MAPK/ERK and JNK pathways regulate lipid synthesis and cell growth of Chlamydomonas reinhardtii under osmotic stress, respectively

• Published in: Scientific reports Vol. 8; no. 1; pp. 13857 - 12
• Main Authors: Yang, Ahreum, Suh, William I., Kang, Nam Kyu, Lee, Bongsoo, Chang, Yong Keun
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 14.09.2018; Nature Publishing Group; Nature Portfolio
• Subjects: 631/337; 631/449/2675; 82/80; 96/95; Algae; Aquatic microorganisms; Biofuels; c-Jun protein; Cell growth; Cellular stress response; Ceramide; Chlamydomonas reinhardtii; Environmental Osmotic Stress; Eukaryotes; Extracellular Signal-regulated Kinase; Humanities and Social Sciences; JNK protein; Kinases; Lipid Production; Lipids; MAP kinase; Metabolic pathways; multidisciplinary; Neutral Lipid Accumulation; Osmosis; Osmotic stress; Protein kinase; Reinhardtii; Science; Science (multidisciplinary); Signal transduction; Sodium chloride; Transcription factors; Reinhardtii; Extracellular Signal-regulated Kinase; Neutral Lipid Accumulation; Environmental Osmotic Stress; Lipid Production
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-018-32216-5

Microalgae have great potential for the production of biofuels due to the ability of the organism to accumulate large quantities of storage lipids under stress conditions. Mitogen activated protein kinase (MAPK) signaling cascades are widely recognized for their role in stress response signal transduction in eukaryotes. To assess the correlation between MAPK activation and lipid productivity, Chlamydomonas reinhardtii was studied under various concentrations of NaCl. The results demonstrated that C . reinhardtii exhibits elevated levels of extracellular-signal regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) activities after undergoing osmotic stress, as well as an increase in cellular lipid content. To establish a more direct causal link between both kinases and lipid productivity, C . reinhardtii was subjected to biochemically induced regulation of ERK and JNK pathways. Activating the MEK-ERK pathway via C6 ceramide treatment increased ERK activation and lipid production simultaneously, while PD98059 mediated inhibition of the pathway yielded opposite results. Interestingly, suppression of the JNK pathway with SP600125 resulted in a substantial decrease in cell viability under osmotic stress. These results suggest that ERK and JNK MAP kinases have important roles in microalgal lipid accumulation and cell growth under osmotic stress, respectively.