Aurora B kinase regulates the postmitotic endoreduplication checkpoint via phosphorylation of the retinoblastoma protein at serine 780.

ABSTRACT: The phenotypic change characteristic of Aurora B inhibition is the induction of polyploidy. Utilizing specific siRNA duplexes and a selective small molecule inhibitor (AZD1152) to inhibit Aurora B activity in tumor cells, we sought to elucidate the mechanism by which Aurora B inhibition results in polyploidy. Cells treated with AZD1152 progressed through mitosis with misaligned chromosomes and exited without cytokinesis and subsequently underwent endoreduplication of DNA despite activation of a p53-dependent pseudo G1 checkpoint. Concomitant with polyploid cell formation, we observed the appearance of Rb hypophosphorylation, an event that occurred independently of cyclin-dependent kinase inhibition. We went on to discover that Aurora B directly phosphorylates Rb at serine 780 both in vitro

SUBMITTER: Nair JS 

PROVIDER: S-EPMC2669029 | biostudies-literature | 2009 Apr

REPOSITORIES: biostudies-literature