Summary
The “Pac-Man” model for explaining chromosome movement is based on three main tenets: (i) the force that moves chromosomes is generated at the kinetochore; (ii) disassembly of the microtubules (MTs) of the kinetochore fibre generates poleward movement; and (iii) the energy required for this movement comes from MT disassembly. We show that these tenets are not valid in some and perhaps many situations. Thus, the Pac-Man model is inadequate and misleading as the central basis for explaining chromosomal motion generally. We argue that multiple mechanisms are involved in mitotic function and that a contractile/elastic spindle matrix is likely involved not only in anchoring kinetochore fibres, but also by exerting force on them. This view of the spindle matrix shares some features with the “tensegrity” model already formulated as a basis for understanding interphase cell behaviour.
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Pickett-Heaps, J.D., Forer, A. & Spurck, T. Rethinking anaphase: where “Pac-Man” fails and why a role for the spindle matrix is likely. Protoplasma 192, 1–10 (1996). https://doi.org/10.1007/BF01273239
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DOI: https://doi.org/10.1007/BF01273239