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Sterol carrier protein-2: not just for cholesterol any more.
MedLine Citation:
PMID:  12479573     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Although sterol carrier protein-2 (SCP-2) mediates cholesterol esterification in L-cell fibroblasts and stimulates an accumulation of cholesterol in these cells, a potential role for SCP-2 in fatty acid uptake and trafficking has not been appreciated. Certainly, recent experiments have shown that SCP-2 binds fatty acids in vitro with an affinity similar to that observed for fatty acid binding proteins. Because of the ubiquitous tissue distribution of SCP-2, as opposed to the specific distribution of fatty acid binding proteins, as well as the need for fatty acid trafficking in all cells, I have recently proposed that SCP-2 is the universal fatty acid trafficking protein. This supposition is based on a number of observations made with L-cell fibroblasts expressing either the 13.2 kDa SCP-2 or the 15 kDa proSCP-2. In L-cells expressing the 13.2 kDa SCP-2, fluorescent fatty acid uptake was increased by 10-30% depending upon the probe used. In 15 kDa proSCP-2 expressing cells, fluorescent fatty acid uptake was increased 20-40% depending upon the probe used. However, only expression of the 15 kDa pro-SCP-2 increased the cytoplasmic diffusion of the fluorescent fatty acid. Expression of either protein increased the uptake of [3H]-oleic acid 1.9-fold compared to control, with targeting of [3H]-oleic acid for esterification into cholesteryl esters. The 13.2 kDa SCP-2 did target a significant amount of [3H]-oleic acid for esterification into the triacylglycerol pool. Expression of either protein markedly reduced total cellular phospholipid levels, however both proteins increased cholesteryl ester levels. Interestingly, expression of the 15 kDa proSCP-2 decreased ethanolamine plasmalogen levels with a concomitant increase in choline plasmalogen. Expression of both proteins increased PUFA content of the phospholipids, although this effect was greater in 15 kDa proSCP-2 expressing cells. Hence, expression of SCP-2 increased fatty acid uptake and targeted fatty acid to unique lipid pools, suggesting that SCP-2 may effectively serve as universal fatty acid binding and trafficking protein.
Authors:
Eric J Murphy
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Molecular and cellular biochemistry     Volume:  239     ISSN:  0300-8177     ISO Abbreviation:  Mol. Cell. Biochem.     Publication Date:  2002 Oct 
Date Detail:
Created Date:  2002-12-13     Completed Date:  2003-08-08     Revised Date:  2005-11-17    
Medline Journal Info:
Nlm Unique ID:  0364456     Medline TA:  Mol Cell Biochem     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  87-93     Citation Subset:  IM    
Affiliation:
Department of Pharmacology, Physiology, and Therapeutics, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA. emurphy@medicine.nodak.edu
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MeSH Terms
Descriptor/Qualifier:
Animals
Carrier Proteins / metabolism*
Cell Line
Cholesterol / metabolism*
Fatty Acids / metabolism
Lipid Metabolism
Mice
Chemical
Reg. No./Substance:
0/Carrier Proteins; 0/Fatty Acids; 0/sterol carrier proteins; 57-88-5/Cholesterol

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