Triglyceride deficiency and diacylglycerol kinase1 activity lead to the upregulation of mevalonate pathway in yeast: A study for the development of potential yeast platform for improved production of triterpenoid

• Published in: Biochimica et biophysica acta. Molecular and cell biology of lipids Vol. 1865; no. 6; p. 158661
• Main Authors: Ranganathan, Poornima Ramani, Nawada, Niveditha, Narayanan, Ananth Krishna, Rao, D.K. Venkata
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.06.2020
• Subjects: Diacylglycerol; Diacylglycerol kinase1; Mevalonate pathway; Phosphatidic acid; Synthetic biology; Terpenoids; Triglyceride-deficient yeast mutants; β-Amyrin; dga1ΔlroΔ; DG; Diacylglycerol; ERG20; βA; Δ; Terpenoids; ERG1; Synthetic biology; WT; SQ; ERG9; Phosphatidic acid; Diacylglycerol kinase1; pahΔ; ERG10; Triglyceride-deficient yeast mutants; HMG1; dga1Δ; PA; Aa-βAS; PC; TG; β-Amyrin; Mevalonate pathway; ERG; MEV
• ISSN: 1388-1981; 1879-2618
• DOI: 10.1016/j.bbalip.2020.158661

Besides energy storage and membrane biogenesis, lipids are known for their numerous biological functions. The two essential lipids, diacylglycerol (DG) and phosphatidic acid (PA), are shown to be associated with cell signalling processes. In this study, we examined whether triglyceride-deficient yeast mutants (tgΔ), dga1Δ and dga1Δlro1Δ, may play an important role in mevalonate (MEV) pathway regulation. Our metabolite analyses revealed that tgΔ cells showed high levels of squalene (SQ) and ergosterol (ERG), which are key indicators of MEV pathway activity. In addition, gene expression studies indicated that the MEV pathway genes in tgΔ cells were significantly upregulated. Interestingly, tgΔ cells exhibited high diacylglycerol kinase1 (DGK1) expression. Furthermore, DGK1 overexpression in WT and tgΔ phenotypes causes a substantial elevation in SQ and ERG levels, and we also found a significant increase in transcript levels of MEV pathway genes, confirming the new role of DGK1 in MEV pathway regulation. This suggests that high DG phosphorylation activity increases the PA pool that may induce the upregulation of MEV pathway in tgΔ cells. The induced MEV pathway is one of the key strategies in the field of synthetic biology for improved production of terpenoids in yeast. Thus, to examine whether increased endogenous MEV pathway flux can be redirected to triterpenoid, β-Amyrin synthase gene was heterologously expressed in DGK1 overexpressing tgΔ cells that led to significant production of β-Amyrin, a natural triterpenoid. In conclusion, our findings provide a novel strategy to increase MEV pathway precursors by modulating endogenous signal lipids for improved production of terpenoids. •Triglyceride (TG) deficiency in yeast induces transcription of mevalonate pathway.•Diacylglycerol kinase1 (DGK1) plays a key role in mevalonate pathway regulation.•DGK1 overexpression with TG deficiency led to high squalene and ergosterol flux.•Overexpression of Aa-βAS and DGK1 in TG-deficit cells improves β-amyrin yield.•Novel strategy to enhance triterpene production through lipid pathway engineering.