Autophagy is a word of Greek origin (self = me and phagia = eat) which means "eat yourself". The term was used in 1963 by Christian de Duve during a symposium on lysosomes, to describe processes involving vesicles associated with these structures, which would be related to cell recycling.
→ How does the autophagy process take place?
Autophagy happens when cells engulf and degrade portions of their own cytoplasm. In this process, membranes are formed, of still controversial origin, which encompass portions of the cytoplasm, producing a closed structure called vacuole autophagic or autophagosome. Subsequently, the vacuole joins lysosomes, giving rise to the autolysosome or autophagolysis. The enzymes found in lysosomes will then be responsible for ensuring that the inner material and membrane are degraded (See the process illustrated at the beginning of this text).
By degrading these particles, the cell, for example, recycles proteins, lipids, nucleotides, amino acids and fatty acids. This process also enables a
cell cleaning, degrading malformed macromolecules, for example. In addition, it relates to several other processes, such as cell remodeling, host defense and even diseases like cancer, since the interruption of autophagy can accelerate carcinogenesis.→ When do cells autophagy?
Today we know that the autophagy process is carried out by cells to, among other functions, maintain their balance and carry out their normal activities. the cells make the autophagy in various situations, like when it occurs:
Accumulation of defective organelles;
Accumulation of large protein aggregates;
Food shortage;
High temperatures;
Low oxygen.
→ Types of autophagy
Autophagy can present itself in three different ways:
Chaperone-mediated autophagy: This process, observed in mammalian cells, is triggered when the heat shock protein (PCT) interacts with altered macromolecules present in the cell's cytoplasm.
Microautophagy: In this case, the components of the cytoplasm are taken up directly by the lysosomes.
Macroautophagy or autophagy: is the most studied type and the one described in this text.
By Ma. Vanessa dos Santos
Source: Brazil School - https://brasilescola.uol.com.br/o-que-e/biologia/o-que-e-autofagia.htm
