Cytokines Web

Cytokines Web Broad Classification of Cytokines

An overall classification of cytokines into fold families is shown here. The three-dimensional structures of all known cytokines have not yet been solved. Analysis of amino acid sequences, however, in conjunction with a consideration of known structures and biological function, suggests what the folds of many of the cytokines may be.
NB Classifications here should be treated with some caution. A similar classification, but including only cytokines of experimantally determined 3-D structure, is also available in the Cytokines Web .

Alpha

Long-chain 4-helix bundle superfamily

Growth hormone (somatotropin), Prolactin

Granulocyte-colony stimulating factor (G-CSF), Myelomonocytic growth factor, Interleukin-6 (IL-6)
Interleukin-3 (IL-3)?
Interleukin-7 (IL-7)?
Leukemia inhibitory factor (LIF), Oncostatin M, Ciliary neurotrophic factor (CNTF), cholinergic differentiation factor (CDF),

Short-chain 4-helix bundle superfamily

Interleukin-2 (IL-2)
Interleukin-4 (IL-4), Interleukin-13 (IL-13) ?, Interferon alpha (IFN-a) ?
Interleukin-5 (IL-5),
Granulocyte-macrophage colony-stimulating factor (GM-CSF), Interleukin-3 (IL-3)
Macrophage colony-stimulating factor (M-CSF)

Dimeric dimeric 4-helix bundles

Interferon gamma (IFN-G),
Interleukin-10 IL-10),
Interferon beta (IFN-B)

Beta

Beta-Trefoil

Interleukin 1-alpha (IL1-A),
Interleukin 1-beta (IL1-B),
Fibroblast growth factor (FGF)

Beta-sandwich

Tumour Necrosis Factor alpha (TNF-A),
Tumour Necrosis Factor beta (TNF-B)

EGF-like

Transforming growth factor alpha (TGF-A)

Cystine knot dimerization domains

Gonadotropin,
Nerve Growth Factor (NGF),
Platelet-derived growth factor (PDGF),
Transforming growth factor beta2 (TGF-B2)

Alpha + Beta

IL-8, IP10, platelet factor 4 (PF-4), bTG, GRO, 9E3, HLA-A2, macrophage inflammatory protein 1 alpha (MIP-1 alpha), macrophage inflammatory protein 1 beta (MIP-1 beta), Melanoma growth stimulating activity (MGSA)