TACC蛋白调控细胞间期微管排布和动态的分子机制

TACC is an evolutionarily conserved microtubule-associated protein (MAP) and is present in various organisms ranging from yeast to human cells. Its protein expression levels are altered in different cancer cells, suggesting its role in tumorigenesis. Mechanistically, TACC has been identified as one of the microtubule-stabilizing proteins regulating spindle dynamics, and the function depends on the localization of TACC to the centrosome. In our recent publication, we revealed that TACC/alp7p is recruited to the spindle pole body (the SPB, the centrosome equivalent) by csi1p to promote bipolar spindle assembly in fission yeast. Despite this significant progress, how TACC/alp7p is involved in direct regulation of microtubule dynamics in interphase remains elusive. Interestingly, our recent work revealed that TACC/alp7p can synergize with various MAPs including mto1p, ase1p and mcp1p to regulate microtubule organization and dynamics. In this proposal, we aim to further dissect the roles of TACC in microtubule nucleation, microtubule bundling and microtubule dynamics regulation during interphase. As TACC is relevant to cancer, this work will not only uncover the roles of TACC in microtubule dynamics regulation but also pave the way for development of new strategies for cancer preventions and interventions.

TACC蛋白是一类高度保守的微管结合蛋白，它在不同的癌症细胞或者组织中表达异常或缺失，然而TACC的致病机理仍然不甚清楚。目前的研究已经发现TACC蛋白是一类微管稳定蛋白，我们和其他小组的研究表明其在有丝分裂期间定位于细胞中心体，参与调控纺锤体的形成和动态。虽然人们对TACC蛋白在有丝分裂期间调控纺锤体动态的分子机制的理解逐渐加深，但是对于其在间期细胞内调控微管排布和动态的研究仍然不足。我们近期的研究发现TACC的裂殖酵母同源蛋白alp7p在间期分别和多种不同微管结合蛋白共定位和相互作用。因此，我们拟通过利用酵母遗传学，生物化学，活细胞荧光显微镜观察等多种技术手段剖析TACC蛋白参与调控细胞间期微管的排布以及动态性的分子机理，从而为研究TACC蛋白在肿瘤形成和发展过程的病理学机制提供理论基础。

微管是细胞内一类重要细胞骨架，微管的生成及其末端动态性调控影响细胞内各项功能的发挥，因此系统探究微管的成核机制及其末端的动态性调控具有重要的生物学意义。本研究利用酵母遗传学，生物化学，活细胞荧光显微镜等技术手段系统剖析微管的成核机制及微管末端动态性调控。本研究揭示了保守微管结合蛋白TACC/alp7p协同TOG/alp14以及CDK5RAP2/mto1在调控间期核膜微管成核过程中的调控机制。实验结果表明TACC/alp7p在细胞核膜表面的微管成核过程中发挥重要作用。本研究还阐明了TOG/alp14，CLIP-170/Tip1以及Kinesin-8/Klp5调控微管末端动态性的功能，最终发现微管末端稳定蛋白TOG/alp14，CLIP-170/Tip1以及微管末端去稳定蛋白Kinesin-8/Klp5协同调控微管末端动态性进而调控间期微管长度的作用机制。以上结果为进一步了解微管成核机制及微管末端动态性调控提供重要依据。