Cdk inhibitors inhibit the function of cyclin-dependent protein kinases. Different inhibitors display varying mechanisms of Cdk inhibition. Which of the following might a Cdk inhibitor block in order to block the Cdk function?
a. cyclin binding
b. ATP binding
c. substrate-binding
d. movement of the T loop into the active site

c) is the correct option

Explanation:

Inhibition of Cdk activity occurs by Cdk inhibitory protein (CIPs)

A group of specific proteins called CIPs binds with active cyclin Cdk complex and cause their inactivationActivated protein retinoblastoma (p53)act as transcriptional factor and induce synthesis of Cdk inhibitory proteins p21CIPsp21CIPs is a Cdk inhibitory protein that binds and inhibit the activity of G1 Cdk cyclin complex as a result cell cycle arrest in G1 phase