免疫グロブリンDの細胞表面発現のためのメカニズムとして,グリコシル・フォスファティディルニノシトール結合
1Max-Planck Institut für Immunbiologie, Freiburg, Germany.
Nature
|March 19, 1992
まとめ
B細胞の受容体であるB細胞受容体.
科学分野:
- 免疫学 免疫学とは
- 分子生物学は分子生物学である.
- 細胞生物学 細胞生物学
背景:
- B細胞抗原受容体 (BCR) は,適応免疫にとって極めて重要です.
- BCRは,免疫グロブリン (Ig) とシグナリングタンパク質Ig-alpha/Ig-betaを含むマルチメリック複合体です.
- IgMとIgDのBCRは,表面表現メカニズムが異なっている.
研究 の 目的:
- IgD BCR表面表現の分子メカニズムを調査する.
- アルファ/ベータ依存 IgD 発現経路と独立 IgD 発現経路を区別する.
主な方法:
- B細胞表面タンパク質発現の分析.
- タンパク質のアンカリングメカニズムを研究する.
- IgD組立におけるIg-alpha/Ig-betaヘテロダイマーの役割を研究する.
主要な成果:
- IgDは,Ig-alpha/Ig-betaとは無関係に,グリコシル・フォスファティディルニノシトール (GPI) アンカーを通じて発現することができる.
- Ig-alpha/Ig-betaの存在下では,GPI関連IgDは主にトランスメブランタンパク質として発現する.
- IgMの表面発現には,Ig-alpha/Ig-betaヘテロダイマーとの結合が厳密に要求される.
結論:
- IgDは二重膜アンカリングメカニズムを示し,柔軟な表面表現を可能にします.
- Ig-alpha/Ig-betaヘテロダイマーは,GPIに固定された形態からトランスメブラン形態へのIgDを調節する.
- これらのメカニズムを理解することは,B細胞のシグナル伝達と免疫応答の鍵です.
さらに関連する動画
07:26Single-molecule Super-resolution Imaging of Phosphatidylinositol 4,5-bisphosphate in the Plasma Membrane with Novel Fluorescent Probes
Published on: October 15, 2016
08:58Characterization of Glycoproteins with the Immunoglobulin Fold by X-Ray Crystallography and Biophysical Techniques
Published on: July 5, 2018
関連する概念動画
Phosphoinositides and PIPs
Phosphoinositides are a group of phospholipids containing a glycerol backbone with two fatty acid chains and a phosphate attached to a myoinositol sugar ring. The inositol head group extends into the cytoplasm, where it is modified by adding phosphate groups to form phosphatidylinositol phosphates or PIPs.
Different phosphoinositides are synthesized and recruited on the cytosolic face of the plasma membrane. The localization of specific phosphoinositides concentrated in separate membrane...
Different phosphoinositides are synthesized and recruited on the cytosolic face of the plasma membrane. The localization of specific phosphoinositides concentrated in separate membrane...
GPI Anchoring of Proteins in the ER Membrane
GPI-anchoring is a post-translational, reversible protein modification that is ubiquitous in eukaryotes. Such proteins are primarily present on the exoplasmic leaflet of the plasma membrane.
GPI-anchor structure
A sequence of 11 enzymatic reactions results in the synthesis of the complete GPI anchor consisting of a hydrophobic and a hydrophilic portion. The hydrophobic portion comprises phosphatidylinositol, while the hydrophilic part comprises polar groups like phosphoethanolamine,...
GPI-anchor structure
A sequence of 11 enzymatic reactions results in the synthesis of the complete GPI anchor consisting of a hydrophobic and a hydrophilic portion. The hydrophobic portion comprises phosphatidylinositol, while the hydrophilic part comprises polar groups like phosphoethanolamine,...
Insulin Secretory Vesicles
Insulin secretory vesicles release insulin to stimulate blood glucose uptake and regulate carbohydrate metabolism. When the blood glucose levels increase, glucose enters the pancreatic β-islet cells through glucose transporters. Once inside, glucose is metabolized through glycolysis, the citric acid cycle, and the electron transport chain, producing ATP. This increase in ATP concentration closes ATP-sensitive potassium channels, leading to depolarization of the membrane and the opening of...
IP3/DAG Signaling Pathway
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 produces two-second...
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...
Insulin: The Receptor and Signaling Pathways
Insulin action is mediated through a receptor tyrosine kinase, akin to the IGF-1 receptor. The number of receptors per cell varies significantly, from 40 on erythrocytes to 300,000 on adipocytes and hepatocytes. The insulin receptor consists of linked α/β subunit dimers, forming a heterotetramer glycoprotein with two extracellular α subunits and two β subunits spanning the membrane. The α subunits inhibit the inherent tyrosine kinase activity of the β subunits, but this inhibition is released...
