The kinetophore is a macromolecular structure that is associated with the centromeres of chromosomes and is responsible for establishing and maintaining the connections with the microtubules of the mitotic spindle. The proteins that reside within the chromosomal domain fall into two broad classes: those that associate with the centromere throughout the cell cycle and those that are found at the centromere in a cell cycle specific manner. Members of the first class include CENP-A, CENP-B, and CENP-C. The members of the second class include several ubiquitous cellular proteins such as calmodulin, tubulin, dynein and p34 cdc2 and also CENP-E and CENP-F. CENP-F appears to be the earliest member to interact with the centromere-kinetochore complex. CENP-F also shows a cell-cycle distribution that is both temporally regulated and diverse in terms of the structural components it localizes to and therefore may play a role in several mitotic events. (1-3)