Expanding the Interactome of TES by Exploiting TES Modules with Different Subcellular Localizations

Area of Science:

• Cell Biology
• Proteomics
• Molecular Biology

Background:

• Eukaryotic proteins are often multimodular, participating in various protein cocomplexes.
• The testin (TES) protein, a tumor suppressor with LIM domains, is involved in actin cytoskeleton adhesion, cell migration, adhesion, and spreading.
• TES module accessibility may vary due to conformational changes, affecting its subcellular localization.

Purpose of the Study:

• To investigate the diversity of protein cocomplexes involving the multimodule protein testin (TES).
• To identify module-specific protein interactions of TES using a proteomics approach.
• To gain deeper insights into the functional roles of TES and its interactors.

Main Methods:

• Application of iMixPro AP-MS (intelligent Mixing of Proteomes - affinity purification-mass spectrometry) to tagged TES modular variants.
• Identification of proteins within module-specific cocomplexes.
• Pathway analysis of identified module interactomes.

Main Results:

• Identification of distinct module-specific interactomes for TES variants.
• Construction of a comprehensive global TES interactome.
• Discovery of both expected (actin-related) and unexpected pathways associated with TES interactions.
• Validation of TGFB1I1 and a short form of the glucocorticoid receptor as new TES cocomplex partners.

Conclusions:

• The study successfully mapped module-specific TES interactomes, expanding our understanding of TES's role in cellular processes.
• The findings highlight the importance of protein modularity in generating diverse protein cocomplexes.
• Opposing effects of TES and TGFB1I1 on cell spreading validate their functional copresence in complexes.