title: A chromosome separation checkpoint: A midzone Aurora B gradient mediates a chromosome separation checkpoint that regulates the anaphase-telophase transition.
abstract: Here we discuss a "chromosome separation checkpoint" that might regulate the anaphase-telophase transition. The concept of cell cycle checkpoints was originally proposed to account for extrinsic control mechanisms that ensure the order of cell cycle events. Several checkpoints have been shown to regulate major cell cycle transitions, namely at G1-S and G2-M. At the onset of mitosis, the prophase-prometaphase transition is controlled by several potential checkpoints, including the antephase checkpoint, while the spindle assembly checkpoint guards the metaphase-anaphase transition. Our hypothesis is based on the recently uncovered feedback control mechanism that delays chromosome decondensation and nuclear envelope reassembly until effective separation of sister chromatids during anaphase is achieved. A central player in this potential checkpoint is the establishment of a constitutive, midzone-based Aurora B phosphorylation gradient that monitors the position of chromosomes along the spindle axis. We propose that this surveillance mechanism represents an additional step towards ensuring mitotic fidelity.
authors.affiliation: Chromosome Instability & Dynamics Laboratory, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal; Cell Division Unit, Department of Experimental Biology, Faculdade de Medicina, Universidade do Porto, Porto, Portugal.
authors.forename: Helder
authors.initials: H
authors.lastname: Maiato
authors.forename: Olga
authors.initials: O
authors.lastname: Afonso
authors.forename: Irina
authors.initials: I
authors.lastname: Matos
mesh_terms: D000705:Anaphase; D000818:Animals; D064107:Aurora Kinase B / Q000378:metabolism; D016203:CDC2 Protein Kinase / Q000378:metabolism; D002460:Cell Line; D020090:Chromosome Segregation; D004331:Drosophila melanogaster; D006801:Humans; D054645:Protein Phosphatase 1 / Q000378:metabolism; D054648:Protein Phosphatase 2 / Q000378:metabolism; D013692:Telophase
chemical_list: D064107:Aurora Kinase B; D016203:CDC2 Protein Kinase; D054645:Protein Phosphatase 1; D054648:Protein Phosphatase 2
keywords: Aurora B; anaphase; checkpoint; gradient; mitosis; nuclear envelope; telophase