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DNA-binding domain of Signal Transducer and Activator of Transcription 6 (STAT6) This family consists of the DNA-binding domain (DBD) of the STAT6 proteins (Signal Transducer and Activator of Transcription 6, or Signal Transduction And Transcription 6). The DNA binding domain has an Ig-like fold. STAT6 is essential for the functional responses of T helper 2 (Th2) lymphocyte mediated by interleukins IL-4 and IL-13. STAT6 almost exclusively mediates the expression of genes activated by these cytokines; IL-4 signaling regulates the expression of genes involved in immune and anti-inflammatory responses. Abnormal production of IL-4 and IL-13 play important roles in the pathogenesis of asthma where upregulation of the Th2 response mediated by IL-4/IL-13 is a main characteristic. STAT6 has a unique extended transactivation domain, not found in other STATs, through which it recruits p300/CBP and NCoA-1, two coactivators needed for transcriptional activation by IL-4. STAT6 activation is linked to Kaposi's sarcoma-associated herpesvirus (KSHV)-associated cancers such as primary effusion lymphoma, a cancerous proliferation of B cells. Studies show that Meningeal solitary fibrous tumor (SFT) and hemangiopericytoma (HPC) represent a histopathologic spectrum linked by STAT6 nuclear expression and recurrent somatic fusions of the two genes, NGFI-A-binding protein 2 (NAB2) and STAT6 (NAB2-STAT6), similar to their soft tissue counterparts. It is associated with local recurrence and late distance metastasis of brain tumors to extracranial sites.
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