Open Access

Endoplasmic reticulum stress activates transglutaminase 2 leading to protein aggregation

  • Authors:
    • Jin-Haeng Lee
    • Jaeho Jeong
    • Eui Man Jeong
    • Sung-Yup Cho
    • Jeong Wook Kang
    • Jisun Lim
    • Jinbeom Heo
    • Hyunsook Kang
    • In-Gyu Kim
    • Dong-Myung Shin
  • View Affiliations

  • Published online on: January 30, 2014     https://doi.org/10.3892/ijmm.2014.1640
  • Pages: 849-855
  • Copyright: © Lee et al. This is an open access article distributed under the terms of Creative Commons Attribution License [CC BY_NC 3.0].

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Abstract

Aberrant activation of transglutaminase 2 (TGase2) contributes to a variety of protein conformational disorders such as neurodegenerative diseases and age-related cataracts. The accumulation of improperly folded proteins in the endoplasmic reticulum (ER) triggers the unfolded protein response (UPR), which promotes either repair or degradation of the damaged proteins. Inadequate UPR results in protein aggregation that may contribute to the development of age-related degenerative diseases. TGase2 is a calcium-dependent enzyme that irreversibly modifies proteins by forming cross-linked protein aggregates. Intracellular TGase2 is activated by oxidative stress which generates large quantities of unfolded proteins. However, the relationship between TGase2 activity and UPR has not yet been established. In the present study, we demonstrated that ER stress activated TGase2 in various cell types. TGase2 activation was dependent on the ER stress-induced increase in the intracellular calcium ion concentration but not on the TGase2 protein expression level. Enzyme substrate analysis revealed that TGase2-mediated protein modification promoted protein aggregation concurrently with decreasing water solubility. Moreover, treatment with KCC009, a TGase2 inhibitor, abrogated ER stress-induced TGase2 activation and subsequent protein aggregation. However, TGase2 activation had no effect on ER stress-induced cell death. These results demonstrate that the accumulation of misfolded proteins activates TGase2, which further accelerates the formation of protein aggregates. Therefore, we suggest that inhibition of TGase2 may be a novel strategy by which to prevent the protein aggregation in age-related degenerative diseases.
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2014-April
Volume 33 Issue 4

Print ISSN: 1107-3756
Online ISSN:1791-244X

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Spandidos Publications style
Lee J, Jeong J, Jeong EM, Cho S, Kang JW, Lim J, Heo J, Kang H, Kim I, Shin D, Shin D, et al: Endoplasmic reticulum stress activates transglutaminase 2 leading to protein aggregation . Int J Mol Med 33: 849-855, 2014.
APA
Lee, J., Jeong, J., Jeong, E.M., Cho, S., Kang, J.W., Lim, J. ... Shin, D. (2014). Endoplasmic reticulum stress activates transglutaminase 2 leading to protein aggregation . International Journal of Molecular Medicine, 33, 849-855. https://doi.org/10.3892/ijmm.2014.1640
MLA
Lee, J., Jeong, J., Jeong, E. M., Cho, S., Kang, J. W., Lim, J., Heo, J., Kang, H., Kim, I., Shin, D."Endoplasmic reticulum stress activates transglutaminase 2 leading to protein aggregation ". International Journal of Molecular Medicine 33.4 (2014): 849-855.
Chicago
Lee, J., Jeong, J., Jeong, E. M., Cho, S., Kang, J. W., Lim, J., Heo, J., Kang, H., Kim, I., Shin, D."Endoplasmic reticulum stress activates transglutaminase 2 leading to protein aggregation ". International Journal of Molecular Medicine 33, no. 4 (2014): 849-855. https://doi.org/10.3892/ijmm.2014.1640