Related Experiment Video
Updated: Jul 4, 2026

A High Resolution Method to Monitor Phosphorylation-dependent Activation of IRF3
Published on: January 24, 2016
Recruitment of Stat1 to chromatin is required for interferon-induced serine phosphorylation of Stat1 transactivation
Iwona Sadzak1, Melanie Schiff, Irene Gattermeier
1Max F. Perutz Laboratories, University of Vienna, Dr. Bohr-Gasse 9, A-1030 Vienna, Austria.
Abstract:
The transcription factor Stat1 plays an essential role in responses to interferons (IFNs). Activation of Stat1 is achieved by phosphorylation on Y701 that is followed by nuclear accumulation. For full transcriptional activity and biological function Stat1 must also be phosphorylated on S727. The molecular mechanisms underlying the IFN-induced S727 phosphorylation are incompletely understood. Here, we show that both Stat1 Y701 phosphorylation and nuclear translocation are required for IFN-induced S727 phosphorylation. We further show that Stat1 mutants lacking the ability to stably associate with chromatin are poorly serine-phosphorylated in response to IFN-gamma. The S727 phosphorylation of these mutants is restored on IFN-beta treatment that induces the formation of the ISGF3 complex (Stat1/Stat2/Irf9) where Irf9 represents the main DNA binding subunit. These findings indicate that Stat1 needs to be assembled into chromatin-associated transcriptional complexes to become S727-phosphorylated and fully biologically active in response to IFNs. This control mechanism, which may be used by other Stat proteins as well, restricts the final activation step to the chromatin-tethered transcription factor.
More Related Videos
13:20Chromatin Immunoprecipitation (ChIP) to Assay Dynamic Histone Modification in Activated Gene Expression in Human Cells
Published on: July 29, 2010
07:12Time-resolved Förster Resonance Energy Transfer Assays for Measurement of Endogenous Phosphorylated STAT Proteins in Human Cells
Published on: September 9, 2021
Related Concept Videos
The JAK-STAT Signaling Pathway
TGF - β Signaling Pathway
Eukaryotic Transcription Activators
The binding domains are capable of recognizing and interacting with regulatory sequences on the DNA. These domains are...
RNA Polymerase II Accessory Proteins
Co-activators and Co-repressors
Amplifying Signals via Enzymatic Cascade