Dissociation of tissue uptake of cholesterol ester from that of apoprotein A-I of rat plasma high density lipoprotein: selective delivery of cholesterol ester to liver, adrenal, and gonad.

Glass, Christopher K.; Pittman, Ray C.; Weinstein, David; Steinberg, Daniel

doi:10.1073/pnas.80.17.5435

Cited by 449 publications

(209 citation statements)

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“…20 Others have similarly reported that HDL was degraded much less readily than LDL in cultured human fibroblasts 35 and in rat aortic smooth muscle cells. 38 In the study reported here, we found that, on average, the fraction of cell-associated 125 I-LDL that was degraded was about 4.4-fold greater than that of 125 I-HDL. This difference agreed well with that reflected by the lipoprotein clearance measurements.…”

Section: Discussionmentioning

confidence: 64%

“…The absolute amounts of 125 I-HDL recovered were too small to allow compositional analysis, but the increased density of the lipoprotein suggests the possible removal of lipids and subsequent release of lipid-depleted HDL. Recent observations of Glass et al 38 and Stein et al 39 are pertinent to this speculation. These workers, using HDL labeled with nonmetabolizable tracers, reported the selective hepatic uptake in rats of the labeled cholesterol ester analogue, compared to labeled HDL-apoprotein.…”

Section: Smentioning

confidence: 94%

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Reversible high affinity uptake of apo E-free high density lipoproteins in cultured pig hepatocytes.

et al. 1985

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We examined the high affinity binding, uptake, and degradation of apo E-free Little is known about how HDL interacts with tissues in vivo. The fractional catabolic rate of HDL apoproteins 11 -13 exceeds that of albumin, 14 -16 which is believed to be cleared by nonspecific mechanisms, suggesting that HDL apoprotein catabolism is facilitated in some way. Recent studies in vivo suggest that 20% to 30% of HDL apoprotein catabolism may occur in the liver, 101718 probably primarily in parenchymal cells. 13 ' 19 High affinity uptake and degradation of HDL apoprotein has been observed in rat and pig hepatocytes. 20- 22 The studies in rat hepatocytes used rat HDL.in which about 10% of the apoprotein is apo E. 23 Since the low density Iipoprotein (LDL) receptor recognizes apo E as well as apo B, the major apoprotein of LDL, 2425 it is not entirely clear whether degradation of rat HDL was mediated by the LDL receptor, an apo E receptor, 26 or by a different high affinity site. We recently described 20 the high affinity uptake and lysosomai degradation of

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Section: Discussionmentioning

confidence: 64%

Section: Smentioning

confidence: 94%

Reversible high affinity uptake of apo E-free high density lipoproteins in cultured pig hepatocytes.

et al. 1985

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“…HDL CE selective uptake is defined as the movement of CE from HDL into target cells without significant internalization and degradation of the HDL particle (Gwynne and Hess, 1980;Glass et al, 1983;Stein et al, 1983;Reaven et al, 1984;Glass et al, 1985;Pittman et al, 1987). This mechanism is distinct from that of the LDL receptor pathway, where LDL is internalized and the particle is degraded in the endosomal/lysosomal pathway (Brown and Goldstein, 1986).…”

Section: Introductionmentioning

confidence: 99%

Scavenger Receptor BI (SR-BI) Clustered on Microvillar Extensions Suggests that This Plasma Membrane Domain Is a Way Station for Cholesterol Trafficking between Cells and High-Density Lipoprotein

Peng

Akmentin

Connelly

et al. 2004

MBoC

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Receptor-mediated trafficking of cholesterol between lipoproteins and cells is a fundamental biological process at the organismal and cellular levels. In contrast to the well-studied pathway of LDL receptor-mediated endocytosis, little is known about the trafficking of high-density lipoprotein (HDL) cholesterol by the HDL receptor, scavenger receptor BI (SR-BI). SR-BI mediates HDL cholesteryl ester uptake in a process in which HDL lipids are selectively transferred to the cell membrane without the uptake and degradation of the HDL particle. We report here the cell surface locale where the trafficking of HDL cholesterol occurs. Fluorescence confocal microscopy showed SR-BI in patches and small extensions of the cell surface that were distinct from sites of caveolin-1 expression. Electron microscopy showed SR-BI in patches or clusters primarily on microvillar extensions of the plasma membrane. The organization of SR-BI in this manner suggests that this microvillar domain is a way station for cholesterol trafficking between HDL and cells. The types of phospholipids in this domain are unknown, but SR-BI is not strongly associated with classical membrane rafts rich in detergent-resistant saturated phospholipids. We speculate that SR-BI is in a more fluid membrane domain that will favor rapid cholesterol flux between the membrane and HDL.

