Regulation of the kinetochore-microtuble interface

描述（由申请人提供）： 在有丝分裂中，微管（MT）与动粒的适当附着对于染色体的忠实分离至关重要。我们的实验室已经表明，在人类组织培养细胞中，动粒附着的错误发生频率很高，必须对这些错误进行纠正以获得准确的分离。芽殖酵母的研究表明，有丝分裂激酶Ipl 1（人极光B直系同源物）的作用，在纠正MT错误附着在着丝粒。 这些研究表明，Ipl 1磷酸化高度保守的外动粒组件Ndc 80（人类Hec 1直系同源物）和MT相关蛋白Dam 1（没有已知的人类直系同源物）。遗传和诱变研究表明，极光B磷酸化这些底物减弱动粒与动粒MT（kMT）的相互作用。我的酵母研究的初步数据表明，极光B调节另一种MT相关蛋白Dim 1（人类EB 1）。已知EB 1蛋白结合正末端kMT并促进其稳定性。我建议研究人类Hec 1和EB 1的功能是如何调节极光B在脊椎动物的kMT接口。我将研究哺乳动物细胞中这些k-MT底物的Aurora B磷酸化存在与否的后果。

DESCRIPTION (provided by applicant): In mitosis, proper microtubule (MT) attachment to kinetochores is critical for faithful chromosome segregation. Our lab has shown that errors in kinetochore attachment occur at a high frequency in human tissue culture cells and these have to be corrected for accurate segregation. Budding yeast studies indicate a role for mitotic kinase Ipl1 (human Aurora B ortholog) in correcting MT misattachments at kinetochores. These studies show that Ipl1 phosphorylates the highly conserved outer kinetochore component Ndc80 (human Hec1 ortholog) and a MT-associated protein Dam1 (no known human ortholog). Genetic and mutagenesis studies indicate that Aurora B phosphorylation of these substrates weakens kinetochore interactions with kinetochore MTs (kMTs). Preliminary data from my yeast studies suggest Aurora B regulates another MT-associated protein Dim1 (human EB1). EB1 proteins are known to bind and promote stability of plus-end kMTs. I propose to investigate how human Hec1 and EB1 function are regulated by aurora B at the vertebrate kMT interface. I will examine the consequences of presence or absence of Aurora B phosphorylation of these k-MT substrates in mammalian cells.