Lipid transport via interorganelle communication zones between the endoplasmic reticulum and chloroplasts in plants

Research abstract

In plant cells, although fatty acids are mainly synthesized in chloroplasts, the assembly of glycerolipids such as phospholipids and glycolipids occurs in the ER and chloroplasts. Moreover, the glycerolipids synthesized in the ER is transported to chloroplasts as a substrate for glycolipid synthesis. Thus, lipid trafficking between the ER and chloroplasts is an essential event in plants for maintaining intracellular membrane structures. Nevertheless, only few proteins have been found to be involved in the lipid transfer and their role for interorganelle MCS formation and thus the regulatory mechanism at the molecular level remained unknown. Our research group aims to elucidate the molecular mechanism of lipid transfer between the ER and chloroplasts by focusing on phosphatidic acid phosphohydrolase (PAH1, PAH2) in plants and its physiological role for plant growth under various stress conditions.

Original papers

1. Yoshitake Y, Sato R, Madoka Y, Ikeda K, Murakawa M, Suruga K, Sugiura D, Noguchi K, Ohta H, Shimojima M. (2017) Arabidopsis phosphatidic acid phosphohydrolases are essential for growth under nitrogen-depleted conditions. Front Plant Sci. 8, 1847
2. Shimojima, M., Madoka, Y., Fujiwara, R., Murakawa, M., Yoshitake, Y., Ikeda, K., Koizumi, R., Endo, K., Ozaki, K., and Ohta, H. (2015) An engineered lipid remodeling system using a galactolipid synthase promoter during phosphate starvation enhances oil accumulation in plants. Front Plant Sci. 6, 664
3. Iwai, M., Ikeda, K., Shimojima, M., and Ohta, H. (2014) Enhancement of extraplastidic oil synthesis in Chlamydomonas reinhardtii using a type-2 diacylglycerol acyltransferase with a phosphorus starvation-inducible promoter. Plant Biotechnol. J. 12, 808-819
4. Yuzawa, Y., Shimojima, M., Sato, R., Mizusawa, N., Ikeda, K., Suzuki, M., Iwai, M., Hori, K., Wada, H., Masuda, S., and Ohta, H. (2014) Cyanobacterial monogalactosyldiacylglycerol-synthesis pathway is involved in normal unsaturation of galactolipids and low-temperature adaptation of Synechocystis PCC 6803. Biochim. Biophys. Acta 1841, 475-483
5. Okazaki, Y., Shimojima, M., Sawada, Y., Toyooka, K., Narisawa, T., Mochida, K., Tanaka, H., Matsuda, F., Hirai, A., Hirai, MY., Ohta, H., and Saito, K. (2009) A chloroplastic UDP-glucose pyrophosphorylase from Arabidopsis is the committed enzyme for the first step of sulfolipid biosynthesis. Plant Cell 21, 892-909

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