Roles of COMM-domain-containing 1 in stability and recruitment of the copper-transporting ATPase in a mouse hepatoma cell line
Roles of COMM-domain-containing 1 in stability and recruitment of the copper-transporting ATPase in a mouse hepatoma cell line
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DOI：
10.1042/bj20100223
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发表时间：
2010-07-01
影响因子：
4.1
通讯作者：
Ogra, Yasumitsu
中科院分区：
文献类型：
--
作者：
Miyayama, Takamitsu;Hiraoka, Daisuke;Ogra, Yasumitsu
采用分子和细胞生物学技术组成的多学科技术，在小鼠肝癌细胞系Hepa 1-6中研究了COMMD 1 {COMM [铜代谢MURR 1（小鼠U2 af 1-rs 1区域1）]-domain-containing 1}（一种与犬铜中毒相关的蛋白质）的新功能。技术、物种形成和元素成像。为了阐明COMMD 1的功能，通过将siRNA（小干扰RNA）引入细胞中来实现COMMD 1敲低。虽然COMMD 1基因敲低不影响铜的掺入，但它抑制了铜的排泄，导致铜的积累，铜主要以与MT（金属硫蛋白）结合的形式存在。已知肝铜转运蛋白Atp 7 b（ATP依赖性铜转运蛋白7 β）在基础铜条件下定位于跨高尔基体网络膜上，并且当其浓度超过一定阈值时易位至细胞质囊泡以排泄铜，其中囊泡分散在细胞的外周中。COMMD 1敲低降低Atp 7 b的表达，并取消了迁移的Atp 7 b从外围到trans-Golgi网络膜时，铜浓度降低与Cu（I）螯合剂处理。在COMMD 1敲除过程中，观察到同样的现象时，另一个Atp 7 b基板，顺二氨二氯铂，和它的螯合剂，谷胱甘肽乙酯，应用。这些结果表明，COMMD 1维持Atp 7 b的量，并促进Atp 7 b从胞质囊泡到trans-Golgi网络膜的募集，即COMMD 1需要穿梭Atp 7 b时，细胞内铜水平低于阈值返回。
A novel function of COMMD1 {COMM [copper metabolism MURR1 (mouse U2af1-rs1 region 1)]-domain-containing 1}, a protein relevant to canine copper toxicosis, was examined in the mouse hepatoma cell line Hepa 1-6 with multi-disciplinary techniques consisting of molecular and cellular biological techniques, speciation and elemental imaging. To clarify the function of COMMD1, COMMD1-knockdown was accomplished by introducing siRNA (small interfering RNA) into the cells. Although COMMD1-knockdown did not affect copper incorporation, it inhibited copper excretion, resulting in copper accumulation, which predominantly existed in the form bound to MT (metallothionein). It is known that the liver copper transporter Atp7b (ATP-dependent copper transporter 7 beta), localizes on the trans-Golgi network membrane under basal copper conditions and translocates to cytoplasmic vesicles to excrete copper when its concentration exceeds a certain threshold, with the vesicles dispersing in the periphery of the cell. COMMD1-knockdown reduced the expression of Atp7b, and abolished the relocation of Atp7b back from the periphery to the trans-Golgi network membrane when the copper concentration was reduced by treatment with a Cu(I) chelator. The same phenomena were observed during COMMD1-knockdown when another Atp7b substrate, cis-diamminedichloroplatinum, and its sequestrator, glutathione ethylester, were applied. These results suggest that COMMD1 maintains the amount of Atp7b and facilitates recruitment of Atp7b from cytoplasmic vesicles to the trans-Golgi network membrane, i.e. COMMD1 is required to shuttle Atp7b when the intracellular copper level returns below the threshold.