Mad2

Mad2 is a protein that in humans is encoded by the MAD2L1 gene. It is a crucial component of the mitotic checkpoint, which serves as a regulatory mechanism to ensure proper chromosome segregation during cell division.

Function

Mad2 is a key player in the spindle assembly checkpoint (SAC), a surveillance mechanism that maintains genome stability by preventing anaphase onset until all chromosomes are properly attached to the mitotic spindle. Mad2 can exist in two conformations: open (O-Mad2) and closed (C-Mad2). The conversion from O-Mad2 to C-Mad2 is facilitated by the Mad1-Mad2 core complex, a process that is essential for the checkpoint signal.

Clinical significance

Alterations in the function of Mad2 have been linked to various forms of cancer. Overexpression of Mad2, which can lead to chromosome instability, has been observed in several types of cancer, including lung cancer, ovarian cancer, and colorectal cancer. On the other hand, loss of Mad2 function can also contribute to tumorigenesis by allowing cells with abnormal chromosome numbers to proliferate.

Interactions

Mad2 has been shown to interact with various proteins, including CDC20, BUB1B, and TTK protein kinase. These interactions are crucial for the function of the spindle assembly checkpoint.

See also

• Mitotic checkpoint
• Cell cycle
• Cancer