Department of Cellular and Molecular Physiology, University of Liverpool, Liverpool L69 3BX, England, UK.
J Cell Biol. 2013 Aug 5;202(3):463-78. doi: 10.1083/jcb.201211127.
A complex of transforming acidic coiled-coil protein 3 (TACC3), colonic and hepatic tumor overexpressed gene (ch-TOG), and clathrin has been implicated in mitotic spindle assembly and in the stabilization of kinetochore fibers by cross-linking microtubules. It is unclear how this complex binds microtubules and how the proteins in the complex interact with one another. TACC3 and clathrin have each been proposed to be the spindle recruitment factor. We have mapped the interactions within the complex and show that TACC3 and clathrin were interdependent for spindle recruitment, having to interact in order for either to be recruited to the spindle. The N-terminal domain of clathrin and the TACC domain of TACC3 in tandem made a microtubule interaction surface, coordinated by TACC3-clathrin binding. A dileucine motif and Aurora A-phosphorylated serine 558 on TACC3 bound to the "ankle" of clathrin. The other interaction within the complex involved a stutter in the TACC3 coiled-coil and a proposed novel sixth TOG domain in ch-TOG, which was required for microtubule localization of ch-TOG but not TACC3-clathrin.
一个转化酸性卷曲螺旋蛋白 3（TACC3）、结肠和肝脏肿瘤过表达基因（ch-TOG）和网格蛋白的复合物与有丝分裂纺锤体的组装以及通过交联微管稳定动粒纤维有关。目前尚不清楚该复合物如何结合微管，以及复合物中的蛋白质如何相互作用。TACC3 和网格蛋白都被认为是纺锤体募集因子。我们已经对复合物内的相互作用进行了定位，并表明 TACC3 和网格蛋白相互依赖于纺锤体募集，它们必须相互作用，才能被招募到纺锤体上。网格蛋白的 N 端结构域和 TACC3 的 TACC 结构域串联在一起形成了一个微管相互作用表面，由 TACC3-网格蛋白结合来协调。TACC3 上的亮氨酸二肽基和 Aurora A 磷酸化丝氨酸 558 结合到网格蛋白的“脚踝”上。复合物中的另一个相互作用涉及 TACC3 卷曲螺旋中的一个停顿和 ch-TOG 中的一个拟议的新型第六个 TOG 结构域，该结构域对于 ch-TOG 的微管定位是必需的，但对于 TACC3-网格蛋白则不是必需的。
