Figure 10.

Simulations using Hill’s biased diffusion model and a working model for kinetochore configuration in G1 and anaphase. (a) Hill’s equation for the microtubule (MT)–kinetochore interaction is shown with a cartoon to depict each variable. During microtubule polymerization, the microtubule moves inside the kinetochore sleeve from M − 1 to M for calculating the k_in. During depolymerization of the microtubule, interactions are broken and reformed in a new position by moving from M to M − 1 for calculating the k_out. (b) The number of couplers is plotted against the probability of detachment (shown by heat map) as a function of anaphase length. Addition of each coupler increases the probability of remaining attached exponentially. (c) The probability of an attachment breaking is plotted against the number of couplers for a 10-, 20-, and 30-min anaphase, revealing that the addition of each coupler exponentially decreases the loss of kinetochore–microtubule interaction. (d) The kinetochore in G1 through metaphase has fewer copies of COMA, MIND, and Ndc80 subcomplexes relative to the kinetochore at the end of anaphase, which experiences addition of the Okp1–COMA (blue), Mtw1–MIND (purple), and Ndc80 (red) subcomplexes. This addition is facilitated by Stu2 (yellow). The Dam1 complex (green) is represented as a similar ringlike structure in G1 and anaphase encircling the microtubule.