cGMP transport by vesicles from human and mouse erythrocytes
cGMP transport by vesicles from human and mouse erythrocytes
复制标题
DOI：
10.1111/j.1742-4658.2006.05591.x
复制
发表时间：
2007-01-01
期刊：
影响因子：
5.4
通讯作者：
Borst, Piet
中科院分区：
文献类型：
--
作者：
de Wolf, Cornelia J. F.;Yamaguchi, Hiroaki;Borst, Piet
细胞的环鸟苷酸（cGMP）分泌可由ATP结合盒（ABC）转运体ABCC4、ABCC5和ABCC11介导。间接证据表明ABCC4和ABCC5有助于红细胞的cGMP转运。我们使用野生型和转运体敲除小鼠的红细胞对该问题进行了重新研究。小鼠野生型红细胞囊泡转运cGMP的表观米氏常数（Kₘ）比人类的高100倍，而表观最大反应速率（Vₘₐₓ）相似。虽然ABCC4特异性底物前列腺素E₁能有效抑制cGMP转运进入人类囊泡，但Abcg2和Abcc4抑制剂/底物对cGMP转运进入小鼠囊泡的抑制作用相同。同样，cGMP转运进入Abcc4⁻/⁻和Abcg2⁻/⁻小鼠的囊泡分别是转运进入野生型小鼠囊泡的42%和51%，而cGMP转运进入Abcc4⁻/⁻/Abcg2⁻/⁻小鼠的囊泡接近背景水平。利用敲除小鼠表明，Abcg2介导的cGMP转运比Abcc4介导的转运亲和力更低，但最大反应速率更高。Abcc4⁻/⁻红细胞囊泡在pH 5.5时的转运高于pH 7.4，这是Abcg2介导转运的一个特征，支持了Abcg2参与cGMP转运。一种新的ABCC4转运抑制剂——蛋白酶抑制剂4 -（2 - 氨乙基）苯磺酰氟，证实了ABCC4/Abcc4和ABCG2/Abcg2在cGMP转运中的相对作用。
cGMP secretion from cells can be mediated by ATP-binding cassette (ABC) transporters ABCC4, ABCC5, and ABCC11. Indirect evidence suggests that ABCC4 and ABCC5 contribute to cGMP transport by erythrocytes. We have re-investigated the issue using erythrocytes from wild-type and transporter knockout mice. Murine wild-type erythrocyte vesicles transported cGMP with an apparent K-m that was 100-fold higher than their human counterparts, the apparent V-max being similar. Whereas cGMP transport into human vesicles was efficiently inhibited by the ABCC4-specific substrate prostaglandin E-1, cGMP transport into mouse vesicles was inhibited equally by Abcg2 and Abcc4 inhibitors/substrates. Similarly, cGMP transport into vesicles from Abcc4(-/-) and Abcg2(-/-) mice was 42% and 51% of that into wild-type mouse vesicles, respectively, whereas cGMP transport into vesicles from Abcc4(-/-)/Abcg2(-/-) mice was near background. The knockout mice were used to show that Abcg2-mediated cGMP transport occurred with lower affinity but higher V-max than Abcc4-mediated transport. Involvement of Abcg2 in cGMP transport by Abcc4(-/-) erythrocyte vesicles was supported by higher transport at pH 5.5 than at pH 7.4, a characteristic of Abcg2-mediated transport. The relative contribution of ABCC4/Abcc4 and ABCG2/Abcg2 in cGMP transport was confirmed with a new inhibitor of ABCC4 transport, the protease inhibitor 4-(2-aminoethyl)benzenesulfonyl fluoride.