Centre for Organelle Research, University of Stavanger, 4021 Stavanger, Norway.
Protoplasma. 2010 Dec;247(3-4):233-56. doi: 10.1007/s00709-010-0190-0. Epub 2010 Aug 24.
Autophagy is an evolutionarily conserved intracellular process for the vacuolar degradation of cytoplasmic constituents. The central structures of this pathway are newly formed double-membrane vesicles (autophagosomes) that deliver excess or damaged cell components into the vacuole or lysosome for proteolytic degradation and monomer recycling. Cellular remodeling by autophagy allows organisms to survive extensive phases of nutrient starvation and exposure to abiotic and biotic stress. Autophagy was initially studied by electron microscopy in diverse organisms, followed by molecular and genetic analyses first in yeast and subsequently in mammals and plants. Experimental data demonstrate that the basic principles, mechanisms, and components characterized in yeast are conserved in mammals and plants to a large extent. However, distinct autophagy pathways appear to differ between kingdoms. Even though direct information remains scarce particularly for plants, the picture is emerging that the signal transduction cascades triggering autophagy and the mechanisms of organelle turnover evolved further in higher eukaryotes for optimization of nutrient recycling. Here, we summarize new research data on nitrogen starvation-induced signal transduction and organelle autophagy and integrate this knowledge into plant physiology.
自噬是一种进化上保守的细胞内过程，用于空泡降解细胞质成分。该途径的中心结构是新形成的双层膜囊泡（自噬体），将多余或受损的细胞成分递送至空泡或溶酶体进行蛋白水解降解和单体回收。自噬通过细胞重塑使生物体能够在广泛的营养饥饿和暴露于非生物和生物胁迫阶段存活。自噬最初是通过在不同生物体中进行电子显微镜研究来研究的，然后首先在酵母中，随后在哺乳动物和植物中进行分子和遗传分析。实验数据表明，在酵母中表征的基本原理、机制和成分在哺乳动物和植物中在很大程度上是保守的。然而，不同的自噬途径似乎在不同的生物界之间存在差异。尽管特别是对于植物，直接信息仍然很少，但出现的情况是，触发自噬的信号转导级联和细胞器周转的机制在高等真核生物中进一步进化，以优化营养物质回收。在这里，我们总结了关于氮饥饿诱导的信号转导和细胞器自噬的新研究数据，并将这些知识整合到植物生理学中。
