Kruckeberg A L, Walsh M C, Van Dam K
E.C. Slater Institute, University of Amsterdam, The Netherlands.
Bioessays. 1998 Dec;20(12):972-6. doi: 10.1002/(SICI)1521-1878(199812)20:12<972::AID-BIES2>3.0.CO;2-M.
A glucose-sensing mechanism has been described in Saccharomyces cerevisiae that regulates expression of glucose transporter genes. The sensor proteins Snf3 and Rgt2 are homologous to the transporters they regulate. Snf3 and Rgt2 are integral plasma membrane proteins with unique carboxy-terminal domains that are predicted to be localized in the cytoplasm. In a recent paper Ozcan and colleagues [Ozcan S, et al. EMBO J 1998; 17:2556-2773 (Ref. 1)] present evidence that the cytoplasmic domains of Snf3 and Rgt2 are required to transmit a glucose signal. They provide additional evidence to support their earlier assertion [Ozcan S, et al. Proc Natl Acad Sci USA 1996;93:12428-12432 (Ref. 2)] that glucose transport via Snf3 and Rgt2 is not involved in glucose sensing but, rather, that these proteins behave like glucose receptors. Other examples of transporter homologs with regulatory functions have recently been described in fungi as well [Madi L, et al. Genetics 1997; 146:499-508 (Ref. 3). and Didion T, et al. Mol Microbiol 1998;27:643-650 (Ref. 4)]. The identification of this class of nutrient sensors is an important step in elucidating the complex of regulatory mechanisms that leads to adaptation of fungi to different environments.
在酿酒酵母中已描述了一种调节葡萄糖转运蛋白基因表达的葡萄糖感应机制。传感蛋白Snf3和Rgt2与它们所调节的转运蛋白同源。Snf3和Rgt2是整合的质膜蛋白，具有预测定位于细胞质中的独特羧基末端结构域。在最近的一篇论文中，奥兹坎及其同事[奥兹坎S等人。《欧洲分子生物学组织杂志》1998年；17:2556 - 2773（参考文献1）]提供证据表明，Snf3和Rgt2的细胞质结构域是传递葡萄糖信号所必需的。他们提供了额外的证据来支持其早期的论断[奥兹坎S等人。《美国国家科学院院刊》1996年；93:12428 - 12432（参考文献2）]，即通过Snf3和Rgt2的葡萄糖转运不参与葡萄糖感应，相反，这些蛋白的行为类似于葡萄糖受体。最近在真菌中也描述了具有调节功能的转运蛋白同源物的其他例子[马迪L等人。《遗传学》1997年；146:499 - 508（参考文献3）。以及迪迪翁T等人。《分子微生物学》1998年；27:643 - 650（参考文献4）]。这类营养传感器的鉴定是阐明导致真菌适应不同环境的复杂调节机制的重要一步。
