Dynamics of inner kinetochore assembly and maintenance in living cells.
To investigate the dynamics of centromere organization, we have assessed the exchange rates of inner centromere proteins (CENPs) by quantitative microscopy throughout the cell cycle in human cells. CENP-A and CENP-I are stable centromere components that are incorporated into centromeres via a "loading-only" mechanism in G1 and S phase, respectively. A subfraction of CENP-H also stays stably bound to centromeres. In contrast, CENP-B, CENP-C, and some CENP-H and hMis12 exhibit distinct and cell cycle-specific centromere binding stabilities, with residence times ranging from seconds to hours. CENP-C and CENP-H are immobilized at centromeres specifically during replication. In mitosis, all inner CENPs become completely immobilized. CENPs are highly mobile throughout bulk chromatin, which is consistent with a binding-diffusion behavior as the mechanism to scan for vacant high-affinity binding sites at centromeres. Our data reveal a wide range of cell cycle-specific assembly plasticity of the centromere that provides both stability through sustained binding of some components and flexibility through dynamic exchange of other components.
Hemmerich
Peter
P
Leibniz Institute for Age Research, Fritz Lipmann Institute, 07745 Jena, Germany. phemmer@fl i-leibniz.de
Weidtkamp-Peters
Stefanie
S
Hoischen
Christian
C
Schmiedeberg
Lars
L
Erliandri
Indri
I
Diekmann
Stephan
S
D001324:Autoantigens / Q000378:metabolism; D001665:Binding Sites / Q000502:physiology; D002453:Cell Cycle / Q000502:physiology*; D002455:Cell Division / Q000502:physiology*; D002460:Cell Line; D002503:Centromere / Q000378:metabolism* / Q000648:ultrastructure; D000076247:Centromere Protein A; D051936:Centromere Protein B / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism; D020090:Chromosome Segregation / Q000502:physiology; D004261:DNA Replication / Q000502:physiology; D004268:DNA-Binding Proteins / Q000378:metabolism; D016193:G1 Phase / Q000502:physiology; D006801:Humans; D018386:Kinetochores / Q000378:metabolism* / Q000648:ultrastructure; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D011485:Protein Binding / Q000502:physiology; D016196:S Phase / Q000502:physiology; D008941:Spindle Apparatus / Q000378:metabolism* / Q000648:ultrastructure
D001324:Autoantigens; C000619700:CENPA protein, human; C497926:CENPB protein, human; C093717:Cenpi protein, rat; D000076247:Centromere Protein A; D051936:Centromere Protein B; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; C492664:MIS12 protein, human; D008869:Microtubule-Associated Proteins; C060905:centromere protein C