FZR1Cdh1

FZR1Cdh1, also known as FZR1 or Cdh1, is a protein involved in cell cycle regulation. It is a key component of the Anaphase-Promoting Complex/Cyclosome (APC/C), a ubiquitin ligase that targets specific proteins for degradation, thereby controlling the progression of the cell cycle. FZR1Cdh1 acts as a recognition subunit for the APC/C, specifically binding to and facilitating the ubiquitylation of substrates that promote mitotic exit and the G1 phase of the cell cycle.

The primary role of FZR1Cdh1 is to ensure the proper dismantling of mitotic structures and the initiation of interphase. It is particularly crucial for the degradation of proteins like cyclin B and securin, which are essential for maintaining mitotic progression. By promoting their degradation, FZR1Cdh1 allows for the separation of sister chromatids and the subsequent exit from mitosis.

The activity of FZR1Cdh1 is tightly regulated by phosphorylation. During mitosis, FZR1Cdh1 is phosphorylated by cyclin-dependent kinases, which inhibits its ability to bind to the APC/C. As cells exit mitosis, dephosphorylation of FZR1Cdh1 by phosphatases allows it to associate with the APC/C and perform its substrate-targeting functions. Dysregulation of FZR1Cdh1 has been implicated in various cancers, where its aberrant activity can lead to genomic instability and uncontrolled cell proliferation.