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

• Main Authors: Kerrie-Ann McMahon, David A Stroud, Yann Gambin, Vikas Tillu, Michele Bastiani, Emma Sierecki, Mark E Polinkovsky, Thomas E Hall, Guillermo A Gomez, Yeping Wu, Marie-Odile Parat, Nick Martel, Harriet P Lo, Kum Kum Khanna, Kirill Alexandrov, Roger Daly, Alpha Yap, Michael T Ryan, Robert G Parton
• Format: Article
• Language: English
• Published: eLife Sciences Publications Ltd 2021-06-01
• Series: eLife
• Subjects: BRCA1; breast cancer; caveolae; cavin proteins
• Online Access: https://elifesciences.org/articles/61407

Caveolae-associated protein 3 (cavin3) is inactivated in most cancers. We characterized how cavin3 affects the cellular proteome using genome-edited cells together with label-free quantitative proteomics. These studies revealed a prominent role for cavin3 in DNA repair, with BRCA1 and BRCA1 A-complex components being downregulated on cavin3 deletion. Cellular and cell-free expression assays revealed a direct interaction between BRCA1 and cavin3 that occurs when cavin3 is released from caveolae that are disassembled in response to UV and mechanical stress. Overexpression and RNAi-depletion revealed that cavin3 sensitized various cancer cells to UV-induced apoptosis. Supporting a role in DNA repair, cavin3-deficient cells were sensitive to PARP inhibition, where concomitant depletion of 53BP1 restored BRCA1-dependent sensitivity to PARP inhibition. We conclude that cavin3 functions together with BRCA1 in multiple cancer-related pathways. The loss of cavin3 function may provide tumor cell survival by attenuating apoptotic sensitivity and hindering DNA repair under chronic stress conditions.