BAG3 Proteomic Signature under Proteostasis Stress

Area of Science:

• Cellular Biology
• Molecular Biology
• Biochemistry

Background:

• The BCL-2-associated athanogene 3 (BAG3) is a crucial co-chaperone of HSP70, vital for cellular proteostasis.
• BAG3 targets misfolded proteins to aggresomes for degradation via selective macroautophagy, aiding cellular adaptation to stress.
• BAG3 dysfunction is implicated in diseases like cancer, myopathies, and neurodegenerative disorders.

Purpose of the Study:

• To identify the BAG3 proteomic signature under proteostasis stress.
• To elucidate the dynamic and multifunctional roles of BAG3 in response to cellular stress.
• To understand how BAG3 interactions change under basal versus stress conditions.

Main Methods:

• Affinity purification coupled with quantitative mass spectrometry was used to identify BAG3 interactomes.
• Proteins interacting with BAG3 under basal and proteostasis stress conditions were analyzed.
• Functional annotation and protein-protein interaction enrichment analyses were performed on identified interactors.

Main Results:

• A BAG3 proteomic signature under proteostasis stress was established.
• Novel BAG3 interactors were identified, and changes in protein interactions upon stress were defined.
• BAG3's role in protein folding, degradation, gene expression, cytoskeleton dynamics, and granulostasis was confirmed.

Conclusions:

• BAG3 is a multifunctional protein essential for maintaining cellular proteostasis and viability under stress.
• Stress-induced alterations in BAG3 interactomes highlight its dynamic regulatory functions.
• Understanding the BAG3 pathway offers insights into therapeutic strategies for related diseases.