The function of lateral attachments in stable chromosome biorientation and in silencing the mitotic checkpoint

Abstract

Proper cell division relies on equal distribution of sister chromatids over daughter cells. This process is executed by a bipolar mitotic spindle, which via microtubule plus ends connects kinetochores of both sister chromatids to opposite poles. Various control systems have evolved to ensure equal segregation, such as destabilization of erroneous kinetochore-microtubule attachments. How these destabilizing actions are eventually repressed to allow for establishment of correct attachments has not yet been completely elucidated. Here, I will discuss a model that explains how destabilization of kinetochore-microtubule attachments can be overcome. In this model, attachments of kinetochores to the sides of microtubules play a crucial role. Properties of such lateral attachments will be examined here, including their effects on stable kinetochore-microtubule attachments, the generation of force on the chromosomes and mitotic progression.