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J Lipid Res. 2004 Mar;45(3):456-65. Epub 2003 Dec 16.

Lipid transfer particle mediates the delivery of diacylglycerol from lipophorin to fat body in larval Manduca sexta.

Author information

1
Department of Biochemistry and Molecular Biophysics and Center for Insect Science, Biological Sciences West, University of Arizona, Tucson, AZ 85721-0088, USA.

Abstract

This work analyzed the process of lipid storage in fat body of larval Manduca sexta, focusing on the role of lipid transfer particle (LTP). Incubation of fat bodies with [(3)H]diacylglycerol-labeled lipophorin resulted in a significant accumulation of diacylglycerol (DAG) and triacylglycerol (TAG) in the tissue. Transfer of DAG to fat body and its storage as TAG was significantly inhibited (60%) by preincubating the tissue with anti-LTP antibody. Lipid transfer was restored to control values by adding LTP to fat body. Incubation of fat body with dual-labeled DAG lipophorin or its treatment with ammonium chloride showed that neither a membrane-bound lipoprotein lipase nor lipophorin endocytosis is a relevant pathway to transfer or to storage lipids into fat body, respectively. Treatment of fat body with suramin caused a 50% inhibition in [(3)H]DAG transfer from lipophorin. Treatment of [(3)H]DAG-labeled fat body with lipase significantly reduced the amount of [(3)H]DAG associated with the tissue, suggesting that the lipid is still on the external surface of the membrane. Whether this lipid represents irreversibly adsorbed lipophorin or a DAG lipase-sensitive pool is unknown. Nevertheless, these results indicate that the main pathway for DAG transfer from lipophorin to fat body is via LTP and receptor-mediated processes.

PMID:
14679163
DOI:
10.1194/jlr.M300242-JLR200
[Indexed for MEDLINE]
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