Department of Biochemistry of Biomembranes, Institute of Animal Biochemistry and Genetics, Centre of Biosciences, Slovak Academy of Sciences, Dubravska cesta 9, Bratislava 840 05, Slovakia.
National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
Biochim Biophys Acta Mol Cell Biol Lipids. 2024 Aug;1869(6):159506. doi: 10.1016/j.bbalip.2024.159506. Epub 2024 May 9.
Lipid droplets (LD) are highly dynamic organelles specialized for the regulation of energy storage and cellular homeostasis. LD consist of a neutral lipid core surrounded by a phospholipid monolayer membrane with embedded proteins, most of which are involved in lipid homeostasis. In this study, we focused on one of the major LD proteins, sterol C24-methyltransferase, encoded by ERG6. We found that the absence of Erg6p resulted in an increased accumulation of yeast perilipin Pet10p in LD, while the disruption of PET10 was accompanied by Erg6p LD over-accumulation. An observed reciprocal enrichment of Erg6p and Pet10p in pet10Δ and erg6Δ mutants in LD, respectively, was related to specific functional changes in the LD and was not due to regulation on the expression level. The involvement of Pet10p in neutral lipid homeostasis was observed in experiments that focused on the dynamics of neutral lipid mobilization as time-dependent changes in the triacylglycerols (TAG) and steryl esters (SE) content. We found that the kinetics of SE hydrolysis was reduced in erg6Δ cells and the mobilization of SE was completely lost in mutants that lacked both Erg6p and Pet10p. In addition, we observed that decreased levels of SE in erg6Δpet10Δ was linked to an overexpression of steryl ester hydrolase Yeh1p. Lipid analysis of erg6Δpet10Δ showed that PET10 deletion altered the composition of ergosterol intermediates which had accumulated in erg6Δ. In conclusion, yeast perilipin Pet10p functionally interacts with Erg6p during the metabolism of ergosterol.
脂滴 (LD) 是专门用于调节能量储存和细胞内稳态的高度动态细胞器。LD 由中性脂质核心组成，周围环绕着一层磷脂单层膜，嵌入其中的蛋白质大多数与脂质内稳态有关。在这项研究中，我们专注于 LD 的主要蛋白质之一，固醇 C24-甲基转移酶，由 ERG6 编码。我们发现 erg6p 的缺失导致酵母 perilipin Pet10p 在 LD 中的积累增加，而 PET10 的破坏伴随着 erg6p LD 的过度积累。在 pet10Δ 和 erg6Δ 突变体中观察到 erg6p 和 Pet10p 在 LD 中的相互富集，这与 LD 中的特定功能变化有关，而不是由于表达水平的调节。Pet10p 在中性脂质稳态中的参与在专注于中性脂质动员动力学的实验中得到了观察，作为三酰基甘油 (TAG) 和甾醇酯 (SE) 含量随时间的变化。我们发现 SE 水解的动力学在 erg6Δ 细胞中降低，并且在缺乏 erg6p 和 Pet10p 的突变体中 SE 的动员完全丧失。此外，我们观察到 erg6Δpet10Δ 中 SE 水平降低与甾醇酯水解酶 Yeh1p 的过表达有关。erg6Δpet10Δ 的脂质分析表明，PET10 的缺失改变了在 erg6Δ 中积累的麦角固醇中间体的组成。总之，酵母 perilipin Pet10p 在麦角固醇代谢过程中与 Erg6p 具有功能相互作用。
