Role of adaptor proteins and clathrin in the trafficking of human kidney anion exchanger 1 (kAE1) to the cell surface.
Kidney anion exchanger 1 (kAE1) plays an important role in acid-base homeostasis by mediating chloride/bicarbornate (Cl-/HCO3-) exchange at the basolateral membrane of α-intercalated cells in the distal nephron. Impaired intracellular trafficking of kAE1 caused by mutations of SLC4A1 encoding kAE1 results in kidney disease - distal renal tubular acidosis (dRTA). However, it is not known how the intracellular sorting and trafficking of kAE1 from trans-Golgi network (TGN) to the basolateral membrane occurs. Here, we studied the role of basolateral-related sorting proteins, including the mu1 subunit of adaptor protein (AP) complexes, clathrin and protein kinase D, on kAE1 trafficking in polarized and non-polarized kidney cells. By using RNA interference, co-immunoprecipitation, yellow fluorescent protein-based protein fragment complementation assays and immunofluorescence staining, we demonstrated that AP-1 mu1A, AP-3 mu1, AP-4 mu1 and clathrin (but not AP-1 mu1B, PKD1 or PKD2) play crucial roles in intracellular sorting and trafficking of kAE1. We also demonstrated colocalization of kAE1 and basolateral-related sorting proteins in human kidney tissues by double immunofluorescence staining. These findings indicate that AP-1 mu1A, AP-3 mu1, AP-4 mu1 and clathrin are required for kAE1 sorting and trafficking from TGN to the basolateral membrane of acid-secreting α-intercalated cells.
['Junking|Mutita|M|', 'Sawasdee|Nunghathai|N|', 'Duangtum|Natapol|N|', 'Cheunsuchon|Boonyarit|B|', 'Limjindaporn|Thawornchai|T|', 'Yenchitsomanus|Pa-thai|PT|']
D033942:Adaptor Proteins, Vesicular Transport D000818:Animals D001457:Anion Exchange Protein 1, Erythrocyte D001483:Base Sequence D002462:Cell Membrane D002966:Clathrin D017931:DNA Primers D004285:Dogs D057809:HEK293 Cells D006801:Humans D061985:Madin Darby Canine Kidney Cells D021381:Protein Transport D034741:RNA, Small Interfering
kidney anion exchanger 1 distal renal tubular acidosis basolateral sorting protein protein trafficking protein-protein interaction