The NPC Motif of Aquaporin-11, Unlike the NPA Motif of Known Aquaporins, Is Essential for Full Expression of Molecular Function
The NPC Motif of Aquaporin-11, Unlike the NPA Motif of Known Aquaporins, Is Essential for Full Expression of Molecular Function
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DOI：
10.1074/jbc.m110.180968
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发表时间：
2011-02-04
影响因子：
4.8
通讯作者：
Ishibashi, Kenichi
中科院分区：
文献类型：
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作者：
Ikeda, Masahiro;Andoo, Ayaka;Ishibashi, Kenichi
最近鉴定的分子水通道蛋白-11（AQP 11）具有独特的氨基酸序列模式，其包括Asn-Pro- Cys（NPC）基序，对应于传统AQPs的N-末端Asn-Pro- Ala（NPA）特征基序。在这项研究中，我们研究了NPC基序的突变对转染的哺乳动物细胞中AQP 11的亚细胞定位，寡聚化和水渗透性的影响。此外，还使用斑马鱼评估了效果。NPC基序的定点突变不影响AQP 11的亚细胞定位，但减少其寡聚化。细胞肿胀试验显示，表达具有突变NPC基序的AQP 11的细胞比表达野生型AQP 11的细胞具有显著更低的渗透水渗透性。内源性AQP 11缺乏的斑马鱼在发育的早期阶段在尾部区域表现出畸形。这种表型通过注射人野生型AQP 11 mRNA而被显著拯救，而具有突变的NPC基序的AQP 11 mRNA的效果不太明显。虽然已知NPA基序对于常规AQP形成透水孔是重要的，但我们的观察表明，相应的NPC基序AQP 11对于分子功能的充分表达是必不可少的。
The recently identified molecule aquaporin-11 (AQP11) has a unique amino acid sequence pattern that includes an Asn-Pro- Cys (NPC) motif, corresponding to the N-terminal Asn-Pro- Ala (NPA) signature motif of conventional AQPs. In this study, we examined the effect of the mutation of the NPC motif on the subcellular localization, oligomerization, and water permeability of AQP11 in transfected mammalian cells. Furthermore, the effect was also assessed using zebrafish. Site-directed mutation at the NPC motif did not affect the subcellular localization of AQP11 but reduced its oligomerization. A cell swelling assay revealed that cells expressing AQP11 with a mutated NPC motif had significantly lower osmotic water permeability than cells expressing wild-type AQP11. Zebrafish deficient in endogenous AQP11 showed a deformity in the tail region at an early stage of development. This phenotype was dramatically rescued by injection of human wild-type AQP11 mRNA, whereas the effect of mRNA for AQP11 with a mutated NPC motif was less marked. Although the NPA motif is known to be important for formation of water-permeable pores by conventional AQPs, our observations suggest that the corresponding NPC motif of AQP11 is essential for full expression of molecular function.