STAT6 - ITS ROLE IN INTERLEUKIN 4-MEDIATED BIOLOGICAL FUNCTIONS

Interleukin (IL) 4 is known to be a cytokine which plays a central rol e in the regulation of immune response. Studies on cytokine signal tra nsduction have clarified the mechanism by which IL4 exerts its functio ns. Two cytoplasmic proteins, signal transducer and activator of trans cription (STAT) 6 and IL4-induced phosphotyrosine substrate/insulin re ceptor substrate 2 (4PS/IRS2), are activated in IL4 signal transductio n. Recent studies from STAT6-deficient mice have revealed the essentia l role of STAT6 in IL4-mediated biological actions. In addition, STAT6 has also been demonstrated to be important for the functions mediated by IL13, which is related to IL4. IL4 and IL13 have been shown to ind uce the production of IgE, which is a major mediator in an allergic re sponse, These findings indicate that STATE activation is involved in I L4- and IL13-mediated disorders such as allergy.