title: The roles of cysteine proteases and phytocystatins in development and germination of cereal seeds.
abstract: Proteolysis is an important process for development and germination of cereal seeds. Among the many types of proteases identified in plants are the cysteine proteases (CPs) of the papain and legumain families, which play a crucial role in hydrolysing storage proteins during seed germination as well as in processing the precursors of these proteins and the inactive forms of other proteases. Moreover, all of the tissues of cereal seeds undergo progressive degradation via programed cell death, which is integral to their growth. In view of the important roles played by proteases, their uncontrolled activity could be harmful to the development of seeds and young seedlings. Thus, the activities of these enzymes are regulated by intracellular inhibitors called phytocystatins (PhyCys). The phytocystatins inhibit the activity of proteases of the papain family, and the presence of an additional motif in their C-termini allows them to also regulate the activity of members of the legumain family. A balance between the levels of cysteine proteases and phytocystatins is necessary for proper cereal seed development, and this is maintained through the antagonistic activities of gibberellins (GAs) and abscisic acid (ABA), which regulate the expression of the corresponding genes. Transcriptional regulation of cysteine proteases and phytocystatins is determined by cis-acting elements located in the promoters of these genes and by the expression of their corresponding transcription factors (TFs) and the interactions between different TFs.
authors: Warsaw University of Life Sciences-SGGW, Faculty of Agriculture and Biology, Department of Biochemistry, Nowoursynowska 159 street, Warsaw 02-776, Poland. Electronic address: joanna_szewinska@sggw.pl.
authors: Joanna
authors: J
authors: Szewińska
authors: Warsaw University of Life Sciences-SGGW, Faculty of Agriculture and Biology, Department of Biochemistry, Nowoursynowska 159 street, Warsaw 02-776, Poland.
authors: Joanna
authors: J
authors: Simińska
authors: Warsaw University of Life Sciences-SGGW, Faculty of Agriculture and Biology, Department of Biochemistry, Nowoursynowska 159 street, Warsaw 02-776, Poland.
authors: Wiesław
authors: W
authors: Bielawski
mesh_terms: D015891:Cystatins / Q000378:metabolism*; D057056:Cysteine Proteases / Q000378:metabolism*; D002523:Edible Grain / Q000378:metabolism*; D018525:Germination; D010937:Plant Growth Regulators / Q000378:metabolism; D012639:Seeds / Q000378:metabolism*
chemical_list: D015891:Cystatins; D010937:Plant Growth Regulators; D057056:Cysteine Proteases
keywords: Cysteine proteinase; Phytocystatin; Proteolysis; Seed development; Seed germination