Conformational change in the active center region of GST P1-1, due to binding of a synthetic conjugate of DXR with GSH, enhanced JNK-mediated apoptosis

Treatment of cells with a synthetic conjugate of DXR with GSH via glutaraldehyde (GSH-DXR) caused cytochrome c to be released from the mitochondria to the cytosol following potent activation of caspase-3 and -9 by typical DNA fragmentation. This apoptosis was regulated by the JNK-signaling pathway....

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Bibliographic Details
Published in:	Apoptosis (London) Vol. 12; no. 7; pp. 1269 - 1280
Main Authors:	Asakura, Tadashi, Sasagawa, Atsuko, Takeuchi, Hitoshi, Shibata, Shun-ichi, Marushima, Hideki, Mamori, Satoshi, Ohkawa, Kiyoshi
Format:	Journal Article
Language:	English
Published:	Netherlands New York : Kluwer Academic Publishers-Plenum Publishers 01-07-2007 Springer Nature B.V
Subjects:	Allosteric properties Animals Apoptosis Binding C-Terminus Caspase-3 Cell Line Conjugates Cytochrome c Cytochromes Cytosol Deletion mutant DNA fragmentation doxorubicin Doxorubicin - analogs & derivatives Doxorubicin - metabolism Doxorubicin - pharmacology Enzymatic activity Enzyme Activation Enzyme activity Enzymes Glutathione - analogs & derivatives Glutathione - metabolism Glutathione - pharmacology Glutathione S-transferase P1-1 Glutathione S-Transferase pi - antagonists & inhibitors Glutathione S-Transferase pi - chemistry Glutathione S-Transferase pi - metabolism Glutathione-Doxorubicin conjugate JNK Mitogen-Activated Protein Kinases - antagonists & inhibitors JNK Mitogen-Activated Protein Kinases - metabolism Kinases Mitochondria mitogen-activated protein kinase Mutants Mutation Proteins Rat hepatoma cell Rats Recombinant Fusion Proteins - metabolism Signal transduction Signaling Transfection
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Summary:	Treatment of cells with a synthetic conjugate of DXR with GSH via glutaraldehyde (GSH-DXR) caused cytochrome c to be released from the mitochondria to the cytosol following potent activation of caspase-3 and -9 by typical DNA fragmentation. This apoptosis was regulated by the JNK-signaling pathway. In the present experiment, binding of GSH-DXR to GST P1-1 allosterically led to the disappearance of its enzyme activity and activated the kinase activity of JNK without dissociation of the JNK-GST P1-1 complex. The recombinant GST P1-1 molecule with a mutation in the active center region (W38H and C47S) lost its GST activity when bound to JNK to the same degree as the wild-type, with the mutated GST P1-1 molecule failing to inhibit the activity of JNK. It has been reported that JNK-signaling is regulated by GST P1-1 via interaction with the C-terminus. We confirmed that GST P1-1 deletion mutant (Δ194-209) and a site-directed mutant (R201A) in the C-terminal region failed to bind and inhibit JNK. These results indicated that not only binding of the C-terminal region of GST P1-1 to the JNK molecule, but also the active center region of GST P1-1 play important roles in the regulation of JNK enzyme activity. The findings suggested that allosteric inhibition of GST P1-1 activity by the binding of GSH-DXR following conformational change may activate JNK and induce apoptosis via the mitochondrial pathway in the cells.
Bibliography:	http://dx.doi.org/10.1007/s10495-007-0053-0 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	1360-8185 1573-675X
DOI:	10.1007/s10495-007-0053-0