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Mol. Cells 2006; 21(3): 395-400

Published online January 1, 1970

© The Korean Society for Molecular and Cellular Biology

Human Glutathione S-Transferase P1 Suppresses MEKK1-mediated Apoptosis by Regulating MEKK1 Kinase Activity in HEK293 Cells

Xin Zhao, Yumei Fan, Jiayin Shen, Yifan Wu, Zhimin Yin

Abstract

Glutathione S-transferase P1 (GSTP1) plays an important role in detoxification and the metabolism of xenobiotics. Here we show that GSTP1 also regulates the MEKK1-MKK7 signaling pathway. Over-expression of GSTP1 in HEK293 cells inhibited both DMEKK1- and etoposide-induced apoptosis, and inhibited pro-caspase-3 activation and PARP cleavage. MEKK1-induced apoptosis requires both its kinase activity and proteolytic cleavage. DMEKK1 activity was inhibited by over-expression of GSTP1 in vivo and MEKK1 kinase activity was also inhibited by GSTP1 in vitro when assayed with bacterially-expressed MKK7(KM) protein as substrate. GSTP1 inhibition of etoposide-induced cell apoptosis was mainly due to its ability to suppress MEKK1 kinase activity. The glutathione-conjugating activity of GSTP1 was essential for the above effects. These findings provide insight into the mechanism by which GSTP1 protects cells from genotoxin-induced apoptosis.

Keywords Apoptosis; Caspase-3; Etoposide; GSTP1; Kinase Activity; MEKK1

Article

Research Article

Mol. Cells 2006; 21(3): 395-400

Published online June 30, 2006

Copyright © The Korean Society for Molecular and Cellular Biology.

Human Glutathione S-Transferase P1 Suppresses MEKK1-mediated Apoptosis by Regulating MEKK1 Kinase Activity in HEK293 Cells

Xin Zhao, Yumei Fan, Jiayin Shen, Yifan Wu, Zhimin Yin

Abstract

Glutathione S-transferase P1 (GSTP1) plays an important role in detoxification and the metabolism of xenobiotics. Here we show that GSTP1 also regulates the MEKK1-MKK7 signaling pathway. Over-expression of GSTP1 in HEK293 cells inhibited both DMEKK1- and etoposide-induced apoptosis, and inhibited pro-caspase-3 activation and PARP cleavage. MEKK1-induced apoptosis requires both its kinase activity and proteolytic cleavage. DMEKK1 activity was inhibited by over-expression of GSTP1 in vivo and MEKK1 kinase activity was also inhibited by GSTP1 in vitro when assayed with bacterially-expressed MKK7(KM) protein as substrate. GSTP1 inhibition of etoposide-induced cell apoptosis was mainly due to its ability to suppress MEKK1 kinase activity. The glutathione-conjugating activity of GSTP1 was essential for the above effects. These findings provide insight into the mechanism by which GSTP1 protects cells from genotoxin-induced apoptosis.

Keywords: Apoptosis, Caspase-3, Etoposide, GSTP1, Kinase Activity, MEKK1

Mol. Cells
Jun 30, 2023 Vol.46 No.6, pp. 329~398
COVER PICTURE
The cellular proteostasis network is adaptively modulated upon cellular stress, thereby protecting cells from proteostasis collapse. Heat shock induces the translocation of misfolded proteins and the chaperone protein HSP70 into nucleolus, where nuclear protein quality control primarily occurs. Nuclear RNA export factor 1 (green), nucleolar protein fibrillarin (red), and nuclei (blue) were visualized in NIH3T3 cells under basal (left) and heat shock (right) conditions (Park et al., pp. 374-386).

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