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

PLoS One. 2017 Jan 11;12(1):e0169682. doi: 10.1371/journal.pone.0169682. eCollection 2017.

Abstract

Acetyl-CoA carboxylase (Acc1p) is a key enzyme in fatty acid biosynthesis and is essential for cell viability. To discover new regulators of its activity, we screened a Saccharomyces cerevisiae deletion library for increased sensitivity to soraphen A, a potent Acc1p inhibitor. The hits identified in the screen (118 hits) were filtered using a chemical-phenotype map to exclude those associated with pleiotropic drug resistance. This enabled the identification of 82 ORFs that are genetic interactors of Acc1p. The main functional clusters represented by these hits were "transcriptional regulation", "protein post-translational modifications" and "lipid metabolism". Further investigation of the "transcriptional regulation" cluster revealed that soraphen A sensitivity is poorly correlated with ACC1 transcript levels. We also studied the three top unknown ORFs that affected soraphen A sensitivity: SOR1 (YDL129W), SOR2 (YIL092W) and SOR3 (YJR039W). Since the C18/C16 ratio of lipid acyl lengths reflects Acc1p activity levels, we evaluated this ratio in the three mutants. Deletion of SOR2 and SOR3 led to reduced acyl lengths, suggesting that Acc1p is indeed down-regulated in these strains. Also, these mutants showed no differences in Snf1p/AMPK activation status and deletion of SNF1 in these backgrounds did not revert soraphen A sensitivity completely. Furthermore, plasmid maintenance was reduced in sor2Δ strain and this trait was shared with 18 other soraphen A sensitive hits. In summary, our screen uncovered novel Acc1p Snf1p/AMPK-independent regulators.

MeSH terms

  • Acetyl-CoA Carboxylase / genetics*
  • Acetyl-CoA Carboxylase / metabolism
  • Down-Regulation
  • Drug Resistance, Fungal / genetics*
  • Gene Expression Regulation, Fungal*
  • Lipid Metabolism
  • Macrolides / pharmacology
  • Open Reading Frames
  • Protein Processing, Post-Translational
  • Protein Serine-Threonine Kinases / genetics*
  • Protein Serine-Threonine Kinases / metabolism
  • Saccharomyces cerevisiae / drug effects
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism

Substances

  • Macrolides
  • soraphen A
  • SNF1-related protein kinases
  • Protein Serine-Threonine Kinases
  • Acetyl-CoA Carboxylase

Grants and funding

This work was supported by grants from Conselho Nacional de Ciência e Tecnologia (CNPq), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) and Fundação de Amparo a Pesquisa do Rio de Janeiro (FAPERJ- Cientistas do Nosso Estado: E – 26 /103.353/2011 and E-26/203.203/2015 to MML; E-26/110.748/2011, E-26/110.236/2011 and E-26/102.259/2013 to TMV; APQ1/Sediadas to CAM, Apoio Técnico to TPR, and Auxílio Instalação to BLBM). BLBM is recipient of a PNPD-CAPES- fellowship (Programa Nacional de Pós Doutorado da CAPES). JBM is recipient of a CNPq fellowship. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.