SLC24A5 encodes a trans-golgi network protein with potassium-dependent sodium-calcium exchange activity that regulates human epidermal melanogenesis
SLC24A5 encodes a trans-golgi network protein with potassium-dependent sodium-calcium exchange activity that regulates human epidermal melanogenesis
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DOI：
10.1074/jbc.m707521200
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发表时间：
2008-02-29
影响因子：
4.8
通讯作者：
Green, Martin R.
中科院分区：
文献类型：
--
作者：
Ginger, Rebecca S.;Askew, Sarah E.;Green, Martin R.
人SLC 24 A5基因的一个非同义单核苷酸多态性与人的自然肤色变异相关多序列比对预测，该基因编码的钾依赖性钠钙交换器家族成员表示NCKX 5。在培养的人表皮黑素细胞中，我们使用亲和纯化的抗血清显示，天然人NCKX 5在SDS-PAGE上以类似于43 kDa的三联体运行，并且部分定位于trans-Golgi网络。通过小干扰RNA介导的敲低去除NCKX 5蛋白破坏人和鼠黑素细胞中的黑素生成，导致黑色素产生显著减少。使用异源表达系统，我们首次确认NCKX 5具有预测的交换活性。NCKX 5和NCKX 2在该系统中的定点突变揭示了SLC 24 A5中的非同义单核苷酸多态性改变了对NCKX 5和NCKX 2活性重要的残基。我们认为NCKX 5通过其细胞内钾依赖性交换活性直接调节人表皮黑素生成和自然肤色。
A non-synonymous single nucleotide polymorphism in the human SLC24A5 gene is associated with natural human skin color variation. Multiple sequence alignments predict that this gene encodes a member of the potassium-dependent sodium-calcium exchanger family denoted NCKX5. In cultured human epidermal melanocytes we show using affinity-purified antisera that native human NCKX5 runs as a triplet of similar to 43 kDa on SDS-PAGE and is partially localized to the trans-Golgi network. Removal of the NCKX5 protein through small interfering RNA-mediated knockdown disrupts melanogenesis in human and murine melanocytes, causing a significant reduction in melanin pigment production. Using a heterologous expression system, we confirm for the first time that NCKX5 possesses the predicted exchanger activity. Site-directed mutagenesis of NCKX5 and NCKX2 in this system reveals that the non-synonymous single nucleotide polymorphism in SLC24A5 alters a residue that is important for NCKX5 and NCKX2 activity. We suggest that NCKX5 directly regulates human epidermal melanogenesis and natural skin color through its intracellular potassium-dependent exchanger activity.