A Chemogenomic Screen Reveals Novel Snf1p/AMPK Independent Regulators of Acetyl-CoA Carboxylase

Bozaquel-Morais, Bruno L.; Madeira, Juliana B.; Venâncio, Thiago M.; Pacheco-Rosa, Thiago; Masuda, Cláudio A.; Montero-Lomelı́, Mónica

doi:10.1371/journal.pone.0169682

Cited by 8 publications

(11 citation statements)

References 43 publications

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“…1, d and e ). This is in agreement with a chemical genomic screen which identified the NuA4 subunit mutant eaf7 Δ as hypersensitive to Sor A ( Bozaquel-Morais et al 2017 ). As previous studies have shown that NuA4 inhibits Snf1/AMPK activity ( Lu et al 2011 ), a key regulator of Acc1, we next sought to determine if the reduction in Acc1 activity in eaf1 Δ cells was fully or partially due to increases in Snf1 activity.…”

Section: Resultssupporting

confidence: 89%

“…Acc1 is also inhibited by Soraphen A (Sor A), a compound discovered from Sonrangium cellulosum , a myxobacteria, which was initially used as an antifungal but has branched into similar compounds being used in clinical trials ( Gerth et al 1994 ; Vahlensieck et al 1994 ; Naini et al 2019 ). Sor A is commonly used as an indirect measurement of Acc1 activity as mutants deficient for Acc1 activity are hypersensitive and mutants with enhanced Acc1 activity (such as Snf1 or acc1 S1157A mutants) are resistant to Sor A treatment ( Shirra et al 2001 ; Bozaquel-Morais et al 2017 ; Dacquay et al 2017 ).…”

Section: Introductionmentioning

confidence: 99%

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Fine-tuning acetyl-CoA carboxylase 1 activity through localization: functional genomics reveals a role for the lysine acetyltransferase NuA4 and sphingolipid metabolism in regulating Acc1 activity and localization

et al. 2022

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Acetyl-CoA Carboxylase 1 catalyzes the conversion of acetyl-CoA to malonyl-CoA, the committed step of de novo fatty acid synthesis. As a master regulator of lipid synthesis, acetyl-CoA carboxylase 1 has been proposed to be a therapeutic target for numerous metabolic diseases. We have shown that acetyl-CoA carboxylase 1 activity is reduced in the absence of the lysine acetyltransferase NuA4 in Saccharomyces cerevisiae. This change in acetyl-CoA carboxylase 1 activity is correlated with a change in localization. In wild-type cells, acetyl-CoA carboxylase 1 is localized throughout the cytoplasm in small punctate and rod-like structures. However, in NuA4 mutants, acetyl-CoA carboxylase 1 localization becomes diffuse. To uncover mechanisms regulating acetyl-CoA carboxylase 1 localization, we performed a microscopy screen to identify other deletion mutants that impact acetyl-CoA carboxylase 1 localization and then measured acetyl-CoA carboxylase 1 activity in these mutants through chemical genetics and biochemical assays. Three phenotypes were identified. Mutants with hyper-active acetyl-CoA carboxylase 1 form 1 or 2 rod-like structures centrally within the cytoplasm, mutants with mid-low acetyl-CoA carboxylase 1 activity displayed diffuse acetyl-CoA carboxylase 1, while the mutants with the lowest acetyl-CoA carboxylase 1 activity (hypomorphs) formed thick rod-like acetyl-CoA carboxylase 1 structures at the periphery of the cell. All the acetyl-CoA carboxylase 1 hypomorphic mutants were implicated in sphingolipid metabolism or very long-chain fatty acid elongation and in common, their deletion causes an accumulation of palmitoyl-CoA. Through exogenous lipid treatments, enzyme inhibitors, and genetics, we determined that increasing palmitoyl-CoA levels inhibits acetyl-CoA carboxylase 1 activity and remodels acetyl-CoA carboxylase 1 localization. Together this study suggests yeast cells have developed a dynamic feed-back mechanism in which downstream products of acetyl-CoA carboxylase 1 can fine-tune the rate of fatty acid synthesis.

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Section: Resultssupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Fine-tuning acetyl-CoA carboxylase 1 activity through localization: functional genomics reveals a role for the lysine acetyltransferase NuA4 and sphingolipid metabolism in regulating Acc1 activity and localization

et al. 2022

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“…Since our data revealed an unexpected role of the Elongator dependent tRNA modifications in regulating LD dynamics and soraphen A resistance, we investigated whether other tRNA modification mutants might display abnormal LD levels, which were identified in a previous screening for changes in soraphen A resistance [ 33 ]. We assembled a set of mutants defective in most of the known tRNA modifications (excluding essential ones) and classified their soraphen A response.…”

