Cyclin E2 is a member of the cyclin family, It is a predicted 404-amino acid protein which contains a cyclin box motif and it is 47% identical to cyclin E1. It is expressed in several normal human tissues, with the highest levels in testis, thymus, and brain. Gudas et al. (1999) found that, like cyclin E1, the human cyclin E2 gene complemented a G1 cyclin defect in S. cerevisiae. Cyclin E2 expressed in mammalian cells associated with CDK2 in a functional kinase complex that was inhibited by both KIP1 and CIP1.