Cdk5 Activator

 In distinction to traditional cyclin-dependent kinases that area unit vital for mitotic organic process, cyclin-dependent enzyme five (CDK5) is preponderantly activated in post-mitotic cells and is concerned in varied cellular events. The enzyme activity of CDK5 is tightly regulated by specific activators as well as p35, p39, and cyclin I (CCNI). Here we tend to show that cyclin I-like (CCNI2), a homolog of CCNI, interacts with CDK5 and activates the enzyme activity of CDK5. totally different from CCNI, that colocalizes with CDK5 within the nuclei in transfected cells, CCNI2 principally retains CDK5 within the living substance moreover as on the plasma membrane. what is more, though the expression level of CCNI2 messenger RNA and CCNI2 macromolecule don't modification considerably throughout cell cycle, depletion of CCNI2 with siRNA affects cell cycle progression moreover as cell proliferation. finally, our knowledge powerfully counsel that CCNI2 could be a novel CDK5 substance and is concerned in cell cycle regulation.   Cyclin-dependent enzyme five (CDK5) could be a proline-directed serine/threonine enzyme. Despite the high degree of similarity between CDK5 and different typical cyclin-dependent kinases (CDKs) that area unit vital for mitotic organic process, CDK5 sometimes isn't directly concerned in cell cycle regulation. Instead, it's copiously expressed in post-mitotic cells like neurons and is important for neural differentiation1,2,3.