Inactivation of Homocitrate Synthase Causes Lysine Auxotrophy in Copper/Zinc-containing Superoxide Dismutase-deficient Yeast Schizosaccharomyces pombe

The fission yeast Schizosaccharomyces pombe lacking copper/zinc-containing superoxide dismutase (CuZn-SOD) is auxotrophic for lysine and sulfurous amino acids under aerobic growth conditions. A multicopy suppressor gene (phx1+) that restored the growth of CuZn-SOD-deficient cells on minimal medium w...

Full description

Saved in:
Bibliographic Details
Published in:The Journal of biological chemistry 2006-01, Vol.281 (3), p.1345-1351
Main Authors: Kwon, Eun-Soo, Jeong, Jae-Hoon, Roe, Jung-Hye
Format: Article
Language:English
Subjects:
Blotting, Northern
Cloning, Molecular
Culture Media
Kinetics
Lysine - genetics
Lysine - metabolism
Oxo-Acid-Lyases - antagonists & inhibitors
Oxo-Acid-Lyases - metabolism
Schizosaccharomyces - enzymology
Schizosaccharomyces - genetics
Schizosaccharomyces - growth & development
Schizosaccharomyces pombe
Schizosaccharomyces pombe Proteins - antagonists & inhibitors
Schizosaccharomyces pombe Proteins - genetics
Superoxide Dismutase - deficiency
Superoxide Dismutase - genetics
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The fission yeast Schizosaccharomyces pombe lacking copper/zinc-containing superoxide dismutase (CuZn-SOD) is auxotrophic for lysine and sulfurous amino acids under aerobic growth conditions. A multicopy suppressor gene (phx1+) that restored the growth of CuZn-SOD-deficient cells on minimal medium was isolated. It encodes a putative DNA-binding protein with a conserved homeobox domain. Overproduction of Phx1 increased the amount of several proteins, and one of those turned out to be a putative homocitrate synthase (HCS) encoded by the lys4+ gene in S. pombe as judged by mass spectrometric analysis. Consistent with this observation, overexpression of the lys4+ gene increased HCS enzyme activity and was sufficient to suppress the lysine requirement of the CuZn-SOD-deficient cells. Enzyme activity and Western blot analyses revealed that the activity and protein level of HCS were dramatically reduced upon depletion of CuZn-SOD. Treatment of exponentially growing S. pombe cells with paraquat, a superoxide generator, caused a decrease in the amount of Lys4 protein as expected. These results led us to conclude that HCS, the first enzyme in the α-aminoadipate-mediated pathway for lysine synthesis common in fungi and some bacteria, is a labile target of oxidative stress caused by CuZn-SOD depletion and that its synthesis is positively regulated by the putative transcriptional regulator Phx1.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M506611200