Cavin3 released from caveolae interacts with BRCA1 to regulate the cellular stress response.

Area of Science:

• Molecular Biology
• Cell Biology
• Cancer Research

Background:

• Caveolae-associated protein 3 (cavin3) is frequently inactivated in various cancers.
• Understanding cavin3's role in cellular processes is critical for cancer therapy.

Purpose of the Study:

• To elucidate the function of cavin3 in the cellular proteome, focusing on its role in DNA repair and cancer cell survival.
• To investigate the interaction between cavin3 and BRCA1 in response to cellular stress.

Main Methods:

• Genome-edited cells and label-free quantitative proteomics were employed to analyze the cellular proteome.
• Cellular and cell-free expression assays were used to determine direct interactions between proteins.
• Overexpression and RNAi-depletion studies assessed the impact of cavin3 on UV-induced apoptosis and PARP inhibition sensitivity.

Main Results:

• Cavin3 deletion led to downregulation of BRCA1 and BRCA1 A-complex components, indicating a role in DNA repair.
• A direct interaction between cavin3 and BRCA1 was identified, occurring upon caveolae disassembly induced by UV and mechanical stress.
• Cavin3 overexpression sensitized cancer cells to UV-induced apoptosis, while cavin3 deficiency increased sensitivity to PARP inhibition, which was modulated by 53BP1.

Conclusions:

• Cavin3 collaborates with BRCA1 in critical cancer-related pathways, including DNA repair and apoptosis regulation.
• Loss of cavin3 function may promote tumor cell survival by reducing apoptotic sensitivity and impairing DNA repair under stress.
• Cavin3 represents a potential therapeutic target for enhancing cancer treatment efficacy.