SR-BI-mediated selective lipid uptake segregates apoA-I and apoA-II catabolism
The HDL receptor scavenger receptor class B type I (SR-BI) binds HDL and mediates the selective uptake of cholesteryl ester. We previously showed that remnants, produced when human HDL2 is catabolized in mice overexpressing SR-BI, become incrementally smaller, ultimately consisting of small α-migrat...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2005-10-01
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| Series: | Journal of Lipid Research |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0022227520329059 |
| _version_ | 1818728298266492928 |
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| author | Maria C. de Beer Deneys van der Westhuyzen Nathan L. Whitaker Nancy R. Webb Frederick C. de Beer |
| author_facet | Maria C. de Beer Deneys van der Westhuyzen Nathan L. Whitaker Nancy R. Webb Frederick C. de Beer |
| author_sort | Maria C. de Beer |
| collection | DOAJ |
| description | The HDL receptor scavenger receptor class B type I (SR-BI) binds HDL and mediates the selective uptake of cholesteryl ester. We previously showed that remnants, produced when human HDL2 is catabolized in mice overexpressing SR-BI, become incrementally smaller, ultimately consisting of small α-migrating particles, distinct from preβ HDL. When mixed with mouse plasma, some remnant particles rapidly increase in size by associating with HDL without the mediation of cholesteryl ester transfer protein, LCAT, or phospholipid transfer protein. Here, we show that processing of HDL2 by SR-BI-overexpressing mice resulted in the preferential loss of apolipoprotein A-II (apoA-II). Short-term processing generated two distinct, small α-migrating particles. One particle (8.0 nm diameter) contained apoA-I and apoA-II; the other particle (7.7 nm diameter) contained only apoA-I. With extensive SR-BI processing, only the 7.7 nm particle remained. Only the 8.0 nm remnants were able to associate with HDL. Compared with HDL2, this remnant was more readily taken up by the liver than by the kidney.We conclude that SR-BI-generated HDL remnants consist of particles with or without apoA-II and that only those containing apoA-II associate with HDL in an enzyme-independent manner. Extensive SR-BI processing generates small apoA-II-depleted particles unable to reassociate with HDL and readily taken up by the liver. This represents a pathway by which apoA-I and apoA-II catabolism are segregated. |
| first_indexed | 2024-12-17T22:27:46Z |
| format | Article |
| id | doaj.art-907cc729163043dabd47f48ecc39d579 |
| institution | Directory Open Access Journal |
| issn | 0022-2275 |
| language | English |
| last_indexed | 2024-12-17T22:27:46Z |
| publishDate | 2005-10-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Lipid Research |
| spelling | doaj.art-907cc729163043dabd47f48ecc39d5792022-12-21T21:30:19ZengElsevierJournal of Lipid Research0022-22752005-10-01461021432150SR-BI-mediated selective lipid uptake segregates apoA-I and apoA-II catabolismMaria C. de Beer0Deneys van der Westhuyzen1Nathan L. Whitaker2Nancy R. Webb3Frederick C. de Beer4Graduate Center for Nutritional Sciences, University of Kentucky Medical Center, Lexington, KY 40536; Department of Physiology, University of Kentucky Medical Center, Lexington, KY 40536Graduate Center for Nutritional Sciences, University of Kentucky Medical Center, Lexington, KY 40536; Department of Internal Medicine, University of Kentucky Medical Center, Lexington, KY 40536Graduate Center for Nutritional Sciences, University of Kentucky Medical Center, Lexington, KY 40536; Department of Internal Medicine, University of Kentucky Medical Center, Lexington, KY 40536Graduate Center for Nutritional Sciences, University of Kentucky Medical Center, Lexington, KY 40536; Department of Internal Medicine, University of Kentucky Medical Center, Lexington, KY 40536To whom correspondence should be addressed.; Graduate Center for Nutritional Sciences, University of Kentucky Medical Center, Lexington, KY 40536; Department of Internal Medicine, University of Kentucky Medical Center, Lexington, KY 40536; Department of Veterans Affair Medical Center, Lexington, KY 40511The HDL receptor scavenger receptor class B type I (SR-BI) binds HDL and mediates the selective uptake of cholesteryl ester. We previously showed that remnants, produced when human HDL2 is catabolized in mice overexpressing SR-BI, become incrementally smaller, ultimately consisting of small α-migrating particles, distinct from preβ HDL. When mixed with mouse plasma, some remnant particles rapidly increase in size by associating with HDL without the mediation of cholesteryl ester transfer protein, LCAT, or phospholipid transfer protein. Here, we show that processing of HDL2 by SR-BI-overexpressing mice resulted in the preferential loss of apolipoprotein A-II (apoA-II). Short-term processing generated two distinct, small α-migrating particles. One particle (8.0 nm diameter) contained apoA-I and apoA-II; the other particle (7.7 nm diameter) contained only apoA-I. With extensive SR-BI processing, only the 7.7 nm particle remained. Only the 8.0 nm remnants were able to associate with HDL. Compared with HDL2, this remnant was more readily taken up by the liver than by the kidney.We conclude that SR-BI-generated HDL remnants consist of particles with or without apoA-II and that only those containing apoA-II associate with HDL in an enzyme-independent manner. Extensive SR-BI processing generates small apoA-II-depleted particles unable to reassociate with HDL and readily taken up by the liver. This represents a pathway by which apoA-I and apoA-II catabolism are segregated.http://www.sciencedirect.com/science/article/pii/S0022227520329059high density lipoproteinhigh density lipoprotein receptorhigh density lipoprotein sizeremnant high density lipoproteinlipoproteinslipoprotein metabolism |
| spellingShingle | Maria C. de Beer Deneys van der Westhuyzen Nathan L. Whitaker Nancy R. Webb Frederick C. de Beer SR-BI-mediated selective lipid uptake segregates apoA-I and apoA-II catabolism Journal of Lipid Research high density lipoprotein high density lipoprotein receptor high density lipoprotein size remnant high density lipoprotein lipoproteins lipoprotein metabolism |
| title | SR-BI-mediated selective lipid uptake segregates apoA-I and apoA-II catabolism |
| title_full | SR-BI-mediated selective lipid uptake segregates apoA-I and apoA-II catabolism |
| title_fullStr | SR-BI-mediated selective lipid uptake segregates apoA-I and apoA-II catabolism |
| title_full_unstemmed | SR-BI-mediated selective lipid uptake segregates apoA-I and apoA-II catabolism |
| title_short | SR-BI-mediated selective lipid uptake segregates apoA-I and apoA-II catabolism |
| title_sort | sr bi mediated selective lipid uptake segregates apoa i and apoa ii catabolism |
| topic | high density lipoprotein high density lipoprotein receptor high density lipoprotein size remnant high density lipoprotein lipoproteins lipoprotein metabolism |
| url | http://www.sciencedirect.com/science/article/pii/S0022227520329059 |
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