GPIHBP1: an endothelial cell molecule important for the lipolytic processing of chylomicrons.
OBJECTIVE
To summarize recent data indicating that glycosylphosphatidylinositol-anchored high density lipoprotein-binding protein 1 (GPIHBP1) plays a key role in the lipolytic processing of chylomicrons.


RESULTS
Lipoprotein lipase hydrolyses triglycerides in chylomicrons at the luminal surface of the capillaries in heart, adipose tissue, and skeletal muscle. The endothelial cell molecule that facilitates the lipolytic processing of chylomicrons has never been clearly defined. Mice lacking GPIHBP1 manifest chylomicronemia, with plasma triglyceride levels as high as 5000 mg/dl. In wild-type mice, GPIHBP1 is expressed on the luminal surface of capillaries in heart, adipose tissue, and skeletal muscle. Cells transfected with GPIHBP1 bind both chylomicrons and lipoprotein lipase avidly.


CONCLUSIONS
The chylomicronemia in Gpihbp1-deficient mice, the fact that GPIHBP1 is located within the lumen of capillaries, and the fact that GPIHBP1 binds lipoprotein lipase and chylomicrons suggest that GPIHBP1 is a key platform for the lipolytic processing of triglyceride-rich lipoproteins.
Young
Stephen G
SG
Department of Medicine/Division of Cardiology, David Geffen School of Medicine, University of California, Los Angeles, California 90095, USA. sgyoung@mednet.ucla.edu
Davies
Brandon S J
BS
Fong
Loren G
LG
Gin
Peter
P
Weinstein
Michael M
MM
Bensadoun
André
A
Beigneux
Anne P
AP
D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000502:physiology*; D002914:Chylomicrons / Q000378:metabolism*; D042783:Endothelial Cells / Q000378:metabolism*; D006801:Humans; D008066:Lipolysis; D008074:Lipoproteins / Q000737:chemistry; D051379:Mice; D008954:Models, Biological; D008969:Molecular Sequence Data; D010641:Phenotype; D018110:Receptors, Lipoprotein / Q000502:physiology*; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D014280:Triglycerides / Q000378:metabolism
D002352:Carrier Proteins; D002914:Chylomicrons; C472779:GPI-HBP1 protein, mouse; C523701:GPIHBP1 protein, human; D008074:Lipoproteins; D018110:Receptors, Lipoprotein; D014280:Triglycerides