title: Regulating cytoplasmic calcium homeostasis can reduce aluminum toxicity in yeast.
abstract: Our previous study suggested that increased cytoplasmic calcium (Ca) signals may mediate aluminum (Al) toxicity in yeast (Saccharomyces cerevisiae). In this report, we found that a yeast mutant, pmc1, lacking the vacuolar calcium ion (Ca(2+)) pump Ca(2+)-ATPase (Pmc1p), was more sensitive to Al treatment than the wild-type strain. Overexpression of either PMC1 or an anti-apoptotic factor, such as Bcl-2, Ced-9 or PpBI-1, decreased cytoplasmic Ca(2+) levels and rescued yeast from Al sensitivity in both the wild-type and pmc1 mutant. Moreover, pretreatment with the Ca(2+) chelator BAPTA-AM sustained cytoplasmic Ca(2+) at low levels in the presence of Al, effectively making the cells more tolerant to Al exposure. Quantitative RT-PCR revealed that the expression of calmodulin (CaM) and phospholipase C (PLC), which are in the Ca(2+) signaling pathway, was down-regulated under Al stress. This effect was largely counteracted when cells overexpressed anti-apoptotic Ced-9 or were pretreated with BAPTA-AM. Taken together, our results suggest that the negative regulation of Al-induced cytoplasmic Ca signaling is a novel mechanism underlying internal resistance to Al toxicity.
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Xuan
authors.initials: X
authors.lastname: Li
authors.forename: Jia
authors.initials: J
authors.lastname: Qian
authors.forename: Chaoqun
authors.initials: C
authors.lastname: Wang
authors.forename: Ke
authors.initials: K
authors.lastname: Zheng
authors.forename: Lan
authors.initials: L
authors.lastname: Ye
authors.forename: Yu
authors.initials: Y
authors.lastname: Fu
authors.forename: Ning
authors.initials: N
authors.lastname: Han
authors.forename: Hongwu
authors.initials: H
authors.lastname: Bian
authors.forename: Jianwei
authors.initials: J
authors.lastname: Pan
authors.forename: Junhui
authors.initials: J
authors.lastname: Wang
authors.forename: Muyuan
authors.initials: M
authors.lastname: Zhu
mesh_terms: D000535:Aluminum / Q000633:toxicity*; D001483:Base Sequence; D002118:Calcium / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism*; D017931:DNA Primers; D006706:Homeostasis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000378:metabolism
chemical_list: D017931:DNA Primers; D000535:Aluminum; D002118:Calcium