Two glucose sensing/signaling pathways stimulate glucose-induced inactivation of maltose permease in Saccharomyces.
Two glucose sensing/signaling pathways stimulate glucose-induced inactivation of maltose permease in Saccharomyces.
复制标题
两条葡萄糖传感/信号传导途径刺激酵母菌中葡萄糖诱导的麦芽糖通透酶失活。
DOI：
10.1091/mbc.8.7.1293
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发表时间：
1997
影响因子：
3.3
通讯作者：
Michels,CA
中科院分区：
文献类型：
--
作者：
Jiang,H;Medintz,I;Michels,CA
葡萄糖是酵母菌的全局代谢调节剂。它在转录水平上控制许多参与碳水化合物利用的基因的表达，并通过翻译后机制诱导几种酶的失活。已知SNF3、RGT2、GRR1和RGT1参与葡萄糖的转录调控。我们测试了这些基因在葡萄糖诱导的麦芽糖渗透酶失活中的作用。我们的研究结果表明，至少有两种信号通路用于监测血糖水平。一种途径需要葡萄糖传感器转录，另一种途径独立于葡萄糖转运。Rgt2p与Snf3p一起监测细胞外葡萄糖水平，似乎是葡萄糖转运不依赖途径的葡萄糖传感器。rgt2p依赖信号的传输需要Grr1p。RGT2和GRR1还在调节HXT基因的表达中发挥作用，HXT基因似乎是调节麦芽糖渗透酶失活的葡萄糖转运依赖途径的上游组分。RGT2-1是一个显性突变，可以引起几个HXT基因的组成性表达，它可以导致麦芽糖渗透酶的组成性蛋白水解，即在没有葡萄糖的情况下。提出了这些葡萄糖传感/信号通路的模型。
Glucose is a global metabolic regulator in Saccharomyces. It controls the expression of many genes involved in carbohydrate utilization at the level of transcription, and it induces the inactivation of several enzymes by a posttranslational mechanism. SNF3, RGT2, GRR1 and RGT1 are known to be involved in glucose regulation of transcription. We tested the roles of these genes in glucose-induced inactivation of maltose permease. Our results suggest that at least two signaling pathways are used to monitor glucose levels. One pathway requires glucose sensor transcript and the second pathway is independent of glucose transport. Rgt2p, which along with Snf3p monitors extracellular glucose levels, appears to be the glucose sensor for the glucose-transport-independent pathway. Transmission of the Rgt2p-dependent signal requires Grr1p. RGT2 and GRR1 also play a role in regulating the expression of the HXT genes, which appear to be the upstream components of the glucose-transport-dependent pathway regulating maltose permease inactivation. RGT2-1, which was identified as a dominant mutation causing constitutive expression of several HXT genes, causes constitutive proteolysis of maltose permease, that is, in the absence of glucose. A model of these glucose sensing/signaling pathways is presented.