Publication: Adaptor protein 1 complexes regulate intracellular trafficking of the kidney anion exchanger 1 in epithelial cells
Issued Date
2012-09-01
Resource Type
ISSN
15221563
03636143
03636143
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2-s2.0-84865759720
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Mahidol University
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SCOPUS
Bibliographic Citation
American Journal of Physiology - Cell Physiology. Vol.303, No.5 (2012)
Suggested Citation
Ensaf Y. Almomani, Jennifer C. King, Janjuree Netsawang, Pa Thai Yenchitsomanus, Prida Malasit, Thawornchai Limjindaporn, R. Todd Alexander, Emmanuelle Cordat Adaptor protein 1 complexes regulate intracellular trafficking of the kidney anion exchanger 1 in epithelial cells. American Journal of Physiology - Cell Physiology. Vol.303, No.5 (2012). doi:10.1152/ajpcell.00124.2012 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/13618
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Title
Adaptor protein 1 complexes regulate intracellular trafficking of the kidney anion exchanger 1 in epithelial cells
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Abstract
Distal renal tubular acidosis (dRTA) can be caused by mutations in the gene encoding the anion exchanger 1 (AE1) and is characterized by defective urinary acidification, metabolic acidosis, and renal stones. AE1 is expressed at the basolateral membrane of type A intercalated cells in the renal cortical collecting duct (kAE1). Two dRTA mutations result in the carboxyl-terminal truncation of kAE1; in one case, the protein trafficked in a nonpolarized way in epithelial cells. A recent yeast two-hybrid assay showed that the carboxyl-terminal cytosolic domain of AE1 interacts with adaptor protein complex 1 (AP-1A) subunit 1A (mu-1A; Sawasdee N, Junking M, Ngaojanlar P, Sukomon N, Ungsupravate D, Limjindaporn T, Akkarapatumwong V, Noisakran S, Yenchitsomanus PT. Biochem Biophys Res Commun 401: 85-91, 2010). Here, we show the interaction between kAE1 and mu-1A and B in vitro by reciprocal coimmunoprecipitation in epithelial cells and in vivo by coimmunoprecipitation from mouse kidney extract. When endogenous mu-1A (and to a lesser extent mu-1B) was reduced, kAE1 protein was unable to traffic to the plasma membrane and was rapidly degraded via a lysosomal pathway. Expression of either small interfering RNA-resistant mu-1A or mu-1B stabilized kAE1 in these cells. We also show that newly synthesized kAE1 does not traffic through recycling endosomes to the plasma membrane, suggesting that AP-1B, located in recycling endosomes, is not primarily involved in trafficking of newly synthesized kAE1 when AP-1A is present in the cells. Our data demonstrate that AP-1A regulates processing of the basolateral, polytopic membrane protein kAE1 to the cell surface and that both AP-1A and B adaptor complexes are required for normal kAE1 trafficking. © 2012 the American Physiological Society.