Affiliation:
1. The University of Arizona Liver Research Institute, 6309 AHSC, POB 245136, 1501 N. Campbell Ave., Tucson, AZ 85724-5136, U.S.A.
Abstract
GSTP1 (glutathione S-transferase pi) is involved in stress responses and in cellular proliferation pathways as an inhibitor of JNK (c-Jun N-terminal kinase). It has been proposed that monomeric GSTP1 functions as a JNK inhibitor. All of the studies to date have been performed using rodent cells, and it is unclear if monomeric GSTP1 exists in human cells. Monomeric GSTP1 was sought in human gastric cancer cells (Kato III) and in normal human erythrocytes using gel filtration, ELISA and Western blots. Monomeric GSTP1 was found in conditioned medium, in cytosol of Kato III cells and in cytosol of erythrocytes. GSTP1 subunits from Kato III cells and erythrocytes were heterogeneous when analysed by MALDI–TOF (matrix-assisted laser-desorption ionization–time-of-flight) MS, suggesting that there were post-translational modifications to GSTP1. One post-translational modification, phosphorylation of a serine residue in the C-terminal portion of GSTP1 where JNK binds, was identified in GSTP1 purified from Kato III cells, but not in GSTP1 purified from human erythrocytes. Therefore normal and malignant human cells contain GSTP1 monomers with post-translational modifications, and it is likely that GSTP1 monomers regulate JNK activity in human cells in the same manner as in rodent cells.
Subject
Cell Biology,Molecular Biology,Biochemistry
Reference39 articles.
1. The glutathione S-transferase supergene family: regulation of GST and the contribution of the isoenzymes to cancer chemoprotection and drug resistance;Hayes;CRC Crit. Rev. Biochem. Mol. Biol.,1995
2. Glutathione transferases – structure and catalytic activity;Mannervik;CRC Crit. Rev. Biochem.,1988
3. Human glutathione S-transferases;Whalen;Semin. Liver Dis.,1998
4. Identification, characterization, and crystal structure of the Omega class glutathione transferases;Board;J. Biol. Chem.,2000
5. Glutathione S-transferases, structure, regulation, and therapeutic implications;Rushmore;J. Biol. Chem.,1993
Cited by
15 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献