Involved in the control of the cell cycle at the G2/M (mitosis) transition. May activate CDKB2-1 kinase. Interacts with CDKB2-1. Expressed in the root apices. Expressed in the G2/M phases and disappears at the anaphase of mitosis. By gibberellic acid (GA3). Belongs to the cyclin family. Cyclin AB subfamily.