Protein–Protein and Protein–Membrane Associations in the Lignin Pathway

Jean-Etienne Bassard (1) , Ludovic Richert (2, 3) , Jan Geerinck , Hugues Renault (1) , Frédéric Duval (1) , Pascaline Ullmann (1) , Martine Schmitt (4) , Etienne Meyer (1) , Jérome Mutterer (1) , Wout Boerjan (5) , Geert de Jaeger (6) , Yves Mély (7, 3) , Alain Goossens , Daniele Werck-Reichhart (1)

1 IBMP - Institut de Biologie Moléculaire des Plantes
2 FDE - Fonctions et dysfonctions épithéliales - UFC (EA 4267)
3 LBP - Laboratoire de Biophotonique et Pharmacologie - UMR 7213
4 LIT - Laboratoire d'Innovation Thérapeutique
5 Department of Plant Biotechnology and Genetics
6 Department of Plant Systems Biology
7 PPCICM - Pharmacologie et physico-chimie des interactions cellulaires et moléculaires

Supramolecular organization of enzymes is proposed to orchestrate metabolic complexity and help channel intermediates in different pathways. Phenylpropanoid metabolism has to direct up to 30% of the carbon fixed by plants to the biosynthesis of lignin precursors. Effective coupling of the enzymes in the pathway thus seems to be required. Subcellular localization, mobility, protein-protein, and protein-membrane interactions of four consecutive enzymes around the main branch point leading to lignin precursors was investigated in leaf tissues of Nicotiana benthamiana and cells of Arabidopsis thaliana. CYP73A5 and CYP98A3, the two Arabidopsis cytochrome P450s (P450s) catalyzing para- and meta-hydroxylations of the phenolic ring of monolignols were found to colocalize in the endoplasmic reticulum (ER) and to form homo- and heteromers. They moved along with the fast remodeling plant ER, but their lateral diffusion on the ER surface was restricted, likely due to association with other ER proteins. The connecting soluble enzyme hydroxycinnamoyltransferase (HCT), was found partially associated with the ER. Both HCT and the 4-coumaroyl-CoA ligase relocalized closer to the membrane upon P450 expression. Fluorescence lifetime imaging microscopy supports P450 colocalization and interaction with the soluble proteins, enhanced by the expression of the partner proteins. Protein relocalization was further enhanced in tissues undergoing wound repair. CYP98A3 was the most effective in driving protein association.

Domaines: Biologie végétale; Biochimie, Biologie Moléculaire

Jean-Etienne Bassard, Ludovic Richert, Jan Geerinck, Hugues Renault, Frédéric Duval, et al.. Protein–Protein and Protein–Membrane Associations in the Lignin Pathway. The Plant cell, 2012, 24 (11), pp.4465-4482. ⟨10.1105/tpc.112.102566⟩. ⟨hal-02438016⟩