Chromosome clustering in mitosis by the nuclear protein Ki-67

Copyright © 2021 The Author(s). Ki-67 is highly expressed in proliferating cells, a characteristic that made the protein a very important proliferation marker widely used in the clinic. However, the molecular functions and properties of Ki-67 remained quite obscure for a long time. Only recently important discoveries have shed some light on its function and shown that Ki-67 has a major role in the formation of mitotic chromosome periphery compartment, it is associated with protein phosphatase one (PP1) and regulates chromatin function in interphase and mitosis. In this review, we discuss the role of Ki-67 during cell division. Specifically, we focus on the importance of Ki-67 in chromosome individualisation at mitotic entry (prometaphase) and its contribution to chromosome clustering and nuclear remodelling during mitotic exit. Wellcome Trust. Investigator award 210742/Z/18/Z (Chromatin Re-Organisation at the Transition from Mitosis to G1: How Phospho-Switches Regulate the Process in Space and Time); Brunel University London (CHMLS scholarship).