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Wenzhe Wang Jianwei Pan Ke Zheng Honghong Shao Hongwu Bian Junhui Wang 《Biochemical and biophysical research communications》2009,383(1):141-145
Our previous data showed that apoptotic suppressors inhibit aluminum (Al)-induced programmed cell death (PCD) and promote Al tolerance in yeast cells, however, very little is known about the underlying mechanisms, especially in plants. Here, we show that the Caenorhabditis elegans apoptotic suppressor Ced-9, a Bcl-2 homologue, inhibited both the Al-induced PCD and Al-induced activity of caspase-like vacuolar processing enzyme (VPE), a crucial executioner of PCD, in tobacco. Furthermore, we show that Ced-9 significantly alleviated Al inhibition of root elongation, decreased Al accumulation in the root tip and greatly inhibited Al-induced gene expression in early response to Al, leading to enhancing the tolerance of tobacco plants to Al toxicity. Our data suggest that Ced-9 promotes Al tolerance in plants via inhibition of Al-induced PCD, indicating that conserved negative regulators of PCD are involved in integrated regulation of cell survival and Al-induced PCD by an unidentified mechanism. 相似文献
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Vercammen D Belenghi B van de Cotte B Beunens T Gavigan JA De Rycke R Brackenier A Inzé D Harris JL Van Breusegem F 《Journal of molecular biology》2006,364(4):625-636
Metacaspases are distant relatives of animal caspases found in plants, fungi and protozoa. We demonstrated previously that two type II metacaspases of Arabidopsis thaliana, AtMC4 and AtMC9 are Arg/Lys-specific cysteine-dependent proteases. We screened a combinatorial tetrapeptide library of 130,321 substrates with AtMC9. Here, we show that AtMC9 is a strict Arg/Lys-specific protease. Based on the position-specific scoring matrix derived from the substrate library results, the tetrapeptide Val-Arg-Pro-Arg was identified as an optimized substrate. AtMC9 had a kcat/KM of 4.6x10(5) M-1 s-1 for Ac-Val-Arg-Pro-Arg-amido-4-methyl-coumarin, representing a more than 10-fold improvement over existing fluorogenic substrates. A yeast two-hybrid screen with catalytically inactive AtMC9 as bait identified a serine protease inhibitor, designated AtSerpin1, which was found to be a potent inhibitor of AtMC9 activity in vitro through cleavage of its reactive center loop and covalent binding to AtMC9. On the basis of the substrate profiling of AtMC9 and confirmation through site-directed mutagenesis, the inhibitory P4-P1 cleavage site of AtSerpin1 was determined to be Ile-Lys-Leu-Arg351. Further mutagenesis of the AtSerpin1 inhibitory cleavage site modulated AtMC9 inhibition positively or negatively. Both AtMC9 and AtSerpin1 were localized in the extracellular space, suggesting an in vivo interaction as well. To our knowledge, this is the first report of plant protease inhibition by a plant serpin. 相似文献
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A cellular suicide strategy of plants: vacuole-mediated cell death 总被引:12,自引:0,他引:12
Hatsugai N Kuroyanagi M Nishimura M Hara-Nishimura I 《Apoptosis : an international journal on programmed cell death》2006,11(6):905-911
Programmed cell death (PCD) occurs in animals and plants under various stresses and during development. Recently, vacuolar
processing enzyme (VPE) was identified as an executioner of plant PCD. VPE is a cysteine protease that cleaves a peptide bond
at the C-terminal side of asparagine and aspartic acid. VPE exhibited enzymatic properties similar to that of a caspase, which
is a cysteine protease that mediates the PCD pathway in animals, although there is limited sequence identity between the two
enzymes. VPE and caspase-1 share several structural properties: the catalytic dyads and three amino acids forming the substrate
pockets (Asp pocket) are conserved between VPE and caspase-1. In contrast to such similarities, subcellular localizations
of these proteases are completely different from each other. VPE is localized in the vacuoles, while caspases are localized
in the cytosol. VPE functions as a key molecule of plant PCD through disrupting the vacuole in pathogenesis and development.
Cell death triggered by vacuolar collapse is unique to plants and has not been seen in animals. Plants might have evolved
a VPE-mediated vacuolar system as a cellular suicide strategy. 相似文献
4.
Urquhart W Gunawardena AH Moeder W Ali R Berkowitz GA Yoshioka K 《Plant molecular biology》2007,65(6):747-761
The hypersensitive response (HR) involves programmed cell death (PCD) in response to pathogen infection. To investigate the
pathogen resistance signaling pathway, we previously identified the Arabidopsis mutant cpr22, which displays constitutive activation of multiple defense responses including HR like cell death. The cpr22 mutation has been identified as a 3 kb deletion that fuses two cyclic nucleotide-gated ion channel (CNGC)-encoding genes,
ATCNGC11 and ATCNGC12, to generate a novel chimeric gene, ATCNGC11/12. In this study, we conducted a characterization of cell death induced by transient expression of ATCNGC11/12 in Nicotiana benthamiana. Electron microscopic analysis of this cell death showed similar characteristics to PCD, such as plasma membrane shrinkage
and vesicle formation. The hallmark of animal PCD, fragmentation of nuclear DNA, was also observed in ATCNGC11/12-induced cell death. The development of cell death was significantly suppressed by caspase-1 inhibitors, suggesting the involvement
of caspases in this process. Recently, vacuolar processing enzyme (VPE) was isolated as the first plant caspase-like protein,
which is involved in HR development. In VPE-silenced plants development of cell death induced by ATCNGC11/12 was much slower and weaker compared to control plants, suggesting the involvement of VPE as a caspase in ATCNGC11/12-induced cell death. Complementation analysis using a Ca2+ uptake deficient yeast mutant demonstrated that the ATCNGC11/12 channel is permeable to Ca2+. Additionally, calcium channel blockers such as GdCl3 inhibited ATCNGC11/12-induced HR formation, whereas potassium channel blockers did not. Taken together, these results indicate that the cell death
that develops in the cpr22 mutant is indeed PCD and that the chimeric channel, ATCNGC11/12, is at the point of, or up-stream of the calcium signal necessary
for the development of HR. 相似文献
5.
Vacuolar processing enzyme activates programmed cell death in the apical meristem inducing loss of apical dominance
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Paula Teper‐Bamnolker Yossi Buskila Eduard Belausov Dalia Wolf Adi Doron‐Faigenboim Shifra Ben‐Dor Renier A.L. Van der Hoorn Amnon Lers Dani Eshel 《Plant, cell & environment》2017,40(10):2381-2392
The potato (Solanum tuberosum L.) tuber is a swollen underground stem that can sprout in an apical dominance (AD) pattern. Bromoethane (BE) induces loss of AD and the accumulation of vegetative vacuolar processing enzyme (S. tuberosum vacuolar processing enzyme [StVPE]) in the tuber apical meristem (TAM). Vacuolar processing enzyme activity, induced by BE, is followed by programmed cell death in the TAM. In this study, we found that the mature StVPE1 (mVPE) protein exhibits specific activity for caspase 1, but not caspase 3 substrates. Optimal activity of mVPE was achieved at acidic pH, consistent with localization of StVPE1 to the vacuole, at the edge of the TAM. Downregulation of StVPE1 by RNA interference resulted in reduced stem branching and retained AD in tubers treated with BE. Overexpression of StVPE1 fused to green fluorescent protein showed enhanced stem branching after BE treatment. Our data suggest that, following stress, induction of StVPE1 in the TAM induces AD loss and stem branching. 相似文献
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