first cyclin box found in G1/S-specific cyclin-E2 (CCNE2)
CCNE2 is essential for the control of the cell cycle at the late G1 and early S phase. It interacts with the CDK2 (in vivo) and CDK3 (in vitro) protein kinases to form a serine/threonine kinase holoenzyme complexes. CCNE2 contains two cyclin boxes. This model corresponds to the first one. The cyclin box is a protein binding domain.