アラビドプシスの守護細胞におけるスフィンゴリピドシグナル伝達には,ヘテロトリメリックGタンパク質が関与する
Sylvie Coursol1, Liu-Min Fan, Hervé Le Stunff
1Department of Biology, Pennsylvania State University, 208 Mueller Laboratory, University Park, Pennsylvania 16802-5301, USA.
Nature
|June 6, 2003
まとめ
スフィンゴシン-1-リン酸 (S1P) 信号伝達は,アブシシ酸 (ABA) に反応するスフィンゴシンキナーゼ (SphK) を活性化することによって,植物のストマタル機能を調節する. この経路は,種間で保存されるヘトロトリメリックGタンパク質を伴う.
科学分野:
- 植物シグナル伝達経路について
- 脂質代謝 脂質代謝とは
- 護衛細胞生理学 護衛細胞生理学
背景:
- スフィンゴシン-1-ホスファート (S1P) は,動物における重要なシグナル伝達分子であり,細胞機能を調節する.
- 植物では,S1Pは最近,アブシシス酸 (ABA) 媒介による守護細胞の回調節における重要な役割を果たしていることが判明しました.
研究 の 目的:
- アラビドプシス・タリアナのABAシグナル伝達におけるスフィンゴシンキナーゼ (SphK) の役割を調査する.
- ストマトの調節におけるS1P信号経路のダウンストリーム構成要素を解明する.
主な方法:
- 酵素活性測定は,ABAによるSphK活性化を決定する.
- ABAとSphKの阻害に対する反応として口腔の開閉の分析.
- 守護細胞のイオンチャンネル (K+とアニオンチャンネル) の電気生理学的記録.
- GPA1 (ヘテロトリメリックGタンパク質アルファサブユニット) のノックアウト変異体を用いた遺伝分析.
主要な成果:
- ABAは,アラビドプシス・タライアナのSphKを活性化する.
- SphKの活動は,ABAの口腔の開閉の調節に不可欠です.
- SphKの阻害は,ガード細胞イオンチャネルのABA媒介の調節に影響する.
- S1Pが口腔の開口とイオンチャネルに及ぼす影響は,ヘトロトリメリックGタンパク質GPA1.1に依存しています.
結論:
- SphKは,口腔機能を制御するABAシグナル伝達経路の重要な構成要素です.
- ヘテロトリメリックGタンパク質は,S1Pのダウンストリームで作用し,ガード細胞のABA反応を媒介する.
- S1PとGタンパク質のシグナル伝達相互作用は,口腔生理を調節するための進化的に保存されたメカニズムを表しています.
キーワード:
非プログラム的なものです.関連する概念動画
GTPases and their Regulation
7.9K
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,...
Large G-proteins,...
7.9K
Assembly of Signaling Complexes
4.7K
Multiprotein signaling complexes are formed in a dynamic process involving protein-protein interactions at the cytoplasmic domain of transmembrane receptors or enzymatic and non-enzymatic proteins associated with the receptor. These complexes ensure the activation and propagation of intracellular signals that regulate cell functions.
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...
4.7K
Amplifying Signals via Enzymatic Cascade
15.3K
When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze...
15.3K
Cell Signaling in Plants
4.5K
Plant cells communicate to coordinate their cycle of growth, flowering and fruiting, and activities in roots, shoots, and leaves in response to the changing environmental conditions. Plant signaling is distinct from animal signaling. Plants primarily utilize enzyme-linked receptors, whereas the largest class of cell-surface receptors in animals are G-protein coupled receptors (GPCRs). Unlike animals, receptor tyrosine kinases are rare in plants. Instead, plants have a diverse class of...
4.5K
Activation and Inactivation of G Proteins
8.9K
Heterotrimeric G proteins are guanine nucleotide-binding proteins. As the name suggests, heterotrimeric G proteins are composed of three subunits: alpha, beta, and gamma. They remain GDP-bound or GTP-bound inside the cells and switch between inactive/active states. The Gα subunit possesses the nucleotide-binding pocket that binds guanine nucleotides and switches between GDP or GTP-bound states. In contrast, the Gꞵ and Gγ subunits are always bound together with high...
8.9K
IP3/DAG Signaling Pathway
12.5K
Membrane lipids such as phosphatidylinositol (PI) are precursors for several membrane-bound and soluble second messengers. Specific kinases phosphorylate PI and produce phosphorylated inositol phospholipids. One such inositol phospholipids are the phosphatidylinositol-4,5 bisphosphate [PI(4,5)P2], present in the inner half of the lipid bilayer. Upon ligand binding, GPCR stimulates Gq proteins to turn on phospholipase Cꞵ. Activated phospholipase Cꞵ cleaves PI(4,5)P2 and...
12.5K


