Table 2 Human IL classification.
From: Evolutionary divergence and functions of the human interleukin (IL) gene family
Group | Genes | Common features and structural Motifs |
|---|---|---|
IL1-like | IL1A, IL1B, IL1RN, IL1F5, IL1F6, IL1F7, IL1F8, IL1F9, IL1F10, IL18, IL33 | Fold rich in β-strands known as a β-trefoil |
γ -chain utilising ('short-chain' class I) | IL2, IL4, IL7, IL9, IL15, IL21, TSPL | Four tightly packed α-helices known as 'four-helix bundle' motif; shorter core helices; receptor complex contains γc chain Subunit |
IL4-like ('short-chain' class I) | IL3, IL4, IL5, IL13, CSF2 | Four tightly packed α-helices known as 'four-helix bundle' motif; shorter core helices |
IL6/12-like ('long-chain' class I) | IL6, IL11, IL12A, IL23A, IL27A, IL31, CLCF1, CNTF, CTF1, LIF, OSM, CSF3 | Four tightly packed α-helices known as 'four-helix bundle' motif; longer core Helices |
IL10-like (class II) | IL10, IL19, IL20, IL22, IL24, IL26 | 'Bundled helix' structural motif containing six or seven stacked helices |
IL28-like (class II) | IL28A, IL28B, IL29 | 'Bundled helix' structural motif containing six or seven stacked helices |
IL17-like | IL17A, IL17B, IL17C, IL17D, IL25 (aka IL17E), IL17F | Neurotrophin-like cysteine-knot fold |
Non-classified | IL8, TXLNA (aka IL14), IL16, IL32, IL34, CSF1 | Varies |