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At SERPIN 1 is an inhibitor of the metacaspase At MC 1‐mediated cell death and autocatalytic processing in planta
Author(s) -
Lema Asqui Saul,
Vercammen Dominique,
Serrano Irene,
Valls Marc,
Rivas Susana,
Van Breusegem Frank,
Conlon Frank L.,
Dangl Jeffery L.,
Coll Núria S.
Publication year - 2018
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.14446
Subject(s) - serpin , programmed cell death , microbiology and biotechnology , caspase , biology , proteases , protease , arabidopsis thaliana , arabidopsis , apoptosis , mutant , biochemistry , enzyme , gene
Summary The hypersensitive response ( HR ) is a localized programmed cell death phenomenon that occurs in response to pathogen recognition at the site of attempted invasion. Despite more than a century of research on HR , little is known about how it is so tightly regulated and how it can be contained spatially to a few cells. At MC 1 is an Arabidopsis thaliana plant metacaspase that positively regulates the HR . Here, we used an unbiased approach to identify new At MC 1 regulators. Immunoaffinity purification of At MC 1‐containing complexes led us to the identification of the protease inhibitor AtSerpin1. Our data clearly showed that coimmunoprecipitation between At MC 1 and AtSerpin1 and formation of a complex between them was lost upon mutation of the At MC 1 catalytic site, and that the At MC 1 prodomain was not required for the interaction. AtSerpin1 blocked At MC 1 self‐processing and inhibited At MC 1‐mediated cell death. Our results constitute an in vivo example of a Serpin acting as a suicide inhibitor in plants, reminiscent of the activity of animal or viral serpins on immune/cell death regulators, including caspase‐1. These results indicate a conserved function of a protease inhibitor on cell death regulators from different kingdoms with unrelated modes of action (i.e. caspases vs metacaspases).