Plays a role in regulating the self-renewal of embryonic stem cells (ESCs) and in maintaining cell survival during terminal differentiation of ESCs (PubMed:22548356). Regulates microtubule organization of metaphase II oocytes (PubMed:12944431). Inhibits cell cycle G1/S phase transition by repressing CDK2 expression and activation; represses CDK2 activation by inhibiting its interaction with cyclin E and A (By similarity). Interacts with MAPK1 (PubMed:12944431). Interacts with CDK2 and CDK2AP1 (By similarity). Accumulates in immature oocytes in the nucleus. During the first meiotic division, accumulates in the cytoplasm and localizes in dots in the vicinity of the chromosomes in a region enriched in microtubules. Oocytes (at protein level). Phosphorylated by MAPK1 and CDK2. Belongs to the CDK2AP family.