2/mitotic-specific cyclin essential for the control of the cell cycle at the G2/M (mitosis) transition. G2/M cyclins accumulate steadily during G2 and are abruptly destroyed at mitosis. Degradation is necessary for the cell to exit from mitosis. Plays a role in morphogenesis by negatively regulating polarized growth. Through binding to CDC28 regulates cytokinesis, partly by phosphorylation of the actomyosin ring component IQG1. Interacts with IQG1. Expressed from S phase through G2 and M phases and is degraded at the end of mitosis. Expression is down-regulated by the anti-fungal agent plagiochin E (PLE). Belongs to the cyclin family. Cyclin AB subfamily.