Morphological features of autophag

A double membrane vesicle forms in the cytosol that encapsulates whole organelles and bulk cytoplasm 细胞中出现大的双层膜包裹的自噬泡，称为自噬小体（autophagosome),双层膜来自内质网或细胞质中的膜泡。

This autophagosome then fuses with the lysosome where the contents are degraded and recycled 自噬小体中包裹着整个的细胞器和部分细胞质，自噬小体与溶酶体融合后，内含物被溶酶体中的水解酶消化。

• [ ] Autophagy is a strategy for survival, not death, in mammalian cells

  动物细胞为了维持细胞内环境的动态平衡，需要不断降解功能失常或不需要的细胞结构，如各种蛋白，细胞器以及各种胞质组分。通常，寿命较短的蛋白如调控蛋白等通过泛素-蛋白酶体系统进行降解；而寿命较长的细胞结构及蛋白则通过细胞自噬途径，由溶酶体进行降解。

• [ ] Growth factor signaling regulates autophagy

  

  The mammalian homologue of ATG8, microtuble-associated protein light chain 3 (LC3), the specific marker of autophagosome formation. In the presence of a growth factor, cells exhibit uniform cytoplasmic LC3 staining, following the withdrawal, LC3 redistributes to a puncate pattern that is characteristic of ongoing autophagy.