scholarly journals Evidence for Two Distinct Binding Sites for Lipoprotein Lipase on Glycosylphosphatidylinositol-anchored High Density Lipoprotein-binding Protein 1 (GPIHBP1)

2015 ◽  
Vol 290 (22) ◽  
pp. 13919-13934 ◽  
Author(s):  
Mart Reimund ◽  
Mikael Larsson ◽  
Oleg Kovrov ◽  
Sergo Kasvandik ◽  
Gunilla Olivecrona ◽  
...  
Keyword(s):  
High Density Lipoprotein ◽  
Lipoprotein Lipase ◽  
Binding Sites ◽  
Binding Protein ◽  
Density Lipoprotein ◽  
High Density ◽  
Lipoprotein Binding

scholarly journals A lipoprotein lipase–GPI-anchored high-density lipoprotein–binding protein 1 fusion lowers triglycerides in mice: Implications for managing familial chylomicronemia syndrome

2019 ◽  
Vol 295 (10) ◽  
pp. 2900-2912 ◽  
Author(s):  
Amitabh V. Nimonkar ◽  
Stephen Weldon ◽  
Kevin Godbout ◽  
Darrell Panza ◽  
Susan Hanrahan ◽  
...  
Keyword(s):  
Fusion Protein ◽  
Enzyme Replacement Therapy ◽  
High Density Lipoprotein ◽  
Replacement Therapy ◽  
Lipoprotein Lipase ◽  
Binding Protein ◽  
Density Lipoprotein ◽  
High Density ◽  
Enzyme Replacement ◽  
Lipoprotein Binding

Lipoprotein lipase (LPL) is central to triglyceride metabolism. Severely compromised LPL activity causes familial chylomicronemia syndrome (FCS), which is associated with very high plasma triglyceride levels and increased risk of life-threatening pancreatitis. Currently, no approved pharmacological intervention can acutely lower plasma triglycerides in FCS. Low yield, high aggregation, and poor stability of recombinant LPL have thus far prevented development of enzyme replacement therapy. Recently, we showed that LPL monomers form 1:1 complexes with the LPL transporter glycosylphosphatidylinositol-anchored high-density lipoprotein–binding protein 1 (GPIHBP1) and solved the structure of the complex. In the present work, we further characterized the monomeric LPL/GPIHBP1 complex and its derivative, the LPL–GPIHBP1 fusion protein, with the goal of contributing to the development of an LPL enzyme replacement therapy. Fusion of LPL to GPIHBP1 increased yields of recombinant LPL, prevented LPL aggregation, stabilized LPL against spontaneous inactivation, and made it resistant to inactivation by the LPL antagonists angiopoietin-like protein 3 (ANGPTL3) or ANGPTL4. The high stability of the fusion protein enabled us to identify LPL amino acids that interact with ANGPTL4. Additionally, the LPL–GPIHBP1 fusion protein exhibited high enzyme activity in in vitro assays. Importantly, both intravenous and subcutaneous administrations of the fusion protein lowered triglycerides in several mouse strains without causing adverse effects. These results indicate that the LPL–GPIHBP1 fusion protein has potential for use as a therapeutic for managing FCS.

scholarly journals Assessing the Role of the Glycosylphosphatidylinositol-anchored High Density Lipoprotein-binding Protein 1 (GPIHBP1) Three-finger Domain in Binding Lipoprotein Lipase

2011 ◽  
Vol 286 (22) ◽  
pp. 19735-19743 ◽  
Author(s):  
Anne P. Beigneux ◽  
Brandon S. J. Davies ◽  
Shelly Tat ◽  
Jenny Chen ◽  
Peter Gin ◽  
...  
Keyword(s):  
High Density Lipoprotein ◽  
Lipoprotein Lipase ◽  
Binding Protein ◽  
Density Lipoprotein ◽  
High Density ◽  
Cell Protein ◽  
Apical Surface ◽  
Amino Terminal ◽  
Acidic Domain ◽  
Lipoprotein Binding

Glycosylphosphatidylinositol-anchored high density lipoprotein-binding protein 1 (GPIHBP1) is an endothelial cell protein that transports lipoprotein lipase (LPL) from the subendothelial spaces to the capillary lumen. GPIHBP1 contains two main structural motifs, an amino-terminal acidic domain enriched in aspartates and glutamates and a lymphocyte antigen 6 (Ly6) motif containing 10 cysteines. All of the cysteines in the Ly6 domain are disulfide-bonded, causing the protein to assume a three-fingered structure. The acidic domain of GPIHBP1 is known to be important for LPL binding, but the involvement of the Ly6 domain in LPL binding requires further study. To assess the importance of the Ly6 domain, we created a series of GPIHBP1 mutants in which each residue of the Ly6 domain was changed to alanine. The mutant proteins were expressed in Chinese hamster ovary (CHO) cells, and their expression level on the cell surface and their ability to bind LPL were assessed with an immunofluorescence microscopy assay and a Western blot assay. We identified 12 amino acids within GPIHBP1, aside from the conserved cysteines, that are important for LPL binding; nine of those were clustered in finger 2 of the GPIHBP1 three-fingered motif. The defective GPIHBP1 proteins also lacked the ability to transport LPL from the basolateral to the apical surface of endothelial cells. Our studies demonstrate that the Ly6 domain of GPIHBP1 is important for the ability of GPIHBP1 to bind and transport LPL.

scholarly journals Glycosylphosphatidylinositol-Anchored High-Density Lipoprotein-Binding Protein 1 Plays a Critical Role in the Lipolytic Processing of Chylomicrons

2007 ◽  
Vol 5 (4) ◽  
pp. 279-291 ◽  
Author(s):  
Anne P. Beigneux ◽  
Brandon S.J. Davies ◽  
Peter Gin ◽  
Michael M. Weinstein ◽  
Emily Farber ◽  
...  
Keyword(s):  
High Density Lipoprotein ◽  
Binding Protein ◽  
Critical Role ◽  
Density Lipoprotein ◽  
High Density ◽  
Lipoprotein Binding
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