タイプIIIの分泌システムによるトランスレーション/分泌結合

J E Karlinsey¹, J Lonner, K L Brown

¹Department of Microbiology, University of Washington, Seattle 98195, USA.

Cell

|August 31, 2000

まとめ

タイプIIIの分泌チャペロンは,タンパク質の翻訳と分泌を調節する. シャパロンFIgNは,flgM遺伝子の翻訳を制御し,細菌の毒性タンパク質の輸出に影響を与えます.

科学分野:

微生物学微生物学とは
分子生物学は分子生物学である.
バクテリア病原菌の発生

背景:

型III分泌システム (T3SS) は,グラム陰性細菌の毒性因子および鞭状成分の輸出に不可欠である.
T3SSチャペロンは基板の分解を防ぐことが知られているが,翻訳におけるその役割はあまり理解されていない.

研究の目的:

分泌されるタンパク質の翻訳を調節するT3SSチャペロンの役割を調査する.
シャペロンが分泌されるタンパク質の運命を影響するかどうかを,そのmRNAトランスクリプトに基づいて判断する.

主な方法:

さまざまなmRNAトランスクリプトから flgM遺伝子の翻訳に付随するFIgNの影響を分析する.
異なるトランスクリプトから生成されたFIgMの細胞局所化 (分泌 vs. 細胞質保持) を比較する.

主要な成果:

FIgNは,フラジェラクラス3のトランスクリプトからflgM遺伝子翻訳に不可欠であるが,クラス2のトランスクリプトには欠かせない.
クラス3のトランスクリプトから翻訳されたFIgMは分泌され,クラス2のトランスクリプトから翻訳されたFIgMはサイトプラズミックのままである.
証拠は,mRNAとアミノ酸の配列の両方がT3SS基板のための分泌信号として作用することを示唆しています.

結論:

タイプIIIの分泌チャペロンは,タンパク質翻訳と分泌を結びつける新しい役割を持っています.
バクテリアの分泌基板は,二重のmRNAとアミノ酸分泌信号を有することがあります.
この発見は,T3SSチャペロンの既知の機能を基板保護を超えて拡張します.

さらに関連する動画

11:33

Monitoring the Assembly of a Secreted Bacterial Virulence Factor Using Site-specific Crosslinking

Published on: December 17, 2013

10:41

Conjugative Mating Assays for Sequence-specific Analysis of Transfer Proteins Involved in Bacterial Conjugation

Published on: January 4, 2017

関連する概念動画

01:33

Overview of Secretory Vesicles

Secretory vesicles, also known as dense core vesicles (DCVs), are membrane-bound vesicles that transport secretory proteins, such as hormones or neurotransmitters. Regulated secretory vesicles transport proteins from the trans-Golgi network to the exterior of the cell. Proteins present in regulated secretory vesicles are required to be rapidly exocytosed in large amounts upon a specific stimulus.
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...

01:26

Insertion of Single-pass Transmembrane Proteins in the RER

Integral membrane proteins are proteins adhered to the lipid bilayer of a cell organelle or membrane. They can be of two types: transmembrane integral proteins that span the lipid bilayer and monotopic proteins that are attached to either side of the membrane but do not pass through it.
Integral transmembrane proteins possess transmembrane and extra membrane domains. The transmembrane domains are primarily made of 20-25 hydrophobic amino acids arranged in a helical secondary confirmation. These...

01:29

Coordination of Gene Expression Processes in Bacteria

The DNA replication, transcription, and translation processes are intricately coupled in bacteria, allowing efficient gene expression and rapid protein synthesis. While this physical and functional coordination is advantageous, it introduces challenges that bacteria overcome through specific regulatory mechanisms.Coupling of Replication, Transcription, and TranslationThe coupling of replication, transcription, and translation is a hallmark of bacterial gene expression. As the replisome unwinds...

01:26

Bacterial Translocation and Protein Secretion

Bacterial protein secretion involves translocation systems to ensure proteins reach their designated locations, including the plasma membrane, periplasm, outer membrane, or the external environment. These translocation systems are vital for bacterial physiology, supporting processes like membrane assembly, enzymatic activity in the periplasm, and interactions with the external environment. The division of labor between Sec and Tat pathways ensures efficiency in handling proteins with diverse...

01:17

Gram-negative Bacterial Protein Secretion Systems

Gram-negative bacteria utilize sophisticated protein secretion systems to transport proteins across their double-membrane envelope into the extracellular environment or host cells. Based on their mechanism of action, these systems are classified into one-step and two-step pathways.One-Step Secretion Systems (Types I, III, IV, and VI)One-step secretion systems bypass the periplasm entirely, forming a continuous channel that spans both the inner and outer membranes:Type I Secretion System (T1SS):...

01:19

Mechanism of Conjugation

Bacterial conjugation is a mechanism of horizontal gene transfer that enables the exchange of genetic material between bacterial cells through direct contact. This process is facilitated by a donor cell carrying a conjugative plasmid, which encodes genes necessary for pilus formation, DNA replication, and transfer. The conjugative plasmid plays a central role in initiating and executing the transfer of genetic material.The tra region of the conjugative plasmid encodes proteins responsible for...

関連する実験動画