Feedback regulation of plastidic acetyl-CoA carboxylase by 18:1-acyl carrier protein in
            <i>Brassica napus</i>

André, Carl; Haslam, Richard P.; Shanklin, John

doi:10.1073/pnas.1204604109

Cited by 140 publications

(122 citation statements)

References 43 publications

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“…If a similar rate of TAG accumulation could be achieved in vegetative tissues of crop plants, a higher TAG level could theoretically be reached by leaf maturation, since many crops have much longer life cycles than Arabidopsis. Further increases in the rate of TAG accumulation may still be possible by overexpression of WRI1, since FA synthesis is insensitive to feedback inhibition (Andre et al, 2012) in the tgd1-1 background (Fan et al, 2013a). Therefore, TGD1 or other TGD proteins represent attractive targets for genetic engineering efforts aimed at enhancing the energy density and nutritional value of vegetative plant biomass.…”

Section: Biotechnological Implications For Tgd Proteinsmentioning

confidence: 99%

Arabidopsis Lipins, PDAT1 Acyltransferase, and SDP1 Triacylglycerol Lipase Synergistically Direct Fatty Acids toward β-Oxidation, Thereby Maintaining Membrane Lipid Homeostasis

et al. 2014

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Triacylglycerol (TAG) metabolism is a key aspect of intracellular lipid homeostasis in yeast and mammals, but its role in vegetative tissues of plants remains poorly defined. We previously reported that PHOSPHOLIPID:DIACYLGLYCEROL ACYLTRANSFERASE1 (PDAT1) is crucial for diverting fatty acids (FAs) from membrane lipid synthesis to TAG and thereby protecting against FA-induced cell death in leaves. Here, we show that overexpression of PDAT1 enhances the turnover of FAs in leaf lipids. Using the trigalactosyldiacylglycerol1-1 (tgd1-1) mutant, which displays substantially enhanced PDAT1-mediated TAG synthesis, we demonstrate that disruption of SUGAR-DEPENDENT1 (SDP1) TAG lipase or PEROXISOMAL TRANSPORTER1 (PXA1) severely decreases FA turnover, leading to increases in leaf TAG accumulation, to 9% of dry weight, and in total leaf lipid, by 3-fold. The membrane lipid composition of tgd1-1 sdp1-4 and tgd1-1 pxa1-2 double mutants is altered, and their growth and development are compromised. We also show that two Arabidopsis thaliana lipin homologs provide most of the diacylglycerol for TAG synthesis and that loss of their functions markedly reduces TAG content, but with only minor impact on eukaryotic galactolipid synthesis. Collectively, these results show that Arabidopsis lipins, along with PDAT1 and SDP1, function synergistically in directing FAs toward peroxisomal b-oxidation via TAG intermediates, thereby maintaining membrane lipid homeostasis in leaves.

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Section: Biotechnological Implications For Tgd Proteinsmentioning

confidence: 99%

Arabidopsis Lipins, PDAT1 Acyltransferase, and SDP1 Triacylglycerol Lipase Synergistically Direct Fatty Acids toward β-Oxidation, Thereby Maintaining Membrane Lipid Homeostasis

et al. 2014

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“…This activation occurs within minutes and is reportedly due to the increase in stromal pH from 7.0 to 8.0 (Hunter and Ohlrogge, 1998) and thioredoxin-dependent reduction of a disulfide bond in CT (Sasaki et al, 1997;Kozaki et al, 2001). HetACCase activity is also suppressed by feedback inhibition through increased levels of acyl-acyl carrier protein (Davis and Cronan, 2001;Andre et al, 2012). Recently, an interaction between hetACCase and a 2-oxoglutarate binding protein PII was shown to reduce hetACCase activity (Feria Bourrellier et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

A Family of Negative Regulators Targets the Committed Step of de Novo Fatty Acid Biosynthesis

et al. 2016

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ORCID ID: 0000-0002-9686-9645 (V.L.)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 in Arabidopsis thaliana annotated as biotin/lipoyl attachment domain containing (BADC) proteins. Results from yeast two-hybrid and coexpression in Escherichia coli confirmed 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 both E. coli and 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.

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“…In this paper, we focus on an example from contemporary botanical research, namely on the feedback regulation of fatty acid biosynthesis in Brassica napus. This particular feedback inhibition mechanism has only recently been identified by Andre et al (2012). 13 Fatty acid biosynthesis is a crucial process for both plants and animals, providing the cell with components for membrane biogenesis and repair and with energy reserves in specialized cells (such as epidermal cells or the cells of oil seeds).…”

Section: Fig 32 the General Mechanism For Feedback Inhibitionmentioning

confidence: 99%

“…Hence, a major challenge for contemporary plant fatty acid research is to provide an understanding of how plants regulate differential fatty acid synthesis. Andre et al (2012) take up this challenge with regard to canola (Brassica napus). Knowing the mechanism of how fatty acid biosynthesis in plants is regulated is important, not least because it may give rise to the design of strategies for increasing fatty acid synthesis in plants (cf.…”

Section: Fig 32 the General Mechanism For Feedback Inhibitionmentioning

confidence: 99%

Causal Graphs and Biological Mechanisms

Gebharter

Kaiser

2013

Explanation in the Special Sciences

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Modeling mechanisms is central to the biological sciences -for purposes of explanation, prediction, extrapolation, and manipulation. A closer look at the philosophical literature reveals that mechanisms are predominantly modeled in a purely qualitative way. That is, mechanistic models are conceived of as representing how certain entities and activities are spatially and temporally organized so that they bring about the behavior of the mechanism in question. Although this adequately characterizes how mechanisms are represented in biology textbooks, contemporary biological research practice shows the need for quantitative, probabilistic models of mechanisms, too. In this paper we argue that the formal framework of causal graph theory is well-suited to provide us with models of biological mechanisms that incorporate quantitative and probabilistic information. On the basis of an example from contemporary biological practice, namely feedback regulation of fatty acid biosynthesis in Brassica napus, we show that causal graph theoretical models can account for feedback as well as for the multi-level character of mechanisms. However, we do not claim that causal graph theoretical representations of mechanisms are advantageous in all respects and should replace common qualitative models. Rather, we endorse the more balanced view that causal graph theoretical models of mechanisms are useful for some purposes, while being insufficient for others.

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Feedback regulation of plastidic acetyl-CoA carboxylase by 18:1-acyl carrier protein in Brassica napus

Cited by 140 publications

References 43 publications

Arabidopsis Lipins, PDAT1 Acyltransferase, and SDP1 Triacylglycerol Lipase Synergistically Direct Fatty Acids toward β-Oxidation, Thereby Maintaining Membrane Lipid Homeostasis

Arabidopsis Lipins, PDAT1 Acyltransferase, and SDP1 Triacylglycerol Lipase Synergistically Direct Fatty Acids toward β-Oxidation, Thereby Maintaining Membrane Lipid Homeostasis

A Family of Negative Regulators Targets the Committed Step of de Novo Fatty Acid Biosynthesis

Causal Graphs and Biological Mechanisms

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