TY - JOUR
T1 - A novel mechanism of aluminium-induced cell death involving vacuolar processing enzyme and vacuolar collapse in tobacco cell line BY-2
AU - Kariya, Koki
AU - Demiral, Tijen
AU - Sasaki, Takayuki
AU - Tsuchiya, Yoshiyuki
AU - Turkan, Ismail
AU - Sano, Toshio
AU - Hasezawa, Seiichiro
AU - Yamamoto, Yoko
N1 - Funding Information:
We thank Prof. Toshiyuki Nagata (Hosei University, Tokyo) for providing us with BY-2 cell line and Dr. Takuya Furuichi (Gifu Women's University, Gifu) for valuable discussion. This study was supported by a Grant-in-Aid for General Scientific Research from the Ministry of Education, Culture, Sports, Science, and Technology of Japan (nos. 21580078 , 24380039 ) and the Ohara Foundation for Agricultural Science . T.D. was supported by JASSO scholarship from Okayama University .
PY - 2013
Y1 - 2013
N2 - The role of vacuole in the cell death mechanism induced by aluminium (Al) was investigated in tobacco (Nicotiana tabacum L.) cell line BY-2. Cells at logarithmic phase of growth were treated without (control) or with Al (up to 150 μM) in a treatment medium containing CaCl2, sucrose and 2-(N-morpholino) ethanesulfonic acid (MES) buffer (pH 5.0). After 18 h treatment, both the integrity of the plasma membrane (estimated by Evans blue uptake) and growth capacity (estimated by post-Al treatment growth in nutrient medium) were decreased, while the activity of vacuolar processing enzyme (VPE) was increased, in the Al dose-dependent manner. The activity of the vacuole (estimated by neutral red uptake) was slightly increased at 50 μM then decreased with an increase in Al concentration. Direct observation of morphological changes of vacuole in a transgenic BY-2 expressing GFP-AtVam3p fusion protein localized on tonoplast indicated Al-induced collapse of vacuole. Time-course experiments indicated that both an increase in VPE activity and a loss of growth capacity were clearly observed at 6 h of the treatment time, prior to the loss of plasma membrane integrity. The presence of Ac-YVAD-CHO (an inhibitor effective to VPE) during Al treatment suppressed a loss of plasma membrane integrity. The expression of VPE genes (VPE-1a, VPE-1b) were significantly enhanced by Al treatment. Taken together, we conclude that an enhancement of VPE activity by Al is controlled at transcriptional level, and is a key factor leading to a loss of integrity of the plasma membrane and a loss of growth capacity.
AB - The role of vacuole in the cell death mechanism induced by aluminium (Al) was investigated in tobacco (Nicotiana tabacum L.) cell line BY-2. Cells at logarithmic phase of growth were treated without (control) or with Al (up to 150 μM) in a treatment medium containing CaCl2, sucrose and 2-(N-morpholino) ethanesulfonic acid (MES) buffer (pH 5.0). After 18 h treatment, both the integrity of the plasma membrane (estimated by Evans blue uptake) and growth capacity (estimated by post-Al treatment growth in nutrient medium) were decreased, while the activity of vacuolar processing enzyme (VPE) was increased, in the Al dose-dependent manner. The activity of the vacuole (estimated by neutral red uptake) was slightly increased at 50 μM then decreased with an increase in Al concentration. Direct observation of morphological changes of vacuole in a transgenic BY-2 expressing GFP-AtVam3p fusion protein localized on tonoplast indicated Al-induced collapse of vacuole. Time-course experiments indicated that both an increase in VPE activity and a loss of growth capacity were clearly observed at 6 h of the treatment time, prior to the loss of plasma membrane integrity. The presence of Ac-YVAD-CHO (an inhibitor effective to VPE) during Al treatment suppressed a loss of plasma membrane integrity. The expression of VPE genes (VPE-1a, VPE-1b) were significantly enhanced by Al treatment. Taken together, we conclude that an enhancement of VPE activity by Al is controlled at transcriptional level, and is a key factor leading to a loss of integrity of the plasma membrane and a loss of growth capacity.
KW - Aluminium toxicity
KW - Cell death
KW - Evans blue
KW - Neutral red
KW - Vacuolar processing enzyme (VPE)
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U2 - 10.1016/j.jinorgbio.2013.07.001
DO - 10.1016/j.jinorgbio.2013.07.001
M3 - Article
C2 - 23891542
AN - SCOPUS:84885957197
VL - 128
SP - 196
EP - 201
JO - Journal of Inorganic Biochemistry
JF - Journal of Inorganic Biochemistry
SN - 0162-0134
ER -