A putative sensor kinase, Hik31, is involved in the response of Synechocystis sp strain PCC 6803 to the presence of glucose
A putative sensor kinase, Hik31, is involved in the response of Synechocystis sp strain PCC 6803 to the presence of glucose
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DOI：
10.1099/mic.0.28510-0
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发表时间：
2006-03-01
期刊：
影响因子：
2.8
通讯作者：
Kaplan, A
中科院分区：
文献类型：
--
作者：
Kahlon, S;Beeri, K;Kaplan, A
某些蓝藻菌株对葡萄糖敏感的原因尚不清楚。集胞藻中编码推定传感器激酶 Hik31 的基因失活。 PCC 6803 菌株产生的突变体在 D-葡萄糖存在下无法生长。在编码葡萄糖转运蛋白的 glcP 失活的突变体中，对 D-葡萄糖、其类似物 2-脱氧-D-葡萄糖和果糖的敏感性减轻。这些数据表明这些底物的渗透是造成细胞死亡所必需的。突变体Delta hik31和集胞蓝藻的葡萄糖敏感菌株不具有葡萄糖激酶活性，尽管存在源自glk、编码葡萄糖激酶的转录物。 glk 失活导致对葡萄糖的严重敏感性，表明细胞内葡萄糖本身的存在造成了这种敏感性。另一方面，Delta glk 对 2-脱氧-D-葡萄糖的敏感性较低，因此区分了葡萄糖本身的作用及其类似物的作用，在没有葡萄糖激酶活性的情况下，后者可能不会被磷酸化。添加葡萄糖导致野生型中葡萄糖-6-磷酸脱氢酶活性小幅上升，但在 Delta hik31 突变体中观察到了组成型活性，无论是否存在葡萄糖。微阵列分析显示，添加葡萄糖后，集胞藻中整体转录本的丰度仅发生微小变化，但几个基因（包括icfG，但不包括glk）的转录水平受到hik31失活的强烈影响。讨论了 Hik31 参与葡萄糖传感和响应的机制。
The reason(s) for glucose sensitivity in certain cyanobacterial strains is poorly understood. Inactivation of genes encoding the putative sensor kinase Hik31 in Synechocystis sp. strain PCC 6803 resulted in a mutant unable to grow in the presence of D-glucose. Sensitivities to D-glucose, its analogue 2-deoxy-D-glucose, and fructose, were alleviated in mutants in which glcP, encoding the glucose transporter, was inactivated. These data indicate that permeation of these substrates is required to inflict cell death, The mutant Delta hik31, and the glucose-sensitive strain of Synechocystis, do not possess glucokinase activity, although a transcript originating from glk, encoding glucokinase, is present. Inactivation of glk led to severe sensitivity to glucose, indicating that the presence of glucose itself, within the cells, inflicted this sensitivity. On the other hand, sensitivity to 2-deoxy-D-glucose was lower in Delta glk, thus distinguishing between the effect of glucose itself and that of its analogue, which, in the absence of glucokinase activity, may not be phosphorylated. Addition of glucose led to a small rise in glucose-6-phosphate dehydrogenase activity in the wild type, but constitutive activity was observed in the Delta hik31 mutant regardless of the presence of glucose. Microarray analyses showed only small changes in the abundance of global transcripts in Synechocystis following glucose addition, but the transcription levels of several genes, including icfG, but not glk, were strongly affected by inactivation of hik31. The mechanism(s) whereby Hik31 is involved in glucose sensing and response is discussed.