Aurora kinase B dependent phosphorylation of 53BP1 is required for resolving merotelic kinetochore-microtubule attachment errors during mitosis

Abstract

Defects in resolving kinetochore-microtubule attachment mistakes during mitosis is linked to chromosome instability associated with carcinogenesis as well as resistance to cancer therapy. Here we report for the first time that tumor suppressor p53-binding protein 1 (53BP1) is phosphorylated at serine 1342 (S1342) by Aurora kinase B both in vitro and in human cells, which is required for optimal recruitment of 53BP1 at kinetochores. Furthermore, 53BP1 staining normally localized on the outer kinetochore, extended to the whole kinetochore when it is merotelically-attached, in concert with mitotic centromere-associated kinesin. Kinetochore-binding of pS1342-53BP1 is essential for efficient resolving of merotelic attachment, a spontaneous kinetochore-microtubule connection error that usually causes aneuploidy. Consistently, loss of 53BP1 results in significant increase in lagging chromosome events, micronuclei formation and aneuploidy, due to the unresolved merotely in both cancer and primary cells, which is prevented by ectopic wild type 53BP1 but not by the nonphophorylable S1342A mutant. We thus document a novel DNA damage-independent function of 53BP1 in maintaining faithful chromosome segregation during mitosis.

Aurora-PLK1 cascades as key signaling modules in the regulation of mitosis

“…Loss of this inactivation leads to aberrant DSB repair, causing AurB-dependent sister telomere fusions and aneuploidy (390). Moreover, the phosphorylation of 53BP1 by AurB is critical for optimal association of 53BP1 with kinetochores and efficient MCAK-dependent resolution of erroneous merotelic kinetochore-MT attachments that cause aneuploidy (391,392). Furthermore, 53BP1 and the ubiquitin carboxyl-terminal hydrolase 28 (USP28) are the key components of the mitotic surveillance checkpoint mechanism that triggers p53-dependent cell cycle arrest or cell death in response to centrosome loss or prolonged mitosis (393)(394)(395).…”

DNA damage response proteins regulating mitotic cell division: double agents preserving genome stability

“…However, 53BP1 is absent from prometaphase kinetochores after prolonged mitotic delay by centrosome loss or inhibition of Eg5 kinesin that activate the mitotic spindle checkpoint, suggesting 53BP1 is not a typical spindle checkpoint component . Aurora B phosphorylates 53BP1 at serine 1342 (S1342) in vitro and in mitotic HeLa cells; furthermore, Aurora B inhibition by a small‐molecule inhibitor or expression of nonphosphorylatable mutant 53BP1‐S1342A protein reduces 53BP1 kinetochore staining compared with control cells, suggesting Aurora B phosphorylates S1342 to promote 53BP1 localization to kinetochores . Depletion of 53BP1 or expression of mutant 53BP1‐S1342A increases the frequency of lagging chromosomes compared with control cells, indicating that 53BP1 is required for optimal chromosome segregation .…”

“…Aurora B phosphorylates 53BP1 at serine 1342 (S1342) in vitro and in mitotic HeLa cells; furthermore, Aurora B inhibition by a small‐molecule inhibitor or expression of nonphosphorylatable mutant 53BP1‐S1342A protein reduces 53BP1 kinetochore staining compared with control cells, suggesting Aurora B phosphorylates S1342 to promote 53BP1 localization to kinetochores . Depletion of 53BP1 or expression of mutant 53BP1‐S1342A increases the frequency of lagging chromosomes compared with control cells, indicating that 53BP1 is required for optimal chromosome segregation . 53BP1 colocalizes with the inner kinetochore marker ACA in merotelic kinetochores; furthermore, 53BP1 associates with MCAK by co‐immunoprecipitation experiments in mitotic cell extracts, suggesting a potential role for 53BP1 in merotelic error correction (Fig.…”

“…53BP1 colocalizes with the inner kinetochore marker ACA in merotelic kinetochores; furthermore, 53BP1 associates with MCAK by co‐immunoprecipitation experiments in mitotic cell extracts, suggesting a potential role for 53BP1 in merotelic error correction (Fig. ) . However, a direct correlation between loss of 53BP1 kinetochore localization and increased frequency of merotelic attachments remains to be established.…”

Nuclear localisation of 53BP1 is regulated by phosphorylation of the nuclear localisation signal

“…In agreement with these studies, we noted that the 53BP1 minimal focus‐forming region is phosphorylated in mitotic cells (Figure B). Aurora‐B has recently been shown to phosphorylate S1342 of 53BP1 and to regulate its attachment to kinetochores [Wang et al., ]. In addition, we and others reported that S1618 is a substrate for PLK1 and several residues in the C‐terminal part of 53BP1 are phosphorylated by CDK1 [Orthwein et al., ; Benada et al., ].…”