細胞内膜の機能的構造 t-SNARE
1Cellular Biochemistry & Biophysics Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.
Nature
|September 23, 2000
まとめ
細胞内標的膜SNAREs (t-SNAREs) は,溶融したSNAP-25タンパク質ではなく,別々の光鎖を使用しています. この発見は,SNAP-25を示唆しています.
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:
- 脂質二層融合は細胞プロセスに不可欠であり,SNAREタンパク質によって媒介されます.
- 溶性N-エチルマレイミド感受因子結合タンパク質受容体 (SNAREs) は,4ヘリクスのバンドルに組み合わされ,膀SNAREs (v-SNAREs) は1ヘリクスを提供し,標的SNAREs (t-SNAREs) は3ヘリクスを提供します.
- プラズマ膜t-SNAREsは,通常,シンタキシンとSNAP-25.5からの2つのヘリクから構成されています.
研究 の 目的:
- 細胞内膜のt-SNAREsの組成を調査する.
- 細胞内t-SNARE複合体におけるSNAP-25を代替する成分を特定する.
- SNAREタンパク質構造の進化的分岐を理解するために.
主な方法:
- 異なる細胞区間のSNAREタンパク質の同類体の比較分析.
- 細胞内t-SNARE複合体の構造と機能の特徴.
- 遺伝子進化とタンパク質領域融合のバイオ情報分析.
主要な成果:
- 細胞内t-SNAREsは,シンタキシン同質の"重鎖"と2つの異なる非シンタキシン"軽鎖"で構成されています.
- プラズマ膜t-SNAREsとは異なり,細胞内t-SNAREsは3つのヘリックスのためにSNAP-25に同類する単一のタンパク質を使用しません.
- 酵母菌Sec9とSpo20は,SNAP-25と関連しているが,血に局所されており,細胞内SNAP-25の機能を代替するものではない.
結論:
- 細胞内t-SNAREsの構造は,プラズマ膜t-SNAREsの構造と大きく異なっており,融合したSNAP-25.5の代わりに独立した光鎖を使用しています.
- SNAP-25は進化上の例外であり,個別の光鎖をコードする遺伝子の融合から生じる可能性がある.
- この研究では,SNARE複合体の分子多様性と,膜輸送経路への影響について解明しています.
さらに関連する動画
10:58SNARE-mediated Fusion of Single Proteoliposomes with Tethered Supported Bilayers in a Microfluidic Flow Cell Monitored by Polarized TIRF Microscopy
Published on: August 24, 2016
08:55Visualizing Intracellular SNARE Trafficking by Fluorescence Lifetime Imaging Microscopy
Published on: December 29, 2017
関連する概念動画
Fusion of Secretory Vesicles with the Plasma Membrane
Proteins and neurotransmitters in secretory vesicles can be released from a cell upon vesicle docking, priming, and fusion with the plasma membrane. Vesicles are docked and primed in preparation for the quick exocytosis of their contents in response to a stimulus. The fusion process is mainly carried out by a SNAP Receptor or SNARE complex, consisting of synaptobrevin, syntaxin-1, and SNAP-25.
In 1993, Jim Rothman proposed that the antiparallel pairing of vesicular and transmembrane SNAREs, or...
In 1993, Jim Rothman proposed that the antiparallel pairing of vesicular and transmembrane SNAREs, or...
SNAREs and Membrane Fusion
Once a transport vesicle has recognized its target organelle, the vesicular membrane needs to fuse with the target membrane to unload the cargo. Transmembrane proteins called SNAREs present on organelle membranes and their vesicles, mediate vesicle fusion.
SNAREs exist in pairs that symmetrically interact and catalyze the fusion of the lipid bilayers in vesicle and target organelle. v-SNARE in the vesicle membrane are single polypeptide chains that bind to a complementary t-SNARE, composed of 2...
SNAREs exist in pairs that symmetrically interact and catalyze the fusion of the lipid bilayers in vesicle and target organelle. v-SNARE in the vesicle membrane are single polypeptide chains that bind to a complementary t-SNARE, composed of 2...
Mechanisms of Membrane Domain Formation
Different physical properties of lipids and proteins allow them to localize and form distinct islands or domains in the membrane. Some membrane domains are formed due to protein-protein interactions, whereas others are formed due to the presence of specific lipids such as sphingolipids and sterols—for example, large proteins, such as bacteriorhodopsin, aggregate and create distinct domains.
Another mechanism for membrane domain formation involves membrane proteins interacting with cytoskeletal...
Another mechanism for membrane domain formation involves membrane proteins interacting with cytoskeletal...
Protein Translocation Machinery on the ER Membrane
The translocon complex situated on the ER membrane is the main gateway for the protein secretory pathway. It facilitates the transport of nascent peptides into the ER lumen and their insertion into the ER membrane.
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the translocon complex.
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the translocon complex.
Clathrin Coated Vesicles
Clathrin-coated vesicles use endocytosis to transport receptors and lysosomal hydrolases from the Golgi to the lysosome in the late secretory pathway. Clathrin-mediated endocytosis was the first described endocytic process, and Clathrin-coated vesicles remain one of the most well-studied transport vesicles. The molecular machinery that generates clathrin-coated vesicles comprises over 50 proteins that precisely coordinate vesicle formation. Cell surface receptors concentrated in indented sites...
Rab Cascades
Rab GTPases act in a regulated cascade during membrane fusion, helping the lipid bilayers mix. The Rab family of proteins are active when bound to GTP, and inactive when bound to GDP. Hence, they act as guanine nucleotide-dependent molecular switches. Rab-GTP recognizes and binds to long or short-range tethering proteins to capture the target vesicle. These tethers coordinate with SNAREs on the vesicle and the target membrane to assemble the trans SNARE complex that locks the mixing bilayers.
