title: The pseudoenzyme PDX1.2 boosts vitamin B6 biosynthesis under heat and oxidative stress in Arabidopsis.
abstract: Vitamin B6 is an indispensable compound for survival, well known as a cofactor for numerous central metabolic enzymes and more recently for playing a role in several stress responses, particularly in association with oxidative stress. Regulatory aspects for the use of the vitamin in these roles are not known. Here we show that certain plants carry a pseudoenzyme (PDX1.2), which is involved in regulating vitamin B6 biosynthesis de novo under stress conditions. Specifically, we demonstrate that Arabidopsis PDX1.2 enhances the activity of its catalytic paralogs by forming a heterododecameric complex. PDX1.2 is strongly induced by heat as well as singlet oxygen stress, concomitant with an enhancement of vitamin B6 production. Analysis of pdx1.2 knockdown lines demonstrates that boosting vitamin B6 content is dependent on PDX1.2, revealing that this pseudoenzyme acts as a positive regulator of vitamin B6 biosynthesis during such stress conditions in plants.
authors: From the Department of Botany and Plant Biology, University of Geneva, 1211 Geneva, Switzerland and.
authors: Cyril
authors: C
authors: Moccand
authors: Svetlana
authors: S
authors: Boycheva
authors: Pedro
authors: P
authors: Surriabre
authors: Marina
authors: M
authors: Tambasco-Studart
authors: Maja
authors: M
authors: Raschke
authors: Markus
authors: M
authors: Kaufmann
authors: Teresa B
authors: TB
authors: Fitzpatrick
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019759:Carbon-Nitrogen Lyases; D055785:Gene Knockdown Techniques; D006358:Hot Temperature; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019884:Nitrogenous Group Transferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress; D013312:Stress, Physiological; D025101:Vitamin B 6 / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; C000588558:PDX1.2 protein, Arabidopsis; D025101:Vitamin B 6; D019884:Nitrogenous Group Transferases; D019759:Carbon-Nitrogen Lyases; C505161:At2g38230 protein, Arabidopsis
keywords: Antioxidants; Biosynthesis; Enzyme Catalysis; Plant Biochemistry; Pyridoxal Phosphate; Stress Response