Chen Qian, Lakshmikanth Gandikota S, Spudich James A, De Lozanne Arturo
Section of Molecular Cell and Developmental Biology, University of Texas at Austin, Austin, TX 78712, USA.
Mol Biol Cell. 2007 Sep;18(9):3366-74. doi: 10.1091/mbc.e06-10-0895. Epub 2007 Jun 13.
The inner centromeric protein (INCENP) and other chromosomal passenger proteins are known to localize on the cleavage furrow and to play a role in cytokinesis. However, it is not known how INCENP localizes on the furrow or whether this localization is separable from that at the midbody. Here, we show that the association of Dictyostelium INCENP (DdINCENP) with the cortex of the cleavage furrow involves interactions with the actin cytoskeleton and depends on the presence of the kinesin-6-related protein Kif12. We found that Kif12 is found on the central spindle and the cleavage furrow during cytokinesis. Kif12 is not required for the redistribution of DdINCENP from centromeres to the central spindle. However, in the absence of Kif12, DdINCENP fails to localize on the cleavage furrow. Domain analysis indicates that the N terminus of DdINCENP is necessary and sufficient for furrow localization and that it binds directly to the actin cytoskeleton. Our data suggest that INCENP moves from the central spindle to the furrow of a dividing cell by a Kif12-dependent pathway. Once INCENP reaches the equatorial cortex, it associates with the actin cytoskeleton where it then concentrates toward the end of cytokinesis.
已知着丝粒内部蛋白（INCENP）和其他染色体乘客蛋白定位于分裂沟，并在胞质分裂中发挥作用。然而，目前尚不清楚INCENP如何定位于分裂沟，以及这种定位是否与中体处的定位可分离。在这里，我们表明盘基网柄菌INCENP（DdINCENP）与分裂沟皮质的关联涉及与肌动蛋白细胞骨架的相互作用，并依赖于驱动蛋白6相关蛋白Kif12的存在。我们发现，在胞质分裂期间，Kif12存在于中央纺锤体和分裂沟上。Kif12对于DdINCENP从着丝粒重新分布到中央纺锤体不是必需的。然而，在没有Kif12的情况下，DdINCENP无法定位于分裂沟。结构域分析表明，DdINCENP的N末端对于分裂沟定位是必需且足够的，并且它直接与肌动蛋白细胞骨架结合。我们的数据表明，INCENP通过Kif12依赖性途径从中央纺锤体移动到分裂细胞的分裂沟。一旦INCENP到达赤道皮质，它就与肌动蛋白细胞骨架结合，然后在胞质分裂末期集中于此。
