin. Cortactin is an F-actin-associated protein that localizes within membrane ruffles in cultured cells, and is a direct binding partner of the large GTPase dynamin.…”

Section: Discussionmentioning

confidence: 99%

“…HAX-1 is associated with the cytoskeleton (15) and it was suggested that HAX-1 participates in clathrin-mediated endocytosis of the surface receptor BSEP in Madin-Darby canine kidney II cells (22). Therefore, we asked whether the knockdown of HAX-1 expression in siRNA transfectants influenced the mIgE-mediated Ag internalization in JW813/4 BCR ϩ .…”

Section: Hax-1 Protein Levels Influence Ag-internalization Efficiencymentioning

confidence: 99%

“…2) Association of HAX-1 with cortactin (or EMS1) (15), polycystic kidney disease protein 2 (15), ATP-binding cassette transporters BSEP, MDR1, and MDR2 (22) and G␣-13, a cell migration-stimulating component (23) emphasizes the involvement of HAX-1 in cell motility processes.…”

Section: Hs1-associated Protein X-1 Interacts With Membrane-boundmentioning

confidence: 99%

“…com͘ (target 1) and ͗www.ambion.com/techlib͘ (target 8). The control target sequence was taken from Ortiz et al (22). Selected target sequences were tested for exact matches of Ͼ12 nucleotides.…”

Section: Rna Interferencementioning

confidence: 99%

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HS1-Associated Protein X-1 Interacts with Membrane-Bound IgE: Impact on Receptor-Mediated Internalization

Oberndorfer

Schmid

Geisberger

et al. 2006

The Journal of Immunology

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Engagement of the BCR triggers signals that control affinity maturation, memory induction, differentiation, and various other physiological processes in B cells. In previous work, we showed that truncation of the cytoplasmic tail of membrane-bound Ig (mIg)E in vivo resulted in lower serum IgE levels, decreased numbers of IgE-secreting plasma cells, and the abrogation of specific secondary responses correlating with a defect in the selection of high-affinity Abs during the germinal center reaction. We concluded that the Ag receptor is necessary at all times during Ab responses not only for the maturation process, but also for the expansion of Ag-specific B cells. Based on these results, we asked whether the cytoplasmic tail of mIgE, or specific proteins binding the cytoplasmic tail in vivo commit a signal transduction accompanying the B cell along its differentiation process. In this study, we present the identification of HS1-associated protein X-1 as a novel protein interacting with the cytoplasmic tail of mIgE. ELISA, surface plasmon resonance analysis, and coimmunoprecipitation experiments confirmed the specific interaction in vitro. In functional assays, we clearly showed that HS1-associated protein X-1 expression levels influence the efficiency of BCR-mediated Ag internalization.

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