Section: Resultsmentioning

confidence: 99%

Protein Phosphatase Sit4 Affects Lipid Droplet Synthesis and Soraphen A Resistance Independent of Its Role in Regulating Elongator Dependent tRNA Modification

et al. 2018

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The protein phosphatase Sit4 has been shown to be required for lipogenesis and resistance against the acetyl-CoA carboxylase inhibitor soraphen A. Since Sit4 is also required for biosynthesis of Elongator dependent tRNA modifications such as 5-methoxycarbonylmethyluridine (mcm5U), we investigated the relevance of tRNA modifications in lipogenesis and soraphen A response. While sit4 and Elongator (elp3) mutants copy defects in mcm5U formation and stress sensitivity, they do not share soraphen A sensitivity and low lipid droplet (LD) phenotypes. In contrast to sit4, we found elp3 mutants to display partial soraphen A resistance and a high LD phenotype. Screening a collection of tRNA modification mutants additionally identified the tRNA pseudo-uridine synthase gene DEG1 to be required for soraphen A sensitivity. Since deg1 and elp3 share high LD and soraphen A resistance phenotypes, these are likely caused by translational defects. In support of this notion, we observe overexpression of tRNAGlnUUG suppresses lipolysis defects of deg1 mutants. Hence, the sit4 mutation results in a composite defect including tRNA modification deficiency and loss of Snf1 kinase dephosphorylation, which induce opposite effects on LD regulation. Importantly, however, the Snf1 kinase regulatory defects of the phosphatase mutant dominate over effects on LD regulation imposed by loss of the tRNA modification alone.

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“…Antimycin A (ethanol), N-acetylcysteine (water), and lithium chloride (water) were obtained from Sigma-Aldrich. The double mutant ubx4⌬snf1⌬ was generated by crossing a haploid MATa ubx4⌬ strain with a haploid MAT␣ snf1⌬ strain previously generated by our group (62). Strains were genotyped using the following primers: SNF1A (5Ј-TAAGAGTATGGC-ACATCAACAGGTA-3Ј), SNF1D (5Ј-TGTAGTAGGTTGT-ATTTTTGTCGCA-3Ј), UBX4A (5Ј-TAAAACGCTAGATG-CTATTTCTTGC-3Ј), UBX4D (5Ј-GAATACAATATCC-CATTTGATCAGG-3Ј), kanB (5Ј-CTGCAGCGAGGAGCC-GTAAT-3Ј), and kanC3 (5Ј-CCTCGACATCATCTGCCC-AGAT-3Ј).…”

Section: Yeast Strains and Growth Conditionsmentioning

confidence: 99%

The yeast protein Ubx4p contributes to mitochondrial respiration and lithium–galactose–mediated activation of the unfolded protein response

De-Souza

Pimentel

De-Queiroz

et al. 2020

Journal of Biological Chemistry

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In the presence of galactose, lithium ions activate the unfolded protein response (UPR) by inhibiting phosphoglucomutase activity and causing the accumulation of galactose-related metabolites, including galactose-1-phosphate. These metabolites also accumulate in humans who have the disease classic galactosemia. Here, we demonstrate that Saccharomyces cerevisiae yeast strains harboring a deletion of UBX4, a gene encoding a partner of Cdc48p in the endoplasmic reticulum–associated degradation (ERAD) pathway, exhibit delayed UPR activation after lithium and galactose exposure because the deletion decreases galactose-1-phosphate levels. The delay in UPR activation did not occur in yeast strains in which key ERAD or proteasomal pathway genes had been disrupted, indicating that the ubx4Δ phenotype is ERAD-independent. We also observed that the ubx4Δ strain displays decreased oxygen consumption. The inhibition of mitochondrial respiration was sufficient to diminish galactose-1-phosphate levels and, consequently, affects UPR activation. Finally, we show that the deletion of the AMP-activated protein kinase ortholog–encoding gene SNF1 can restore the oxygen consumption rate in ubx4Δ strain, thereby reestablishing galactose metabolism, UPR activation, and cellular adaption to lithium–galactose challenge. Our results indicate a role for Ubx4p in yeast mitochondrial function and highlight that mitochondrial and endoplasmic reticulum functions are intertwined through galactose metabolism. These findings also shed new light on the mechanisms of lithium action and on the pathophysiology of galactosemia.

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A Chemogenomic Screen Reveals Novel Snf1p/AMPK Independent Regulators of Acetyl-CoA Carboxylase

Cited by 8 publications

References 43 publications

Fine-tuning acetyl-CoA carboxylase 1 activity through localization: functional genomics reveals a role for the lysine acetyltransferase NuA4 and sphingolipid metabolism in regulating Acc1 activity and localization

Fine-tuning acetyl-CoA carboxylase 1 activity through localization: functional genomics reveals a role for the lysine acetyltransferase NuA4 and sphingolipid metabolism in regulating Acc1 activity and localization

Protein Phosphatase Sit4 Affects Lipid Droplet Synthesis and Soraphen A Resistance Independent of Its Role in Regulating Elongator Dependent tRNA Modification

The yeast protein Ubx4p contributes to mitochondrial respiration and lithium–galactose–mediated activation of the unfolded protein response

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