American Association for Cancer Research
00085472can130504-sup-fig5.pdf (106.51 kB)

Supplementary Figure 5 from BRCA2 Phosphorylated by PLK1 Moves to the Midbody to Regulate Cytokinesis Mediated by Nonmuscle Myosin IIC

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journal contribution
posted on 2023-03-30, 22:31 authored by Miho Takaoka, Hiroko Saito, Katsuya Takenaka, Yoshio Miki, Akira Nakanishi

PDF file - 106K, Abnormal midbody and binucleated cells induced by expression of NM-IIC (A1) or BRCA2 (R1) (Related to Figure 4).



Cytokinesis is the critical final step in cell division. BRCA2 disruption during cytokinesis is associated with chromosome instability, but mechanistic information is lacking that could be used to prevent cancer cell division. In this study, we report that BRCA2 phosphorylation by the mitotic polo-like kinase (PLK1) governs the localization of BRCA2 to the Flemming body at the central midbody, permitting an interaction with nonmuscle myosin IIC (NM-IIC). Formation of an NM-IIC ring-like structure at the Flemming body shows that the IIC-ring relies on its ATPase activity stimulated by interaction with BRCA2 and associated proteins. Notably, inhibiting this binding inactivated the ATPase activity, causing disassembly of the IIC-ring, defective formation of the midbody, and interruption of cytokinesis. An analysis of cancer-associated mutations in BRCA2 at the PLK1-binding site suggests that they may contribute to cytokinetic defects by altering BRCA2 localization. Our findings suggest that BRCA2-dependent IIC-ring formation is a critical step in proper formation of the midbody, offering an explanation for how chromosome instability may arise in breast cancer. Cancer Res; 74(5); 1518–28. ©2014 AACR.

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