Effect of mutation of C-terminal and heme binding region of Arabidopsis catalase on the import to peroxisomes

Abstract

We evaluated the import of Arabidopsis catalase to peroxisomes under homogenous transient expression. The amino acids at −11 to −4 from the C-terminus are necessary for catalase import. The results are in agreement with the previous work under stable expression. We first demonstrate that heme-binding sites are important for peroxisomal import, suggesting the importance of catalase folding. Abbreviations: AtCat: Arabidopsis catalase; PTS: peroxisomal targeting signal; PEX: Peroxin

Nuclear and peroxisomal targeting of catalase

“…There is little consensus regarding the importance of sequences within the conserved C terminal region of catalase in targeting to peroxisomes (Fujikawa et al, 2019 ; Kamigaki et al, 2003 ; Mullen et al, 1997 ). Previous studies have used different approaches that rendered interpretation of the findings difficult.…”

“…In contrast, the last 10 amino acids of the pumpkin CAT were not required for the peroxisomal localisation of green fluorescent protein (GFP) in stably transformed BY‐2 cells (Kamigaki et al, 2003 ). Other mutations elsewhere in the protein also prevented import (Fujikawa et al, 2019 ).…”

Overexpressing the N‐terminus of CATALASE2 enhances plant jasmonic acid biosynthesis and resistance to necrotrophic pathogen Botrytis cinerea B05.10

“…If CAT2 really can promote ACX2/3 activity through its interaction and a mutated CAT2 with low or no H 2 O 2 ‐decomposing activity can still interact with ACX2 or ACX3, the mutated CAT2 should also stimulate ACX2/3 activity. Therefore, we expressed four mutated CAT2 proteins, CAT2‐H65A, CAT2‐V106A, CAT2‐F143V, and CAT2‐Y348V, according to previous reports (Diaz et al, 2012 ; Fujikawa et al, 2019 ; Poulos, 2010 ). Consistently, the four mutated CAT2 proteins had extremely low catalase activity compared with the wildtype CAT2 (Figure 2a ).…”

“…CAT2 is synthesized in the cytoplasm and imported into peroxisomes based on its C‐terminal atypical PTS1, Q480‐K481‐L482 (Fujikawa et al, 2019 ). The truncated N‐terminus of CAT2 cannot be properly localized in peroxisomes due to a lack of PTS, thus the interaction between CAT2 and ACX2/3 was in the cytoplasm, as shown in our results (Figure 3c,d ).…”

“…Previous reports documented some key amino acid sites necessary for catalase activity (Fujikawa et al, 2019;Poulos, 2010). If CAT2 really can promote ACX2/3 activity through its interaction and a mutated CAT2 with low or no H 2 O 2 -decomposing activity can still interact with ACX2 or ACX3, the mutated CAT2 should also stimulate ACX2/3 activity.…”