Interleukin 5 (IL5)

E-CSF; ESGF; EDF; TRF; Colony-Stimulating Factor,Eosinophil; T-Cell replacing Factor; B Cell Differentiation Factor I; Eosinophil Differentiation Factor

SPN	W632
HGNC	6016
MGI	96557
PubMed	19231596
RGD	2900
UniProt	P05113
Wiki	Interleukin_5

IL-5 is secreted by a restricted number of mesenchymal cell types. In its native state, mature IL-5 is synthesized as a 115 aa, highly glycosylated 22 kDa monomer that forms a 40-50 kDa disulfide-linked homodimer. 

Although the content of  carbohydrate  is  high, carbohydrate is not needed for bioactivity.  Monomeric IL-5 has no activity and requires a homodimer for function, which is in contrast to the receptor-related IL-3 and GM-CSF cytokines that exist only as monomers.  Just as one IL-3 and GM-CSF monomer binds to one receptor, one IL-5 homodimer is able to engage only one IL-5 receptor.  It has been suggested that IL-5 (as a dimmer) undergoes a general conformational change after binding to one receptor molecule and this change precludes binding to a second receptor.

Reference

"Cloning of cDNA for human T-cell replacing factor (interleukin-5) and comparison with the murine homologue."
Nucleic Acids Res. 14:9149-9158(1986) [PubMed] [Europe PMC] [Abstract]

"Molecular cloning and structure of the human interleukin-5 gene."
J. Biol. Chem. 262:16580-16584(1987) [PubMed] [Europe PMC] [Abstract]

"Molecular cloning, nucleotide sequence, and expression of the gene encoding human eosinophil differentiation factor (interleukin 5)."
Proc. Natl. Acad. Sci. U.S.A. 84:6629-6633(1987) [PubMed] [Europe PMC] [Abstract]

"Isolation and characterization of lymphokine cDNA clones encoding mouse and human IgA-enhancing factor and eosinophil colony-stimulating factor activities: relationship to interleukin 5."
Proc. Natl. Acad. Sci. U.S.A. 84:7388-7392(1987) [PubMed] [Europe PMC] [Abstract]

"The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC)."
Genome Res. 14:2121-2127(2004) [PubMed] [Europe PMC] [Abstract]

"Structure of recombinant human interleukin 5 produced by Chinese hamster ovary cells."
J. Biochem. 107:292-297(1990) [PubMed] [Europe PMC] [Abstract]

"Human interleukin-5 expressed in Escherichia coli: assignment of the disulfide bridges of the purified unglycosylated protein."
FEBS Lett. 283:61-64(1991) [PubMed] [Europe PMC] [Abstract]

"A novel dimer configuration revealed by the crystal structure at 2.4-A resolution of human interleukin-5."
Nature 363:172-176(1993) [PubMed] [Europe PMC] [Abstract]

"Structure analysis of the IL-5 ligand-receptor complex reveals a wrench-like architecture for IL-5Ralpha."
Structure 19:1864-1875(2011) [PubMed] [Europe PMC] [Abstract]