Document Detail

Opposite effect of caveolin-1 in the metabolism of high-density and low-density lipoproteins.
MedLine Citation:
PMID:  16443388     Owner:  NLM     Status:  MEDLINE    
Receptors of the scavenger class B family were reported to be localized in caveolae, the cell surface microdomains rich in free cholesterol and glycosphyngolipids, which are characterized by the presence of caveolin-1. Parenchymal hepatic and hepatoma HepG2 cells express very low levels of caveolin-1. In the present study, stable transformants of HepG2 cells expressing caveolin-1 were generated to address the effect of caveolin-1 on receptor activity. Compared to normal cells, these cells show higher (125)I-bovine serum albumin (BSA) uptake and cholesterol efflux, two indicators of functional caveolae. By immunoprecipitation, cell fractionation and confocal analyses, we found that caveolin-1 is well colocalized with the cluster of differentiation-36 (CD36) and the low-density lipoprotein (LDL) receptor (LDLr) but to a lesser extent with the scavenger receptor class B type I (SR-BI) in HepG2 cells expressing caveolin-1. However, caveolin-1 expression favors the dimerization of SR-BI. Two clones of cells expressing caveolin-1 were investigated for their lipoprotein metabolism activity. Compared to normal cells, these cells show a 71-144% increase in (125)I-LDL degradation. The analysis of the cholesteryl esters (CE)-selective uptake (CE association minus protein association) revealed that the expression of caveolin-1 in HepG2 cells decreases by 59%-73% LDL-CE selective uptake and increases high-density lipoprotein (HDL)-CE selective uptake by 44%-66%. We conclude that the expression of caveolin-1 in HepG2 cells moves the balance of LDL degradation/CE selective uptake towards degradation and favors HDL-CE selective uptake. Thus, in the normal hepatic parenchymal situation where caveolin-1 is poorly expressed, LDL-CE selective uptake is the preferred pathway.
To Quyen Truong; Dominique Aubin; Philippe Bourgeois; Louise Falstrault; Louise Brissette
Related Documents :
10608898 - Salinity and hyperosmotic stress induce rapid increases in phosphatidylinositol 4,5-bis...
2161438 - Incorporation of inositol into the phosphoinositides of lymphoblastoid cell lines estab...
10064728 - Cholesteryl ester hydrolysis in j774 macrophages occurs in the cytoplasm and lysosomes.
2384278 - Metabolism of low-density lipoprotein in differentiated and undifferentiated ht29 colon...
10639738 - Dual immunofluorescence labeling with cell-specific markers localizes brca1 in both bas...
9224298 - Initial evaluation of cyfra 21-1 diagnostic performances as a urinary marker in bladder...
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2006-01-18
Journal Detail:
Title:  Biochimica et biophysica acta     Volume:  1761     ISSN:  0006-3002     ISO Abbreviation:  Biochim. Biophys. Acta     Publication Date:  2006 Jan 
Date Detail:
Created Date:  2006-03-13     Completed Date:  2006-05-16     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0217513     Medline TA:  Biochim Biophys Acta     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  24-36     Citation Subset:  IM    
Département des Sciences Biologiques, Université du Québec à Montréal, C.P. 8888, Succursale Centre-ville, Montréal, Québec, Canada H3C 3P8.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Biological Transport
Caveolin 1 / genetics,  physiology*
Cell Line
Cell Line, Tumor
Lipoproteins, HDL / metabolism*
Lipoproteins, LDL / metabolism*
Liver Neoplasms
RNA, Messenger / genetics
Recombinant Proteins / pharmacology
Reverse Transcriptase Polymerase Chain Reaction
Serum Albumin, Bovine / metabolism
Reg. No./Substance:
0/Caveolin 1; 0/Lipoproteins, HDL; 0/Lipoproteins, LDL; 0/RNA, Messenger; 0/Recombinant Proteins; 0/Serum Albumin, Bovine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

Previous Document:  Evaluation of P53 and BAX gene expression and induction of apoptosis and necrosis by the cis-Pt(II) ...
Next Document:  The use of MRI in the evaluation of myopathy.