Integrin, alpha E (ITGAE) also known as CD103 (cluster of differentiation 103) is an
integrin
Integrins are transmembrane receptors that facilitate cell-cell and cell-extracellular matrix (ECM) adhesion. Upon ligand binding, integrins activate signal transduction pathways that mediate cellular signals such as regulation of the cell cycle ...
protein that in human is encoded by the ''ITGAE''
gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
.
CD103 binds integrin beta 7 (β7–
ITGB7
Integrin beta-7 is an integrin protein that in humans is encoded by the ''ITGB7'' gene. It can pair with ITGA4 (CD49d) to form the heterodimeric integrin receptor αβ, or with ITGAE (CD103) to form αβ.
Structure
Like all integrin subunits, ...
) to form the complete heterodimeric integrin molecule αEβ7, which has no distinct name. The αEβ7 complex is often referred to as "CD103" though this strictly refers only to the αE chain. Note that the β7 subunit can bind with other integrin α chains, such as α4 (
CD49d
CD49d is an integrin alpha subunit. It makes up half of the α4β1 lymphocyte homing receptor.
Function
The product of this gene belongs to the integrin alpha chain family of proteins. Integrins are heterodimeric integral membrane proteins com ...
).
Tissue distribution
CD103 is expressed widely on
intraepithelial lymphocyte Intraepithelial lymphocytes (IEL) are lymphocytes found in the epithelial layer of mammalian mucosal linings, such as the gastrointestinal (GI) tract and reproductive tract. However, unlike other T cells, IELs do not need priming. Upon encounteri ...
(IEL) T cells (both αβ T cells and
γδ T cells) and on some peripheral
regulatory T cell
The regulatory T cells (Tregs or Treg cells), formerly known as suppressor T cells, are a subpopulation of T cells that modulate the immune system, maintain tolerance to self-antigens, and prevent autoimmune disease. Treg cells are immunosu ...
s (Tregs).
It has also been reported on
lamina propria T cells.
A subset of
dendritic cells
Dendritic cells (DCs) are antigen-presenting cells (also known as ''accessory cells'') of the mammalian immune system. Their main function is to process antigen material and present it on the cell surface to the T cells of the immune system. The ...
in the gut
mucosa and
mesenteric lymph nodes
The superior mesenteric lymph nodes may be divided into three principal groups:
* mesenteric lymph nodes
* ileocolic lymph nodes
* mesocolic lymph nodes
Structure
Mesenteric lymph nodes
The mesenteric lymph nodes or mesenteric glands are one of ...
, known as CD103 dendritic cells, also expresses this marker.
It is useful in identifying
hairy cell leukemia
Hairy cell leukemia is an uncommon hematological malignancy characterized by an accumulation of abnormal B lymphocytes. It is usually classified as a subtype of chronic lymphocytic leukemia (CLL). Hairy cell leukemia makes up about 2% of all leu ...
which is positive for this marker in contrast to most other hematologic malignancies which are negative for CD103 except for
hairy cell leukemia variant, a fraction of
splenic marginal zone lymphomas, and
enteropathy-associated T cell lymphoma
Enteropathy-associated T-cell lymphoma (EATL), previously termed enteropathy-associated T-cell lymphoma, type I and at one time termed enteropathy-type T-cell lymphoma (ETTL), is a complication of coeliac disease in which a malignant T-cell lympho ...
.
Function
The chief ligand for αEβ7 is
E-cadherin
Cadherin-1 or Epithelial cadherin (E-cadherin), (not to be confused with the APC/C activator protein CDH1) is a protein that in humans is encoded by the ''CDH1'' gene. Mutations are correlated with gastric, breast, colorectal, thyroid, and ovarian ...
, a cellular adhesion molecule (
CAM
Calmodulin (CaM) (an abbreviation for calcium-modulated protein) is a multifunctional intermediate calcium-binding messenger protein expressed in all eukaryotic cells. It is an intracellular target of the secondary messenger Ca2+, and the bin ...
) found on
epithelial
Epithelium or epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of compactly packed cells with a little intercell ...
cells.
It is probably important for T cell homing to the intestinal sites
and thymocyte contacts with thymic reticuloepithelial cells.
Tregs are important for decreasing the immune response and appear to play a crucial role in the prevention of
autoimmune diseases. Tregs are defined as
CD4+/
CD25
Interleukin-2 receptor alpha chain (also called CD25) is the human protein encoded by the ''IL2RA'' gene.
The interleukin 2 (IL2) receptor alpha (IL2RA) and beta ( IL2RB) chains, together with the common gamma chain (IL2RG), constitute the high-a ...
+/
Foxp3
FOXP3 ( forkhead box P3), also known as scurfin, is a protein involved in immune system responses. A member of the FOX protein family, FOXP3 appears to function as a master regulator of the regulatory pathway in the development and function of ...
+ cells.
Some CD4
+/FoxP3
− cells also express
CD103 and have been attributed regulatory activity. It is unclear whether the presence of CD103 on Treg cells represents a specialized feature for Treg, or Treg differentiation of IEL T cells.
See also
*
Cluster of differentiation
The cluster of differentiation (also known as cluster of designation or classification determinant and often abbreviated as CD) is a protocol used for the identification and investigation of cell surface molecules providing targets for immunophen ...
*
Tissue-resident memory T cell
References
Further reading
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External links
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ITGAEInfo with links in th
Cell Migration Gateway
{{Integrins