Background：

The protein encoded by this gene is a pleiotropic cytokine produced by activated T cells. This cytokine is a ligand for interleukin 4 receptor. The interleukin 4 receptor also binds to IL13， which may contribute to many overlapping functions of this cytokine and IL13. STAT6， a signal transducer and activator of transcription， has been shown to play a central role in mediating the immune regulatory signal of this cytokine. This gene， IL3， IL5， IL13， and CSF2 form a cytokine gene cluster on chromosome 5q， with this gene particularly close to IL13. This gene， IL13 and IL5 are found to be regulated coordinately by several long-range regulatory elements in an over 120 kilobase range on the chromosome. Two alternatively spliced transcript variants of this gene encoding distinct isoforms have been reported. [provided by RefSeq， Jul 2008]