Model for the role of the EB1–Kinesin-14 complex during spindle function. Schematic description of spindle assembly and kinetochore bi-orientation in wild-type cells (top row), cells with a disrupted EB1–Kinesin 14 complex (middle row), and simultaneous loss of EB1–Kinesin-14 and Ase1/PRC1 (bottom row). Left side depicts effects on spindle microtubule organization. Right side describes consequences for sister chromatid bi-orientation. Please see Discussion for details.