Molecular structure of stress granules and their role in the eukaryotic cell

Stress granules (SGs) are cytoplasmic structures found in eukaryotic cells, from yeast to human cells. They are made up of proteins, RNA and small ribosome subunits (40S). They arise as a result of the rapid shutdown of active protein biosynthesis in the cell, which is the result of the appearance of a stress factor. The mechanism of regulation of protein biosynthesis in response to stress takes place at two control nodes: (1) phosphorylation of the α subunit of the eIF2 factor as a result of the action of stress-recognizing kinases or by modulation of the mTOR pathway activity, which regulates the initiation of protein biosynthesis by the formation of a complex within the so-called cap structure. The protein arrest causes aggregation of the translation process components and other cell components (other proteins or mRNA molecules) into SGs. A lot of data indicates the active participation of SGs in metabolic processes, their control role over pro- and anti-apoptotic processes as well as in the development of cancer, neurodegenerative diseases and their defensive role in viral infections.

Running title: Stress granules in the cell