Interleukin 1

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Crystal structure of IL-1a
Interleukin 1 alpha
Identifiers
Symbol IL1A , IL1F1
HUGO 5991
Entrez 3552
OMIM 147760
RefSeq NM_000575
UniProt P01583
PDB 2ILA
Other data
Locus Chr. 2 q12-q21
Crystal structure of IL-1b
Interleukin 1 beta
Identifiers
Symbol IL1B , IL1F2
HUGO 5992
Entrez 3553
OMIM 147720
RefSeq NM_000576
UniProt P01584
PDB 2MIB
Other data
Locus Chr. 2 q13-q21
Interleukin 1 receptor antagonist
Identifiers
Symbol IL1RN , IL1RA, ICIL-1RA, IL1F3
HUGO 6000
Entrez 3557
OMIM 147679
RefSeq NM_173843
UniProt P18510
Other data
Locus Chr. 2 q14.2
Interleukin 18
Identifiers
Symbol IL18 , IGIF, IL1F4, IL-1g
HUGO 5986
Entrez 3606
OMIM 600953
RefSeq NM_001562
UniProt Q14116
Other data
Locus Chr. 11 q22.2-q22.3
Interleukin 1 family member 5
Identifiers
Symbol IL1F5 , FIL1, IL1HY1, IL-1RP3, IL1L1
HUGO 15561
Entrez 26525
OMIM 605507
RefSeq NM_012275
UniProt Q9UBH0
Other data
Locus Chr. 2 q14
Interleukin 1 family member 6
Identifiers
Symbol IL1F6 , FIL1
HUGO 15562
Entrez 27179
OMIM 605509
RefSeq NM_014440
UniProt Q9UHA7
Other data
Locus Chr. 2 q14
Interleukin 1 family member 7
Identifiers
Symbol IL1F7 , FIL1, IL-1H4, IL-1RP1
HUGO 15563
Entrez 27178
OMIM 605510
RefSeq NM_173203
UniProt Q9NZH6
Other data
Locus Chr. 2 q14
Interleukin 1 family member 8
Identifiers
Symbol IL1F8 , FIL1, IL-1H2
HUGO 15564
Entrez 27177
OMIM 605508
RefSeq NM_014438
UniProt Q9NZH7
Other data
Locus Chr. 2 q14
Interleukin 1 family member 9
Identifiers
Symbol IL1F9 , IL-1H1, IL-1RP2
HUGO [1]
Entrez 56300
OMIM 605542
RefSeq NM_019618
UniProt Q9NZH8
Other data
Locus Chr. 2 q12-q21
Interleukin 1 family member 10
Identifiers
Symbol IL1F10 , FKSG75, IL-1HY2, FIL1- theta
HUGO 15552
Entrez 84639
RefSeq NM_173161
UniProt Q8WWZ1
Other data
Locus Chr. 2 q13-14.1


Interleukin-1 (IL-1) is one of the first cytokines ever described. Its initial discovery was as a factor that could induce fever, control lymphocytes, increase the number of bone marrow cells and cause degeneration of bone joints. At this time, IL-1 was known under several other names including endogenous pyrogen, lymphocyte activating factor, haemopoetin-1 and mononuclear cell factor, amongst others. It was around 1984-1985 when scientists confirmed that IL-1 was actually composed of two distinct proteins, now called IL-1α and IL-1β.[1] These belong to a family of cytokines known as the interleukin-1 superfamily.


Contents

[edit] The Interleukin-1 superfamily

The original members of the IL-1 superfamily are IL-1α, IL-1β, and the IL-1 Receptor antagonist (IL-1RA). IL-1α and -β are pro-inflammatory cytokines involved in immune defence against infection. The IL-1RA is a molecule that competes for receptor binding with IL-1α and IL-1β, blocking their role in immune activation. Recent years have seen the addition of other molecules to the IL-1 superfamily including IL-18[2] and six more genes with structural homology to IL-1α, IL-1β or IL-1RA. These latter six members are named IL-1F5, IL-1F6, IL-1F7, IL-1F8, IL-1F9, and IL-1F10. In accord, IL-1α, IL-1β, and IL-1RA have been renamed IL-1F1, IL-1F2, and IL-1F3, respectively.[3][4] A further putative member of the IL-1 family has been recently described that is called IL-33 or IL-1F11, although this name is not officially accepted in the HGNC gene family nomenclature database.[5]

[edit] IL-1α and IL-1β

Both IL-1α and IL-1β are produced by macrophages, monocytes and dendritic cells. They form an important part of the inflammatory response of the body against infection. These cytokines increase the expression of adhesion factors on endothelial cells to enable transmigration of leukocytes, the cells that fight pathogens, to sites of infection and re-set the hypothalamus thermoregulatory center, leading to an increased body temperature which expresses itself as fever. IL-1 is therefore called an endogenous pyrogen. The increased body temperature helps the body's immune system to fight infection. IL-1 is also important in the regulation of hematopoiesis.

For the most part, these two forms of IL-1 bind to the same cellular receptor. This receptor is composed of two related, but non-identical, subunits that transmit intracellular signals via a pathway that is mostly shared with certain other receptors. These include the Toll family of innate immune receptors and the receptor for IL-18.

[edit] IL-1RA

The IL-1 receptor antagonist (IL-1RA) was initially called the IL-1 inhibitor and was discovered separately in 1984 by two independent laboratories.[1] IL-1RA, is an agent which binds to the same receptor on the cell surface as IL-1, and thus prevents IL-1 from sending a signal to that cell. It is used in the treatment of rheumatoid arthritis, an autoimmune disease in which IL-1 plays a key role. It is commercially produced as anakinra, which is a human recombinant form of IL-1RA. In terms of protein similarities, IL-1β is more closely related to IL-1RA than it is to IL- 1α. The amino acids that are identical between mature human IL-1α and mature IL-1β is 22% while it is 26% when comparing IL-1β to IL-1RA and only 18% when comparing IL-1α to IL-1RA.[1]

[edit] Structure of the IL-1 superfamily

IL-1α and IL-1β are produced as precursor peptides. In other words they are made as a long protein that is then processed to release a shorter, active molecule, which is called the mature protein. Mature IL-1β, for instance, is released from Pro-IL-1β following cleavage by a certain member of the caspase family of proteins, called caspase-1 or the interleukin-1 converting enzyme (ICE). The 3-dimensional structure of the mature forms of each member of the human IL-1 superfamily is composed of 12-14 β-strands producing a barrel-shaped protein.[1]

[edit] References

  1. ^ a b c d C.A. Dinarello. The interleukin-1 family: 10 years of discovery. FASEB Journal. Volume 8, Issue 15, 1994, pages 1314-25.
  2. ^ M.O. Huising et al., The molecular evolution of the interleukin-1 family of cytokines; IL-18 in teleost fish, Developmental and Comparative Immunology, Volume 28, Issue 5, 2004, pages 395-413.
  3. ^ J.E. Sims et al., A new nomenclature for IL-1-family genes. Trends in Immunology, Volume 22, Issue 10, 2001, 536-7.
  4. ^ E. Dunn et al., Annotating genes with potential roles in the immune system: six new members of the IL-1 family. Trends in Immunology, Volume 22, Issue 10, 2001, 533-6.
  5. ^ http://www.gene.ucl.ac.uk/nomenclature/