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Phytaspase, a relocalisable cell death promoting plant protease with caspase specificity
Author(s) -
Chichkova Nina V,
Shaw Jane,
Galiullina Raisa A,
Drury Georgina E,
Tuzhikov Alexander I,
Kim Sang Hyon,
Kalkum Markus,
Hong Teresa B,
Gorshkova Ele,
Torrance Lesley,
Vartapetian Andrey B,
Taliansky Michael
Publication year - 2010
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/emboj.2010.1
Subject(s) - proteases , caspase , biology , protease , caspase 2 , cysteine protease , programmed cell death , microbiology and biotechnology , nlrp1 , subtilisin , apoptosis , gene silencing , biochemistry , enzyme , caspase 1 , gene
Caspases are cysteine‐dependent proteases and are important components of animal apoptosis. They introduce specific breaks after aspartate residues in a number of cellular proteins mediating programmed cell death (PCD). Plants encode only distant homologues of caspases, the metacaspases that are involved in PCD, but do not possess caspase‐specific proteolytic activity. Nevertheless, plants do display caspase‐like activities indicating that enzymes structurally distinct from classical caspases may operate as caspase‐like proteases. Here, we report the identification and characterisation of a novel PCD‐related subtilisin‐like protease from tobacco and rice named phytaspase (plant asp artate‐specific prote ase ) that possesses caspase specificity distinct from that of other known caspase‐like proteases. We provide evidence that phytaspase is synthesised as a proenzyme, which is autocatalytically processed to generate the mature enzyme. Overexpression and silencing of the phytaspase gene showed that phytaspase is essential for PCD‐related responses to tobacco mosaic virus and abiotic stresses. Phytaspase is constitutively secreted into the apoplast before PCD, but unexpectedly is re‐imported into the cell during PCD providing insights into how phytaspase operates.