title: Human glutamylcysteine synthetase protects HEK293 cells against UV-induced cell death through inhibition of c-Jun NH2-terminal kinase.
abstract: Human glutamylcysteine ligase catalytic subunit (GCLC) is the rate-limiting enzyme for glutathione synthesis. The heavy subunit possesses all the catalytic activities. UV irradiation (UV-C, 30 J/m(2)) induced apoptosis in HEK293 cells, but the morphological changes were inhibited significantly by expression of GCLC. MTS assay and flow cytometry results also indicated that GCLC and JNK1(APF) expression enhanced cellular resistance to UV irradiation. Western blotting showed that irradiation strongly activated the c-Jun NH(2)-terminal kinases (JNKs) and caspase-3 as well as p38 in HEK293 cells. Interestingly, existing data show that GCLC blocks JNK1 phosphorylation but does not affect p38 phosphorylation. Therefore, overexpression of GCLC protected HEK293 cells against UV irradiation-induced cell death by inhibiting the phosphorylation and activation of JNK1, concomitantly with the inhibition of caspase-3 activation and p21(WAF1)-luciferase activity downstream of JNK.
authors.affiliation: Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, China.
authors.forename: Yumei
authors.initials: Y
authors.lastname: Fan
authors.forename: Dongmei
authors.initials: D
authors.lastname: Wu
authors.forename: Lina
authors.initials: L
authors.lastname: Jin
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Yin
mesh_terms: D017209:Apoptosis / Q000528:radiation effects*; D015153:Blotting, Western; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000187:drug effects; D005434:Flow Cytometry; D005721:Glutamate-Cysteine Ligase / Q000627:therapeutic use*; D006801:Humans; D007668:Kidney / Q000166:cytology / Q000528:radiation effects; D008156:Luciferases / Q000378:metabolism; D010766:Phosphorylation; D016755:Proto-Oncogene Proteins c-jun / Q000037:antagonists & inhibitors*; D014466:Ultraviolet Rays; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D016755:Proto-Oncogene Proteins c-jun; D008156:Luciferases; D048051:p38 Mitogen-Activated Protein Kinases; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D005721:Glutamate-Cysteine Ligase