Abstract

The metaphase spindle is an evident example why the size of intracellular organelles matters: The spindle must be large enough and span sufficient distance to physically separate chromosomes into two opposite halves of the cell. While approaching a near to complete proteomic parts lists of the metaphase spindle, mechanisms that control their defined size remain poorly understood. Cytoplasmic extracts prepared from eggs of the African clawed frog Xenopus laevis have proven valuable for studying cellular processes such as spindle assembly and organization. More recently, comparison with extracts of the related frog Xenopus tropicalis allowed the identification of spindle scaling factors. We are interested in how the biochemistry of the basic building block of the spindle, αβ-tubulin, contributes to spindle assembly and morphology. We combine in vitro reconstitution assays, state-of-the art imaging and simulations to show how biochemical adaptation on the molecular scale can create physiological structures in the μm scale that enable faithful chromosome segregation.