開催日：2026/05/21
時間：13:30-15:00
場所：図書館3階セミナー室(B301)
演者：Gunjan Mehta
演題：Single molecule tracking of a cancer therapy target aurora kinase B (Ipl1) in live yeast
cells to understand its mechanism of phosphorylating various proteins during cell division.
要旨：Aurora kinases (AKs), a group of serine/threonine phosphorylases, play several essential roles during mitosis,especially in checkpoint regulation, spindle assembly/disassembly, chromosome segregation, and cytokinesis.
Their impaired function leads to severe chromosome missegregation, aneuploidy, and cancers.Overexpression of AKs and their mutations have been reported in various human cancers. AK-B is overexpressed in several human cancers including lung, colorectal, breast, renal, hepatocellular, prostate, ovarian, glioblastoma, and thyroid cancers. It is reported that overexpressed AK-B is an essential marker related to tumor invasiveness, early recurrence, and dismal prognosis. Hence, AK-B is currently one of the most promising targets for cancer therapy and many AK-B inhibitors are under clinical investigation.
Despite several years of research on AK-B using ensemble averaging methods (such as ChIP,immunofluorescence, FRAP, western blotting, and mass-spec analysis), the dynamic information about the AK-B function is not yet captured and fully understood. Here, we use single-molecule imaging and tracking (SMIT) to quantify the recruitment dynamics of Ipl1, AK-B in yeast S. cerevisiae, at the kinetochores and spindles in live cells. Our data suggest that Ipl1 is recruited to these locations with different dynamics. We have demonstrated how the recruitment dynamics of Ipl1 at the kinetochores during metaphase change in the
presence and absence of tension across the kinetochores, in the absence of protein phosphatase 1 (Glc7), and in the absence of its known recruiters (Ctf19 and Bub1). The SMIT of other chromosome passenger complex members (Bir1, Nbl1, Sli15) suggests their hierarchical assembly at the kinetochore. Hence, SMIT provides a dynamic view of the Ipl1 trafficking at the kinetochores and spindles. The method (SMIT) that we developed here is versatile as it can be applied to quantify the dynamics of any DNA-interacting proteins or protein-protein interactions in live cells of bacteria, yeast, and cell lines.
References:
1) Podh et al. 2025. Single-molecule tracking reveals the dynamic turnover of Ipl1 at the kinetochores in S.
cerevisiae. Life Science Alliance 2025; 8(7),e202503290.
2) Podh et al. 2022. Single-Molecule Tracking for studying protein dynamics and target-search mechanism in
live cells of S. cerevisiae. STAR Protocols (Cell Press) 2022; 3(4): 101900.
3) Podh et al. 2021. In-vivo Single-Molecule Imaging in Yeast: Applications and Challenges. Journal of
Molecular Biology 2021; 433(22):167250.
司会：Kazuhiro Maeshima
言語：英語
連絡先：Kazuhiro Maeshima