Targeting the interaction of AIMP2-DX2 with HSP70 suppresses cancer development


A tumorigenic factor, AIMP2 lacking exon 2 (AIMP2-DX2), is often upregulated in many cancers. However, how its cellular level is determined is not understood. Here, we report heat-shock protein HSP70 as a critical determinant for the level of AIMP2-DX2. Interaction of the two factors was identified by interactome analysis and structurally determined by X-ray crystallography and NMR analyses. HSP70 recognizes the amino (N)-terminal flexible region, as well as the glutathione S-transferase domain of AIMP2-DX2, via its substrate-binding domain, thus blocking the Siah1-dependent ubiquitination of AIMP2-DX2. AIMP2-DX2-induced cell transformation and cancer progression in vivo was further augmented by HSP70. A positive correlation between HSP70 and AIMP2-DX2 levels was shown in various lung cancer cell lines and patient tissues. Chemical intervention in the AIMP2-DX2–HSP70 interaction suppressed cancer cell growth in vitro and in vivo. Thus, this work demonstrates the importance of the interaction between AIMP2-DX2 and HSP70 on tumor progression and its therapeutic potential against cancer.

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Fig. 1: Interaction between DX2 and HSP70.
Fig. 2: Significance of HSP70 for stabilization of DX2.
Fig. 3: Structural determination of the interaction between DX2 and HSP70.
Fig. 4: HSP70-mediated protection of DX2 from Siah1-mediated degradation.
Fig. 5: Effect of the protein–protein interaction inhibitor, BC-DXI-495, on DX2-mediated proliferation.
Fig. 6: Mode of action of BC-DXI-495 on DX2.

Data availability

All data generated or analyzed during this study are included in this published article or are available from the corresponding author upon request. The structure coordinates have been deposited in the Protein Data Bank under codes 6JPV for HSP70 395-537-MYRLPNVHG and 6K39 for HSP70 395-537-YRLPNVHG. NMR assignment data for 13C- and 15N-labeled DX251-251-C136S-C222S have been deposited at the Biological Magnetic Resonance Bank (BMRB) with accession code 27914.


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This work was supported by the Global Frontier Project grant (no. NRF-M3A6A4-2010-0029785) and the IMRCTR grant (no. NRF-2018R1A5A2023127) of the National Research Foundation funded by the Ministry of Science and ICT of Korea. We thank T. Otomo of The Scripps Research Institute for helpful discussions. X-ray diffraction data were collected at Pohang Accelerator Laboratory beamlines 5C, 7A and 11C and Photon Factory beamline 1A. We used the NMR instruments of the Protein Structure Group at the Korea Basic Science Institute.

Author information




S.L., H.Y.C., D.G.K. and S.K. conceived the study. S.L., H.Y.C., D.G.K., M.H.K., K.L., Y.H.J. and S.K. designed all the experiments. S.L., D.G.K. and Y.R. performed and analyzed most experiments including cell and molecular biological experiment and in vivo analysis. H.Y.C., S.Y.S. and A.U.M. performed and analyzed X-ray crystallography and NMR experiments. M.K., D.B. and A.S. synthesized all the BC-DXI compounds. Y.L. performed and analyzed the in vitro pull-down assay between DX2 and HSP70 or HSP90. J.L. and W.S.Y. performed mass spectrometry analysis. H.K.K. took the required fluorescence images. M.H.K., K.L., Y.H.J. and S.K. reviewed and discussed the data. S.L., H.Y.C., D.G.K. and S.K. wrote the manuscript. All authors edited the manuscript.

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Correspondence to Sunghoon Kim.

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Lim, S., Cho, H.Y., Kim, D.G. et al. Targeting the interaction of AIMP2-DX2 with HSP70 suppresses cancer development. Nat Chem Biol 16, 31–41 (2020).

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