A small-molecule inhibitor of Haspin alters the kinetochore functions of Aurora B.

Journal article

By phosphorylating Thr3 of histone H3, Haspin promotes centromeric recruitment of the chromosome passenger complex (CPC) during mitosis. Aurora B kinase, a CPC subunit, sustains chromosome bi-orientation and the spindle assembly checkpoint (SAC). Here, we characterize the small molecule 5-iodotubercidin (5-ITu) as a potent Haspin inhibitor. In vitro, 5-ITu potently inhibited Haspin but not Aurora B. Consistently, 5-ITu counteracted the centromeric localization of the CPC without affecting the bulk of Aurora B activity in HeLa cells. Mislocalization of Aurora B correlated with dephosphorylation of CENP-A and Hec1 and SAC override at high nocodazole concentrations. 5-ITu also impaired kinetochore recruitment of Bub1 and BubR1 kinases, and this effect was reversed by concomitant inhibition of phosphatase activity. Forcing localization of Aurora B to centromeres in 5-ITu also restored Bub1 and BubR1 localization but failed to rescue the SAC override. This result suggests that a target of 5-ITu, possibly Haspin itself, may further contribute to SAC signaling downstream of Aurora B.

Authors: De Antoni, A; Maffini, S; Knapp, S; Musacchio, A; Santaguida, S

• Publication status: Published
• Journal: Journal of cell biology
• Volume: 199
• Issue: 2
• Pages: 269-284
• Publication date: 2012-10-01
• DOI: 10.1083/jcb.201205119
• EISSN: 1540-8140
• ISSN: 0021-9525
• Language: English
• Keywords: M Phase Cell Cycle Checkpoints; Cell Line, Tumor; Nuclear Proteins; Aurora Kinases; Chromosome Segregation; Autoantigens; Signal Transduction; Cell Cycle Proteins; Humans; Phosphorylation; Kinetochores; Chromosomal Proteins, Non-Histone; Aurora Kinase B; Protein-Serine-Threonine Kinases; Tubercidin; Hela Cells; Nocodazole; Intracellular Signaling Peptides and Proteins