Integrin, alpha E also known as CD103 (Cluster of Differentiation 103) is an integrin

Integrin

Integrins are receptors that mediate attachment between a cell and the tissues surrounding it, which may be other cells or the ECM. They also play a role in cell signaling and thereby regulate cellular shape, motility, and the cell cycle....

 protein that in human is encoded by the ITGAE gene

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

. CD103 binds integrin beta 7 (β7– ITGB7

ITGB7

Integrin beta-7 is a protein that in humans is encoded by the ITGB7 gene.-External links:* Info with links in the...

) to form the complete heterodimeric integrin molecule αEβ7, which has no distinct name. The αEβ7 complex is often referred to as "CD103" though this appellation strictly refers only to the αE chain. Note that the β7 subunit can bind with other integrin α chains, such as α4 (CD49d

CD49d

CD49d is an integrin alpha subunit. It makes up half of the α4β1 lymphocyte homing receptor.-Interactions:CD49d has been shown to interact with LGALS8 and Paxillin.-External links:* Info with links in the...

).

Tissue Distribution

CD103 is expressed widely on intraepithelial lymphocyte

Intraepithelial lymphocyte

Intraepithelial lymphocytes are lymphocytes found in the epithelial layer of mammalian mucosal linings, such as the gastrointestinal tract and reproductive tract. However, unlike other T cells, IELs do not need priming. Upon encountering antigens, they immediately release cytokines and cause...

 (IEL) T cells (both αβ T cells and γδ T cells) and on some peripheral regulatory T cell

Regulatory T cell

Regulatory T cells , sometimes known as suppressor T cells, are a specialized subpopulation of T cells which suppresses activation of the immune system and thereby maintains tolerance to self-antigens. The existence of regulatory T cells was the subject of significant controversy among...

s (Tregs). It has also been reported on lamina propria

Lamina propria

The lamina propria is a constituent of the moist linings known as mucous membranes or mucosa, which line various tubes in the body ....

 T cells. A subset of dendritic cells in the gut mucosa and in mesenteric lymph nodes

Mesenteric lymph nodes

The mesenteric lymph nodes lie between the layers of the mesentery.They vary from one hundred to one hundred and fifty in number, and may be grouped into three sets, viz.:...

 also expresses this marker and is known as CD103 DCs.

It is useful in identifying Hairy cell leukemia

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 sub-type of chronic lymphoid leukemia...

 which is positive for this marker in contrast to most other hematologic malignancies which are negative for CD103 except Enteropathy associated T cell lymphoma.

Function

The chief ligand for αEβ7 is E-cadherin

CDH1 (gene)

Cadherin-1 also known as CAM 120/80 or epithelial cadherin or uvomorulin is a protein that in humans is encoded by the CDH1 gene. CDH1 has also been designated as CD324 . It is a tumor suppressor gene.- Function :Cadherin-1 is a classical member of the cadherin superfamily...

, an adhesion molecule (CAM

Cell adhesion molecule

Cell Adhesion Molecules are proteins located on the cell surface involved with the binding with other cells or with the extracellular matrix in the process called cell adhesion....

) found on epithelial

Epithelium

Epithelium is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands. Functions of epithelial cells include secretion, selective...

 cells. It is probably important for T cell homing to the intestinal sites.

Tregs are important for decreasing the immune response and appear to play a crucial role in the prevention of autoimmune disease

Autoimmune disease

Autoimmune diseases arise from an overactive immune response of the body against substances and tissues normally present in the body. In other words, the body actually attacks its own cells. The immune system mistakes some part of the body as a pathogen and attacks it. This may be restricted to...

s. Tregs are defined as CD4

CD4

CD4 is a glycoprotein expressed on the surface of T helper cells, monocytes, macrophages, and dendritic cells. It was discovered in the late 1970s and was originally known as leu-3 and T4 before being named CD4 in 1984...

⁺/CD25

CD25

CD25 is the alpha chain of the IL-2 receptor. It is a type I transmembrane protein present on activated T cells, activated B cells, some thymocytes, myeloid precursors, and oligodendrocytes that associates with CD122 to form a heterodimer that can act as a high-affinity receptor for IL-2.CD25 is...

⁺/Foxp3

FOXP3

FOXP3 is a protein involved in immune system responses. A member of the FOX protein family, FOXP3 appears to function as a master regulator in the development and function of regulatory T cells....

⁺ 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.

External links

• ITGAE Info with links in the Cell Migration Gateway