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Identification of Inositol Phosphate or Phosphoinositide Interacting Proteins by Affinity Chromatography Coupled to Western Blot or Mass Spectrometry
08:07

Identification of Inositol Phosphate or Phosphoinositide Interacting Proteins by Affinity Chromatography Coupled to Western Blot or Mass Spectrometry

Published on: July 26, 2019

Role played by microphthalmia transcription factor phosphorylation and its Zip domain in its transcriptional

Carmit Levy1, Amir Sonnenblick, Ehud Razin

  • 1Department of Biochemistry, Hebrew University Hadassah Medical School, Jerusalem 91120, Israel.

Molecular and Cellular Biology
|December 4, 2003
PubMed

Insights

Microphthalmia transcription factor (MITF) mutations cause developmental issues. PIAS3 inhibits MITF, but phosphorylation, especially on Ser409, modulates this interaction and MITF activity.

Area of Science:

  • Molecular Biology
  • Genetics
  • Cell Biology

Background:

  • Microphthalmia transcription factor (MITF) mutations are linked to deafness, bone loss, and pigmentation defects.
  • PIAS3 is identified as a STAT3 inhibitor that suppresses MITF transcriptional activity in vivo.

Purpose of the Study:

  • To identify MITF-interacting proteins.
  • To determine the role of the MITF Zip domain in PIAS3 interaction.
  • To investigate the impact of MITF phosphorylation on PIAS3 binding and MITF activity.

Main Methods:

  • Screening a mast cell library with the MITF Zip domain construct.
  • Investigating direct protein-protein interactions between MITF and PIAS3.
  • Analyzing the effect of MITF phosphorylation on MITF-PIAS3 association.

Main Results:

  • PIAS3 was isolated as an MITF-interacting protein.
  • The MITF Zip domain mediates direct interaction with PIAS3.
  • Phosphorylation of MITF, particularly on Ser409, significantly affects PIAS3 binding and MITF transcriptional activity.

Conclusions:

  • The MITF Zip domain is crucial for PIAS3 interaction.
  • MITF phosphorylation acts as a regulatory mechanism, fine-tuning MITF transcriptional activity.
  • Phosphorylation on Ser409 notably reduces PIAS3 inhibition, offering an alternative regulatory pathway.

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