Quilty Janne A, Li Jing, Reithmeier Reinhart A
Canadian Institutes of Health Research Group in Membrane Biology, Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A8.
Am J Physiol Renal Physiol. 2002 May;282(5):F810-20. doi: 10.1152/ajprenal.00216.2001.
Distal renal tubular acidosis (dRTA) is an inherited disease characterized by the failure of the kidneys to appropriately acidify urine and is associated with mutations in the anion exchanger (AE)1 gene. The effect of the R589H dRTA mutation on the expression of the human erythroid AE1 and the truncated kidney form (kAE1) was examined in transfected human embryonic kidney 293 cells. AE1, AE1 R589H, and kAE1 were present at the cell surface, whereas kAE1 R589H was located primarily intracellularly as shown by immunofluorescence, cell surface biotinylation, N-glycosylation, and anion transport assays. Coexpression of kAE1 R589H reduced the cell surface expression of kAE1 and AE1 by a dominant-negative effect, due to heterodimer formation. The mutant AE1 and kAE1 bound to an inhibitor affinity resin, suggesting that they were not grossly misfolded. Other mutations at R589 also prevented the formation of the cell surface form of kAE1, indicating that this conserved arginine residue is important for proper trafficking. The R589H dRTA mutation creates a severe trafficking defect in kAE1 but not in erythroid AE1.
远端肾小管酸中毒（dRTA）是一种遗传性疾病，其特征是肾脏无法适当地酸化尿液，且与阴离子交换蛋白（AE）1基因突变有关。在转染的人胚肾293细胞中研究了R589H dRTA突变对人红细胞AE1和截短的肾脏形式（kAE1）表达的影响。免疫荧光、细胞表面生物素化、N-糖基化和阴离子转运分析表明，AE1、AE1 R589H和kAE1存在于细胞表面，而kAE1 R589H主要位于细胞内。由于异源二聚体的形成，kAE1 R589H的共表达通过显性负效应降低了kAE1和AE1的细胞表面表达。突变型AE1和kAE1与抑制剂亲和树脂结合，表明它们没有严重错误折叠。R589处的其他突变也阻止了kAE1细胞表面形式的形成，表明这个保守的精氨酸残基对于正确的运输很重要。R589H dRTA突变在kAE1中造成了严重的运输缺陷，但在红细胞AE1中没有。
