Galello Fiorella, Pautasso Constanza, Reca Sol, Cañonero Luciana, Portela Paula, Moreno Silvia, Rossi Silvia
Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento Química Biológica and CONICET - Universidad de Buenos Aires, Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales, Buenos Aires, Argentina.
Yeast. 2017 Dec;34(12):495-508. doi: 10.1002/yea.3252. Epub 2017 Sep 14.
Yeast cells can adapt their growth in response to the nutritional environment. Glucose is the favourite carbon source of Saccharomyces cerevisiae, which prefers a fermentative metabolism despite the presence of oxygen. When glucose is consumed, the cell switches to the aerobic metabolism of ethanol, during the so-called diauxic shift. The difference between fermentative and aerobic growth is in part mediated by a regulatory mechanism called glucose repression. During glucose derepression a profound gene transcriptional reprogramming occurs and genes involved in the utilization of alternative carbon sources are expressed. Protein kinase A (PKA) controls different physiological responses following the increment of cAMP as a consequence of a particular stimulus. cAMP-PKA is one of the major pathways involved in the transduction of glucose signalling. In this work the regulation of the promoters of the PKA subunits during respiratory and fermentative metabolism are studied. It is demonstrated that all these promoters are upregulated in the presence of glycerol as carbon source through the Snf1/Cat8 pathway. However, in the presence of glucose as carbon source, the regulation of each PKA promoter subunits is different and only TPK1 is repressed by the complex Hxk2/Mig1 in the presence of active Snf1. Copyright © 2017 John Wiley & Sons, Ltd.
酵母细胞能够根据营养环境调整其生长。葡萄糖是酿酒酵母最喜爱的碳源，尽管有氧存在，它仍偏好发酵代谢。当葡萄糖被消耗时，细胞在所谓的二次生长转换期间转向乙醇的有氧代谢。发酵生长与有氧生长之间的差异部分由一种称为葡萄糖阻遏的调节机制介导。在葡萄糖去阻遏过程中，会发生深刻的基因转录重编程，参与利用替代碳源的基因得以表达。蛋白激酶A（PKA）在特定刺激导致cAMP增加后控制不同的生理反应。cAMP-PKA是参与葡萄糖信号转导的主要途径之一。在这项工作中，研究了呼吸代谢和发酵代谢过程中PKA亚基启动子的调控。结果表明，在以甘油作为碳源时，所有这些启动子通过Snf1/Cat8途径上调。然而，在以葡萄糖作为碳源时，每个PKA启动子亚基的调控是不同的，并且在活性Snf1存在的情况下，只有TPK1被Hxk2/Mig1复合物抑制。版权所有© 约翰·威利父子有限公司2017年。
