National Laboratory of Biomacromolecules, Institute of Biophysics, Beijing, China; National Laboratory of Biomacromolecules, Graduate University of Chinese Academy of Sciences, Beijing, China.
National Laboratory of Biomacromolecules, Institute of Biophysics, Beijing, China.
J Lipid Res. 2012 Mar;53(3):399-411. doi: 10.1194/jlr.M021899. Epub 2011 Dec 15.
Storage of cellular triacylglycerols (TAGs) in lipid droplets (LDs) has been linked to the progression of many metabolic diseases in humans, and to the development of biofuels from plants and microorganisms. However, the biogenesis and dynamics of LDs are poorly understood. Compared with other organisms, bacteria seem to be a better model system for studying LD biology, because they are relatively simple and are highly efficient in converting biomass to TAG. We obtained highly purified LDs from Rhodococcus sp. RHA1, a bacterium that can produce TAG from many carbon sources, and then comprehensively characterized the LD proteome. Of the 228 LD-associated proteins identified, two major proteins, ro02104 and PspA, constituted about 15% of the total LD protein. The structure predicted for ro02104 resembles that of apolipoproteins, the structural proteins of plasma lipoproteins in mammals. Deletion of ro02104 resulted in the formation of supersized LDs, indicating that ro02104 plays a critical role in cellular LD dynamics. The putative α helix of the ro02104 LD-targeting domain (amino acids 83-146) is also similar to that of apolipoproteins. We report the identification of 228 proteins in the proteome of prokaryotic LDs, identify a putative structural protein of this organelle, and suggest that apolipoproteins may have an evolutionarily conserved role in the storage and trafficking of neutral lipids.
细胞三酰基甘油 (TAG) 的储存与人类许多代谢疾病的发展以及植物和微生物生物燃料的发展有关。然而，脂滴 (LDs) 的生物发生和动态变化还知之甚少。与其他生物相比，细菌似乎是研究 LD 生物学的更好模型系统，因为它们相对简单，并且能够非常有效地将生物质转化为 TAG。我们从能够从许多碳源生产 TAG 的 Rhodococcus sp. RHA1 中获得了高度纯化的 LDs，并对 LD 蛋白质组进行了全面表征。在鉴定的 228 种 LD 相关蛋白中，两种主要蛋白 ro02104 和 PspA 约占总 LD 蛋白的 15%。ro02104 的预测结构类似于哺乳动物血浆脂蛋白的结构蛋白载脂蛋白。ro02104 的缺失导致超大尺寸 LDs 的形成，表明 ro02104 在细胞 LD 动力学中起着关键作用。ro02104 LD 靶向结构域 (氨基酸 83-146) 的假定α螺旋也类似于载脂蛋白。我们报告了在原核 LDs 蛋白质组中鉴定出 228 种蛋白质，鉴定了该细胞器的一种假定结构蛋白，并表明载脂蛋白可能在中性脂质的储存和运输中具有进化上保守的作用。
