Functional analysis of aquaporin-1 deficient red cells - The Colton-null phenotype
Functional analysis of aquaporin-1 deficient red cells - The Colton-null phenotype
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DOI：
10.1074/jbc.271.3.1309
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发表时间：
1996-01-19
影响因子：
4.8
通讯作者：
Agre, P
中科院分区：
文献类型：
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作者：
Mathai, JC;Mori, S;Agre, P
水通道蛋白-1(AQP1)水转运蛋白含有与Colton红细胞抗原对应的多态。为了确定AQP1介导的膜透性分数，从具有罕见Colton零表型的人的家系中获得红细胞。AQP1基因外显子I缺失的纯合性或杂合性与AQP1蛋白的全部或部分缺失相关。纯合子红细胞形态看起来正常，但临床实验室研究显示，体内红细胞寿命略有缩短；变形性研究显示，膜表面积略有减少。用脉冲场梯度核磁共振方法测定了等渗条件下的扩散水渗透率(P-d)。通过红细胞快速暴露于细胞外渗透浓度升高后光散射的变化来测量渗透水通透性(P-f)。水通道通透性与相似(P-d=1.5×10~(-3)cm/S)，脂类通透性明显接近23%。相反，AQP_1占总渗透水通透性途径的85%(P-f=19×10~(-3)cm/S)，而脂质渗透仅占相似的10%。AQP1介导的P-f与P-d的比率预测房水孔的长度为36埃。
The aquaporin-1 (AQP1) water transport protein contains a polymorphism corresponding to the Colton red blood cell antigens. To define the fraction of membrane water permeability mediated by AQP1, red cells were obtained from human kindreds with the rare Colton-null phenotype. Homozygosity or heterozygosity for deletion of exon I in AQP1 correlated with total or partial deficiency of AQP1 protein. Homozygote red cell morphology appeared normal, but clinical laboratory studies revealed slightly reduced red cell life span in vivo; deformability studies revealed a slight reduction in membrane surface area. Diffusional water permeability (P-d) was measured under isotonic conditions by pulsed field gradient NMR. Osmotic water permeability (P-f) was measured by change in light scattering after rapid exposure of red cells to increased extracellular osmolality. AQP1 contributes similar to 64% (P-d = 1.5 x 10(-3) cm/s) of the total diffusional water permeability pathway, and lipid permeation apparently comprises similar to 23%. In contrast, AQP1 contributes >85% (P-f = 19 x 10(-3) cm/s) of the total osmotic water permeability pathway, and lipid permeation apparently comprises only similar to 10%. The ratio of AQP1-mediated P-f to P-d predicts the length of the aqueous pore to be 36 Angstrom.