Hrr25依存のリン酸化状態は,pre-40Sサブユニットの組織を調節する
Thorsten Schäfer1, Bohumil Maco, Elisabeth Petfalski
1Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany.
Nature
|June 2, 2006
まとめ
タンパク質キナーゼHrrr25は,リボソームタンパク質Rps3.3の統合を制御することによって,酵母40Sリボソームサブユニットの成熟を調節する. このリン酸化に依存するプロセスは,成熟した40Sサブユニット構造の形成に不可欠です.
科学分野:
- 分子生物学は分子生物学である.
- 細胞生物学 細胞生物学
- バイオケミストリー バイオケミストリー
背景:
- ユカリオットリボソームの生体生成は,多数の一時的な要因を含む複雑で,複数の区画のプロセスです.
- リボソーム前成熟の正確なメカニズム的な詳細は,ほとんど解明されていないままです.
- リボソームの組み立てを理解することは,細胞機能と疾患の研究に不可欠です.
研究 の 目的:
- 酵母40Sリボソームサブユニット生物発生に関わる重要な規制ステップと要因を特定する.
- プレ-40S粒子の成熟におけるタンパク質キナーゼHrr25の役割を調査する.
- リボソームタンパク質Rps3が40Sサブユニットに統合するメカニズムを解明する.
主な方法:
- 塩分が高い条件下で,前リボソーム粒子からタンパク質の放出を評価するための生化学的分析.
- 電子顕微鏡で,40S前と成熟した40Sサブユニット間の構造的な違いを視覚化します.
- 遺伝子の減少とリボソームサブユニット組成の分析を含むインビボ研究.
主要な成果:
- Rps3は,孤立した40S前粒子から放出されますが,成熟した40Sサブユニットから放出されません.
- プレ-40S粒子は"ノック"構造を欠いているが,これはRps3.3の近くにある18S rRNAヘリックス33によって形成される特徴である.
- Hrr25はRps3とEnp1をリン酸化し,その解離を促進する;脱リン酸化はの形成と安定したRps3統合につながる.
- Hrr25の枯渇は,成長抑制を引き起こし,不安定なRps3.3を持つ不成熟な40Sサブユニットの蓄積を引き起こします.
結論:
- タンパク質キナーゼHrrr25は,酵母40Sリボソームサブユニットの成熟に重要な規制的役割を果たしています.
- Hrr25によるRps3とEnp1のリン酸化およびその後の脱リン酸化は,適切な40Sサブユニット組立と構造的完全性にとって不可欠です.
- この研究は,キナーゼ活性によって制御されるリボソーム生体生成の重要なステップを明らかにし,サブユニットの安定性と機能に影響を与えています.
関連する概念動画
Ribosomes
Ribosomes translate genetic information encoded by messenger RNA (mRNA) into proteins. Both prokaryotic and eukaryotic cells have ribosomes. Cells that synthesize large quantities of protein—such as secretory cells in the human pancreas—can contain millions of ribosomes.Ribosome Structure and AssemblyRibosomes are composed of ribosomal RNA (rRNA) and proteins. In eukaryotes, rRNA is transcribed from genes in the nucleolus—a part of the nucleus that specializes in ribosome production. Within the...
Phosphorylation
The addition or removal of phosphate groups from proteins is the most common chemical modification that regulates cellular processes. These modifications can affect the structure, activity, stability, and localization of proteins within cells as well as their interactions with other proteins.
During phosphorylation, protein kinases transfer the terminal phosphate group of ATP to specific amino acid side chains of substrate proteins. Serine, threonine, and tyrosine are the most commonly...
During phosphorylation, protein kinases transfer the terminal phosphate group of ATP to specific amino acid side chains of substrate proteins. Serine, threonine, and tyrosine are the most commonly...
Ribosomal RNA Synthesis
Ribosome synthesis is a highly complex and coordinated process involving more than 200 assembly factors. The synthesis and processing of ribosomal components occurs not only in the nucleolus but also in the nucleoplasm and the cytoplasm of eukaryotic cells.
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
Directing Proteins to the Rough Endoplasmic Reticulum
The organelle-specific signaling sequences direct proteins synthesized in the cytosol to their final destination like ER, mitochondria, peroxisomes, etc. Some of the proteins directed to ER are then trafficked via vesicles to other organelles within the cell or the extracellular environment through the Golgi complex. For example, the rough ER synthesizes soluble proteins for transportation to the lysosomes or secretion out of the cell. It can also synthesize transmembrane proteins that can...
Post-translational Translocation of Proteins to the RER
A sizable fraction of proteins destined for ER are first synthesized in the cell cytosol and then transported across the ER membrane–a process called post-translational translocation. Similar to cotranslationally translocated proteins, these proteins also use the Sec translocon complex to enter the ER lumen.
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
Ribosomes
Ribosomes translate genetic information encoded by messenger RNA (mRNA) into proteins. Both prokaryotic and eukaryotic cells have ribosomes. Cells that synthesize large quantities of protein—such as secretory cells in the human pancreas—can contain millions of ribosomes.
Ribosome Structure and Assembly
Ribosomes are composed of ribosomal RNA (rRNA) and proteins. In eukaryotes, rRNA is transcribed from genes in the nucleolus—a part of the nucleus that specializes in ribosome production. Within...
Ribosome Structure and Assembly
Ribosomes are composed of ribosomal RNA (rRNA) and proteins. In eukaryotes, rRNA is transcribed from genes in the nucleolus—a part of the nucleus that specializes in ribosome production. Within...


