title: The involvement of PUMP from mitochondria of Araucaria angustifolia embryogenic cells in response to cold stress.
abstract: In this study, the responses of plant uncoupling mitochondrial protein (PUMP) and alternative oxidase (AOX) in mitochondria from embryogenic cells of A. angustifolia subjected to cold stress (4°C for 24 h or 48 h) is reported. In the mitochondria of stressed cells, PUMP activity increased by approximately 45% (at 24h and 48 h), which was determined by measuring the oxygen consumption after the addition of linoleic acid and the inhibition by BSA and ATP. PUMP activation was confirmed using transmembrane electrical potential (Δψ) assays. Immunoblot assays showed an increase of PUMP expression by 40% and 150% after 24h and 48 h of cold stress, respectively. AOX activity, measured under conditions similar to those of the PUMP assays, was only slightly increased in the mitochondria from stressed cells (at 24h and 48 h), as demonstrated by oxygen consumption experiments. Cell viability was unaffected by cold stress, indicating that the effects on PUMP and AOX were not caused by cell death. These results show that the main response of this gymnosperm to cold stress is the activation of PUMP, which suggests that this protein may be involved in the control of reactive oxygen species generation, which has been previously associated with this condition.
authors.affiliation: Department of Biochemistry and Molecular Biology, Federal University of Paraná, Curitiba, Paraná, Brazil.
authors.forename: Caroline
authors.initials: C
authors.lastname: Valente
authors.forename: Patrícia
authors.initials: P
authors.lastname: Pasqualim
authors.forename: Thiago
authors.initials: T
authors.lastname: Jacomasso
authors.forename: Juliana Bello Baron
authors.initials: JB
authors.lastname: Maurer
authors.forename: Emanuel Maltempi de
authors.initials: EM
authors.lastname: Souza
authors.forename: Glaucia Regina
authors.initials: GR
authors.lastname: Martinez
authors.forename: Maria Eliane Merlin
authors.initials: ME
authors.lastname: Rocha
authors.forename: Eva Gunilla Skare
authors.initials: EG
authors.lastname: Carnieri
authors.forename: Sílvia Maria Suter Correia
authors.initials: SM
authors.lastname: Cadena
mesh_terms: D018929:Cell Culture Techniques; D002470:Cell Survival; D003080:Cold Temperature; D007473:Ion Channels / Q000378:metabolism*; D053078:Membrane Potential, Mitochondrial / Q000502:physiology*; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D013312:Stress, Physiological; D064028:Tracheophyta / Q000033:anatomy & histology / Q000196:embryology / Q000201:enzymology / Q000502:physiology*; D000071256:Uncoupling Protein 1; D000099188:Alternative Oxidase
chemical_list: D007473:Ion Channels; D024101:Mitochondrial Proteins; D010088:Oxidoreductases; D010100:Oxygen; D010940:Plant Proteins; D000071256:Uncoupling Protein 1; D000099188:Alternative Oxidase