AZ 3146 is a potent and selective monopolar spindle 1 (Mps1) kinase inhibitor with an IC50 of 35 nM. AZ3146 efficiently prevented autophosphorylation of full-length Mps1 immunoprecipitated from human cells. AZ 3146 revealed selectivity over 46 other kinases including Cdk1 and aurora kinase B. AZ 3146 is thought to act by interfering with chromosome alignment and overriding the spindle assembly checkpoint. Furthermore, AZ 3146 prevented the recruitment of Mad1, Mad2 and centromere protein E (CENP-E) to kinetochores. AZ3146 also silenced an already established SAC signal; after release from a nocodazole block, AZ3146 dramatically accelerated mitotic exit. Significantly, although Mad1 was present at kinetochores in controls, kinetochores in cells treated with nocodazole plus AZ3146 were devoid of Mad1. AZ 3146 prevented kinetochore localization of Mad2 regardless of the experimental regimen.

NMS-P715 analog

NMS-P715

Mps1-IN-3

Mps1-IN-2