Bub2 Activators

Bub2 is a protein prominently studied in yeast, particularly in the context of cell cycle regulation. It plays a crucial role in the mitotic exit network (MEN) and spindle assembly checkpoint (SAC), two critical pathways that ensure the proper segregation of chromosomes during cell division.Functioning as a GTPase-activating protein (GAP), Bub2 primarily targets Tem1, a small GTPase. This interaction is vital for controlling the timing of mitotic exit. The spindle assembly checkpoint, where Bub2 is actively involved, is a safeguard mechanism that blocks the cell from progressing to anaphase until all chromosomes are correctly attached to the spindle microtubules. This checkpoint ensures that the genetic material is accurately distributed between the daughter cells, thus maintaining genomic stability.

Bub2, along with its partner protein Bfa1, forms a complex that inhibits the MEN pathway. This inhibition is crucial in delaying the exit from mitosis under conditions where spindle alignment or attachment is faulty. By doing so, Bub2 ensures that cells do not proceed to the next phase of the cell cycle with unsegregated or damaged chromosomes, which could lead to aneuploidy or other forms of genomic instability.