Prevention of Copper-Induced Calcium Influx and Cell Death by Prion-Derived Peptide in Suspension-Cultured Tobacco Cells

Abstract

Impact of copper on the oxidative and calcium signal transductions leading to cell death in plant cells and the effects of the copper-binding peptide derived from the human prion protein (PrP) as a novel plant-protecting agent were assessed using a cell suspension culture of transgenic tobacco (Nicotiana tabacum L., cell line BY-2) expressing the aequorin gene. Copper induces a series of biological and chemical reactions in plant cells including the oxidative burst reflecting the production of reactive oxygen species (ROS), such as hydroxyl radicals, and stimulation of calcium channel opening, allowing a transient increase in cytosolic calcium concentrations. The former was proven by the action of specifiC ROS scavengers blocking the calcium responses and the latter was proven by an increase in aequorin luminescence and its inhibition by specifi c channel blockers. Following these early events completed within 10 min, the development of copper-induced cell death was observed during additional 1 h in a dose-dependent manner. Addition of a synthetic peptide (KTNMKHMA) corresponding to the neurotoxic sequence in human PrP, prior to the addition of copper, effectively blocked both calcium influx and cell death induced by copper. Lastly, a possible mechanism of peptide action and future applications of this peptide in the protection of plant roots from metal toxicity or in favour of phytoremediation processes are discussed

Peroxyacetyl nitrate-induced oxidative and calcium signaling events leading to cell death in ozone-sensitive tobacco cell-line

“…Large contribution of copper ions in the induced cell death is consistent with the previously reported high toxicity of copper ions in tobacco cells. 28 Taken together with the effect of DMTU, we can conclude at present that metal-requiring reactions most likely to be Fentontype reactions, catalyzed by highly toxic copper ions and moderately toxic iron ions might take place, finally leading to the production of HO…”

Copper-Binding Peptides from Human Prion Protein and Newly Designed Peroxidative Biocatalysts

“…The neurotoxic sequence (peptide 3) has strong Cu-binding property and, therefore, protection of living plant cells from copper toxicity has been attempted (Kagenishi et al, 2009). However, peptide 3 was shown to be catalytically inactive towards all of the substrates tested here.…”

Production and removal of superoxide anion radical by artificial metalloenzymes and redox-active metals

“…According to Kageenishi et al, 77 PrP-derived redox-inert copper-binding octapeptide, K-T-N-M-K-H-M-A, effectively protected the plant cells from the toxicity of copper which initiates the apoptotic cell death development in plant cells.…”