Budding Uninhibited By Benzimidazoles 1B (BUB1B)

BUB1B encodes a kinase involved in spindle checkpoint function. The protein has been localized to the kinetochore and plays a role in the inhibition of the anaphase-promoting complex/cyclosome (APC/C), delaying the onset of anaphase and ensuring proper chromosome segregation. Impaired spindle checkpoint function has been found in many forms of cancer. The predicted BUB1B protein contains the conserved CD1 and CD2 domains that are found in yeast, human, and mouse BUB1; the human and mouse BUB1B proteins are 29% identical in these regions. CD1 directs kinetochore localization and binding to Bub3, and CD2 contains the kinase domain. Between CD1 and CD2, the BUB1B protein has a putative nuclear localization signal, which is present in human and mouse BUB1 but not in yeast BUB1.