Hung Hui-Fang, Hehnly Heidi, Doxsey Stephen
Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
Department of Cell and Developmental Biology, State University of New York Upstate Medical School, Syracuse, NY 13210, USA.
Curr Biol. 2016 Mar 21;26(6):793-801. doi: 10.1016/j.cub.2016.01.025. Epub 2016 Mar 3.
Establishing apical-basal polarity is instrumental in the functional shaping of a solitary lumen within an acinus. By exploiting micropatterned slides, wound healing assays, and three-dimensional culture systems, we identified a mother centriole subdistal appendage protein, cenexin, as a critical player in symmetric lumen expansion through the control of microtubule organization. In this regard, cenexin was required for both centrosome positioning in interphase cells and proper spindle orientation during mitosis. In contrast, the essential mother centriole distal appendage protein CEP164 did not play a role in either process, demonstrating the specificity of subdistal appendages for these events. Importantly, upon closer examination we found that cenexin depletion decreased astral microtubule length, disrupted astral microtubule minus-end organization, and increased levels of the polarity protein NuMA at the cell cortex. Interestingly, spindle misorientation and NuMA mislocalization were reversed by treatment with a low dose of the microtubule-stabilizing agent paclitaxel. Taken together, these results suggest that cenexin modulates microtubule organization and stability to mediate spindle orientation.
建立顶-基极性对于腺泡内单个管腔的功能形成至关重要。通过利用微图案化载玻片、伤口愈合试验和三维培养系统，我们鉴定出一种母中心粒亚远端附属蛋白cenexin，它是通过控制微管组织在对称管腔扩张中起关键作用的因子。在这方面，cenexin对于间期细胞中的中心体定位和有丝分裂期间纺锤体的正确定向都是必需的。相比之下，必需的母中心粒远端附属蛋白CEP164在这两个过程中均未发挥作用，这表明亚远端附属物对这些事件具有特异性。重要的是，经过更仔细的检查，我们发现cenexin缺失会缩短星状微管长度、破坏星状微管负端组织，并增加细胞皮层处极性蛋白NuMA的水平。有趣的是，用低剂量的微管稳定剂紫杉醇处理可逆转纺锤体定向错误和NuMA定位错误。综上所述，这些结果表明cenexin调节微管组织和稳定性以介导纺锤体定向。