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“…6 Subsequently, murine SR-BI was shown to mediate the uptake of lipid, but not apoprotein, from HDL into cells, 1 a process described as selective uptake. [7][8][9] This finding established SR-BI as the first HDL transmembrane receptor to be identified and cloned. Further studies of the human homologue demonstrated that it also is a multilipoprotein receptor that binds HDL, LDL, and VLDL.…”

mentioning

confidence: 99%

Association of Polymorphisms at the SR-BI Gene Locus With Plasma Lipid Levels and Body Mass Index in a White Population

Acton

Osgood

Donoghue

et al. 1999

ATVB

193

158

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Abstract-The scavenger receptor class B type I (SR-BI) is a lipoprotein receptor that has been shown to be important in high density lipoprotein cholesterol (HDL-C) metabolism in mice. To determine its role in humans, we have characterized the human SR-BI gene and investigated its genetic variation in 489 white men and women. Five variants were demonstrated: 2 in introns (3 and 5) and 3 in exons (1, 8, and 11). Three variants at exons 1 and 8 and intron 5 with allele frequencies Ͼ0.1 were used to examine associations with lipid or anthropometric variables. The exon 1 variant was significantly (PϽ0.05) associated with increased HDL-C and lower low density lipoprotein cholesterol (LDL-C) values in men, but no associations were observed in women. The exon 8 variant was associated in women with lower LDL-C concentrations (3.05Ϯ0.98 mmol/L and 3.00Ϯ0.93 mmol/L for heterozygotes and homozygotes, respectively) compared with women homozygous for the common allele T he scavenger receptor class B type I (SR-BI) is a multilipoprotein receptor found in the liver and steroidogenic glands of both mice 1 and humans 2,3 (for a review, see Reference 4). The cDNA for human SR-BI (also known as CLA-1) was originally cloned by homology to human CD36 and rat LIMPII, which are members of a family of transmembrane proteins. 5 An independent expression cloning study identified the hamster homologue by its ability to mediate the binding of modified LDL, and it was also shown to bind native LDL. 6 Subsequently, murine SR-BI was shown to mediate the uptake of lipid, but not apoprotein, from HDL into cells, 1 a process described as selective uptake. [7][8][9] This finding established SR-BI as the first HDL transmembrane receptor to be identified and cloned. Further studies of the human homologue demonstrated that it also is a multilipoprotein receptor that binds HDL, LDL, and VLDL. 2,10 Further analysis in vivo in mice and rats has supported a role for SR-BI in cholesterol metabolism. Targeted disruption of apoAI, the major protein component of HDL, leads to an increase in SR-BI expression in the adrenal glands of mice, 11 where HDL-C is used for steroid hormone synthesis. In addition, SR-BI expression levels in the adrenal glands are increased in response to adrenocorticotropic hormone and decreased in response to dexamethasone. 12 Estrogen treatment at high doses in rats greatly reduces SR-BI expression in the liver while it increases SR-BI expression in the adrenal gland and ovarian corpus luteal cells. 13 Transient overexpression of SR-BI in the livers of mice by adenoviral infection leads to a marked reduction in plasma HDL levels and a concomitant increase in plasma LDL/IDL cholesterol levels. 14 Finally, targeted disruption of the SR-BI gene in mice leads to a significant increase in plasma HDL 15,16 and reduced selective uptake of cholesterol from HDL into the liver. 16 Thus, SR-BI has clearly been shown to be a very important player in HDL metabolism in mice. However, although mice have HDL as the major cholesterol-carrying lipopr...

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Dissociation of tissue uptake of cholesterol ester from that of apoprotein A-I of rat plasma high density lipoprotein: selective delivery of cholesterol ester to liver, adrenal, and gonad.

Cited by 449 publications

References 23 publications

Reversible high affinity uptake of apo E-free high density lipoproteins in cultured pig hepatocytes.

Reversible high affinity uptake of apo E-free high density lipoproteins in cultured pig hepatocytes.

Scavenger Receptor BI (SR-BI) Clustered on Microvillar Extensions Suggests that This Plasma Membrane Domain Is a Way Station for Cholesterol Trafficking between Cells and High-Density Lipoprotein

Association of Polymorphisms at the SR-BI Gene Locus With Plasma Lipid Levels and Body Mass Index in a White Population

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