Document Detail

Controlling lipid fluxes at glycerol-3-phosphate acyltransferase step in yeast: unique contribution of Gat1p to oleic acid-induced lipid particle formation.
MedLine Citation:
PMID:  22267742     Owner:  NLM     Status:  MEDLINE    
The ability to channel excess fatty acids into neutral lipids like triacylglycerol (TAG) is a critical strategy used by cells to maintain lipid homeostasis. Upon activation to acyl-CoA, fatty acids become readily available as substrates for acyltransferases involved in neutral lipid synthesis. Neutral lipids are then packed into organelles derived from the endoplasmic reticulum called lipid particles (LPs). The first acylation step in the de novo pathway for TAG synthesis is catalyzed by glycerol-3-phosphate acyltransferases (GPATs). Two isoforms, Gat1p/Gpt2p and Gat2p/Sct1p, are present in the yeast Saccharomyces cerevisiae. Previous evidence indicated that these enzymes contribute differentially to the synthesis of TAG in actively growing cells. In this work we studied the role of the yeast GPATs in the formation of LPs induced by a surplus of oleic acid. Yeast lacking Gat1p (but not Gat2p) were sensitive to oleate and failed to accumulate LPs induced by this unsaturated fatty acid. It is shown that oleate induces dephosphorylation of Gat1p as well as an increment in its levels. Most importantly, we identified novel Gat1p crescent structures that are formed in the presence of oleate. These structures are connected with the endoplasmic reticulum and are intimately associated with LPs. No such structures were observed for Gat2p. A crucial point of control of lipid fluxes at the GPAT step is proposed.
Nancy Marr; Julena Foglia; Mauricio Terebiznik; Karin Athenstaedt; Vanina Zaremberg
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2012-01-21
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  287     ISSN:  1083-351X     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2012 Mar 
Date Detail:
Created Date:  2012-03-26     Completed Date:  2012-05-16     Revised Date:  2013-06-26    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  10251-64     Citation Subset:  IM    
Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada.
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MeSH Terms
Endoplasmic Reticulum / enzymology*,  genetics
GATA Transcription Factors / genetics,  metabolism*
Glycerol-3-Phosphate O-Acyltransferase / genetics,  metabolism*
Oleic Acid / pharmacology*
Saccharomyces cerevisiae / genetics,  metabolism*
Triglycerides / genetics,  metabolism*
Grant Support
P 21251-B12//Austrian Science Fund FWF
Reg. No./Substance:
0/GAT1 protein, S cerevisiae; 0/GATA Transcription Factors; 0/Triglycerides; 112-80-1/Oleic Acid; EC O-Acyltransferase

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