Basto Renata, Gergely Fanni, Draviam Viji M, Ohkura Hiroyuki, Liley Kathryn, Raff Jordan W
The Wellcome Trust/Cancer Research UK Gurdon Institute of Cancer and Developmental Biology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK.
J Cell Sci. 2007 Apr 1;120(Pt 7):1278-87. doi: 10.1242/jcs.000604.
During mitosis, cyclin B is extremely dynamic and although it is concentrated at the centrosomes and spindle microtubules (MTs) in organisms ranging from yeast to humans, the mechanisms that determine its localisation are poorly understood. To understand how cyclin B is targeted to different locations in the cell we have isolated proteins that interact with cyclin B in Drosophila embryo extracts. Here we show that cyclin B interacts with the molecular chaperone Hsp90 and with the MT-associated protein (MAP) Mini spindles (Msps; the Drosophila orthologue of XMAP215/ch-TOG). Both Hsp90 and Msps are concentrated at centrosomes and spindles, and we show that Hsp90, but not Msps, is required for the efficient localisation of cyclin B to these structures. We find that, unlike what happens with other cell cycle proteins, Hsp90 is not required to stabilise cyclin B or Msps during mitosis. Thus, we propose that Hsp90 plays a novel role in regulating the localisation of cyclin B and Msps during mitosis.
在有丝分裂期间，细胞周期蛋白B极具动态性，尽管它在从酵母到人类的生物体中都集中于中心体和纺锤体微管（MTs），但其定位机制却知之甚少。为了了解细胞周期蛋白B是如何靶向细胞内不同位置的，我们从果蝇胚胎提取物中分离出了与细胞周期蛋白B相互作用的蛋白质。在此我们表明，细胞周期蛋白B与分子伴侣热休克蛋白90（Hsp90）以及与微管相关蛋白（MAP）小纺锤体（Msps；XMAP215/ch-TOG的果蝇同源物）相互作用。Hsp90和Msps都集中于中心体和纺锤体，并且我们表明，细胞周期蛋白B有效定位于这些结构需要Hsp90，而非Msps。我们发现，与其他细胞周期蛋白不同，有丝分裂期间稳定细胞周期蛋白B或Msps不需要Hsp90。因此，我们提出Hsp90在有丝分裂期间调节细胞周期蛋白B和Msps的定位中发挥着新作用。
