STAT1:DNA sequence-dependent binding modulation by phosphorylation, protein:protein interactions and small-molecule inhibition

Nucleic Acids Res. 2013 Jan;41(2):754-63. doi: 10.1093/nar/gks1085. Epub 2012 Nov 24.


The DNA-binding specificity and affinity of the dimeric human transcription factor (TF) STAT1, were assessed by total internal reflectance fluorescence protein-binding microarrays (TIRF-PBM) to evaluate the effects of protein phosphorylation, higher-order polymerization and small-molecule inhibition. Active, phosphorylated STAT1 showed binding preferences consistent with prior characterization, whereas unphosphorylated STAT1 showed a weak-binding preference for one-half of the GAS consensus site, consistent with recent models of STAT1 structure and function in response to phosphorylation. This altered-binding preference was further tested by use of the inhibitor LLL3, which we show to disrupt STAT1 binding in a sequence-dependent fashion. To determine if this sequence-dependence is specific to STAT1 and not a general feature of human TF biology, the TF Myc/Max was analysed and tested with the inhibitor Mycro3. Myc/Max inhibition by Mycro3 is sequence independent, suggesting that the sequence-dependent inhibition of STAT1 may be specific to this system and a useful target for future inhibitor design.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Base Sequence
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / metabolism
  • DNA / chemistry
  • DNA / metabolism*
  • Phosphorylation
  • Protein Multimerization
  • Proto-Oncogene Proteins c-myc / metabolism
  • Repressor Proteins / metabolism
  • STAT1 Transcription Factor / antagonists & inhibitors
  • STAT1 Transcription Factor / chemistry
  • STAT1 Transcription Factor / metabolism*


  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
  • MNT protein, human
  • MYC protein, human
  • Proto-Oncogene Proteins c-myc
  • Repressor Proteins
  • STAT1 Transcription Factor
  • STAT1 protein, human
  • DNA