Lack of Aquaporin 3 in bovine erythrocyte membranes correlates with low glycerol permeation
Lack of Aquaporin 3 in bovine erythrocyte membranes correlates with low glycerol permeation
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DOI：
10.1016/j.bbrc.2011.04.057
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发表时间：
2011-05-13
影响因子：
3.1
通讯作者：
Soveral, Graca
中科院分区：
文献类型：
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作者：
Campos, Elisa;Moura, Teresa F.;Soveral, Graca
通常，红细胞对水、尿素和甘油具有高度渗透性。然而，水通道蛋白亚型在红细胞中的表达似乎是种属特征。在本研究中，选择人（hRBC）和牛（bRBC）红细胞进行比较研究，因为它们在膜甘油渗透性方面存在显著差异。人和牛细胞分别为（2.89 +/- 0.37）x 10（-2）和（5.12 +/- 0.61）x 10（-2）cm s（-1），水转运的活化能相似。人的甘油渗透性（P（gly））（（1.37 +/- 0.26）x 10（-5）cm s（-1））与牛红细胞（（5.82 +/- 0.37）x 10（-8）cm s（-1））相差三个数量级，牛红细胞也显示出较高的甘油转运活化能。与人相比，牛红细胞在免疫印迹分析中显示出类似的AQP 1糖基化形式的表达模式，尽管水平略高，这可能与发现的1.5倍大的P（f）相关，但是没有检测到AQP 3的表达。免疫荧光分析证实牛红细胞膜上没有AQP 3的表达，因此，牛红细胞中AQP 3的缺失表明脂质途径是甘油渗透的主要途径，这也解释了反刍动物甘油渗透性低和转运E（a）高的原因。(C)2011 Elsevier Inc. All rights reserved.
In general, erythrocytes are highly permeable to water, urea and glycerol. However, expression of aquaporin isoforms in erythrocytes appears to be species characteristic. In the present study, human (hRBC) and bovine (bRBC) erythrocytes were chosen for comparative studies due to their significant difference in membrane glycerol permeability.Osmotic water permeability (P(f)) at 23 degrees C was (2.89 +/- 0.37) x 10(-2) and (5.12 +/- 0.61) x 10(-2) cm s(-1) for human and bovine cells, respectively, with similar activation energies for water transport. Glycerol permeability (P(gly)) for human ((1.37 +/- 0.26) x 10(-5) cm s(-1)) differed in three orders of magnitude from bovine erythrocytes ((5.82 +/- 0.37) x 10(-8) cm s(-1)) that also showed higher activation energy for glycerol transport. When compared to human, bovine erythrocytes showed a similar expression pattern of AQP1 glycosylated forms on immunoblot analysis, though in slight higher levels, which could be correlated with the 1.5-fold larger P(f) found. However, AQP3 expression was not detectable. Immunofluorescence analysis confirmed the absence of AQP3 expression in bovine erythrocyte membranes.In conclusion, lack of AQP3 in bovine erythrocytes points to the lipid pathway as responsible for glycerol permeation and explains the low glycerol permeability and high E(a) for transport observed in ruminants. (C) 2011 Elsevier Inc. All rights reserved.