Enhanced gluconeogenesis and increased energy storage as hallmarks of aging in Saccharomyces cerevisiae
Enhanced gluconeogenesis and increased energy storage as hallmarks of aging in Saccharomyces cerevisiae
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DOI：
10.1074/jbc.m103509200
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发表时间：
2001-09-21
影响因子：
4.8
通讯作者：
Gordon, JI
中科院分区：
文献类型：
--
作者：
Lin, SS;Manchester, JK;Gordon, JI
寿命和细胞葡萄糖代谢之间的关系已经从模式生物的遗传操作和热量限制中推断出来。在这份报告中，我们使用了Snf 1 p葡萄糖传感途径的酿酒酵母，探讨葡萄糖代谢和衰老之间的遗传和生化联系。snf 1 p是一种丝氨酸/苏氨酸激酶，调节细胞对葡萄糖剥夺的反应。Snf 1 p的激活剂Snf 4p的缺失延长了世代寿命，而假定的激酶抑制剂Sip 2 p的缺失导致加速老化表型。从DNA微阵列研究中产生了等基因野生型、sip 2 Delta和snf 4 Delta菌株中基因表达的全球年龄相关变化的注释数据库。转录反应表明，随着野生型细胞的老化，新陈代谢和葡萄糖储存增加，这种代谢进化在快速老化的sip 2 δ细胞中被夸大，并且在寿命较长的snf 4 δ细胞中被减弱。为了直接验证这一假设，我们将微量分析生化方法应用于来自每个菌株的世代匹配的细胞，并测量了酶的活性和代谢产物的浓度，这些代谢产物包括糖原、糖酵解和乙醛酸途径，以及糖原、ATP和NAD（+）。检测的灵敏度允许使用用于转录谱分析的相同细胞群的等分试样进行全面的生化谱分析。这些结果为S.酿酒酵母与从糖酵解向糖异生和能量储存的转变有关。他们还披露，这种转变是通过两种延长寿命的操作来预防的，即热量限制和Snf 1 p活性正常年龄相关增加的遗传衰减。总之，这些发现表明Snf 1 p激活不仅是衰老的标志，也是一种候选介质，因为向能量储存的转变可能会影响细胞维护和修复的各个方面。
A relationship between life span and cellular glucose metabolism has been inferred from genetic manipulations and caloric restriction of model organisms. In this report, we have used the Snf1p glucose-sensing pathway of Saccharomyces cerevisiae to explore the genetic and biochemical linkages between glucose metabolism and aging. Snf1p is a serine/threonine kinase that regulates cellular responses to glucose deprivation. Loss of Snf4p, an activator of Snf1p, extends generational life span whereas loss of Sip2p, a presumed repressor of the kinase, causes an accelerated aging phenotype. An annotated data base of global age-associated changes in gene expression in isogenic wild-type, sip2 Delta, and snf4 Delta, strains was generated from DNA microarray studies. The transcriptional responses suggested that gluconeogenesis and glucose storage increase as wild-type cells age, that this metabolic evolution is exaggerated in rapidly aging sip2 Delta cells, and that it is attenuated in longer-lived snf4 Delta, cells. To test this hypothesis directly, we applied microanalytic biochemical methods to generation-matched cells from each strain and measured the activities of enzymes and concentrations of metabolites in the gluconeogenic, glycolytic, and glyoxylate pathways, as well as glycogen, ATP, and NAD(+). The sensitivity of the assays allowed comprehensive biochemical profiling to be performed using aliquots of the same cell populations employed for the transcriptional profiling. The results provided additional evidence that aging in S. cerevisiae is associated with a shift away from glycolysis and toward gluconeogenesis and energy storage. They also disclosed that this shift is forestalled by two manipulations that extend life span, caloric restriction and genetic attenuation of the normal age-associated increase in Snf1p activity. Together, these findings indicate that Snf1p activation is not only a marker of aging but also a candidate mediator, because a shift toward energy storage over expenditure could impact myriad aspects of cellular maintenance and repair.