CDK-activating Kinase

CDK-activating kinase (CAK) activates the cyclin-CDK complex by phosphorylating threonine residue 160 in the CDK activation loop. CAK itself is a member of the Cdk family and functions as a positive regulator of Cdk1, Cdk2, Cdk4, and Cdk6.

Read more about CDK-activating Kinase:  Catalytic Activity, Orthologs, Structure, Additional Functions