The vertebrate cell kinetochore and its roles during mitosis Trends in Biology Diagrams Kinetochores are dynamic complexes containing MT motor and cell-cycle regulatory proteins, which serve three functions during cell division. They attach each replicated chromosome to the opposing poles of the mitotic spindle, help position the chromosome on the spindle and then inhibit chromatid separation (and anaphase onset) until all of the In mitosis, chromosomes condense and the two copies become visible as "sister chromatids". One kinetochore is assembled on each of the two sister chromatids of a chromosome, and both sister kinetochores become attached to opposite spindle poles by metaphase. 1. An Overview of Kinetochore Structure and Functions In eukaryotes, the kinetochore is a proteinaceous multi-subunit assembly whose main function is to generate load-bearing attachments of sister chromatids (the replicated chromosomes held together by the protein complex cohesin) to spindle microtubules during cell division (mitosis or meiosis) (Figure 1 A). Kinetochores couple sister
381 Kinetochore function: molecular motors, switches and gates Tim J Yen* and Bruce T Schaart Kinetochores are essential for accurate chromosome grow and shorten in a coordinated fashion to move the segregation. Recent studies reveal that vertebrate chromosome throughout mitosis (see Fig. 1 and [6-8]). kinetochores are sophisticated propulsion systems composed This bidirectional movement of At the onset of mitosis, rapidly growing and shrinking microtubules (MTs) probe the cytoplasm in search of kinetochores, which are macromolecular complexes assembled on opposite sides of the centromere that mediate interactions between the chromosomes and MTs.
Kinetochore Orientation in Mitosis and Meiosis: Cell Biology Diagrams
Introduction During mitosis, sister chromatids are segregated to the two daughter cells. This process requires the interaction between specialized chromosomal structures (kinetochores) and polymers of alpha- and beta-tubulin called microtubules. Abstract The kinetochore is the multiprotein complex of eukaryotic organisms that is assembled on mitotic or meiotic centromeres to connect centromeric DNA with microtubules. Its function involves the coordinated action of more than 100 different proteins. The kinetochore acts as an organiser hub that establishes physical connections with microtubules and centromere-associated proteins and Kinetochore proteins can be grouped according to their concentration at kinetochores during mitosis: some proteins remain bound throughout cell division, whereas some others change in concentration. Furthermore, they can be recycled in their binding site on kinetochores either slowly (they are rather stable) or rapidly (dynamic).
