Binds to the catalytic subunit of the cyclin dependent kinases and is essential for their biological function. Has a role in the exit from M phase during early mitotic cell division. More specifically, thought to act by the degrading B-type cyclins that causes breakdown of nuclear envelope and exit mitosis (By similarity). Forms a homohexamer that can probably bind six kinase subunits. Interacts with cdk-1 (By similarity). Belongs to the CKS family.