Isolation and proteomic study of fish liver lipid droplets
image: A Proteins were separated by SDS-PAGE after extracting from LD, TM, Cyto, and PNS fractions, and then stained by colloidal blue. Red arrowheads marked unique protein bands of LDs. B Proteins of LDs were precipitated by acetone and then subjected to nano-LC-ESI-LTQ Orbitrap XL MS/MS analysis. The Venn diagram showed the overlap of two independent mass spectrum results. C The 259 proteins of LDs identified in two samples were categorized into 11 groups: perilipin family, lipid metabolism, mitochondria, endoplasmic reticulum, cytoskeleton, chaperone, cell signal, membrane trafficking, protein translation and modification degradation, other protein and unknown function protein. D Proteins of LDs of two independent mass spectrum results were categorized into previously reported proteins and newly identified proteins in this study
Credit: Yuwei Sun, Jian Heng, Feng Liu, Shuyan Zhang, Pingsheng Liu
Lipid droplets (LDs) are a neutral lipid storage organelle that is conserved in almost all species. Excessive storage of neutral lipids in LDs is directly associated with many metabolic syndromes. Zebrafish is a better model animal for the study of LD biology due to its transparent embryonic stage compared to other organisms. However, the study of LDs in fish has been difficult due to the lack of specific LD marker proteins and the limitation of purification technology. In this paper, the purification and proteomic analysis of liver LDs of fish including zebrafish and Carassius auratus were performed for the first time. 259 and 267 proteins were identified respectively. Besides most of the identified proteins were reported in previous LD proteomes of mammals, indicating the similarity between mammal and fish LDs. The authors also identified many unique proteins of liver LDs in fish that are involved in the regulation of LD dynamics. Through morphological and biochemical analysis, they found that the marker protein Plin2 of zebrafish LD was located on LDs in Huh7 cells. These results will facilitate further study of LDs in fish and liver metabolic diseases using fish as a model animal.
The work entitled “Isolation and proteomic study of fish liver lipid droplets”was published on Biophysics Reports (published in Jun. 2023).