Expression of algal nuclear ATP synthase subunit 6 in human cells results in protein targeting to mitochondria but no assembly into ATP synthase
Expression of algal nuclear ATP synthase subunit 6 in human cells results in protein targeting to mitochondria but no assembly into ATP synthase
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DOI：
10.1089/rej.2006.9.455
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发表时间：
2006-12-01
影响因子：
2.6
通讯作者：
Holt, Ian J.
中科院分区：
文献类型：
--
作者：
Bokori-Brown, Monika;Holt, Ian J.
人工将线粒体基因转移到细胞核对理解线粒体功能、进化和人类健康具有重要意义。因此，我们创建了与线粒体靶向信号相关的ATP合酶的人亚基a（A6）的核相容版本。将人核亚基a的表达和靶向与天然存在于细胞核中的莱茵衣藻亚基a进行比较。藻类亚基a比人类核亚基a变体更有效地靶向线粒体。然而，没有证据表明培养的细胞中线粒体功能得到改善;相反，藻类亚基a的长期表达与存活率低和对需要严重依赖氧化磷酸化的生长条件的不耐受有关。天然凝胶上富集的线粒体膜组分的分析揭示了含有FLAG标记的亚基a的高分子量复合物;然而，该复合物不与ATP合酶共定位。因此，没有证据表明藻类亚基a组装成全酶，也没有人类核亚基a与ATP合酶全酶共定位。总之，线粒体基因转移到细胞核的功能表达仍然存在障碍。
Artificial transfer of mitochondrial genes to the nucleus has implications for the understanding of mitochondrial function, evolution, and human health. Therefore, we created nuclear compatible versions of human subunit a (A6) of ATP synthase, linked to a mitochondrial targeting signal. Expression and targeting of human nuclear subunit a were compared to subunit a of Chlamydomonas reinhardtii, which naturally occurs in the nucleus. Algal subunit a was targeted to mitochondria more efficiently than human nuclear subunit a variants. However, there was no evidence of improved mitochondrial function in cultured cells; on the contrary, long-term expression of algal subunit a was associated with poor survival and intolerance of growth conditions that demand heavy reliance on oxidative phosphorylation. Analysis of enriched mitochondrial membrane fractions on native gels revealed a high-molecular-weight complex containing FLAG-tagged subunit a; however, this complex did not colocalize with ATP synthase. Thus, there was no evidence of assembly of algal subunit a into holoenzyme, nor did human nuclear subunit a colocalize with ATP synthase holoenzyme. In conclusion, obstacles remain to functional expression of mitochondrial genes transferred to the nucleus.