title: A Family of Negative Regulators Targets the Committed Step of de Novo Fatty Acid Biosynthesis.
abstract: Acetyl-CoA carboxylase (ACCase) catalyzes the committed step of de novo fatty acid biosynthesis. In prokaryotes, green algae, and most plants, this enzyme is a heteromeric complex requiring four different subunits for activity. The plant complex is recalcitrant to conventional purification schemes and hence the structure and composition of the full assembly have been unclear. In vivo coimmunoprecipitation using subunit-specific antibodies identified a novel family of proteins inArabidopsis thalianaannotated as biotin/lipoyl attachment domain containing (BADC) proteins. Results from yeast two-hybrid and coexpression inEscherichia coliconfirmed that all three BADC isoforms interact with the two biotin carboxyl carrier protein (BCCP) isoforms of Arabidopsis ACCase. These proteins resemble BCCP subunits but are not biotinylated due to a mutated biotinylation motif. We demonstrate that BADC proteins significantly inhibit ACCase activity in bothE. coliand Arabidopsis. Targeted gene silencing of BADC isoform 1 in Arabidopsis significantly increased seed oil content when normalized to either mass or individual seed. We conclude the BADC proteins are ancestral BCCPs that gained a new function as negative regulators of ACCase after initial loss of the biotinylation motif. A functional model is proposed.
authors: Department of Biochemistry, University of Missouri-Columbia, Christopher S. Bond Life Sciences Center, Columbia, Missouri 65211.
authors: Matthew J
authors: MJ
authors: Salie
authors: Informatics Institute and Department of Computer Science, University of Missouri-Columbia, Christopher S. Bond Life Sciences Center, Columbia, Missouri 65211.
authors: Ning
authors: N
authors: Zhang
authors: Department of Biochemistry, University of Missouri-Columbia, Christopher S. Bond Life Sciences Center, Columbia, Missouri 65211.
authors: Veronika
authors: http://orcid.org/0000-0002-9686-9645
authors: V
authors: Lancikova
authors: Informatics Institute and Department of Computer Science, University of Missouri-Columbia, Christopher S. Bond Life Sciences Center, Columbia, Missouri 65211.
authors: Dong
authors: D
authors: Xu
authors: Department of Biochemistry, University of Missouri-Columbia, Christopher S. Bond Life Sciences Center, Columbia, Missouri 65211 thelenj@missouri.edu.
authors: Jay J
authors: JJ
authors: Thelen