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mRNAキャップへのリボソームの負荷は,eIF4GとeIF4Eのコンフォーメーションカップリングによって引き起こされます.
John D Gross1, Nathan J Moerke, Tobias von der Haar
1Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
Cell
|December 17, 2003
まとめ
ユカリオット初期化因子4G (eIF4G) は,eIF4EとmRNAキャップを結合し,分子ブレスレットを形成する. この構造は,翻訳開始を促進し,細胞成長に不可欠です.
科学分野:
- 分子生物学は分子生物学である.
- 構造生物学 構造生物学とは
- 遺伝子発現の規制について
背景:
- ユカリオット初期化因子4G (eIF4G) は,遺伝子発現を制御する翻訳初期化の中心的役割を果たします.
- eIF4Gは,eIF3とeIF4E/cap-mRNA複合体と相互作用し,mRNAにリボソームの負荷を容易にする.
- カップ依存翻訳は,タンパク質合成の重要なプロセスです.
研究 の 目的:
- 酵母eIF4E/capとeIF4Gの断片 (393-490) の間の複合体の溶液構造を決定する.
- eIF4GとeIF4Eが相互作用して翻訳開始を制御するメカニズムを解明する.
主な方法:
- eIF4E/capおよびeIF4G (393-490) 複合体の溶液構造の決定.
- 両タンパク質に結合する構造的影響の分析.
主要な成果:
- eIF4G (393-490) が eIF4E/cap に結合すると,カップリングされた折り畳み移行が起こります.
- 安定した"分子ブレスレット"が形成され,eIF4G (393-490) は,eIF4EのN端の周りに螺旋状のリングを形成します.
- この共折り合いは,eIF4EのmRNAキャップとの関連をアロステリックに強化する.
結論:
- eIF4G-eIF4Eの相互作用と結果として生じる構造は,最適な細胞成長とポリソーム分布に不可欠です.
- 安定したメッセンジャーリボヌクレオプロテイン (mRNP) 複合体は,リボソーム負荷の複数のラウンドを促進し,タンパク質合成速度に影響を与えます.
関連する概念動画
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02:22Regulated mRNA Transport
In eukaryotes, transcription and translation are compartmentalized; an mRNA is first synthesized in the nucleus and then selectively transported to the cytoplasm for protein synthesis. Before transport, a pre-mRNA undergoes several steps of post-transcriptional modifications including splicing, 5' capping, and the addition of a poly-adenine tail. Various proteins bind to the pre-mRNA during these modifications. The mRNA transport takes place with the help of multiple proteins playing specific...
02:31Nuclear Export of mRNA
Before mRNAs are exported to the cytoplasm, it is crucial to check each mRNA for structural and functional integrity. Eukaryotic cells use several different mechanisms, collectively known as mRNA surveillance, to look for irregularities in mRNAs. Irregular or aberrant mRNA are rapidly degraded by various enzymes. If a defective mRNA escapes the surveillance, it would be translated into a protein which would either be non-functional or not function properly. One of the primary irregularities in...
02:33Initiation of Translation
Initiating translation is complex because it involves multiple molecules. Initiator tRNA, ribosomal subunits, and eukaryotic initiation factors (eIFs) are all required to assemble on the initiation codon of mRNA. This process consists of several steps that are mediated by different eIFs.
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
02:22Regulated mRNA Transport
In eukaryotes, transcription and translation are compartmentalized; an mRNA is first synthesized in the nucleus and then selectively transported to the cytoplasm for protein synthesis. Before transport, a pre-mRNA undergoes several steps of post-transcriptional modifications including splicing, 5' capping, and the addition of a poly-adenine tail. Various proteins bind to the pre-mRNA during these modifications. The mRNA transport takes place with the help of multiple proteins playing specific...