Dixon J E
Department of Biological Chemistry, University of Michigan, Ann Arbor 48109-0606, USA.
Recent Prog Horm Res. 1996;51:405-14; discussion 415.
Protein tyrosine phosphatases play critical roles in a number of cellular signal transduction pathways. Receptor-like PTPases such as CD45 are essential for antigen-induced proliferative responses of T-cells. Intracellular PTPases have been shown to associate with specific growth factor receptors and this association has a dramatic effect on receptor signaling mechanisms. Other phosphatases (e.g., the product of the CDC25 gene) are essential for cell cycle progression. It appears that the cellular location of the intracellular PTPases plays an important role in defining the substrate specificity. Phosphatases are also present in both pathogenic bacteria and viruses. These PTPases most likely function to disrupt important signal transduction pathways present in the host. More than 30 different phosphatases have been cloned and characterized. A detailed understanding of their catalytic properties suggests that all PTPases use a common mechanism for removing phosphatase from various phosphoproteins. Two PTPase structures recently have been determined. The structural information along with biochemical and kinetic data provides a basis for understanding the catalytic properties of these enzymes.
蛋白质酪氨酸磷酸酶在许多细胞信号转导途径中发挥关键作用。诸如CD45之类的受体样蛋白酪氨酸磷酸酶对于T细胞的抗原诱导增殖反应至关重要。细胞内蛋白酪氨酸磷酸酶已被证明与特定的生长因子受体相关联，并且这种关联对受体信号传导机制具有显著影响。其他磷酸酶（例如，CDC25基因的产物）对于细胞周期进程至关重要。细胞内蛋白酪氨酸磷酸酶的细胞定位似乎在确定底物特异性方面起着重要作用。磷酸酶也存在于致病细菌和病毒中。这些蛋白酪氨酸磷酸酶很可能起到破坏宿主中存在的重要信号转导途径的作用。已经克隆并鉴定了30多种不同的磷酸酶。对它们催化特性的详细了解表明，所有蛋白酪氨酸磷酸酶都使用一种共同机制从各种磷蛋白上去除磷酸基团。最近已经确定了两种蛋白酪氨酸磷酸酶的结构。该结构信息以及生化和动力学数据为理解这些酶的催化特性提供了基础。
