特殊性ドメインは,Rasに関連したGTPases Ypt1とSec4を区別する
B Dunn1, T Stearns, D Botstein
1Department of Genetics, Stanford University School of Medicine, California 94305.
Nature
|April 8, 1993
まとめ
研究者らは,Ypt1 GTPaseの重要な9残基セグメントを特定し,酵母分泌におけるYpt1とSec4の両方の機能を遂行することを可能にしました. この発見は,タンパク質の機能と輸送に関する理解を深める.
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:
- Ypt1とSec4は,酵母Saccharomyces cerevisiaeのRas関連GTPasesとして不可欠である.
- Ypt1は,エンドプラズマの網膜をゴルギ輸送に介し,Sec4は,プラズマ膜の膀融合に不可欠である.
研究 の 目的:
- Ypt1とSec4の異なる機能に責任を負う特定のタンパク質セグメントを特定する.
- 分泌経路におけるこれらのGTPasesの構造-機能関係を理解するために.
主な方法:
- キメリックGTPaseタンパク質の構築と分析.
- Saccharomyces cerevisiaeにおけるインビヴォ機能性アッセイ.
主要な成果:
- Ypt1 (ループL7) からSec4に置換された9残留セグメントは,最小限の二重機能を付与しました.
- ループL7とエフェクタ領域 (ループL2) を含むより大きな24残基Ypt1セグメントは,Sec4を機能するYpt1タンパク質に完全に変換した.
結論:
- 特定の領域,特にループL7とエフェクター領域は,Ypt1とSec4.4の異なる役割を決定する.
- この研究は,膀輸送におけるRas関連GTPasesの機能的分岐と特異性についての洞察を提供します.
関連する概念動画
GTPases and their Regulation
Guanine nucleotide-binding proteins (G-proteins), also known as GTPases, are a superfamily of proteins that regulate many cellular processes, such as cell signaling, vesicular transport, and the regulation of cell shape and motility. Mutation or dysfunction of these proteins can lead to disease. There are around 40,000 known G-proteins that can broadly be classified into two groups ‒ small G-proteins consisting of a single domain and large multi-domain G-proteins.
Large G-proteins, also known...
Large G-proteins, also known...
Coat Assembly and GTPases
Vesicles incorporate different coat protein subunits in different cell locations, which changes the properties of the coat, such as the shape and geometry of the transport vesicles. Thus, vesicle coat proteins also play a significant role in cargo selection.
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
Rab Proteins
Rab proteins constitute the largest family of monomeric GTPases, of which 70 members are present in humans. Rab proteins and their effectors regulate consecutive stages of vesicle transport such as vesicle transport, docking, and fusion to the correct recipient membrane.
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
Tail-anchoring of Proteins in the ER Membrane
Tail-anchored, or TA, proteins are estimated to make up to 3-5% of membrane proteins found in the eukaryotic cell. Such proteins have a single transmembrane domain located approximately 30 amino acid residues upstream from the C-terminal end. As a result, the signal recognition particle (SRP) cannot guide a TA protein to the ER membrane for cotranslational insertion. Hence, they are integrated into the ER membrane post-translationally using their C-terminal end as the anchor. TA proteins...
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.
Small GTPases - Ras and Rho
Ras and Rho are small monomeric GTPases that act downstream of receptor tyrosine kinase (RTK) and regulate various cellular processes. These GTPases switch between active and inactive states by binding to guanine nucleotides.
Three regulatory proteins control their activity:
Three regulatory proteins control their activity:


