BUB1B-PAK6 ELISA Kits

Benzimidazole protein 1 Bub1 is a protein kinase involved in monitoring microtubule attachment to the kinetochores. It is one of the first proteins that localizes at the forming kinetochore during prophase and is required for the recruitment of other proteins to the kinetochore. It is also necessary for chromosome congression and the correct alignment of chromosomes on the metaphase plate. In response to spindle damage, Bub1 phosphorylates Mad1, leading to the dissociation of the Mad1-Mad2 complex. Unbound Mad2 can then bind and inhibit Cdc20, an activator of APC/C. Bub1 can also interact with Bub3 on the kinetochore suggesting a complex regulatory pathway that is being intensively investigated using various biochemical, cellular and genetic approaches.

Mutations and epigenetic inactivation of the BUB1 and BUBR1 genes have been identified in a subset of human colon cancers that exhibit chromosomal instability. A critical role for Bub1in mitotic regulation, which is necessary for tumor suppression, is also supported by animal studies that showed increased tumor susceptibility in Bub1 hypomorphic mice with reduced expression of Bub1.Interestingly, Bub1 is also targeted by the large T antigen of the DNA tumor virus SV-40 and is required to promote tetraploidy, which can contribute to oncogenic transformation, in response to viral infection. A study also identified a surprising role for Bub1 in the activation of the DNA damage response. This suggests that Bub1 may serve as a link between the DNA damage response and the spindle assembly checkpoint (SAC), two key mechanisms in the maintenance of genomic stability.