Acts as an inhibitor of protein phosphatase PP2A . Promotes anchorage-independent cell growth and tumor formation by preventing dephosphorylation of MYC, thereby stabilizing MYC in human malignancies . Together with TOPBP1, plays an essential role in the response to genome instability generated by the presence of acentric chromosome fragments derived from shattered chromosomes within micronuclei ( , ). Micronuclei, which are frequently found in cancer cells, consist of chromatin surrounded by their own nuclear membrane: following breakdown of the micronuclear envelope, a process associated with chromothripsis, the CIP2A-TOPBP1 complex tethers chromosome fragments during mitosis to ensure clustered segregation of the fragments to a single daughter cell nucleus, facilitating re-ligation with limited chromosome scattering and loss (, ).
Subcellular locations: Cytoplasm, Chromosome
Predominantly localizes within the cytoplasm . Localizes to broken chromosomes within micronuclei during interphase and following chromothripsis (, ). Localization to broken chromosomes is mainly independent of MDC1 (, ).
Expressed at low levels in most of the tissues. Overexpressed in head-and-neck squamous cell carcinomas (HNSCC). Present in liver cancer cells (at protein level).