| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Address correspondence to Matthew R. Pincus, M.D., Ph.D., Department of Pathology and Laboratory Medicine, New York Harbor VA Medical Center, 800 Poly Place, Brooklyn, NY 11209, USA; tel 718-630-3688; fax 718 630 2960; e-mail matthew.pincus2{at}med.va.gov.
We have previously found that the pi-isozyme of glutathione-S-transferase (GST-pi) is a strong and selective inhibitor of the phosphorylation of the transcriptional activating protein jun by its activating kinase, jun-N-terminal kinase (JNK). We further performed molecular dynamics calculations on the 3-dimensional structure of GST-pi free and bound to an inhibitor that blocks its ability to inhibit the JNK-jun activation. We thus identified 4 putative domains that may be involved in the interaction between GST-pi and the JNK-jun complex: residues 34–50, 99–121, 165–182 (with 2 overlapping sub-domains 165–175 and 169–182), and 194–201. We have synthesized each of these domains and tested them for their abilities to affect the GST-JNK-jun system, first in a cell-free system. We find that peptides corresponding to residues 99–121 and 194–201 strongly inhibit the binding of GST to the JNK-jun complex but do not inhibit JNK-induced phosphorylation of jun, while peptides corresponding to residues 34–50 and 165–182 do not inhibit GST binding but, except for the 165–175 subdomain peptide, strongly inhibit jun phosphorylation. A control peptide, X13, had no effect on either process. Peptide effects on jun phosphorylation appear to be selective for the JNK-jun system since the 34–50 peptide has no effect on other kinase systems (eg, casein kinase, MAP kinase). Three of the domain peptides, 34–50, 165–175, and 194–201 have been attached on their carboxyl-terminal ends to a penetratin sequence, enabling transmembrane transport into cells, and have been introduced into human astrocytes in which JNK was activated with anisomycin. We find that the 34–50-penetratin peptide strongly inhibits intracellular jun phosphorylation while the 194–201-penetratin peptide has no effect; the 165–175-penetratin peptide has a weak effect on this process. Thus, the effects in cells parallel those in the cell-free system. We conclude that all putative domains, identified in our prior structural studies, appear to interact with the JNK-jun complex. The 34–50 peptide may be useful in selectively blocking uncontrolled mitogenic signaling involving the JNK-jun pathway and may be a potential agent for blocking oncogenic ras-p21-induced cell transformation.
Keywords: glutathione-S-transferase-pi (GST-pi), jun-N-terminal kinase (JNK), jun, GST domain peptides
This article has been cited by other articles:
|
|
 |
|
  S. L. Holley, A. A. Fryer, J. W. Haycock, S. E.W. Grubb, R. C. Strange, and P. R. Hoban Differential effects of glutathione S-transferase pi (GSTP1) haplotypes on cell proliferation and apoptosis Carcinogenesis, November 1, 2007; 28(11): 2268 - 2273. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. A. Williams, A. E. Mars, S. G. Buyske, E. S. Stenroos, R. Wang, M. F. Factura-Santiago, G. H. Lambert, and W. G. Johnson Risk of Autistic Disorder in Affected Offspring of Mothers With a Glutathione S-Transferase P1 Haplotype Arch Pediatr Adolesc Med, April 1, 2007; 161(4): 356 - 361. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Smeyne, J. Boyd, K. Raviie Shepherd, Y. Jiao, B. B. Pond, M. Hatler, R. Wolf, C. Henderson, and R. J. Smeyne GST{pi} expression mediates dopaminergic neuron sensitivity in experimental parkinsonism PNAS, February 6, 2007; 104(6): 1977 - 1982. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
