Comparison of angiopoietin-like protein 3 and 4 reveals structural and mechanistic similarities
| Autor: | Jian Liu, Kathryn H. Gunn, Yongmei Xu, Aspen R. Gutgsell, Caitlin V. Johnson, Saskia B. Neher |
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| Rok vydání: | 2021 |
| Předmět: |
0301 basic medicine
Very low-density lipoprotein SEC size-exclusion chromatography Protein Conformation CAD coronary artery disease small-angle X-ray scattering (SAXS) very-low-density lipoprotein (VLDL) Coronary Artery Disease Lipoproteins VLDL Biochemistry Substrate Specificity DGGR 1 2-Di-O-lauryl-rac-glycero-3-glutaric acid 6′-methylresorufin ester 03 medical and health sciences Non-competitive inhibition ANGPTL4 enzyme kinetics protein purification ANGPTL3 Protein purification medicine Angiopoietin-Like Protein 4 Humans Enzyme kinetics Molecular Biology Triglycerides lipoprotein lipase (LPL) Angiopoietin-Like Protein 3 lipoprotein metabolism Lipoprotein lipase noncompetitive inhibition 030102 biochemistry & molecular biology Heparin Chemistry SAXS small-angle X-ray scattering VLDL very-low-density lipoprotein Cell Biology Lipoprotein Lipase Angiopoietin-like Proteins heparin-binding protein LPL lipoprotein lipase NEFA nonesterified fatty acid 030104 developmental biology Protein Binding Research Article medicine.drug |
| Zdroj: | The Journal of Biological Chemistry |
| ISSN: | 0021-9258 |
| DOI: | 10.1016/j.jbc.2021.100312 |
| Popis: | Elevated plasma triglycerides are a risk factor for coronary artery disease, which is the leading cause of death worldwide. Lipoprotein lipase (LPL) reduces triglycerides in the blood by hydrolyzing them from triglyceride-rich lipoproteins to release free fatty acids. LPL activity is regulated in a nutritionally responsive manner by macromolecular inhibitors including angiopoietin-like proteins 3 and 4 (ANGPTL3 and ANGPTL4). However, the mechanism by which ANGPTL3 inhibits LPL is unclear, in part due to challenges in obtaining pure protein for study. We used a new purification protocol for the N-terminal domain of ANGPTL3, removing a DNA contaminant, and found DNA-free ANGPTL3 showed enhanced inhibition of LPL. Structural analysis showed that ANGPTL3 formed elongated, flexible trimers and hexamers that did not interconvert. ANGPTL4 formed only elongated flexible trimers. We compared the inhibition of ANGPTL3 and ANGPTL4 using human very-low-density lipoproteins as a substrate and found both were noncompetitive inhibitors. The inhibition constants for the trimeric ANGPTL3 (7.5 ± 0.7 nM) and ANGPTL4 (3.6 ± 1.0 nM) were only 2-fold different. Heparin has previously been reported to interfere with ANGPTL3 binding to LPL, so we questioned if the negatively charged heparin was acting in a similar fashion to the DNA contaminant. We found that ANGPTL3 inhibition is abolished by binding to low-molecular-weight heparin, whereas ANGPTL4 inhibition is not. Our data show new similarities and differences in how ANGPTL3 and ANGPTL4 regulate LPL and opens new avenues of investigating the effect of heparin on LPL inhibition by ANGPTL3. |
| Databáze: | OpenAIRE |
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