Kirstein Janine, Strahl Henrik, Molière Noël, Hamoen Leendert W, Turgay Kürşad
Institut für Biologie - Mikrobiologie, FU Berlin, Berlin, Germany.
Mol Microbiol. 2008 Nov;70(3):682-94. doi: 10.1111/j.1365-2958.2008.06438.x. Epub 2008 Sep 10.
Protein degradation mediated by ATP-dependent proteases, such as Hsp100/Clp and related AAA+ proteins, plays an important role in cellular protein homeostasis, protein quality control and the regulation of, e.g. heat shock adaptation and other cellular differentiation processes. ClpCP with its adaptor proteins and other related proteases, such as ClpXP or ClpEP of Bacillus subtilis, are involved in general and regulatory proteolysis. To determine if proteolysis occurs at specific locations in B. subtilis cells, we analysed the subcellular distribution of the Clp system together with adaptor and general and regulatory substrate proteins, under different environmental conditions. We can demonstrate that the ATPase and the proteolytic subunit of the Clp proteases, as well as the adaptor or substrate proteins, form visible foci, representing active protease clusters localized to the polar and to the mid-cell region. These clusters could represent a compartmentalized place for protein degradation positioned at the pole close to where most of the cellular protein biosynthesis and also protein quality control are taking place, thereby spatially separating protein synthesis and degradation.
由ATP依赖性蛋白酶介导的蛋白质降解，如Hsp100/Clp及相关的AAA+蛋白，在细胞蛋白质稳态、蛋白质质量控制以及例如热休克适应和其他细胞分化过程的调节中发挥着重要作用。ClpCP及其衔接蛋白和其他相关蛋白酶，如枯草芽孢杆菌的ClpXP或ClpEP，参与一般和调节性蛋白水解。为了确定蛋白质水解是否发生在枯草芽孢杆菌细胞的特定位置，我们在不同环境条件下分析了Clp系统与衔接蛋白、一般和调节性底物蛋白的亚细胞分布。我们可以证明，Clp蛋白酶的ATP酶和蛋白水解亚基，以及衔接蛋白或底物蛋白，形成可见的焦点，代表定位于极性和细胞中部区域的活性蛋白酶簇。这些簇可能代表一个用于蛋白质降解的区室化场所，位于靠近大多数细胞蛋白质生物合成以及蛋白质质量控制发生的极部，从而在空间上分离蛋白质合成和降解。
