Publication: Interaction of integrin-linked kinase with the kidney chloride/bicarbonate exchanger, kAE1
Issued Date
2007-08-10
Resource Type
ISSN
1083351X
00219258
00219258
Other identifier(s)
2-s2.0-34548159996
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Mahidol University
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SCOPUS
Bibliographic Citation
Journal of Biological Chemistry. Vol.282, No.32 (2007), 23205-23218
Suggested Citation
Thitima Keskanokwong, Haley J. Shandro, Danielle E. Johnson, Saranya Kittanakom, Gonzalo L. Vilas, Paul Thorner, Reinhart A F Reithmeier, Varaporn Akkarapatumwong, Pa Thai Yenchitsomanus, Joseph R. Casey Interaction of integrin-linked kinase with the kidney chloride/bicarbonate exchanger, kAE1. Journal of Biological Chemistry. Vol.282, No.32 (2007), 23205-23218. doi:10.1074/jbc.M702139200 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/24141
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Title
Interaction of integrin-linked kinase with the kidney chloride/bicarbonate exchanger, kAE1
Abstract
Kidney anion exchanger 1 (kAE1) mediates chloride/bicarbonate exchange at the basolateral membrane of kidney α-intercalated cells, thereby facilitating bicarbonate reabsorption into the blood. Human kAE1 lacks the N-terminal 65 residues of the erythroid form (AE1, band 3), which are essential for binding of cytoskeletal and cytosolic proteins. Yeast two-hybrid screening identified integrin-linked kinase (ILK), a serine/threonine kinase, and an actin-binding protein as an interacting partner with the N-terminal domain of kAE1. Interaction between kAE1 and ILK was confirmed in co-expression experiments in HEK 293 cells and is mediated by a previously unidentified calponin homology domain in the kAE1 N-terminal region. The calponin homology domain of kAE1 binds the C-terminal catalytic domain of ILK to enhance association of kAE1 with the actin cytoskeleton. Overexpression of ILK increased kAE1 levels at the cell surface as shown by flow cytometry, cell surface biotinylation, and anion transport activity assays. Pulse-chase experiments revealed that ILK associates with kAE1 early in biosynthesis, likely in the endoplasmic reticulum. ILK co-localized with kAE1 at the basolateral membrane of polarized Madin-Darby canine kidney cells and in α-intercalated cells of human kidneys. Taken together these results suggest that ILK and kAE1 traffic together from the endoplasmic reticulum to the basolateral membrane. ILK may provide a linkage between kAE1 and the underlying actin cytoskeleton to stabilize kAE1 at the basolateral membrane, resulting in higher levels of cell surface expression. © 2007 by The American Society for Biochemistry and Molecular Biology, Inc.