Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, Japan.
Department of Biological Sciences, Faculty of Sciences, Kyushu University, Fukuoka, Japan.
J Lipid Res. 2017 Dec;58(12):2334-2347. doi: 10.1194/jlr.M079897. Epub 2017 Oct 12.
Thraustochytrids are marine single-cell protists that produce large amounts of PUFAs, such as DHA. They accumulate PUFAs in lipid droplets (LDs), mainly as constituent(s) of triacylglycerol (TG). We identified a novel protein in the LD fraction of F26-b using 2D-difference gel electrophoresis. The protein clustered with orthologs of thraustochytrids; however, the cluster was evolutionally different from known PAT family proteins or plant LD protein; thus, we named it thraustochytrid-specific LD protein 1 (TLDP1). TLDP1 surrounded LDs when expressed as a GFP-tagged form. Disruption of the gene decreased the content of TG and number of LDs per cell; however, irregular and unusually large LDs were generated in -deficient mutants. Although the level of TG synthesis was unchanged by the disruption of , the level of TG degradation was higher in -deficient mutants than in the WT. These phenotypic abnormalities in -deficient mutants were restored by the expression of These results indicate that TLDP1 is a thraustochytrid-specific LD protein and regulates the TG accumulation and LD morphology in F26-b.
裂殖壶菌是一种海洋单细胞原生生物，能够大量生产多不饱和脂肪酸（PUFAs），如二十二碳六烯酸（DHA）。它们将 PUFAs 积累在脂滴（LDs）中，主要作为三酰基甘油（TG）的组成部分。我们使用二维差异凝胶电泳在 F26-b 的 LD 部分鉴定到一种新型蛋白质。该蛋白与裂殖壶菌的同源蛋白聚类；然而，该聚类在进化上与已知的 PAT 家族蛋白或植物 LD 蛋白不同；因此，我们将其命名为裂殖壶菌特异性 LD 蛋白 1（TLDP1）。TLDP1 以 GFP 标记形式表达时会围绕 LD。 基因的破坏会降低 TG 的含量和每个细胞中的 LD 数量；然而，在缺陷突变体中会产生不规则且异常大的 LD。尽管 基因的破坏对 TG 合成水平没有影响，但在缺陷突变体中，TG 的降解水平高于 WT。WT 中表达 可以恢复缺陷突变体中的这些表型异常。这些结果表明 TLDP1 是一种裂殖壶菌特异性 LD 蛋白，可调节 F26-b 中的 TG 积累和 LD 形态。
