Programmed cell death-involved aluminum toxicity in yeast alleviated by antiapoptotic members with decreased calcium signals.
The molecular mechanisms of aluminum (Al) toxicity and tolerance in plants have been the focus of ongoing research in the area of stress phytophysiology. Recent studies have described Al-induced apoptosis-like cell death in plant and animal cells. In this study, we show that yeast (Saccharomyces cerevisiae) exposed to low effective concentrations of Al for short times undergoes enhanced cell division in a manner that is dose and cell density dependent. At higher concentrations of Al or longer exposure times, Al induces cell death and growth inhibition. Several apoptotic features appear during Al treatment, including cell shrinkage, vacuolation, chromatin marginalization, nuclear fragmentation, DNA degradation, and DNA strand breaks, as well as concomitant cell aggregation. Yeast strains expressing Ced-9, Bcl-2, and PpBI-1 (a plant Bax inhibitor-1 isolated from Phyllostachys praecox), respectively, display more resistance to Al toxicity compared with control cells. Data from flow cytometric studies show these three antiapoptotic members do not affect reactive oxygen species levels, but decrease calcium ion (Ca(2+)) signals in response to Al stress, although both intracellular reactive oxygen species and Ca(2+) levels were increased. The data presented suggest that manipulation of the negative regulation process of programmed cell death may provide a novel mechanism for conferring Al tolerance.
Zheng
Ke
K
State Key Lab of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
Pan
Jian-Wei
JW
Ye
Lan
L
Fu
Yu
Y
Peng
Hua-Zheng
HZ
Wan
Bai-Yu
BY
Gu
Qing
Q
Bian
Hong-Wu
HW
Han
Ning
N
Wang
Jun-Hui
JH
Kang
Bo
B
Pan
Jun-Hang
JH
Shao
Hong-Hong
HH
Wang
Wen-Zhe
WZ
Zhu
Mu-Yuan
MY
D000535:Aluminum / Q000633:toxicity*; D000595:Amino Acid Sequence; D017209:Apoptosis / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism*; D049109:Cell Proliferation / Q000187:drug effects; D004249:DNA Damage; D008969:Molecular Sequence Data; D017382:Reactive Oxygen Species / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D015398:Signal Transduction
D017382:Reactive Oxygen Species; D029701:Saccharomyces cerevisiae Proteins; D000535:Aluminum; D002118:Calcium