FCER1

File:FcεRI Receptor.jpgThe structure of the FcεRI receptor File:IgE FcεRI Receptor Signal Cascade.jpgSummary of IgE/FcεRI receptor mediated downward signal cascade high-affinity IgE receptor; alpha

Identifiers
Symbol| FCER1A
Alt. symbols| FcεRIα, FCE1A
Entrez| 2205
HUGO| 3609
OMIM| 147140
RefSeq| NM_002001
UniProt| P12319
Other data
Locus| Chr. 1 q23
high affinity IgE receptor; beta

Identifiers
Symbol| MS4A2
Alt. symbols| FcεRIβ, FCER1B, IGER, APY
Entrez| 2206
HUGO| 7316
OMIM| 147138
RefSeq| NM_000139
UniProt| Q01362
Other data
Locus| Chr. 1 q23
high affinity IgE receptor; gamma

Identifiers
Symbol| FCER1G
Alt. symbols| FcεRIγ
Entrez| 2207
HUGO| 3611
OMIM| 147139
RefSeq| NM_004106
UniProt| P30273
Other data
Locus| Chr. 1 q23

The high-affinity IgE receptor, also known as FcεRI, or Fc epsilon RI, is the high-affinity receptor for the Fc region of immunoglobulin E (IgE), an antibody isotype involved in the allergy disorder and parasites immunity. FcεRI is a tetrameric receptor complex that binds Fc portion of the ε heavy chain of IgE.[1] It consists of one alpha (FcεRIα - antibody binding site), one beta (FcεRIβ - which amplifies the downstream signal), and two gamma chains (FcεRIγ - the site where the downstream signal initiates) connected by two disulfide bridges. It is constitutively expressed on mast cells and basophils[2] and is inducible in eosinophils.

## Contents

* 1 Tissue distribution
* 2 Mechanism of action
* 3 See also
* 4 References
* 5 External links

## Tissue distribution

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FcεRI is found on epidermal Langerhans cells, eosinophils, mast cells, and basophils.[3][4] As a result of its cellular distribution, this receptor plays a major role in controlling allergic responses. FcεRI is also expressed on antigen-presenting cells, and controls the production of important immune mediators (cytokines, interleukins, leukotrienes, and prostaglandins) that promote inflammation.[5] The most known mediator is histamine, which results in the five symptoms of inflammation: heat, swelling, pain, redness and loss of function.

## Mechanism of action

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Crosslinking of the FcεRI via IgE-antigen complexes leads to degranulation of mast cells or basophils and release of inflammatory mediators.[6] Under laboratory conditions, degranulation of isolated basophils can also be induced with antibodies to the FcεRIα, which crosslink the receptor. Such crosslinking and potentially pathogenic autoantibodies to the FcεRIα have been isolated from human cord blood, which suggest that they occur naturally and are present already at birth. However, their epitope on FcεRIα was masked by IgE, and the affinity of the corresponding autoantibodies found in healthy adults appeared lowered.[7]

## See also

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* Omalizumab

## References

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1. ↑ Kumar, Vinay; Abbas, Abul K.; Aster, Jon (2012-05-01). Robbins Basic Pathology (9 ed.). Saunders.
2. ↑ Pawankar R (February 2001). "Mast cells as orchestrators of the allergic reaction: the IgE-IgE receptor mast cell network". Curr Opin Allergy Clin Immunol. 1 (1): 3–6. doi:10.1097/00130832-200102000-00002. PMID 11964662.
3. ↑ Ochiai K, Wang B, Rieger A, Kilgus O, Maurer D, Födinger D, Kinet J, Stingl G, Tomioka H (1994). "A review on Fc epsilon RI on human epidermal Langerhans cells". Int Arch Allergy Immunol. 104. Suppl 1 (1): 63–4. doi:10.1159/000236756. PMID 8156009.
4. ↑ Prussin C, Metcalfe D (2006). "5. IgE, mast cells, basophils, and eosinophils". J Allergy Clin Immunol. 117 (2 Suppl Mini-Primer): S450–6. doi:10.1016/j.jaci.2005.11.016. PMID 16455345.
5. ↑ von Bubnoff D, Novak N, Kraft S, Bieber T (2003). "The central role of FcepsilonRI in allergy". Clin Exp Dermatol. 28 (2): 184–7. doi:10.1046/j.1365-2230.2003.01209.x. PMID 12653710.
6. ↑ Siraganian RP (December 2003). "Mast cell signal transduction from the high-affinity IgE receptor". Curr. Opin. Immunol. 15 (6): 639–46. doi:10.1016/j.coi.2003.09.010. PMID 14630197.
7. ↑ Bobrzynski T, Fux M, Vogel M, Stadler MB, Stadler BM, Miescher SM (November 2005). "A high-affinity natural autoantibody from human cord blood defines a physiologically relevant epitope on the FcepsilonRIalpha". J. Immunol. 175 (10): 6589–96. doi:10.4049/jimmunol.175.10.6589. PMID 16272313.

## External links

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* Fc+epsilon+RI at the US National Library of Medicine Medical Subject Headings (MeSH)

* v
* t
* e

Transmembrane receptors: immunoglobulin superfamily immune receptors

Antibody receptor:
Fc receptor|

| Epsilon (ε)|

* FcεRI
* (FcεRII is C-type lectin)

|

Gamma (γ)|

* FcγRI
* FcγRII
* FcγRIII
* Neonatal

Alpha (α)/mu (μ)|

* FcαRI
* Fcα/μR

Secretory|

* Polymeric immunoglobulin receptor

Antigen receptor|

| B cells|

| Antigen receptor|

* BCR

|

Co-receptor|

| stimulate:|

* CD21/CD19/CD81

|

inhibit:|

* CD22

Accessory molecules|

* Ig-α/Ig-β (CD79)

T cells|

| Ligands|

* MHC
* MHC class I
* MHC class II

|

Antigen receptor|

* TCR: TRA@
* TRB@
* TRD@
* TRG@

Co-receptors|

* CD8 (with two glycoprotein chains CD8α and CD8β)
* CD4

Accessory molecules|

* CD3
* CD3γ
* CD3δ
* CD3ε
* ζ-chain (also called CD3ζ and TCRζ)

Cytokine receptor|

* see cytokine receptors

Killer-cell IG-like receptors|

* KIR2DL1
* KIR2DL2
* KIR2DL3
* KIR2DL4
* KIR2DL5A
* KIR2DL5B
* KIR2DS1
* KIR2DS2
* KIR2DS3
* KIR2DS4
* KIR2DS5
* KIR3DL1
* KIR3DL2
* KIR3DL3
* KIR3DS1

Leukocyte IG-like receptors|

* LILRA1
* LILRA2
* LILRA3
* LILRA4
* LILRA5
* LILRA6
* LILRB1
* LILRB2
* LILRB3
* LILRB4
* LILRB5
* LILRA6
* LILRA5

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*[e]: Edit this template