A motor goes mitotic and divorces the Golgi complex

Use of two-hybrid screening has previously shown that the Rab6-binding kinesin Rab6-KIFL is a partner of Rab6, a Golgi-associated GTPase implicated in intra-Golgi membrane traffic. Hill et al. 1 have now characterized the expression, localization and tentative function of human Rab6-KIFL. Rab6-KIFL accumulates in mitotic HeLa cells, where it localizes to central spindle microtubules and to the midbody during cytokinesis. Using an antiserum raised against the Rab6-binding domain of Rab6-KIFL, Hill et al. demonstrate that levels of the protein oscillate in a cell-cycle-controlled manner, mirroring the behavior of cyclin B2. This suggests that Rab6-KIFL is a kinesin found solely in cells during mitosis. Most interestingly, microinjection of antibodies against Rab6-KIFL blocks cytokinesis and results in a dramatic accumulation of binucleate cells. Furthermore, overexpression of Rab6-KIFL in HeLa cells causes cell death. Thus, Rab6-KIFL might be a microtubule motor with functions during formation of the cleavage furrow and cytokinesis.