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Updated: Jul 15, 2026
09:31
Heterokaryon Technique for Analysis of Cell Type-specific Localization
Published on: March 11, 2011
Distinct Nuclear Localization Signals Confer Differential Microtubule Dependence among ZFTA Fusion Oncoproteins
Masaki Ishii1, Naoki Suto2, Ruri Kojima1
1Research Institute of Pharmaceutical Sciences, Faculty of Pharmacy, Musashino University, 1-1-20 Shinmachi, Nishitokyo, Tokyo, 202-8585, Japan.
The Journal of Biological Chemistry
|July 13, 2026
Summary
Colchicine inhibits nuclear localization of ZFTA-RELA fusion proteins in ependymoma by targeting microtubule transport. This finding suggests microtubule-dependent nuclear import as a potential therapeutic strategy for ZFTA-fusion-positive tumors.
Area of Science:
- Oncology
- Molecular Biology
- Cell Biology
Background:
- Ependymomas, particularly ZFTA-fusion-positive supratentorial ependymoma (ST-EPN-ZFTA), are aggressive glial tumors resistant to chemotherapy.
- ZFTA-RELA fusion proteins constitutively localize to the nucleus, driving oncogenic gene expression and contributing to poor prognosis.
Purpose of the Study:
- To identify inhibitors of aberrant gene expression driven by ZFTA-RELA fusion proteins.
- To investigate the role of microtubule-dependent nuclear transport in ZFTA-fusion proteins.
Main Methods:
- Screened 9,600 diverse compounds using a ZFTA-RELA-responsive luciferase reporter system.
- Evaluated the most potent inhibitor, colchicine, a microtubule polymerization inhibitor.
- Assessed the effect of colchicine and other inhibitors on nuclear localization of various ZFTA-fusion proteins and identified nuclear localization signals (NLS).
Main Results:
- Colchicine was identified as a potent inhibitor (IC50 of 90 nM) of ZFTA-RELA-driven gene expression, including L1CAM.
- Colchicine and vinblastine partially inhibited ZFTA-RELA nuclear localization, mediated by the RELA region, suggesting intact microtubule-dependent import.
- Colchicine affected nuclear localization of ZFTA-NCOA2 and ZFTA-MKL2, but not ZFTA-MAML2/3, highlighting variability in microtubule dependence among fusion partners due to unique NLS.
Conclusions:
- Microtubule-dependent nuclear transport is a critical mechanism for ZFTA-RELA nuclear localization and oncogenic activity.
- The dependence on microtubule transport varies among different ZFTA-fusion proteins, influenced by specific NLS sequences.
- Targeting microtubule-dependent nuclear transport presents a promising therapeutic strategy for ZFTA-fusion-positive ependymomas.
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