Requirement of cytosolic phospholipase A2 gamma in lipid droplet formation.
Lipid droplet (LD) accumulation in hepatocytes is a typical character of steatosis. Hepatitis C virus (HCV) infection, one of the risk factors related to steatosis, induced LD accumulation in cultured cells. However, the mechanisms of which HCV induce LD formation are not fully revealed. Previously we identified cytosolic phospholipase A2 gamma (PLA2G4C) as a host factor upregulated by HCV infection and involved in HCV replication. Here we further revealed that PLA2G4C plays an important role in LD biogenesis and refined the functional analysis of PLA2G4C in LD biogenesis and HCV assembly. LD formation upon fatty acid and HCV stimulation in PLA2G4C knockdown cells was impaired and could not be restored by complementation with PLA2G4A. PLA2G4C was tightly associated in the membrane with the domain around the amino acid residues 260-292, normally in ER but relocated into LDs upon oleate stimulation. Mutant PLA2G4C without enzymatic activity was not able to restore LD formation in PLA2G4C knockdown cells. Thus, both the membrane attachment and the enzymatic activity of PLA2G4C were required for its function in LD formation. The participation of PLA2G4C in LD formation is correlated with its involvement in HCV assembly. Finally, PLA2G4C overexpression itself led to LD formation in hepatic cells and enhanced LD accumulation in the liver of high-fat diet (HFD)-fed mice, suggesting its potential role in fatty liver disease.
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China; University of Chinese Academy of Sciences, Beijing, China.
Xi
X
Su
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China; University of Chinese Academy of Sciences, Beijing, China.
Shuhui
S
Liu
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China; University of Chinese Academy of Sciences, Beijing, China.
Xianwen
X
Zhang
State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
Sin Man
SM
Lam
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
Xue
X
Hu
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
Yuan
Y
Zhou
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
Jizheng
J
Chen
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
Yun
Y
Wang
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
Chunchen
C
Wu
State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
Guanghou
G
Shui
Department of Infectious Disease, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
Mengji
M
Lu
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China. Electronic address: rongjuan_pei@wh.iov.cn.
Rongjuan
R
Pei
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China; University of Chinese Academy of Sciences, Beijing, China. Electronic address: chenxw@wh.iov.cn.
Xinwen
X
Chen
D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D003600:Cytosol / Q000378:metabolism* / Q000821:virology; D004721:Endoplasmic Reticulum / Q000378:metabolism / Q000821:virology; D005227:Fatty Acids / Q000378:metabolism; D054513:Group IV Phospholipases A2 / Q000378:metabolism*; D057809:HEK293 Cells; D016174:Hepacivirus / Q000472:pathogenicity; D006526:Hepatitis C / Q000378:metabolism; D022781:Hepatocytes / Q000378:metabolism / Q000821:virology; D006801:Humans; D066292:Lipid Droplets / Q000378:metabolism* / Q000821:virology; D050356:Lipid Metabolism / Q000502:physiology*; D008099:Liver / Q000378:metabolism / Q000821:virology; D008297:Male; D008566:Membranes / Q000378:metabolism / Q000821:virology; D051379:Mice; D008810:Mice, Inbred C57BL
D000596:Amino Acids; D005227:Fatty Acids; D054513:Group IV Phospholipases A2
Assemble; Cytosolic phospholipase A2 gamma; HCV; Lipid droplet; PLA2G4C; Steatosis