Regulation of cardiolipin biosynthesis by fatty acid transport protein-1 IN HEK 293 cells.
Cardiolipin (CL) is a major phospholipid involved in energy metabolism mammalian mitochondria and fatty acid transport protein-1 (FATP-1) is a fatty acid transport protein that may regulate the intracellular level of fatty acyl-Coenzyme A's. Since fatty acids are required for oxidative phosphorylation via mitochondrial oxidation, we examined the effect of altering FATP-1 levels on CL biosynthesis. HEK-293 mock- and FATP-1 siRNA transfected cells or mock and FATP-1 expressing cells were incubated for 24 h with 0.1 mM oleic acid bound to albumin (1:1 molar ratio) then incubated for 24 h with 0.1 mM [1,3-(3)H]glycerol and radioactivity incorporated into CL determined. FATP-1 siRNA transfected cells exhibited reduced FATP-1 mRNA and increased incorporation of [1,3-(3)H]glycerol into CL (2-fold, p<0.05) compared to controls indicating elevation in de novo CL biosynthesis. The reason for this was an increase in [1,3-(3)H]glycerol uptake and increase in activity and mRNA expression of the CL biosynthetic enzymes. In contrast, expression of FATP-1 resulted a reduction in incorporation of [1,3-(3)H]glycerol into CL (65%, p<0.05) indicating reduced CL synthesis. [1,3-(3)H]Glycerol uptake was unaltered whereas activity of cytidine-5'-diphosphate-1,2-diacyl-sn-glycerol synthetase (CDS) and CDS-2 mRNA expression were reduced in FATP-1 expressing cells compared to control. In addition, in vitro CDS activity was reduced by exogenous addition of oleoyl-Coenzyme A. The data indicate that CL de novo biosynthesis may be regulated by FATP-1 through CDS-2 expression in HEK 293 cells.
Mitchell
Ryan W
RW
Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Manitoba, Canada R3E 0T6.
Hatch
Grant M
GM
D000214:Acyl Coenzyme A / Q000378:metabolism; D015153:Blotting, Western; D002308:Cardiolipins / Q000096:biosynthesis* / Q000235:genetics; D002478:Cells, Cultured; D015180:Electrophoresis, Gel, Two-Dimensional; D050612:Fatty Acid Transport Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism; D005786:Gene Expression Regulation; D005990:Glycerol / Q000378:metabolism; D006801:Humans; D007668:Kidney / Q000166:cytology / Q000196:embryology; D008928:Mitochondria / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction
D000214:Acyl Coenzyme A; D002308:Cardiolipins; D050612:Fatty Acid Transport Proteins; D005227:Fatty Acids; D010743:Phospholipids; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C493568:SLC27A1 protein, human; D005990:Glycerol