41. Shugoshin also acts as a diffusible and mediates formation of kinetochore -microtubules during bipolar spindle assembly. 42. Plus ends that encounter kinetochores or sites of polarity become captured and no longer display growth or shrinkage. 43. Micrograph showing condensed chromosomes in blue, kinetochores in pink, and microtubules in green during metaphase of mitosis 44. During prometaphase, CDC20 and the SAC proteins concentrate at the kinetochores before attachment to the spindle assembly. 45. Thus, the kinetochore is essential for the chromosome segregation that is classically associated with mitosis and meiosis. 46. In addition, kinetochore localization of Bub1 early during G2 or prophase is another aspect of SAC functioning. 47. In late prometaphase, " kinetochore microtubules " begin to search for and attach to chromosomal kinetochores. 48. In late prometaphase, " kinetochore microtubules " begin to search for and attach to chromosomal kinetochores . 49. At the kinetochore , a variety of complexes have been shown to capture microtubule ( + )-ends. 50. These proteins keep the SAC activated until they are removed and the correct kinetochore -microtubule attachment is made.
