Signal Transducer and Activator of Transcription 4
Species; Human
Expression Host: Baculovirus-insect cell
Tag: His-tag
Purity: 90%
Molecular Weight: 87.8 kDa.
Gene Accession Number: NM_003151.
Purification and Quality Control
The His-tag recombinant protein is purified by affinity chromatography in combination with FPLC columns. The purified STAT4 is greater than 90% homogeneous based on SDS-PAGE analysis.
Unit Definition (Activity)
1 unit equals 1 nanogram of purified protein.
Applications
STAT4 For Research Use Only
Formulation and Storage
The protein is in 20mM Tris-HCl pH7.9,100mM NaCl, 0.2mM EDTA, 1mM DTT and 20% glycerol. Stored at -70°C before use. Avoid repeated freeze thaw cycles.
Signal transducer and activator of transcription (STAT) proteins are a family of latent cytoplasmic transcription factors involved in cytokine, hormone, and growth factor signal transduction (1). Seven members of the STAT family of transcription factors have been identified in mammalian cells: STAT1, STAT2, STAT3, STAT4, STAT5a, STAT5b, and STAT6. STAT proteins mediate broadly diverse biologic processes, including cell growth, differentiation, apoptosis, fetal development, transformation, inflammation, and immune response (reviewed in 2, 3). Receptor-recruited STATs are phosphorylated on a single tyrosine residue in the carboxy terminal portion. The modified STATs are released from the cytoplasmic region of the receptor subunits to form homodimers or heterodimers through reciprocal interaction between the phosphotyrosine of one STAT and the SH2 domain of another (4-6). Following dimerization, STATs rapidly translocate to the nucleus and interact with specific regulatory elements to induce target gene transcription (7, 8). Recently, STAT-1 has been implicated in modulating pro- and anti-apoptotic genes following several stress-induced responses. These effects are dependent on STAT-1 phosphorylation on serine-727 and require the C-terminal transactivation domain of STAT-1 to enhance its pro-apoptotic effect or inhibit its anti-apoptotic effects. The STAT-1 C-terminal domain has been demonstrated to be important for protein-protein interaction with other transcriptional activators. The reports that STAT-1-deficient mice develop spontaneous and chemically induced tumours more rapidly compared to wild-type mice and that STAT-1-deficient cells are more resistant to agents that induce apoptosis strongly support the argument that STAT-1 acts as a tumour suppressor.(9)
References
1. Darnell JE, Kerr IM, Stark GR.(1994) Science 264:1415-1421 2. Levy, D.E., and J.E. Darnell Jr. (2002) Nat. Rev. Mol. Cell Biol.3:651–662 3. Takeda K, Akira S. (2000) Cytokine Growth Factor Rev. 11:199-207 4. Heldin CH. (1995) Cell 80:213-223 5. Bromberg JF. (2001) Bioessays 23:161-169 6. Shuai K, et al. (1993) Science 261:1744-1746 7. Wells JA, et al. (1996) Annu Rev Biochem 65:609-634 8. Darnell JE Jr (1997) Science. 277:1630-1635 9. Stephanou A et al (2003) Int J Exp Pathol.Dec;84(6):239-44
DISCLAIMER
This products is recommended For RESEARCH USE ONLY and is Not qualified for Use in Diagnostic or Therapeutic Procedures.
