title: Up-regulation of leucine aminopeptidase-A in cadmium-treated tomato roots.
abstract: The effects of cadmium (Cd) on aminopeptidase (AP) activities and Leucine-AP (LAP) expression were investigated in the roots of tomato (Solanum lycopersicum L., var Ibiza) plants. Three-week-old plants were grown for 10 days in the presence of 0.3-300 μM Cd and compared to control plants grown in the absence of Cd. AP activities were measured using six different p-nitroanilide (p-NA) substrates. Leu, Met, Arg, Pro and Lys hydrolyzing activities increased in roots of Cd-treated plants, while Phe-pNA cleavage was not enhanced after Cd treatments. The use of peptidase inhibitors showed that most of the Leu-pNA hydrolyzing activity was related to one or several metallo-APs. Changes in Lap transcripts, protein and activities were measured in the roots of 0 and 30-μM Cd-treated plants. LapA transcript levels increased in Cd-treated roots, whereas LapN RNAs levels were not modified. To assess amount of Leu-pNA hydrolyzing activity associated with the hexameric LAPs, LAP activity was measured following immunoprecipitation with a LAP polyclonal antiserum. LAP activity increased in Cd-treated roots. There was a corresponding increase in LAP-A protein levels detected in 2D-immunoblots. The role of LAP-A in the proteolytic response to Cd stress is discussed.
authors: Département de Biologie, Faculté des Sciences de Tunis El Manar, Unité de Recherche de Biologie et Physiologie Cellulaires Végétales, 1060 Tunis, Tunisia.
authors: Latifa
authors: L
authors: Boulila-Zoghlami
authors: Philippe
authors: P
authors: Gallusci
authors: Frances M
authors: FM
authors: Holzer
authors: Gilles J
authors: GJ
authors: Basset
authors: Whabi
authors: W
authors: Djebali
authors: Wided
authors: W
authors: Chaïbi
authors: Linda L
authors: LL
authors: Walling
authors: Renaud
authors: R
authors: Brouquisse
mesh_terms: D000626:Aminopeptidases / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D002104:Cadmium / Q000494:pharmacology*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D007931:Leucyl Aminopeptidase / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D018551:Solanum lycopersicum / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D010936:Plant Extracts; D018515:Plant Leaves / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D011480:Protease Inhibitors / Q000494:pharmacology*; D018749:RNA, Plant / Q000235:genetics; D036226:Seedlings / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D013312:Stress, Physiological; D013379:Substrate Specificity; D013997:Time Factors; D015854:Up-Regulation
chemical_list: D010936:Plant Extracts; D011480:Protease Inhibitors; D018749:RNA, Plant; D002104:Cadmium; D000626:Aminopeptidases; D007931:Leucyl Aminopeptidase