Identification of a heparin-releasable lipoprotein lipase binding protein from endothelial cells.

摘要: Triglycerides in circulating plasma lipoproteins are hydrolyzed by lipoprotein lipase (LPL) which is thought to bind proteoglycans on the luminal endothelial cell surface. Previous studies from this laboratory using LPL-Sepharose affinity chromatography identified a 220-kDa LPL binding proteoglycan. Using ligand blotting with 125I-LPL, we now report 116-kDa protein membrane preparations of cells. 125I-LPL was abolished addition unlabeled LPL. When surface cells labeled biotin, biotinylated. Furthermore, biotinylated bound and eluted 0.4 M NaCl suggesting that present detergent extracts were applied presence 0.15 NaCl, 116-kDa, but not 220-kDa, still LPL-Sepharose. The 35SO4 DEAE-cellulose prior proteoglycans, it However, metabolically [35S]methionine. This dissociated incubating heparin (50 units/ml)-containing buffer. After treatment cells, internalization decreased greater than 70% compared control These results suggest synthesize heparin-releasable, high protein. We postulate associated surfaces mediates binding, internalization, recycling. name hrp (heparin-releasable protein)-116.