Open AccessBiochemical and functional characterization of a mitochondrial citrate carrier in Arabidopsis thaliana
Author(s) -
Danielle Santos Brito,
Gennaro Agrimi,
Lennart Charton,
Dominik Brilhaus,
Maria Gabriella Bitetto,
Jaciara Lana-Costa,
Eugenia Messina,
Carolina Pereira Nascimento,
Elias FeitosaAraujo,
Marcel Viana Pires,
Jorge Luis Pérez-Díaz,
Toshihiro Obata,
Vito Porcelli,
Luigi Palmieri,
Wagner L. Araújo,
Andreas Weber,
Nicole Linka,
Alisdair R. Fernie,
Ferdinando Palmieri,
Adriano NunesNesi
Publication year - 2020
Publication title -
biochemical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.706
H-Index - 265
eISSN - 1470-8728
pISSN - 0264-6021
DOI - 10.1042/bcj20190785
Subject(s) - biochemistry , biology , citrate synthase , glyoxylate cycle , arabidopsis thaliana , mitochondrion , chloroplast , gene , metabolism , enzyme , mutant
A homolog of the mitochondrial succinate/fumarate carrier from yeast (Sfc1p) has been found in the Arabidopsis genome, named AtSFC1. The AtSFC1 gene was expressed in Escherichia coli, and the gene product was purified and reconstituted in liposomes. Its transport properties and kinetic parameters demonstrated that AtSFC1 transports citrate, isocitrate and aconitate and, to a lesser extent, succinate and fumarate. This carrier catalyzes a fast counter-exchange transport as well as a low uniport of substrates, exhibits a higher transport affinity for tricarboxylates than dicarboxylates, and is inhibited by pyridoxal 5′-phosphate and other inhibitors of mitochondrial carriers to various degrees. Gene expression analysis indicated that the AtSFC1 transcript is mainly present in heterotrophic tissues, and fusion with a green-fluorescent protein localized AtSFC1 to the mitochondria. Furthermore, 35S-AtSFC1 antisense lines were generated and characterized at metabolic and physiological levels in different organs and at various developmental stages. Lower expression of AtSFC1 reduced seed germination and impaired radicle growth, a phenotype that was related to reduced respiration rate. These findings demonstrate that AtSFC1 might be involved in storage oil mobilization at the early stages of seedling growth and in nitrogen assimilation in root tissue by catalyzing citrate/isocitrate or citrate/succinate exchanges.