Nine IL-1 family ligand members (IL-1A, IL-1B, IL-1RA, IL-36α, IL-36β, IL-36γ, IL-36Ra, IL-37 and IL-38) are located on chromosome 2. IL-33 is located on chromosome 9, and IL-18 are located on the chromosome 11.
The activity of each member of the IL-1 family cytokines is mediated by its own receptor. Each ligand binds specifically to the extracellular "ligand binding chain" containing three Ig-like regions. The biological properties of IL-1 family ligands are typically pro-inflammatory.
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IL-1 (Interleukin 1) Family Ligands all share structural similarities including the absence of a signal peptide, the presence of N-terminal pro-peptide sequence that is cleaved by serine proteases (e.g. caspase-1) and a conserved A-X-D sequence (A is an aliphatic amino acid such as isoleucine, methionine, or leucine; X is any amino acid; and D is aspartic acid), which plays a role in the folding and tertiary structure of active IL-1 family members.
IL-1 family ligands can be divided into three subfamilies according to the length of the precursor and the length of the propiece for each precursor.
| Category | Ligand | Receptor | Chromosome (hu) |
| IL-1 subfamily | IL1A/IL-1A/IL-1F1 | IL1R1/IL-1R1/IL-1 RI, IL-1R2/CD121b, IL-1RAcP/IL-1R3 | 2q14 |
| IL-1 subfamily | IL1B/IL-1B/IL-1 beta | IL1R1/IL-1R1/IL-1 RI, IL-1R2/CD121b, IL-1RAcP/IL-1R3 | 2q14 |
| IL-1 Receptor Antagonist | IL-1RA/IL1RN | IL1R1/IL-1R1/IL-1 RI, IL-1R2/CD121b | 2q14.2 |
| IL-18 subfamily | IL18/IL-18/Interleukin 18 | IL18R1, IL18RAP, IL18BP / IL18BPa | 11q22.2-q22.3 |
| IL-1 subfamily | IL-33 | IL-1RAcP/IL-1R3, IL1RL1/IL-1 R4 | 9p24.1 |
| IL-36 subfamily | IL-1F5/IL36RN | IL1RL2/IL1RRP2 | 2q14 |
| IL-36 subfamily | IL-1F6/IL36A | IL1RL2/IL1RRP2, IL-1RAcP/IL-1R3 | 2q12-q14.1 |
| IL-36 subfamily | IL36B/IL1F8 | IL1RL2/IL1RRP2, IL-1RAcP/IL-1R3 | 2q14 |
| IL-36 subfamily | IL36G/IL-1F9 | IL1RL2/IL1RRP2, IL-1RAcP/IL-1R3 | 2q12-q21 |
| IL-18 subfamily | IL37 / IL1F7 / IL-1H4 | IL18R1 | 2q12-q14.1 |
| IL-36 subfamily | IL1F10 / IL-38 | IL1R1/IL-1R1/IL-1 RI, IL1RL2/IL1RRP2 | 2q13 |
Interleukin-1 (IL-1) is a central mediator of innate immunity and inflammation. IL-1 family ligands include seven molecules with agonist activity (IL-1α and IL-1β, IL-18, IL-33, IL-36α, IL-36β, IL-36γ), three receptor antagonists (IL-1Ra, IL-36Ra, IL-38), and an anti-inflammatory cytokine (IL-37). The IL-1 family ligand members include 11 molecules.
These members are classified into IL-1 family ligands, mainly based on similar amino acid sequence, gene structure, and three-dimensional structure.
The following are outlines of "IL-1 (Interleukin 1) Family Ligand Review Page", which briefly introduce each IL-1 family ligand. If you want more details, please click here.
1. IL-1 subfamily: IL-1α (IL-1F1), IL-1β (IL-1F2) and IL-33 (IL-1F11)
2. IL-1 receptor antagonist: IL-1Ra (IL-1F3)
3. IL-18 subfamily: IL-18 (IL-1F4) and IL-37 (IL-1F7)
4. IL-36 subfamily: IL-36α (IL-1F6), IL-36β (IL-1F8), IL-36γ (IL-1F9), IL-36Ra (IL-1F5) and IL-38(IL-1F10)
