TY - JOUR
T1 - Phosphate disruption and metal toxicity in Saccharomyces cerevisiae
T2 - Effects of RAD23 and the histone chaperone HPC2
AU - Rosenfeld, Leah
AU - Culotta, Valeria C.
N1 - Funding Information:
We thank Forrest Spencer for providing the yeast genomic DNA library and Edison Leung and Mark Carroll for analysis of genomic DNA plasmids. This work was supported by the JHU NIEHS center and by NIH grant ES 08996. LR was supported by NIEHS training grant ES 007308.
PY - 2012/2/10
Y1 - 2012/2/10
N2 - In cells, there exists a delicate balance between accumulation of charged metal cations and abundant anionic complexes such as phosphate. When phosphate metabolism is disrupted, cell-wide spread disturbances in metal homeostasis may ensue. The best example is a yeast pho80 mutant that hyperaccumulates phosphate and as result, also hyperaccumulates metal cations from the environment and shows exquisite sensitive to toxicity from metals such as manganese. In this study, we sought to identify genes that when over-expressed would suppress the manganese toxicity of pho80 mutants. Two classes of suppressors were isolated, including the histone chaperones SPT16 and HPC2, and RAD23, a well-conserved protein involved in DNA repair and proteosomal degradation. The histone chaperone gene HPC2 reversed the elevated manganese and phosphate of pho80 mutants by specifically repressing PHO84, encoding a metal-phosphate transporter. RAD23 also reduced manganese toxicity by lowering manganese levels, but RAD23 did not alter phosphate nor repress PHO84. We observed that the RAD23-reversal of manganese toxicity reflected its role in protein quality control, not DNA repair. Our studies are consistent with a model in which Rad23p partners with the deglycosylating enzyme Png1p to reduce manganese toxicity through proteosomal degradation of glycosylated substrate(s).
AB - In cells, there exists a delicate balance between accumulation of charged metal cations and abundant anionic complexes such as phosphate. When phosphate metabolism is disrupted, cell-wide spread disturbances in metal homeostasis may ensue. The best example is a yeast pho80 mutant that hyperaccumulates phosphate and as result, also hyperaccumulates metal cations from the environment and shows exquisite sensitive to toxicity from metals such as manganese. In this study, we sought to identify genes that when over-expressed would suppress the manganese toxicity of pho80 mutants. Two classes of suppressors were isolated, including the histone chaperones SPT16 and HPC2, and RAD23, a well-conserved protein involved in DNA repair and proteosomal degradation. The histone chaperone gene HPC2 reversed the elevated manganese and phosphate of pho80 mutants by specifically repressing PHO84, encoding a metal-phosphate transporter. RAD23 also reduced manganese toxicity by lowering manganese levels, but RAD23 did not alter phosphate nor repress PHO84. We observed that the RAD23-reversal of manganese toxicity reflected its role in protein quality control, not DNA repair. Our studies are consistent with a model in which Rad23p partners with the deglycosylating enzyme Png1p to reduce manganese toxicity through proteosomal degradation of glycosylated substrate(s).
KW - Manganese
KW - Metals
KW - Phosphate
KW - Yeasts
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U2 - 10.1016/j.bbrc.2012.01.047
DO - 10.1016/j.bbrc.2012.01.047
M3 - Article
C2 - 22281500
AN - SCOPUS:84856686888
SN - 0006-291X
VL - 418
SP - 414
EP - 419
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 2
ER -