Human kidney anion exchanger 1 interacts with adaptor-related protein complex 1 μ1A (AP-1 mu1A)

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• 作者：Nunghathai Sawasdee ; Mutita Junking ; Piengpaga Ngaojanlar ; Nattakan Sukomon ; Duangporn Ungsupravate ; Thawornchai Limjindaporn ; Varaporn Akkarapatumwong ; Sansanee Noisakran ; Pa-thai Yenchitsomanus
• 关键词：Kidney anion exchanger 1 ; Band 3 ; Adaptor-related protein complex 1 mu1A ; Distal renal tubular acidosis ; Protein– ; protein interaction ; Protein trafficking
• 刊名：Biochemical and Biophysical Research Communications
• 出版年：2010
• 出版时间：8 October 2010
• 年：2010
• 卷：401
• 期：1
• 页码：85-91
• 全文大小：978 K

文摘

Kidney anion exchanger 1 (kAE1) mediates chloride (Cl⁻) and bicarbonate (HCO₃⁻) exchange at the basolateral membrane of kidney α-intercalated cells. Impaired trafficking of kAE1 leads to defect of the Cl⁻/HCO₃⁻ exchange at the basolateral membrane and failure of proton (H⁺) secretion at the apical membrane, causing a kidney disease – distal renal tubular acidosis (dRTA). To gain a better insight into kAE1 trafficking, we searched for proteins physically interacting with the C-terminal region of kAE1 (Ct-kAE1), which contains motifs crucial for intracellular trafficking, by a yeast two-hybrid (Y2H) system. An adaptor-related protein complex 1 μ1A (AP-1 mu1A) subunit was found to interact with Ct-kAE1. The interaction between either Ct-kAE1 or full-length kAE1 and AP-1 mu1A were confirmed in human embryonic kidney (HEK) 293T by co-immunoprecipitation, affinity co-purification, co-localization, yellow fluorescent protein (YFP)-based protein fragment complementation assay (PCA) and GST pull-down assay. The interacting site for AP-1 mu1A on Ct-kAE1 was found to be Y904DEV907, a subset of YXXØ motif. Interestingly, suppression of endogenous AP-1 mu1A in HEK 293T by small interfering RNA (siRNA) decreased membrane localization of kAE1 and increased its intracellular accumulation, suggesting for the first time that AP-1 mu1A is involved in the kAE1 trafficking of kidney α-intercalated cells.