We FRET so You Don’t Have To: New Models of the Lipoprotein Lipase Dimer

Hayne, Cassandra K.; Yumerefendi, Hayretin; Cao, Lu; Gauer, Jacob W.; Lafferty, Michael; Kuhlman, Brian; Erie, Dorothy A.; Neher, Saskia B.

doi:10.1021/acs.biochem.7b01009

Cited by 12 publications

(9 citation statements)

References 68 publications

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“…This indicates that the LPL/GPIHBP1 complex, as well as the fusion protein, consists of one LPL and one GPIHBP1 molecule. These data suggest that LPL exists in vivo as a 1:1 LPL/GPIHBP1 complex and not as a head-to-tail dimer as has been suggested previously (18,19). This 1:1 model also agrees well with the recently solved crystal structure of the coexpressed LPL/GPIHBP1 complex (13).…”

Section: Lpl-gpihbp1 Fusion Protein Is Homogeneous and Stable And Hassupporting

confidence: 88%

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

Nimonkar¹,

Weldon

Godbout

et al. 2020

Journal of Biological Chemistry

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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.

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Section: Lpl-gpihbp1 Fusion Protein Is Homogeneous and Stable And Hassupporting

confidence: 88%

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

Nimonkar¹,

Weldon

Godbout

et al. 2020

Journal of Biological Chemistry

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“…Despite the central role of LPL in the lipoprotein metabolism and despite having been first studied more than 50 y ago, until very recently (16), structural information about LPL was limited to homology models (15), presumably due to the tendency of purified LPL to unfold and aggregate. Although LPL can be stabilized by binding to heparin (22), no experimentally determined structures of LPL bound to heparin have been reported.…”

Section: Discussionmentioning

confidence: 99%

“…For many years it was generally believed that LPL is only active as a homodimer and that the dimer subunits are arranged in a head-to-tail orientation (15,(17)(18)(19). However, a new publication revisited this assumption and used analytical ultracentrifugation to show that LPL in the absence of heparin or LPL in complex with GPIHBP1 can be active as a monomer (20).…”

Section: Discussionmentioning

confidence: 99%

“…Structural homology modeling (13)(14)(15) and a recently reported X-ray crystal structure of LPL bound to GPIHBP1 (16) indicate that LPL has a similar overall structure as pancreatic lipase (PL) and consists of a N-terminal catalytic domain (NTD) with an α/β-hydrolase fold and a C-terminal domain (CTD) with a β-sandwich fold (13)(14)(15)(16). In contrast to PL, which is monomeric, LPL has been reported to be homodimeric with a head-to-tail orientation (15,(17)(18)(19). Furthermore, active LPL homodimers have been reported to spontaneously dissociate into inactive monomers (17,19).…”

Section: Significancementioning

confidence: 99%

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Structure of lipoprotein lipase in complex with GPIHBP1

Arora¹,

Nimonkar²,

Baird³

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

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Lipoprotein lipase (LPL) plays a central role in triglyceride (TG) metabolism. By catalyzing the hydrolysis of TGs present in TG-rich lipoproteins (TRLs), LPL facilitates TG utilization and regulates circulating TG and TRL concentrations. Until very recently, structural information for LPL was limited to homology models, presumably due to the propensity of LPL to unfold and aggregate. By coexpressing LPL with a soluble variant of its accessory protein glycosylphosphatidylinositol-anchored high-density lipoprotein binding protein 1 (GPIHBP1) and with its chaperone protein lipase maturation factor 1 (LMF1), we obtained a stable and homogenous LPL/GPIHBP1 complex that was suitable for structure determination. We report here X-ray crystal structures of human LPL in complex with human GPIHBP1 at 2.5-3.0 Å resolution, including a structure with a novel inhibitor bound to LPL. Binding of the inhibitor resulted in ordering of the LPL lid and lipid-binding regions and thus enabled determination of the first crystal structure of LPL that includes these important regions of the protein. It was assumed for many years that LPL was only active as a homodimer. The structures and additional biochemical data reported here are consistent with a new report that LPL, in complex with GPIHBP1, can be active as a monomeric 1:1 complex. The crystal structures illuminate the structural basis for LPL-mediated TRL lipolysis as well as LPL stabilization and transport by GPIHBP1.

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“…B, computational model of dimeric LPL generated by Hayne et al (Original model, see Ref. 39). Peptide sequences with differential deuterium exchange in the complex state at every time point are colored blue for decreased exchange and red for increased exchange.…”

Section: Human Lpl Hl Chimeric Molecules Are Insensitive To Inhibitiomentioning

confidence: 99%

Mapping the sites of the lipoprotein lipase (LPL)–angiopoietin-like protein 4 (ANGPTL4) interaction provides mechanistic insight into LPL inhibition

Gutgsell

Ghodge

Bowers

et al. 2019

Journal of Biological Chemistry

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Edited by George M. CarmanCardiovascular disease has been the leading cause of death throughout the world for nearly 2 decades. Hypertriglyceridemia affects more than one-third of the population in the United States and is an independent risk factor for cardiovascular disease. Despite the frequency of hypertriglyceridemia, treatment options are primarily limited to diet and exercise. Lipoprotein lipase (LPL) is an enzyme responsible for clearing triglycerides from circulation, and its activity alone can directly control plasma triglyceride concentrations. Therefore, LPL is a good target for triglyceride-lowering therapeutics. One approach for treating hypertriglyceridemia may be to increase the amount of enzymatically active LPL by preventing its inhibition by angiopoietin-like protein 4 (ANGPTL4). However, little is known about how these two proteins interact. Therefore, we used hydrogen-deuterium exchange MS to identify potential binding sites between LPL and ANGPTL4. We validated sites predicted to be located at the protein-protein interface by using chimeric variants of LPL and an LPL peptide mimetic. We found that ANGPTL4 binds LPL near the active site at the lid domain and a nearby ␣-helix. Lipase lid domains cover the active site to control both enzyme activation and substrate specificity. Our findings suggest that ANGPTL4 specifically inhibits LPL by binding the lid domain, which could prevent substrate catalysis at the active site. The structural details of the LPL-ANGPTL4 interaction uncovered here may inform the development of therapeutics targeted to disrupt this interaction for the management of hypertriglyceridemia.

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We FRET so You Don’t Have To: New Models of the Lipoprotein Lipase Dimer

Cited by 12 publications

References 68 publications

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

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

Structure of lipoprotein lipase in complex with GPIHBP1

Mapping the sites of the lipoprotein lipase (LPL)–angiopoietin-like protein 4 (ANGPTL4) interaction provides mechanistic insight into LPL inhibition

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