Moonlighting proteins Hal3 and Vhs3 form a heteromeric PPCDC with Ykl088w in yeast CoA biosynthesis
Moonlighting proteins Hal3 and Vhs3 form a heteromeric PPCDC with Ykl088w in yeast CoA biosynthesis
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DOI：
10.1038/nchembio.243
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发表时间：
2009-12-01
影响因子：
14.8
通讯作者：
Arino, Joaquin
中科院分区：
文献类型：
--
作者：
Ruiz, Amparo;Gonzalez, Asier;Arino, Joaquin
与大多数其他生物不同，必需的五步辅酶A生物合成途径在酵母中尚未完全解决。具体地，编码磷酸泛酰半胱氨酸脱羧酶（PPCDC）活性的基因仍然未被鉴定。序列同源性分析表明，三个候选人Ykl 088 w，Hal 3和Vhs 3-作为推定的PPCDC酶在酿酒酵母。值得注意的是，Hal 3和Vhs 3已被表征为Ppz 1蛋白磷酸酶的负调节亚基。在这里，我们表明，YKL 088 w不编码第三Ppz 1调节亚基，Ykl 088 w和Hal 3和Vhs 3对的基本作用是互补的，不能互换，可以归因于PPCDC相关的功能。我们证明，虽然已知的真核PPCDC是同源三聚体，活性酵母酶是异源三聚体，其由Ykl 088 w和Hal 3/Vhs 3单体组成，其分别提供两个必需的催化残基。我们的研究结果揭示Hal 3和Vhs 3作为兼职蛋白参与CoA生物合成和蛋白磷酸酶调节。
Unlike most other organisms, the essential five-step coenzyme A biosynthetic pathway has not been fully resolved in yeast. Specifically, the genes encoding the phosphopantothenoylcysteine decarboxylase (PPCDC) activity still remain unidentified. Sequence homology analyses suggest three candidates-Ykl088w, Hal3 and Vhs3-as putative PPCDC enzymes in Saccharomyces cerevisiae. Notably, Hal3 and Vhs3 have been characterized as negative regulatory subunits of the Ppz1 protein phosphatase. Here we show that YKL088w does not encode a third Ppz1 regulatory subunit, and that the essential roles of Ykl088w and the Hal3 and Vhs3 pair are complementary, cannot be interchanged and can be attributed to PPCDC-related functions. We demonstrate that while known eukaryotic PPCDCs are homotrimers, the active yeast enzyme is a heterotrimer that consists of Ykl088w and Hal3/Vhs3 monomers that separately provides two essential catalytic residues. Our results unveil Hal3 and Vhs3 as moonlighting proteins involved in both CoA biosynthesis and protein phosphatase regulation.