アレルギー反応におけるGab2の重要な役割
1Cancer Biology Program, Division of Hematology and Oncology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA hgu@caregroup.harvard.edu.
Nature
|July 13, 2001
まとめ
Gab2は,IgE受容体の活性化に対するマスト細胞の反応に不可欠です. Gab2が欠けているマウスは,アレルギー反応の障害を示し,Gab2が免疫におけるPI(3) Kシグナル伝達の主な活性化剤であることを強調しています.
科学分野:
- 免疫学 免疫学とは
- 細胞シグナリング
- 分子生物学は分子生物学である.
背景:
- Dos/Gabファミリーのタンパク質は,シャッフルとして作用し,Shp-2やPI (3) のような信号リレー分子に結合します.
- これらのアダプターは,成長因子,サイトカイン,抗原受容体によって開始される信号伝達経路に関与しています.
- Gab1のノックアウトマウスは胚の致死性を示すが,Gab2のノックアウトマウスは生存可能である.
研究 の 目的:
- 免疫反応,特にマスト細胞におけるGab2の役割を調査する.
- 高親和性IgE受容体 (FcεRI) によって開始されるシグナリングカスケードにおけるGab2の機能を決定する.
- アレルギー性疾患におけるGab2を標的とした治療の可能性を調査する.
主な方法:
- Gab2ノックアウト (Gab2-/-) マウスの生成とフェノタイプ分析.
- FcεRI刺激によるマスト細胞脱粒化とサイトカイン遺伝子発現の評価.
- 野生型およびGab2-/-マスト細胞におけるPI(3) Kシグナル伝達経路の生化学分析.
主要な成果:
- Gab2-/-マウスは健康状態は正常だが,FcεRIの活性化に対するマスト細胞の反応は欠陥がある.
- 皮質および全身のアナフィラキシーを含むアレルギー反応は,Gab2-/-マウスでは著しく低下しています.
- FcεRIに依存するPI(3) Kシグナル伝達経路は,Gab2-/-マスト細胞に欠陥があり,この文脈でPI(3) Kの主な活性化剤としてGab2を識別します.
結論:
- Gab2は,FcεRI媒介のマスト細胞活性化とアレルギー反応に不可欠です.
- Gab2は,FcεRIの下流にあるPI(3) Kの主な活性化剤として作用する.
- Gab2とその関連するシグナル伝達分子は,アレルギーの治療のための潜在的な治療標的を表しています.
関連する概念動画
Antibody Structure
Overview
Antibodies, also known as immunoglobulins (Ig), are essential players of the adaptive immune system. These antigen-binding proteins are produced by B cells and make up 20 percent of the total blood plasma by weight. In mammals, antibodies fall into five different classes, which each elicits a different biological response upon antigen binding.
The Y-Shaped Structure of Antibodies Consists of Four Polypeptide Chains
Antibodies consist of four polypeptide chains: two identical heavy...
Antibodies, also known as immunoglobulins (Ig), are essential players of the adaptive immune system. These antigen-binding proteins are produced by B cells and make up 20 percent of the total blood plasma by weight. In mammals, antibodies fall into five different classes, which each elicits a different biological response upon antigen binding.
The Y-Shaped Structure of Antibodies Consists of Four Polypeptide Chains
Antibodies consist of four polypeptide chains: two identical heavy...
Allergic Reactions
Overview
Activation and Inactivation of G Proteins
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 affinity and are together...
GPCRs Regulate Adenylyl Cylase Activity
Some GPCRs transmit signals through adenylyl cyclase (AC), a transmembrane enzyme. AC helps synthesize second messenger cyclic adenosine monophosphate (cAMP). AC catalyzes cyclization reaction and converts ATP to cAMP by releasing a pyrophosphate. The pyrophosphate is further hydrolyzed to phosphate by the enzyme pyrophosphatase, which drives cAMP synthesis to completion. However, cAMP is rapidly degraded to 5′ AMP by the enzymes phosphodiesterase (PDE), preventing overstimulation of cells.
Two...
Two...
Immunoglobulin-like Cell Adhesion Molecules
Immunoglobulin-like cell adhesion molecules or Ig-CAMs are a versatile group of cell surface glycoproteins belonging to the immunoglobulin protein superfamily. Ig-CAMs possess the characteristic immunoglobulin protein domains and other domains such as the fibronectin type III domain. The Ig domains are glycosylated to varying degrees in different Ig-CAMs.
Ig-CAMs exhibit either homophilic binding (to other Ig-CAMs) or heterophilic binding (to other ligands such as integrins). While most Ig-CAMs...
Ig-CAMs exhibit either homophilic binding (to other Ig-CAMs) or heterophilic binding (to other ligands such as integrins). While most Ig-CAMs...
Allergic Drug Reactions
Allergic reactions related to drugs are hypersensitivity responses driven by the immune system and bear no connection to the drug's therapeutic action. While drugs in isolation do not trigger an immune response, they can interact with endogenous proteins to form antigens. These antigens stimulate lymphocytes to produce antibodies. IgE-type antibodies attach themselves to mast cells. Upon subsequent exposure to the same stimulus, the antigen-antibody interaction is initiated, unleashing numerous...


