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Increased Stability of Nucleolar PinX1 in the Presence of TERT

  • Keo, Ponnarath (Department of Bioscience and Biotechnology, Konkuk University) ;
  • Choi, Joong Sub (Department of Obstetrics and Gynecology, Hanyang University College of Medicine) ;
  • Bae, Jaeman (Department of Obstetrics and Gynecology, Hanyang University College of Medicine) ;
  • Shim, Yhong-Hee (Department of Bioscience and Biotechnology, Konkuk University) ;
  • Oh, Bong-Kyeong (Institute of Medical Science, Hanyang University College of Medicine)
  • Received : 2015.05.22
  • Accepted : 2015.05.29
  • Published : 2015.09.30

Abstract

PinX1, a nucleolar protein of 328 amino acids, inhibits telomerase activity, which leads to the shortening of telomeres. The C-terminal region of PinX1 is responsible for its nucleolar localization and binding with TERT, a catalytic component of telomerase. A fraction of TERT localizes to the nucleolus, but the role of TERT in the nucleolus is largely unknown. Here, we report a functional connection between PinX1 and TERT regarding PinX1 stability. The C-terminal of $PinX1^{205-328}$, a nucleolar fragment, was much more stable than the N-terminal of $PinX1^{1-204}$, a nuclear fragment. Interestingly, PinX1 was less stable in TERT-depleted cells and more stable in TERT-myc expressing cells. Stability assays for PinX1 truncation forms showed that both $PinX1^{1-328}$ and $PinX1^{205-328}$, nucleolar forms, were more rapidly degraded in TERT-depleted cells, while they were more stably maintained in TERT-overexpressing cells, compared to each of the controls. However, $PinX1^{1-204}$ was degraded regardless of the TERT status. These results reveal that the stability of PinX1 is maintained in nucleolus in the presence of TERT and suggest a role of TERT in the regulation of PinX1 steady-state levels.

Acknowledgement

Supported by : National Research Foundation of Korea (NRF)

