MOTORS INVOLVED IN SPINDLE ASSEMBLY AND CHROMOSOME SEGREGATION

During the past two years, major advances have been made in our unders tanding of the role of motor proteins in chromosome-microtubule intera ctions in the spindle. The discovery of kinesin-like proteins (KLPs) a ssociated with chromosome arms has shed some light on the mechanism of chromosome congression and the establishment of spindle bipolarity. R ecent results also indicate that kinetochore KLPs may tether the ends of growing and shrinking microtubules to kinetochores during chromosom e movements. Finally, new data indicate that phosphorylation of KLPs m ay be one of the mechanisms by which they are targeted to specific spi ndle domains.