Nuclear and peroxisomal targeting of catalase

Abstract

Catalase is a well-known component of the cellular antioxidant network, but there have been conflicting conclusions reached regarding the nature of its peroxisome targeting signal. It has also been reported that catalase can be hijacked to the nucleus by effector proteins of plant pathogens. Using a physiologically relevant system where native untagged catalase variants are expressed in a cat2-1 mutant background, the C terminal most 18 amino acids could be deleted without affecting activity, peroxisomal targeting or ability to complement multiple phenotypes of the cat2-1 mutant. In contrast, converting the native C terminal tripeptide PSI to the canonical PTS1 sequence ARL resulted in lower catalase specific activity. Localisation experiments using split superfolder green fluorescent protein revealed that catalase can be targeted to the nucleus in the absence of any pathogen effectors, and that C terminal tagging in combination with alterations of the native C terminus can interfere with nuclear localisation. These findings provide fundamental new insights into catalase targeting and pave the way for exploration of the mechanism of catalase targeting to the nucleus and its role in non-infected plants.

Astaxanthin Ameliorates Diabetic Retinopathy in Swiss Albino Mice via Inhibitory Processes of Neuron-Specific Enolase Activity

“…Catalase is one of the heme enzymes and it is present in the peroxisome of all cells. Physiologically, it reduces the accumulation of free radicals via conversion of reactive oxygen species i.e., hydrogen peroxide to water and oxygen [55]. In pathological conditions, catalase mitigates the toxic effects of free radicals especially hydrogen peroxide in retinal tissue, and degeneration of retinal pigment.…”

Bacterioplankton Associated with Toxic Cyanobacteria Promote Pisum sativum (Pea) Growth and Nutritional Value through Positive Interactions

“…Stored beyond the required levels and cellular elimination capacities, ROS trigger cellular apoptosis by disrupting intracellular redox homeostasis and causing irreversible oxidative modifications of lipids, proteins, or DNA, which can activate oxidative stress-induced apoptotic signaling [ 111 , 112 ]. Drobac et al (2017) [ 23 ], investigating the toxic effects of MC on the antioxidant capacity of Capsicum annuum leaves and fruits, reported that the concentration of 2.22–100 µg/mL of MC increased the activities of antioxidant enzymes and caused the accumulation of polyphenols and Malondialdehyde, suggesting that the exposure to MC reduced the antioxidant capacity of the experimental plants and altered the homeostasis of C. annuum .…”

Protein-protein interactions in plant antioxidant defense

“…High-throughput assays indicated several nuclear CAT interactors (Table S2), which may shed light on the recently discovered nuclear targeting of CAT (Al-Hajaya et al, 2022). CAT isoforms might be associated with the nuclear pore complex (NPC) as indicated by the possible interaction of all three CATs with nuclear pore complex protein 43 (NUP43; also known as nucleoporin).…”

“…Typical CATs represent a most abundant group occurring in most living organisms, including eubacteria, archaebacteria, protista, fungi, animals and plants ( Zamocky et al., 2008 ; Pan et al., 2022 ). Although plant CATs are recognized as peroxisomal proteins, the presence of CATs has been also detected in nucleus ( Al-Hajaya et al., 2022 ), cytoplasm, mitochondria and chloroplasts ( Mullen et al., 1997 ). Three CAT isoforms (CAT1, CAT2, and CAT3) documented in Arabidopsis have diverse developmental and stress-related functions ( Palma et al., 2020 ).…”