Smith Ewan W, Lima Wanessa C, Charette Steve J, Cosson Pierre
Dept. for Cell Physiology and Metabolism, Centre Medical Universitaire, Geneva Faculty of Medicine, 1211 Geneva 4, Switzerland.
Eukaryot Cell. 2010 Mar;9(3):387-92. doi: 10.1128/EC.00285-09. Epub 2010 Jan 22.
Dictyostelium discoideum amoebae have been used extensively to study the structure and dynamics of the endocytic pathway. Here, we show that while the general structure of the endocytic pathway is maintained in starved cells, its dynamics rapidly slow down. In addition, analysis of apm3 and lvsB mutants reveals that the functional organization of the endocytic pathway is profoundly modified upon starvation. Indeed, in these mutant cells, some of the defects observed in rich medium persist in starved cells, notably an abnormally slow transfer of endocytosed material between endocytic compartments. Other parameters, such as endocytosis of the fluid phase or the rate of fusion of postlysosomes to the cell surface, vary dramatically upon starvation. Studying the endocytic pathway in starved cells can provide a different perspective, allowing the primary (invariant) defects resulting from specific mutations to be distinguished from their secondary (conditional) consequences.
盘基网柄菌变形虫已被广泛用于研究内吞途径的结构和动力学。在此，我们表明，虽然饥饿细胞中内吞途径的总体结构得以维持，但其动力学迅速减慢。此外，对apm3和lvsB突变体的分析表明，饥饿时内吞途径的功能组织会发生深刻改变。实际上，在这些突变细胞中，在丰富培养基中观察到的一些缺陷在饥饿细胞中持续存在，尤其是内吞物质在内吞区室之间异常缓慢的转运。其他参数，如液相内吞作用或后溶酶体与细胞表面融合的速率，在饥饿时会发生显著变化。研究饥饿细胞中的内吞途径可以提供一个不同的视角，使特定突变导致的主要（不变）缺陷与其次要（条件性）后果得以区分。
