Hydrogen peroxide homeostasis: Activation of plant catalase by calcium/calmodulin

Abstract

Environmental stimuli such as UV, pathogen attack, and gravity can induce rapid changes in hydrogen peroxide (H2O2) levels, leading to a variety of physiological responses in plants. Catalase, which is involved in the degradation of H2O2 into water and oxygen, is the major H2O2-scavenging enzyme in all aerobic organisms. A close interaction exists between intracellular H2O2 and cytosolic calcium in response to biotic and abiotic stresses. Studies indicate that an increase in cytosolic calcium boosts the generation of H2O2. Here we report that calmodulin (CaM), a ubiquitous calcium-binding protein, binds to and activates some plant catalases in the presence of calcium, but calcium͞CaM does not have any effect on bacterial, fungal, bovine, or human catalase. These results document that calcium͞CaM can down-regulate H2O2 levels in plants by stimulating the catalytic activity of plant catalase. Furthermore, these results provide evidence indicating that calcium has dual functions in regulating H2O2 homeostasis, which in turn influences redox signaling in response to environmental signals in plants.

Cloning and Characterization of Two NAD Kinases from Arabidopsis. Identification of a Calmodulin Binding Isoform

“…Improper tertiary folding in E. coli or the absence of posttranslational modifications or other regulatory components (such as additional, unidentified subunits) are possible explanations for the biochemical differences between the recombinant and native enzymes, but they remain speculative at this point. Our observations are reminiscent of a recent report on a CaM-binding catalase from tobacco in which the native enzyme was responsive to CaM, whereas the recombinant protein expressed in E. coli was not (Yang and Poovaiah, 2002). However, our immunoblot analysis (Fig.…”

Effects of Feeding Spodoptera littoralis on Lima Bean Leaves. III. Membrane Depolarization and Involvement of Hydrogen Peroxide

“…A close interaction exists between H 2 O 2 and cytosolic calcium in response to biotic and abiotic stimuli both in plants (Sanders et al, 1999;Murata et al, 2001;Sagi and Fluhr, 2001;Yang and Poovaiah, 2002;Foreman et al, 2003) and animals (Castro et al, 2004;Redondo et al, 2004;Rosado et al, 2004;Tabet et al, 2004) systems (see Hepler, 2005, for a historical perspective assay). The same independent assay using transgenic soybean cell suspensions that was successfully applied to analyze the activities of herbivore regurgitate components (Maffei et al, 2004) was fundamental to demonstrate that H 2 O 2 is also able to elicit [Ca 21 ] cyt release (Fig.…”

“…ROS play two divergent roles in plant adaptation to the changing environment: enhancement of damage by a highly oxidizing microenvironment or mediating the activation of other defense responses under certain biotic and abiotic stresses (Lamb and Dixon, 1997;Yang and Poovaiah, 2002). In contrast to most animal cells, plant cells are able to produce ROS, mainly H 2 O 2 , constitutively in significant amounts, and this production is developmentally regulated by light, phytohormones, or wounding and predominantly associated with the cell's exocellular matrix (ECM; Bolwell and Wojtaszek, 1997;Bolwell, 1999).…”

“…The production of H 2 O 2 appears not only to be limited to the ECM, as shown by CeCl 3 staining, but also involves the protoplast. (Price et al, 1994;Yang and Poovaiah, 2002), for instance by activating calcium channels (Pei et al, 2000), we first investigated the possibility whether H 2 O 2 could trigger a Ca 21 response in transgenic soybean suspension cells expressing the Ca 21 -sensitive aequorin system (Mithöfer et al, 1999;Mithöfer and Mazars, 2002). The Ca 21 response was determined in a concentration-dependent fashion, and the transiently accumulating [Ca 21 ] cyt appeared to be linearly correlated with the amount of H 2 O 2 up to 0.1 mM (Fig.…”

Evaluation of Allelopathic Effect of White Lupin (Lupinus termis L.) Leaf Extract on the Biochemical Dynamics of Common Purslane (Portulaca oleracea L.)

“…Also, the induction of CaM in P. oleracea may be due to its contribution in the activation of antioxidant enzymes under allelochemicals stress. In support, CaM was found to stimulate the activity of plant catalase (Yang and Poovaiah, 2002) to remove H2O2 and thus prevents lipid peroxidation.…”