In:
Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 97, No. 12 ( 2000-06-06), p. 6538-6543
Abstract:
The scavenger receptor class B type I (SR-BI) mediates the selective uptake of cholesteryl esters from high-density lipoprotein (HDL) and cholesterol secretion into bile in the liver. In this study, we identified an SR-BI-associated protein from rat liver membrane extracts by using an affinity chromatography technique. This protein of 523 amino acids contains four PDZ domains and associates with the C terminus of SR-BI by using its N-terminal first PDZ domain. Therefore, we denoted this protein as CLAMP ( C -terminal l inking a nd m odulating p rotein). CLAMP was located mostly in the sinusoidal membranes, whereas SR-BI was detected in both sinusoidal and canalicular membranes. After the solubilization of the liver membranes with Triton X-100, SR-BI was immunoprecipitated with anti-CLAMP monoclonal antibody, suggesting the association of these proteins in vivo . By coexpressing SR-BI with CLAMP in Chinese hamster ovary cells, we observed ( i ) the increase in the expression level of SR-BI, ( ii ) the reduction in the deacylation rate of the cholesteryl esters taken up from HDL, and ( iii ) the change in the intracellular distribution of fluorescent lipid 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine percholate taken up from HDL. Taken together, these data suggest that CLAMP, a four-PDZ-domain-containing protein, is associated with SR-BI in the liver sinusoidal plasma membranes and may modulate the intracellular transport and metabolism of cholesteryl esters taken up from HDL.
Type of Medium:
Online Resource
ISSN:
0027-8424
,
1091-6490
DOI:
10.1073/pnas.100114397
Language:
English
Publisher:
Proceedings of the National Academy of Sciences
Publication Date:
2000
detail.hit.zdb_id:
209104-5
detail.hit.zdb_id:
1461794-8
SSG:
11
SSG:
12
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