Latest revision as of 14:23, 21 February 2025

FCER1[edit]

FCER1 (Fc epsilon receptor I) is a high-affinity IgE receptor that plays a crucial role in allergic reactions and immune system responses. It is primarily found on the surface of mast cells, basophils, and dendritic cells. The interaction between IgE and FCER1 is central to the pathophysiology of allergic diseases such as asthma, allergic rhinitis, and anaphylaxis.

Structure[edit]

FCER1 is a tetrameric receptor composed of one alpha (α) chain, one beta (β) chain, and two gamma (γ) chains. The α chain is responsible for binding to the Fc region of IgE, while the β and γ chains are involved in signal transduction.

Alpha (α) chain: This chain contains the IgE binding site and is crucial for the high-affinity interaction with IgE.
Beta (β) chain: This chain amplifies the signal transduction initiated by the receptor.
Gamma (γ) chains: These chains contain immunoreceptor tyrosine-based activation motifs (ITAMs) that are essential for initiating downstream signaling pathways.

Function[edit]

The primary function of FCER1 is to mediate the allergic response. Upon binding of IgE to the α chain, the receptor becomes cross-linked by multivalent antigens, leading to the activation of the receptor.

Signal Transduction[edit]

The cross-linking of FCER1 by antigen-bound IgE triggers a cascade of intracellular signaling events:

1. Phosphorylation of ITAMs: The γ chains' ITAMs are phosphorylated by Src family kinases, such as Lyn. 2. Activation of Syk kinase: The phosphorylated ITAMs recruit and activate Syk kinase, which further propagates the signal. 3. Downstream signaling: This leads to the activation of multiple signaling pathways, including the MAPK pathway, PI3K pathway, and NF-κB pathway. 4. Degranulation: The signaling culminates in the degranulation of mast cells and basophils, releasing histamine, cytokines, and other mediators of inflammation.

Clinical Significance[edit]

FCER1 is a critical component in the development of allergic diseases. The receptor's high affinity for IgE makes it a target for therapeutic interventions aimed at reducing allergic responses. Inhibiting the interaction between IgE and FCER1 can potentially alleviate symptoms of allergic diseases.

Related Pages[edit]

@@ Line 1: / Line 1: @@
-{{Short description|Overview of the high-affinity IgE receptor (Fc_RI)}}
+= FCER1 =
-==Overview==
+[[File:FcεRI_Receptor.jpg|thumb|right|Diagram of the FcεRI receptor structure.]]
-The high-affinity [[IgE]] receptor, known as Fc_RI, is a crucial component of the immune system, primarily involved in allergic reactions. It is a tetrameric receptor complex found on the surface of [[mast cells]], [[basophils]], and [[dendritic cells]]. Fc_RI plays a pivotal role in the pathophysiology of [[allergic diseases]] by mediating the release of inflammatory mediators upon activation by IgE antibodies.
-==Structure==
+'''FCER1''' (Fc epsilon receptor I) is a high-affinity [[IgE]] receptor that plays a crucial role in [[allergic reactions]] and [[immune system]] responses. It is primarily found on the surface of [[mast cells]], [[basophils]], and [[dendritic cells]]. The interaction between IgE and FCER1 is central to the pathophysiology of allergic diseases such as [[asthma]], [[allergic rhinitis]], and [[anaphylaxis]].
-[[File:IgE receptor structure.png|thumb|right|Diagram of the Fc_RI structure.]]
-Fc_RI is composed of four subunits: one alpha (_) chain, one beta (_) chain, and two gamma (_) chains. The _ chain is responsible for binding to the Fc region of IgE antibodies. The _ and _ chains are involved in signal transduction, with the _ chains containing immunoreceptor tyrosine-based activation motifs (ITAMs) that are crucial for downstream signaling.
-==Function==
+== Structure ==
-The primary function of Fc_RI is to bind IgE antibodies with high affinity. When an allergen cross-links IgE molecules bound to Fc_RI on the surface of mast cells or basophils, it triggers the degranulation of these cells. This process releases histamine and other inflammatory mediators, leading to the symptoms of an allergic reaction, such as itching, swelling, and bronchoconstriction.
-==Role in Allergic Reactions==
+FCER1 is a tetrameric receptor composed of one alpha (α) chain, one beta (β) chain, and two gamma (γ) chains. The α chain is responsible for binding to the Fc region of IgE, while the β and γ chains are involved in signal transduction.
-[[File:Allergic reaction diagram.png|thumb|left|Illustration of an allergic reaction mediated by Fc_RI.]]
-Fc_RI is central to the development of allergic responses. Upon exposure to an allergen, IgE antibodies specific to that allergen bind to Fc_RI on mast cells and basophils. This binding leads to cell activation and the release of mediators that cause the symptoms of allergies. Fc_RI is also involved in the late-phase allergic response, which can lead to chronic inflammation and tissue damage.
-==Clinical Significance==
+* '''Alpha (α) chain''': This chain contains the IgE binding site and is crucial for the high-affinity interaction with IgE.
-Understanding the role of Fc_RI in allergic reactions has significant clinical implications. Targeting Fc_RI or its signaling pathways can be a therapeutic strategy for treating allergic diseases. For instance, monoclonal antibodies that block IgE binding to Fc_RI are used in the treatment of severe allergic asthma and chronic urticaria.
+* '''Beta (β) chain''': This chain amplifies the signal transduction initiated by the receptor.
+* '''Gamma (γ) chains''': These chains contain immunoreceptor tyrosine-based activation motifs (ITAMs) that are essential for initiating downstream signaling pathways.
-==Research and Developments==
+== Function ==
-Recent research has focused on the regulation of Fc_RI expression and its role in various immune responses beyond allergies. Studies are exploring how modulating Fc_RI activity can influence immune tolerance and autoimmunity. Additionally, novel therapeutic approaches aim to desensitize Fc_RI-mediated responses in allergic individuals.
-==Related pages==
+The primary function of FCER1 is to mediate the allergic response. Upon binding of IgE to the α chain, the receptor becomes cross-linked by multivalent antigens, leading to the activation of the receptor.
-* [[Immunoglobulin E]]
+=== Signal Transduction ===
+[[File:IgE_FcεRI_Receptor_Signal_Cascade.jpg|thumb|left|Illustration of the IgE FcεRI receptor signal cascade.]]
+The cross-linking of FCER1 by antigen-bound IgE triggers a cascade of intracellular signaling events:
+. '''Phosphorylation of ITAMs''': The γ chains' ITAMs are phosphorylated by [[Src family kinases]], such as [[Lyn]].
+. '''Activation of Syk kinase''': The phosphorylated ITAMs recruit and activate [[Syk kinase]], which further propagates the signal.
+. '''Downstream signaling''': This leads to the activation of multiple signaling pathways, including the [[MAPK]] pathway, [[PI3K]] pathway, and [[NF-κB]] pathway.
+. '''Degranulation''': The signaling culminates in the degranulation of mast cells and basophils, releasing [[histamine]], [[cytokines]], and other mediators of inflammation.
+== Clinical Significance ==
+FCER1 is a critical component in the development of allergic diseases. The receptor's high affinity for IgE makes it a target for therapeutic interventions aimed at reducing allergic responses. Inhibiting the interaction between IgE and FCER1 can potentially alleviate symptoms of allergic diseases.
+== Related Pages ==
+* [[IgE]]
 * [[Mast cell]]
 * [[Basophil]]
 * [[Allergic reaction]]
-* [[Histamine]]
+* [[Anaphylaxis]]
 [[Category:Immunology]]
-[[Category:Allergology]]
+[[Category:Receptors]]

FCER1: Difference between revisions