Nuclear and peroxisomal targeting of catalase

• Published in: Plant, cell and environment cell and environment, 2022-04, Vol.45 (4), p.1096-1108
• Main Authors: Al‐Hajaya, Yousef, Karpinska, Barbara, Foyer, Christine H., Baker, Alison
• Format: Article
• Language: English
• Subjects: Amino acids; Antioxidants; C-Terminus; CAT2 gene; CAT2 protein; Catalase; Catalase - metabolism; Cellular communication; Fluorescence; Green fluorescent protein; Green Fluorescent Proteins - metabolism; Localization; Mutants; Nuclei (cytology); nucleus; Original; Pathogens; peroxisome; Peroxisome-Targeting Signal 1 Receptor - metabolism; Peroxisomes - metabolism; Phenotypes; Proteins; Receptors, Cytoplasmic and Nuclear - metabolism; redox signalling; ROS
• ISSN: 0140-7791; 1365-3040
• DOI: 10.1111/pce.14262

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. Summary statement Arabidopsis thaliana CAT2 is targeted to the nucleus and the peroxisome. Peroxisome targeting was independent of the C terminus and required the noncanonical import pathway for optimal activity. Modification to the C terminus interfered with nuclear targeting in the absence of pathogen effectors.