nuclear stress granule

Definition

Target type: cellularcomponent

A dense aggregation in the nucleus composed of proteins and RNAs that appear when the cell is under stress. [GOC:ans, PMID:10359787, PMID:12865437]

Nuclear stress granules (SGs) are dynamic, non-membranous, cytoplasmic aggregates that assemble in response to cellular stress, such as heat shock, oxidative stress, or viral infection. These granules are enriched in RNA-binding proteins (RBPs), mRNAs, and small ribosomal subunits. The cellular component of nuclear stress granules is characterized by the following features:
* **Composition:** Nuclear SGs are primarily composed of RNA-binding proteins, including TTP, TIA-1, and G3BP1. These proteins bind to mRNA molecules and facilitate their sequestration within the granule.
* **Structure:** Nuclear SGs are typically spherical or ovoid in shape and can vary in size depending on the level of stress. They are not enclosed by a membrane, but rather are held together by protein-protein interactions.
* **Formation:** Nuclear SGs assemble in response to stress signals, which trigger the phosphorylation of specific RBPs. These phosphorylated RBPs then interact with each other and with mRNA molecules, leading to the formation of the granule.
* **Function:** Nuclear SGs are thought to play a role in protecting cells from stress by sequestering mRNAs that could be harmful if translated. This process is known as mRNA silencing. They also contribute to the regulation of gene expression by controlling the translation of specific mRNAs.
* **Disassembly:** Once the stress signal is removed, nuclear SGs disassemble, releasing their contents back into the cytoplasm. The disassembly process is mediated by dephosphorylation of RBPs and the degradation of specific granule components.
* **Nuclear Localization:** Nuclear SGs, despite their name, are generally found in the cytoplasm. However, in certain cases, they can be observed in the nucleus, particularly in the nucleolus. The presence of nuclear SGs is often associated with alterations in nuclear function and cell fate.
'"

Proteins (1)

Compounds (11)