Information on STAT3
Basic details
Alt. symbols: APRF
Approved name: signal transducer and activator of transcription 3
Alt. names: signal transducer and activator of transcription 3 (acute-phase response factor)
Location: 17q21.2: 42313324 - 42388568 (-)
Gene type: protein_coding, 51 transcripts.
Scores: LoFtool: 0.035900 | pLI: 0.99998919 | LOEUF: 0.095
Normal function
STAT3 encodes an important and widely expressed developmental transcription factor (TF) with key roles in many aspects of cellular immunity, proliferation, apoptosis and differentiation. All STAT family TFs share a common structure consisting of N-terminal, coiled-coil, DNA-binding, linker, Src homology 2 (SH2), and C-terminal transactivation domains. The N-terminal and SH2 domains mediate homo- or hetero-dimerization, while the coiled-coil domain partially functions as a nuclear localization signal (NLS) and the DNA-binding and transactivation domains direct DNA targeting and transcriptional activity, respectively. STAT3 is activated in response to cytokines, such as interferons and interleukins, epidermal growth factors or other mitogens. Ligand stimulation leads to intracellular receptor-associated Janus kinase (JAK) activation, which in turn promotes STAT3 phosphorylation on key residues such as Tyr705. In addition, STAT3 phosphorylation of Ser727 by Mitogen-activated protein kinases (MAPK) can occur through Src (non-receptor tyrosine kinase) activation. Once phosphorylated, STAT3 dimerizes and translocates to the nucleus to regulate target gene expression. In epithelial cells, STAT3 controls the expression of genes important for cell survival and proliferation, cell migration and oncogenic transformation. In immune cells, it regulates the expression of genes involved in immune evasion, cell survival, cytokine signaling, and pre-metastatic niche formation. STAT3 modulates the inflammatory response by regulating the differentiation of naive T-cells into specific subsets of T-helper (Th) or regulatory T-cells (Tregs). In the skeletal system, STAT3 is involved in the formation of osteoclasts, which are essential for bone development and maintenance. Unrestrained activity of STAT3 is implicated in tumorigenesis, as it can upregulate the expression of genes involved in proliferation and angiogenesis, promote the expression of oncogenes, and downregulate the expression of genes mediating immune surveillance and apoptosis.
Dysfunction and disease
Mutations in STAT3 have been associated with a variety of clinical phenotypes. All inherited conditions known thus far show an autosomal dominant mode of transmission. Germline STAT3 gain-of-function mutations (STAT3 GOF) are associated with early-onset multi-organ autoimmunity, while germline dominant-negative loss-of-function (STAT3 DN LOF) mutations develop autosomal-dominant Hyper-IgE syndrome (AD-HIES). Unlike STAT3 GOF, which is thought in part to arise from increased Th17 polarization, ST AT3 LOF leading to AD-HIES is thought to be due to an enhanced Th2 skewing at the cost of Th1 and Th17 lineages. The overactivity of STAT3, in STAT3 GOF, can be explained by increased intrinsic transcriptional activity of the STAT3 dimer rather than by enhanced phosphorylation. STAT3 GOF patients show a broad spectrum of phenotypes, often with infantile or childhood onset, including many autoimmune phenotypes, such as type I diabetes mellitus (T1D), hypothyroidism, and other endocrinopathies; hepatitis, enteropathy, and achalasia; arthritis, interstitial lung disease, cytopenias, lymphoproliferation, and vasculitis, in addition to short stature, growth failure, and recurrent infections (PMID: 30825606). Laboratory studies usually show hypogammaglobulinemia, along with T and/or B cell lymphopenia (PMID: 25359994). Predominantly missense mutations are distributed in important functional domains through the protein, including within N-terminal, coiled-coil, DNA binding, linker, Src-homology 2 (SH2), and transactivation (TA) domains (PMID: 30825606). Increasing evidence suggests that combined use of tocilizumab (an anti-IL-6 agent) and JAK inhibitors such as ruxolitinib and tofacitinib may be effective for controlling disease activity in STAT3 GOF patients (PMID: 30092289, 33731004, 30825606). On the other hand, AD-HIES due to STAT3 DN LOF is characterized by cutaneous and sinopulmonary infections (bacterial, viral and fungal, oral candidiasis, atopic manifestations including eczema, peripheral eosinophilia and high IgE levels, along with vascular, skeletal and connective tissue abnormalities (PMID: 17881745, 20159255, 30466772). Most of the autosomal-dominant loss-of-function mutations lay in the DNA-binding domain or SH2 domain and impair STAT3 homodimers´ ability to bind to DNA in order to activate transcription. As STAT3 forms homodimers, mutant STAT3 molecules can exert a dominant-negative effect on the wild-type STAT3 molecules and hence weaken the cytokine signalling via STAT3. Finally, somatic GOF mutations, mostly in the SH2 domain, have been found in 30-40% of large granular lymphocytic leukemia (LGLL) patients (PMID: 22591296, 22859607). LGLL is a rare lymphoproliferative disorder characterized by the expansion of clonal CD3+CD8+ cytotoxic T cells, often found in association with a history of autoimmune disorders and immune-mediated cytopenias. [Load More]
[Reviewed by Virginia Andreani on 2022-05-24 13:04:40]
Associated conditions
Transcripts of STAT3
Name | ENSEMBL_ID | LRG_ID | CCDS_ID | MANE | Transcript.type | Exons | Canonical | CDS_length | REFSEQ_ID |
---|---|---|---|---|---|---|---|---|---|
236 | ENST00000678535.1 | protein_coding | 23 | No | 3288 | NM_001384988 | |||
243 | ENST00000678905.1 | protein_coding | 24 | No | 4768 | NM_001384986 | |||
223 | ENST00000677442.1 | protein_coding | 24 | No | 4829 | NM_001384991 | |||
239 | ENST00000678674.1 | protein_coding | 23 | No | 4703 | NM_001384989 | |||
237 | ENST00000678572.1 | protein_coding | 24 | No | 4739 | NM_001384990 | |||
249 | ENST00000679185.1 | protein_coding | 24 | No | 4782 | NM_001369520 | |||
217 | ENST00000677152.1 | protein_coding | 24 | No | 3395 | NM_001384993 | |||
227 | ENST00000677723.1 | CCDS32657 | protein_coding | 24 | No | 4834 | NM_001369514,NM_001369516,NM_003150 | ||
224 | ENST00000677479.1 | protein_coding | 24 | No | 4731 | NM_001369519 | |||
201 | ENST00000264657.10 | 1 | CCDS32656 | Select | protein_coding | 24 | Yes | 4921 | NM_001369512,NM_001369513,NM_001384985,NM_001384992,NM_139276 |
232 | ENST00000678048.1 | protein_coding | 23 | No | 4740 | NM_001384984 | |||
211 | ENST00000585517.5 | CCDS59288 | protein_coding | 24 | No | 3319 | XM_047436585 | ||
216 | ENST00000677030.1 | CCDS59288 | protein_coding | 24 | No | 4812 | NM_001369518,NM_213662 | ||
202 | ENST00000389272.7 | protein_coding | 23 | No | 2615 | XM_047436586 | |||
230 | ENST00000678043.1 | protein_coding | 24 | No | 4837 | NM_001384987 | |||
242 | ENST00000678827.1 | CCDS59288 | protein_coding | 24 | No | 4800 | NM_001369517 |