Positioning of the mitotic spindle by a cortical-microtubule capture mechanism.

Correct positioning of the mitotic spindle is critical for cell division and development. Spindle positioning involves a search-and-capture mechanism whereby dynamic microtubules find and then interact with specific sites on the submembrane cortex. Genetic, biochemical, and imaging experiments suggest a mechanism for cortical-microtubule capture. Bim1p, located at microtubule distal ends, bound Kar9p, a protein associated with the daughter cell cortex. Bim1p is the yeast ortholog of human EB1, a binding partner for the adenomatous polyposis coli tumor suppressor. EB1 family proteins may have a general role in linking the microtubule cytoskeleton to cortical polarity determinants.