IL-2 receptor

Source: Wikipedia, the free encyclopedia.
Chr. 10 p15.1
Search for
StructuresSwiss-model
DomainsInterPro
Chr. 22 q13
Search for
StructuresSwiss-model
DomainsInterPro
Chr. X q13
Search for
StructuresSwiss-model
DomainsInterPro

The interleukin-2 receptor (IL-2R) is a

heterotrimeric protein expressed on the surface of certain immune cells, such as lymphocytes, that binds and responds to a cytokine called IL-2
.

Composition

IL-2 binds to the IL-2 receptor, which has three forms, generated by different combinations of three different proteins, often referred to as "chains": α (alpha) (also called IL-2Rα, CD25, or Tac antigen), β (beta) (also called IL-2Rβ, or CD122), and γ (gamma) (also called IL-2Rγ, γc, common gamma chain, or CD132); these subunits are also parts of receptors for other cytokines.[2]: 713  The β and γ chains of the IL-2R are members of the type I cytokine receptor family.[3]

Structure-activity relationships of the IL-2/IL-2R interaction

The three receptor chains are expressed separately and differently on various cell types and can assemble in different combinations and orders to generate low, intermediate, and high affinity IL-2 receptors.

The α chain binds IL-2 with low affinity, the combination of β and γ together form a complex that binds IL-2 with intermediate affinity, primarily on

regulatory T cells. The intermediate and high affinity receptor forms are functional and cause changes in the cell when IL-2 binds to them.[3]

The structure of the stable complex formed when IL-2 binds to the high affinity receptor has been determined using X-ray crystallography. The structure supports a model wherein IL-2 initially binds to the α chain, then the β is recruited, and finally γ.[3][4][5]

Signaling

The three IL-2 receptor chains span the

JAK-STAT pathway.[3][4]

Once IL-2 binds to the high affinity receptor, the complex is rapidly internalized and has only a short time to signal. IL-2, IL-2Rβ, and γc are rapidly degraded, but IL-2Rα is recycled to the cell surface. Thus, the concentration of IL-2 and its receptor available determines the tempo, magnitude and extent of T cell immune responses.[3][4]

IL-2 and its receptor have key roles in key functions of the immune system,

memory T cells when the initial T cells is also stimulated by an antigen, thus helping the body fight off infections.[3] Through their role in the development of T cell immunologic memory, which depends upon the expansion of the number and function of antigen-selected T cell clones, they also have a key role in enduring cell-mediated immunity.[3][4]

Clinical implications

Drugs that inhibit IL-2 receptors, such as basiliximab and daclizumab are used in conjunction with other drugs to prevent immune rejection of transplants.[6]

History

According to an immunology textbook: "IL-2 is particularly important historically, as it is the first type I cytokine that was cloned, the first type I cytokine for which a receptor component was cloned, and was the first short-chain type I cytokine whose receptor structure was solved. Many general principles have been derived from studies of this cytokine, including its being the first cytokine demonstrated to act in a growth factor–like fashion through specific high-affinity receptors, analogous to the growth factors being studied by endocrinologists and biochemists".[2]: 712 

See also

CD25 deficiency

References

  1. S2CID 85394260
    .
  2. ^
    ISBN 9780781765190
    .
  3. ^
    PMID 21889323
    .
  4. ^
    PMID 20732639
    .
  5. PMID 22650257
    .
  6. S2CID 3296555
    .

External links
Retrieved from "https://en.wikipedia.org/w/index.php?title=IL-2_receptor&oldid=1079538691"