Ota I M, Varshavsky A
Division of Biology, California Institute of Technology, Pasadena 91125.
Science. 1993 Oct 22;262(5133):566-9. doi: 10.1126/science.8211183.
Many bacterial signaling pathways involve a two-component design. In these pathways, a sensor kinase, when activated by a signal, phosphorylates its own histidine, which then serves as a phosphoryl donor to an aspartate in a response regulator protein. The Sln1 protein of the yeast Saccharomyces cerevisiae has sequence similarities to both the histidine kinase and the response regulator proteins of bacteria. A missense mutation in SLN1 is lethal in the absence but not in the presence of the N-end rule pathway, a ubiquitin-dependent proteolytic system. The finding of SLN1 demonstrates that a mode of signal transduction similar to the bacterial two-component design operates in eukaryotes as well.
许多细菌信号通路采用双组分设计。在这些通路中，一种传感激酶在被信号激活后，会将自身的组氨酸磷酸化，然后该组氨酸作为磷酰基供体，将磷酰基转移给应答调节蛋白中的天冬氨酸。酿酒酵母的Sln1蛋白在序列上与细菌的组氨酸激酶和应答调节蛋白都有相似之处。SLN1中的一个错义突变在缺乏N端规则途径（一种泛素依赖性蛋白水解系统）时是致死的，但在有该途径时则不会致死。对SLN1的这一发现表明，一种类似于细菌双组分设计的信号转导模式在真核生物中也存在。
