Mizrahi Itzhak, Biran Dvora, Ron Eliora Z
Department of Molecular Microbiology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel.
Mol Microbiol. 2006 Oct;62(1):201-11. doi: 10.1111/j.1365-2958.2006.05360.x.
Protein degradation is a central component of the protein quality control system. Here we show that efficient proteolysis in Escherichia coli requires the active acetyl phosphate pathway. Deletion of this pathway, leading to depletion of acetyl phosphate, results in temperature sensitivity and reduced rate of ATP-dependent proteolysis. The effect on proteolysis is general, as can be seen from the slowing down of the degradation of unstable proteins, including puromycin-derived peptides. In addition, reduced intracellular concentrations of acetyl phosphate brings about an increase in the levels of protein aggregates, which contain a wide range of proteins, as expected if a broad spectrum of substrates are involved. Additional outcomes of acetyl phosphate deficiency are elevation in the transcript levels of heat shock genes and increased thermotolerance. In E. coli the acetyl phosphate pathway is the only source of acetyl phosphate, which is a key metabolic compound involved in major cellular processes. In this communication we present evidence for the general role of the acetyl phosphate pathway in protein degradation.
蛋白质降解是蛋白质质量控制系统的核心组成部分。我们在此表明，大肠杆菌中的高效蛋白水解需要活跃的乙酰磷酸途径。该途径的缺失会导致乙酰磷酸的消耗，从而导致温度敏感性和ATP依赖性蛋白水解速率降低。对蛋白水解的影响是普遍的，从不稳定蛋白质（包括嘌呤霉素衍生肽）降解的减慢中可以看出。此外，细胞内乙酰磷酸浓度的降低导致蛋白质聚集体水平的增加，其中包含多种蛋白质，正如涉及广泛底物时所预期的那样。乙酰磷酸缺乏的其他结果是热休克基因转录水平的升高和耐热性的增加。在大肠杆菌中，乙酰磷酸途径是乙酰磷酸的唯一来源，乙酰磷酸是参与主要细胞过程的关键代谢化合物。在本通讯中，我们提供了乙酰磷酸途径在蛋白质降解中普遍作用的证据。
