A small-molecule inhibitor of Haspin alters the kinetochore functions of Aurora B.
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.
Department of Experimental Oncology, European Institute of Oncology, 20139 Milan, Italy.
Anna
A
De Antoni
Stefano
S
Maffini
Stefan
S
Knapp
Andrea
A
Musacchio
Stefano
S
Santaguida
D064107:Aurora Kinase B; D064127:Aurora Kinases; D001324:Autoantigens / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D000076247:Centromere Protein A; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism; D020090:Chromosome Segregation; D003598:Cytoskeletal Proteins; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors*; D018386:Kinetochores / Q000378:metabolism*; D059566:M Phase Cell Cycle Checkpoints / Q000187:drug effects*; D015739:Nocodazole / Q000494:pharmacology; D009687:Nuclear Proteins / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D015398:Signal Transduction; D014372:Tubercidin / Q000031:analogs & derivatives* / Q000494:pharmacology
D001324:Autoantigens; C000619700:CENPA protein, human; D018797:Cell Cycle Proteins; D000076247:Centromere Protein A; D002868:Chromosomal Proteins, Non-Histone; D003598:Cytoskeletal Proteins; D047908:Intracellular Signaling Peptides and Proteins; C120529:NDC80 protein, human; D009687:Nuclear Proteins; C034214:5-iodotubercidin; C576921:AURKB protein, human; D064107:Aurora Kinase B; D064127:Aurora Kinases; C584277:BUB1 protein, human; C090464:Bub1 spindle checkpoint protein; C530656:HASPIN protein, human; D017346:Protein Serine-Threonine Kinases; D014372:Tubercidin; D015739:Nocodazole