Mgat5 N-グリコシル化によるT細胞活性化と自己免疫の負の調節
M Demetriou1, M Granovsky, S Quaggin
1Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada.
Nature
|February 24, 2001
まとめ
ベータ1,6 N-アセチルグルコサミニルトランスフェラーゼV (Mgat5) の欠乏は,T細胞受容体 (TCR) クラスタリングを強化することにより,T細胞活性化値を下げます. このMgat5酵素は,
科学分野:
- 免疫学とグリコ生物学について
- 細胞シグナル伝達とT細胞の活性化
背景:
- T細胞の活性化には,抗原プレゼンテーションサイトでのT細胞受容体 (TCR) クラスタリングが必要です.
- CD28共受容体結合は,シグナル伝達タンパク質を勧誘することによって,TCRのクラスタリングに影響を与えます.
研究 の 目的:
- T細胞活性化値におけるβ1,6N-アセチルグルコサミニルトランスフェラーゼV (Mgat5) の役割を調査する.
- Mgat5欠乏がTCRのクラスタリングと,その後の免疫応答に影響するかどうかを判断する.
主な方法:
- Mgat5欠乏 (Mgat5-/-) のマウスとT細胞の分析.
- TCRの募集,シグナリング,アクティンの再編成,および拡散の評価.
- TCR複合体とのガレクチン-3の相互作用の調査.
- ガレクチン結合を阻害するためにラクトースを使用したインビトロ実験.
主要な成果:
- Mgat5欠乏症は,T細胞のTCR徴募,シグナル伝達,アクチン再編成,増殖を強めた.
- Mgat5-/-マウスは,自己免疫性腎臓疾患,遅延型過敏性の高まり,実験的自己免疫性脳内炎に対する感受性の高まりを示した.
- Mgat5はGlcNAc beta1,6の分岐を促進し,TCR複合体と結合するガレクチン-3を含むガレクチンのN-アセチラクトサミンのリガンドを増加させます.
- ラクトースの前治療はMgat5-/- T細胞のクラスタリングを模倣し,ガレクチン-グリカン相互作用の役割を示唆しました.
結論:
- Mgat5媒介のグリコシライゼーションは,TCRの採用を制限するガレクチン-グリコタンパク質の格子を強化します.
- Mgat5の調節不良は,多発性硬化症などの自己免疫疾患に個人を誘発する可能性があります.
- Mgat5依存性経路をターゲットにすることで,自己免疫疾患に対する治療戦略を提供することができる.
関連する概念動画
mTOR Signaling and Cancer Progression
The mammalian target of rapamycin or mTOR protein was discovered in 1994 due to its direct interaction with rapamycin. The protein gets its name from a yeast homolog called TOR. The mTOR protein complex in mammalian cells plays a major role in balancing anabolic processes such as the synthesis of proteins, lipids, and nucleotides and catabolic processes, such as autophagy in response to environmental cues, such as availability of nutrients and growth factors.
The mTOR pathway or the...
The mTOR pathway or the...
Receptor Downregulation in MVBs
Multivesicular bodies (MVBs) are mature endosomes that sort ubiquitinated proteins and then fuse with lysosomes to degrade the sorted proteins. Epidermal growth factor (EGF) and its receptor (EGFR) form a complex that can be internalized through endocytosis, sorted into an MVB, and later degraded.
The EGFR can initiate signaling pathways that lead to cell proliferation, migration, and differentiation. Overexpression of EGFR stimulates cells to proliferate. Excessive EGFR activation may...
The EGFR can initiate signaling pathways that lead to cell proliferation, migration, and differentiation. Overexpression of EGFR stimulates cells to proliferate. Excessive EGFR activation may...
Proteoglycans
Glycans, a class of complex heterogeneous molecules, can be covalently attached to proteins to form glycosylated proteins that regulate various physiological and pathological processes. Glycosylated proteins or glycoproteins comprise N-linked and O-linked oligosaccharides. O-glycosylation is the most common type of protein glycosylation. Here, glycans attach to the oxygen atom of the hydroxyl groups of Serine or Threonine residues. O-linked glycosylation occurs later in protein processing,...
TGF - β Signaling Pathway
The TGF-β signaling pathway regulates cell growth, differentiation, adhesion, motility, and development. TGF-β ligands that induce TGF-β signaling are synthesized in their latent form. Several proteases or cell surface receptors such as integrins act upon the latent form, releasing the active ligand. There are three types of mammalian TGF-βs: (TGF-β1, TGF-β2, and TGF-β3) that bind as homodimers or heterodimers to TGF-β receptors. The TGF-β receptors are of three kinds RI, RII, and RIII. The RI...
T Cell Types and Functions
When T cells with CD4 markers are activated, they give rise to two types of effector cells: helper T cells and regulatory T cells. Meanwhile, T cells with CD8 markers differentiate into effector cytotoxic T cells. The differentiation of CD4 T cells into helper T cell subsets, such as Th1, Th2, and Th17 cells, is dependent on the antigen type, antigen-presenting cell, and regulatory cytokines.
Th1 cells stimulate dendritic cells to express necessary co-stimulatory molecules on their surfaces for...
Th1 cells stimulate dendritic cells to express necessary co-stimulatory molecules on their surfaces for...
Myasthenia Gravis ll: Pathophysiology
The disease process of myasthenia gravis begins at the neuromuscular junction, where antibodies attack key proteins needed for muscle activation. This immune reaction weakens signal transmission, leading to the characteristic muscle fatigue and weakness that define the condition.Immune-Mediated DamageIn most individuals, antibodies target acetylcholine receptors (AChRs) on the postsynaptic membrane of muscle cells. By blocking acetylcholine binding, these antibodies prevent the nerve signal...