References

  1. Autexier, C., and Lue, N.F. (1998). The structure and function of telomerase reverse transcriptase. Annu. Rev. Biochem. 75, 493-517.
  2. Avilion, A.A., Piatyszek, M.A., Gupta, J., Shay, J.W., Bacchetti, S., and Greider, C.W. (1996). Human telomerase RNA and telomerase activity in immortal cell lines and tumor tissues. Cancer Res. 56, 645-650.
  3. Banik, S.S., and Counter, C.M. (2004). Characterization of interactions between PinX1 and human telomerase subunits hTERT and hTR. J. Biol. Chem. 279, 51745-51748. https://doi.org/10.1074/jbc.M408131200
  4. Beattie, T.L., Zhou, W., Robinson, M.O., and Harrington, L. (1998). Reconstitution of human telomerase activity in vitro. Curr. Biol. 8, 177-180.
  5. Bryan, T.M., and Reddel, R.R. (1997). Telomere dynamics and telomerase activity in in vitro immortalised human cells. Eur. J. Cancer. 33, 767-773. https://doi.org/10.1016/S0959-8049(97)00065-8
  6. Chen, G., Da, L., Xu, Y., Xu, M., Song, L., Li, T., and Zhao, M. (2010). C-terminal amino acids 290-328 of LPTS/PinX1 confer telomerase inhibition. Biochem. Biophys. Res. Commun. 398, 683-689. https://doi.org/10.1016/j.bbrc.2010.06.136
  7. Cheung, D.H., Kung, H.F., Huang, J.J., and Shaw, P.C. (2012). PinX1 is involved in telomerase recruitment and regulates telomerase function by mediating its localization. FEBS Lett. 586, 3166-3171. https://doi.org/10.1016/j.febslet.2012.06.028
  8. Counter, C.M., Meyerson, M., Eaton, E.N., Ellisen, L.W., Caddle, S.D., Haber, D.A., and Weinberg, R.A. (1998). Telomerase activity is restored in human cells by ectopic expression of hTERT (hEST2), the catalytic subunit of telomerase. Oncogene 16, 1217-1222. https://doi.org/10.1038/sj.onc.1201882
  9. Djojosubroto, M.W., Yoon, S.C., Lee, H.W., and Rudolph, K.L. (2003). Telomeres and telomerase in aging, regeneration and cancer. Mol. Cells 15,164-175.
  10. Etheridge, K.T., Banik, S.S., Armbruster, B.N., Zhu, Y., Terns, R.M., Terns, M.P., and Counter, C.M. (2002). The nucleolar localization domain of the catalytic subunit of human telomerase. J. Biol. Chem. 277, 24764-24770. https://doi.org/10.1074/jbc.M201227200
  11. Hahn, W.C., Stewart, S.A., Brooks, M.W., York, S.G., Eaton, E., Kurachi, A., Beijersbergen, R.L, Knoll, J.H.M, Meyerson, M., and Weinberg, R.A. (1999). Inhibition of telomerase limits the growth of human cancer cells. Nat. Med. 5, 1164-1170. https://doi.org/10.1038/13495
  12. Herbert, B.S., Pitts, A.E., Baker, S.I., Hamilton, S.E., Wright, W.E., and Shay, J.W., Corey, D.R. (1999). Inhibition of human telomerase in immortal human cells leads to progressive telomere shortening and cell death. Proc. Natl. Acad. Sci. USA. 96, 14276-14281. https://doi.org/10.1073/pnas.96.25.14276
  13. Jung, A.R., Yoo, J.E., Shim, Y.H., Choi, Y.N., Jeung, H.C., Chung, H.C., Rha, R.Y, and Oh, B.K. (2013). Increased alternative lengthening of telomere phenotypes of telomerase-negative immortal cells upon trichostatin-a treatment. Anticancer Res. 33, 821-829.
  14. Lin, J., and Blackburn, E.H. (2004). Nucleolar protein PinX1p regulates telomerase by sequestering its protein catalytic subunit in an inactive complex lacking telomerase RNA. Genes Dev. 18, 387-396. https://doi.org/10.1101/gad.1171804
  15. Lin, J., Jin, R., Zhang, B., Yang, P.X., Chen, H., Bai, Y.X., Xie, Y., Huang, C., and Huang, J. (2007). Characterization of a novel effect of hPinX1 on hTERT nucleolar localization. Biochem. Biophys. Res. Commun. 353, 946-952. https://doi.org/10.1016/j.bbrc.2006.12.123
  16. Lingner, J., Hughes, T.R., Shevchenko, A., Mann, M., Lundblad, V., and Cech, T.R. (1997). Reverse transcriptase motifs in the catalytic subunit of telomerase. Science 276, 561-567. https://doi.org/10.1126/science.276.5312.561
  17. McEachern, M.J., Krauskopf, A., and Blackburn, E.H. (2000). Telomere and their control. Annu. Rev. Genet. 34, 331-358. https://doi.org/10.1146/annurev.genet.34.1.331
  18. Meyerson, M., Counter, C.M., Eaton, E.N., Ellisen, L.W., Steiner, P., Caddle, S.D., Ziaugra, L., Beijersbergen, R.L, Davidoff, M.J., Liu, Q., et al. (1997). hEST2, the putative human telomerase catalytic subunit gene, is up-regulated in tumor cells and during immortalization. Cell 90, 785-795. https://doi.org/10.1016/S0092-8674(00)80538-3
  19. Nakamura, T.M., Morin, G.B., Chapman, K.B., Weinrich, S.L., Andrews, W.H., Lingner, J., Harley, C.B, and Cech, T.R. (1997). Telomerase catalytic subunit homologs from fission yeast and human. Science 277, 955-959. https://doi.org/10.1126/science.277.5328.955
  20. Nakayama, J., Tahara, H., Tahara, E., Saito, M., Ito, K., Nakamura, H., Nakanishi, T., Tahara, E., Ide, T., and Ishikawa, F. (1998). Telomerase activation by hTRT in human normal fibroblasts and hepatocellular carcinomas. Nat. Genet. 18, 65-68. https://doi.org/10.1038/ng0198-65
  21. Palm, W., and de Lange, T. (2008). How shelterin protects mammalian telomeres. Annu. Rev. Genet. 42, 301-334. https://doi.org/10.1146/annurev.genet.41.110306.130350
  22. Tomlinson, R.L., Ziegler, T.D., Supakorndej, T., Terns, R.M., and Terns, M.P. (2006). Cell cycle-regulated trafficking of human telomerase to telomeres. Mol. Biol. Cell 17, 955-965.
  23. Wang, C., Yu, J., Yuan, K., Lan, J., Jin, C., and Huang, H. (2010). Plk1-mediated mitotic phosphorylation of PinX1 regulates its stability. Eur. J. Cell Biol. 89, 748-756. https://doi.org/10.1016/j.ejcb.2010.05.005
  24. Wong, J.M., Kusdra, L., and Collins, K. (2002). Subnuclear shuttling of human telomerase induced by transformation and DNA damage. Nat. Cell Bio. 4, 731-736. https://doi.org/10.1038/ncb846
  25. Yang, Y., Chen, Y., Zhang, C., Huang, H., and Weissman, S.M. (2002). Nucleolar localization of hTERT protein is associated with telomerase function. Exp. Cell Res. 277, 201-209. https://doi.org/10.1006/excr.2002.5541
  26. Yoo, J.E., Oh, B.K., and Park, Y.N. (2009). Human PinX1 mediates TRF1 accumulation in nucleolus and enhances TRF1 binding to telomeres. J. Mol. Biol. 388, 928-940. https://doi.org/10.1016/j.jmb.2009.02.051
  27. Yoo, J.E., Park, Y.N., and Oh, B.K. (2014). PinX1, a telomere repeat-binding factor 1 (TRF1)-interacting protein, maintains telomere integrity by modulating TRF1 homeostasis, the process in which human telomerase reverse Transcriptase (hTERT) plays dual roles. J. Biol. Chem. 289, 6886-6898. https://doi.org/10.1074/jbc.M113.506006
  28. Zhang, X., Mar, V., Zhou, W., Harrington, L., and Robinson, M.O. (1999). Telomere shortening and apoptosis in telomeraseinhibited human tumor cells. Genes Dev. 13, 2388-2399. https://doi.org/10.1101/gad.13.18.2388
  29. Zhang, B., Bai, Y.X., Ma, H.H., Feng, F., Jin, R., Wang, Z.L., Lin, J., Sun, S.P., Yang, P., Wang, X.X., et al. (2009). Silencing PinX1 compromises telomere length maintenance as well as tumorigenicity in telomerase-positive human cancer cells. Cancer Res. 69, 75-83.
  30. Zhou, X.Z., and Lu, K.P. (2001). The Pin2/TRF1-interacting protein PinX1 is a potent telomerase inhibitor. Cell 107, 347-359. https://doi.org/10.1016/S0092-8674(01)00538-4
  31. Zhou, X.Z., Huang, P., Shi, R., Lee, T.H., Lu, G., Zhang, Z., Bronson, R., and Lu, K.P. (2011). The telomerase inhibitor PinX1 is a major haploinsufficient tumor suppressor essential for chromosome stability in mice. J. Clin. Invest. 121, 1266-1282. https://doi.org/10.1172/JCI43452

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