Posas F, Wurgler-Murphy S M, Maeda T, Witten E A, Thai T C, Saito H
Dana-Farber Cancer Institute and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA.
Cell. 1996 Sep 20;86(6):865-75. doi: 10.1016/s0092-8674(00)80162-2.
An osmosensing mechanism in the budding yeast (Saccharomyces cerevisiae) involves both a two-component signal transducer (Sln1p, Ypd1p and Ssk1p) and a MAP kinase cascade (Ssk2p/Ssk22p, Pbs2p, and Hog1p). The transmembrane protein Sln1p contains an extracellular sensor domain and cytoplasmic histidine kinase and receiver domains, whereas the cytoplasmic protein Ssk1p contains a receiver domain. Ypd1p binds to both Sln1p and Ssk1p and mediates the multistep phosphotransfer reaction (phosphorelay). This phosphorelay system is initiated by the autophosphorylation of Sln1p at His576. This phosphate is then sequentially transferred to Sln1p-Asp-1144, then to Ypd1p-His64, and finally to Ssk1p-Asp554. We propose that the multistep phosphorelay mechanism is a universal signal transduction apparatus utilized both in prokaryotes and eukaryotes.
芽殖酵母（酿酒酵母）中的渗透感应机制涉及一个双组分信号转导器（Sln1p、Ypd1p和Ssk1p）和一个MAP激酶级联反应（Ssk2p/Ssk22p、Pbs2p和Hog1p）。跨膜蛋白Sln1p包含一个细胞外传感器结构域以及细胞质组氨酸激酶和受体结构域，而细胞质蛋白Ssk1p包含一个受体结构域。Ypd1p与Sln1p和Ssk1p都结合，并介导多步磷酸转移反应（磷酸中继）。这种磷酸中继系统由Sln1p在His576处的自磷酸化启动。然后该磷酸基团依次转移至Sln1p-Asp-1144，接着转移至Ypd1p-His64，最后转移至Ssk1p-Asp554。我们提出，多步磷酸中继机制是一种在原核生物和真核生物中都使用的通用信号转导装置。
