Acetyl-CoA synthetase is activated as part of the PDH-bypass in the oleaginous green alga Chlorella desiccata
| Autor: | Uri Pick, Omri Avidan |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
Chlorella desiccata
ATP citrate lyase Physiology Nitrogen ATP Citrate (pro-S)-Lyase Chlamydomonas reinhardtii Acetate-CoA Ligase Pyruvate Dehydrogenase Complex Plant Science Chlorella PDH-bypass chemistry.chemical_compound Biosynthesis triacylglycerol biosynthesis Lipid biosynthesis Acetyl-CoA synthase Plastids Triglycerides Alcohol dehydrogenase biology Alcohol Dehydrogenase food and beverages Acetyl—CoA synthetase Pyruvate dehydrogenase complex biology.organism_classification green algae Enzyme Activation Oxygen chemistry Biochemistry biology.protein Research Paper |
| Zdroj: | Journal of Experimental Botany |
| ISSN: | 1460-2431 0022-0957 |
| Popis: | Highlight Plastidic acetyl-CoA synthase (ptACS-2) and ATP citrate lyase are upregulated in the oleaginous alga Chlorella desiccata during nitrogen deprivation. ptACS-2 is part of the pyruvate dehydrogenase bypass which supports triacylglycerol accumulation. In a recent study, it has been shown that biosynthesis of triacylglycerol (TAG) in the oleaginous green alga Chlorella desiccata is preceded by a large increase in acetyl-coenzyme A (Ac-CoA) levels and by upregulation of plastidic pyruvate dehydrogenase (ptPDH). It was proposed that the capacity to accumulate high TAG critically depends on enhanced production of Ac-CoA. In this study, two alternative Ac-CoA producers—plastidic Ac-CoA synthase (ptACS) and ATP citrate lyase (ACL)—are shown to be upregulated prior to TAG accumulation under nitrogen deprivation in the oleaginous species C. desiccata, but not in the moderate TAG accumulators Dunaliella tertiolecta and Chlamydomonas reinhardtii. Measurements of endogenous acetate production and of radiolabelled acetate incorporation into lipids are consistent with the upregulation of ptACS, but suggest that its contribution to the overall TAG biosynthesis is negligible. Induction of ACS and production of endogenous acetate are correlated with activation of alcohol dehydrogenase, suggesting that the upregulation of ptACS is associated with activation of PDH-bypass in C. desiccata. It is proposed that activation of the PDH-bypass in C. desiccata is needed to enable a high rate of lipid biosynthesis under nitrogen deprivation by controlling the level of pyruvate reaching ptPHD and/or mtPDH. This may be an important parameter for massive TAG accumulation in microalgae. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|