Kinetochore localisation of the DNA damage response component 53BP1 during mitosis

摘要: 53BP1 is a vertebrate BRCT motif protein, originally described as direct interactor of p53, which has recently been shown to be implicated in the early response DNA damage. Upon damage, re-localises discrete nuclear foci that are thought represent sites lesions and becomes hyperphosphorylated. Several observations suggest substrate for ataxia telangiectasia mutated (ATM) kinase. So far, behaviour during mitosis not reported detail. We have examined subcellular distribution mitotic cells using several antibodies against 53BP1, ectopic expression GFP-tagged 53BP1. found significantly colocalised with CENP-E kinetochores. loaded kinetochores prophase, before CENP-E, released by mid-anaphase. By expressing various truncations, kinetochore binding domain mapped 380 residue portion protein excludes localisation signal motifs. Like many kinetochore-associated proteins involved checkpoint signalling, more appears accumulate on chromosomes aligned metaphase plate. Finally, we show hyperphosphorylated cells, undergoes an even higher level phosphorylation spindle disruption colcemid. Our data may role signalling provide evidence damage machinery share common molecular components.