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__NOTOC__ Stress granules are dense aggregations in the cytosol composed of proteins & RNAs that appear when the cell is under stress. The RNA molecules stored are stalled translation pre-initiation complexes - failed attempts to make protein from mRNA. Stress granules are 100-200 nm in size, not surrounded by membrane, and associated with the endoplasmatic reticulum. Note that there are also nuclear stress granules. This article is about the cytosolic variety. == Proposed functions == The purpose of stress granules might be to protect RNAs from harmful conditions, thus their appearance under stress. The accumulation of RNAs into dense globules could keep them from reacting with harmful chemicals and safe-guard the information coded in their RNA sequence. Stress granules might also function as a decision point for untranslated mRNAs. Molecules can go down one of three paths: further storage, degradation, or re-initiation of translation. 〔(Paul J. Anderson, Brigham and Women's Hospital )〕 The stress proteins that are the main component of stress granules in plant cells are molecular chaperones that sequester, protect, and possibly repair proteins that unfold during heat and other types of stress. Therefore any association of mRNAs with stress granules may simply be a side effect of the association of partially unfolded RNA-binding proteins with stress granules, similar to the association of mRNAs with proteasomes. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Stress granule」の詳細全文を読む スポンサード リンク
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