Expression of Candida albicans glutathione transferases is induced inside phagocytes and upon diverse environmental stresses
Expression of Candida albicans glutathione transferases is induced inside phagocytes and upon diverse environmental stresses
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DOI：
10.1111/j.1567-1364.2010.00613.x
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发表时间：
2010-06-01
影响因子：
3.2
通讯作者：
Herrero, Enrique
中科院分区：
文献类型：
--
作者：
Garcera, Ana;Casas, Celia;Herrero, Enrique
白色念珠菌有四个GTT类谷胱甘肽转移酶（GST）的ORF，另一个编码Omega类成员。在实验室条件下，只有GTT 11（GTT 1/2类）和GTO 1（Omega类）在指数生长的细胞中显着表达，特别是当这些细胞受到不同的环境应激，包括氧化应激时。它们也在早期稳定期短暂上调。因此，CaGto 1和CaGtt 11蛋白质的水平在用氧化剂处理后和在渗透胁迫时增加，除了早期稳定期之外。GTT 11和GTO 1的转录表现出对Hog 1和Cap 1因子的复杂依赖性。纯化的CaGtt 11和CaGto 1蛋白显示类似于酿酒酵母同源物的酶活性。因此，CaGtt 11具有针对标准GST底物的活性，并且也具有过氧化物酶活性，而CaGto 1显示硫醇氧化还原酶和脱氢抗坏血酸还原酶活性。荧光显微镜和亚分级研究表明，CaGto 1是胞质，而CaGtt 11是与颗粒部分。在离体条件下，CaGto 1和CaGtt 11在巨噬细胞和中性粒细胞内瞬时上调。在这些条件下，GTT 14（GTT 1/2类）的启动子也被激活。这些观察结果表明了C.白色念珠菌GST在防御吞噬细胞中的作用。
Candida albicans has four ORFs for glutathione transferases (GSTs) of the GTT classes, and another one coding for an Omega class member. Under laboratory conditions, only GTT11 (GTT1/2 class) and GTO1 (Omega class) are expressed significantly in exponentially growing cells, particularly when these are subjected to diverse environmental stresses, including oxidative stress. They also become transitorily upregulated at the early stationary phase. Accordingly, the levels of the CaGto1 and CaGtt11 proteins increase after treatment with oxidants and upon osmotic stress, in addition to the early stationary phase. GTT11 and GTO1 transcription shows a complex dependence on the Hog1 and Cap1 factors upon different stresses. Purified CaGtt11 and CaGto1 proteins display enzyme activities similar to the Saccharomyces cerevisiae homologues. Thus, CaGtt11 has activity against standard GST substrates and is also active as peroxidase, while CaGto1 displays thiol oxidoreductase and dehydroascorbate reductase activities. Fluorescence microscopy and subfractionation studies indicate that CaGto1 is cytosolic, while CaGtt11 is associated with a particulate fraction. Under ex vivo conditions, CaGto1 and CaGtt11 become transitorily upregulated inside macrophages and neutrophils. Under these conditions, the promoter of GTT14 (GTT1/2 class) also becomes activated. These observations point to the importance of C. albicans GSTs in the defence against phagocytes.