HFA1 encoding an organelle-specific acetyl-CoA carboxylase controls mitochondrial fatty acid synthesis in Saccharomyces cerevisiae
HFA1 encoding an organelle-specific acetyl-CoA carboxylase controls mitochondrial fatty acid synthesis in Saccharomyces cerevisiae
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DOI：
10.1074/jbc.m401071200
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发表时间：
2004-05-21
影响因子：
4.8
通讯作者：
Schweizer, E
中科院分区：
文献类型：
--
作者：
Hoja, U;Marthol, S;Schweizer, E
酿酒酵母基因HFA 1编码一种> 250- kDa的蛋白质，这是线粒体功能所必需的。Hfa 1 p与ACC 1编码的酵母胞质乙酰辅酶A羧化酶具有72%的序列相似性（54%的同一性）.然而，HFA 1和ACC 1的功能并不重叠，因为这两个基因的突变体具有不同的表型，并且不互补。尽管ACC 1参与细胞质脂肪酸合成，但hfa 1 Delta破坏物的表型类似于线粒体脂肪酸合成酶突变体的表型。它们不能在乳酸盐或甘油上生长，并且线粒体辅因子，硫辛酸，减少到其正常细胞浓度的< 10%。除了Acc 1 p之外，Hfa 1 p的N-末端序列包含典型的线粒体靶向信号以及基质蛋白酶切割位点。因此，HFA 1编码的蛋白质通过适当细胞组分的Western印迹特异性地分配到线粒体区室。去除线粒体靶向序列消除了HFA 1 DNA互补hfal无效突变体的能力。相反，与完整的HFA 1序列相反，无信号序列的HFA 1基因补充了细胞质乙酰辅酶A羧化酶的突变损失.在ACC 1启动子的控制下表达HFA 1使ACC 1缺陷型酵母突变体中的细胞ACC活性恢复至野生型水平。从这一发现可以得出结论，HFA 1编码一种特定的线粒体乙酰辅酶A羧化酶，为细胞器内脂肪酸，特别是硫辛酸的合成提供丙二酰辅酶A。
The Saccharomyces cerevisiae gene, HFA1, encodes a > 250- kDa protein, which is required for mitochondrial function. Hfa1p exhibits 72% overall sequence similarity ( 54% identity) to ACC1- encoded yeast cytoplasmic acetyl- CoA carboxylase. Nevertheless, HFA1 and ACC1 functions are not overlapping because mutants of the two genes have different phenotypes and do not complement each other. Whereas ACC1 is involved in cytoplasmic fatty acid synthesis, the phenotype of hfa1Delta disruptants resembles that of mitochondrial fatty- acid synthase mutants. They fail to grow on lactate or glycerol, and the mitochondrial cofactor, lipoic acid, is reduced to < 10% of its normal cellular concentration. Other than Acc1p, the N- terminal sequence of Hfa1p comprises a canonical mitochondrial targeting signal together with a matrix protease cleavage site. Accordingly, the HFA1- encoded protein was specifically assigned by Western blotting of appropriate cell fractions to the mitochondrial compartment. Removal of the mitochondrial targeting sequence abolished the competence of HFA1 DNA to complement hfal null mutants. Conversely and in contrast to the intact HFA1 sequence, the signal sequence- free HFA1 gene complemented the mutational loss of cytoplasmic acetyl- CoA carboxylase. Expression of HFA1 under the control of the ACC1 promoter restored cellular ACC activity in ACC1- defective yeast mutants to wild type levels. From this finding, it is concluded that HFA1 encodes a specific mitochondrial acetyl- CoA carboxylase providing malonyl- CoA for intraorganellar fatty acid and, in particular, lipoic acid synthesis.