Required to maintain individual mitotic chromosomes dispersed in the cytoplasm following nuclear envelope disassembly (PubMed:27362226). Associates with the surface of the mitotic chromosome, the perichromosomal layer, and covers a substantial fraction of the chromosome surface (PubMed:27362226). Prevents chromosomes from collapsing into a single chromatin mass by forming a steric and electrostatic charge barrier: the protein has a high net electrical charge and acts as a surfactant, dispersing chromosomes and enabling independent chromosome motility (PubMed:27362226). Binds DNA, with a preference for supercoiled DNA and AT-rich DNA (PubMed:10878551). Does not contribute to the internal structure of mitotic chromosomes (By similarity). May play a role in chromatin organization (PubMed:24867636). It is however unclear whether it plays a direct role in chromatin organization or whether it is an indirect consequence of its function in maintaining mitotic chromosomes dispersed (Probable). Interacts with KIF15 (PubMed:10878014). Interacts (via the FHA domain) with NIFK (PubMed:11342549, PubMed:14659764, PubMed:16244663). Interacts with PPP1CC (PubMed:24867636). Component of a complex at least composed of ZNF335, HCFC1, CCAR2, EMSY, MKI67, RBBP5, ASH2L and WDR5; the complex is formed as a result of interactions between components of a nuclear receptor-mediated transcription complex and a histone methylation complex (PubMed:19131338). Interacts with ZNF335 (PubMed:19131338, PubMed:23178126). Associates with the surface of the mitotic chromosome, the perichromosomal layer, and covers a substantial fraction of the mitotic chromosome surface (PubMed:27362226). Associates with satellite DNA in G1 phase (PubMed:9510506). Binds tightly to chromatin in interphase, chromatin-binding decreases in mitosis when it associates with the surface of the condensed chromosomes (PubMed:15896774, PubMed:22002106). Predominantly localized in the G1 phase in the perinucleolar region, in the later phases it is also detected throughout the nuclear interior, being predominantly localized in the nuclear matrix (PubMed:22002106). Expression occurs preferentially during late G1, S, G2 and M phases of the cell cycle, while in cells in G0 phase the antigen cannot be detected (at protein level) (PubMed:6206131). Present at highest level in G2 phase and during mitosis (at protein level). In interphase, forms fiber-like structures in fibrillarin-deficient regions surrounding nucleoli (PubMed:2674163, PubMed:8799815). Phosphorylated. Hyperphosphorylated in mitosis (PubMed:10502411, PubMed:10653604). Hyperphosphorylated form does not bind DNA. Widely used as a marker to assess cell proliferation, as it is detected in the nucleus of proliferating cells only (PubMed:6339421, PubMed:21960707). In cancer research field for example, MKI67 is the most widely used marker for comparing proliferation between tumor samples (PubMed:21960707, PubMed:26680267). Was thought to play a key role in cell proliferation, and is commonly used as a marker of cell proliferation (PubMed:6339421, PubMed:21960707). However, its primary function is uncoupled from cell proliferation: it is required to maintain mitotic chromosomes dispersed by forming a steric and electrostatic charge barrier (PubMed:27362226). Ki-67 entry The contours of heredity - Issue 186 of December 2016