Studies on inactivation of lipoprotein lipase: role of the dimer to monomer dissociation

Osborne, James C.; Bengtsson‐Olivecrona, Gunilla; Lee, Nancy S.; Olivecrona, Thomas

doi:10.1021/bi00341a048

Cited by 168 publications

(140 citation statements)

References 20 publications

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“…Intact, catalytically active LPL is a metastable noncovalent dimer, which readily dissociates to inactive monomers. Monomerisation can be induced by moderate concentrations of, for example, guanidinium chloride (Osborne et al, 1985). The heparin affinity of c-LPL indicated that it was dimeric and this was further proved by sedimentation experiments in sucrose density gradients.…”

Section: Discussionmentioning

confidence: 85%

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Chymotryptic cleavage of lipoprotein lipase

Lóokene

Bengtsson‐Olivecrona

1993

European Journal of Biochemistry

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Treatment of bovine lipoprotein lipase (LPL) with chymotrypsin results in cleavage between residues Phe390-Ser391 and between Trp392-Sa393, indicating that this region is exposed in the native conformation of LPL. Two main fragments are generated, one large including the aminoterminus (chymotrypsin-truncated LPL = c-LPL) and one small, carboxy-terminal fragment. The small fragment is not stable, but is further degraded by the protease. Isolated c-LPL has full catalytic activity against tributyryl glycerol (tributyrin) and p-nitrophenyl butyrate, while the activity against emulsions of long-chain triacylglycerols and against liposomes is reduced and the activity against milk fat globules and chylomicrons is lost. Several. properties of c-LPL were investigated. It was found that c-LPL interacts with apolipoprotein CII (apo CII) as efficiently as intact LPL. The truncated enzyme bound to liposomes and to emulsions of long-chain triacylglycerols as well as the intact enzyme did. In contrast, c-LPL did not bind to milk fat globules or to chylomicrons. The activity of c-LPL was more sensitive to inhibition by other lipid-binding proteins, e.g. apolipoprotein CIII (apo CIII), than was the intact enzyme. The affinity for heparin was as high with c-LPL as with intact LPL. Like intact LPL, c-LPL is dimeric in its active form, as evidenced by sucrose density gradient centrifugation.It is concluded that the reduced catalytic and lipid-binding properties of c-LPL compared with intact LPL are related to the properties of the substrate interface. It is speculated that the carboxyterminal part of LPL contains a secondary lipid-binding site, which is important for activity against chylomicrons and related substrates.

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Section: Discussionmentioning

confidence: 85%

“…Intact LPL is a non-covalent dimer which can be dissociated by guanidinium chloride to stable, but inactive, monomers (Osborne et al, 1985). To study whether this was the case also for c-LPL, the sedimentation behavior of intact LPL and its monomer was compared to that of c-LPL and to c-LPL treated with guanidinium chloride (Fig.…”

Section: Subunit Interactionmentioning

confidence: 99%

Chymotryptic cleavage of lipoprotein lipase

Lóokene

Bengtsson‐Olivecrona

1993

European Journal of Biochemistry

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“…The triglyceride/phospholipase ratios of EL-EL and wild-type EL were not statistically different experimentally whatever the cell types used for the transfection. associated almost exclusively with the dimer fraction (24). Sucrose density gradient centrifugation was also used to determine that monomeric LPL refolded in the presence of calcium becomes dimeric (44).…”

Section: Table 1 Triglyceride Lipase and Phospholipase Activities Of mentioning

confidence: 99%

“…The catalytically active forms of both LPL and HL have been shown to be homodimers (18,(21)(22)(23)(24)(25)(26)(27), and in the case of LPL, the orientation of the subunits of the dimer has been shown to be head-to-tail (28 -30). The present study tested the hypothesis that EL also functions as a head-to-tail dimer.…”

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confidence: 99%

Identification of the Active Form of Endothelial Lipase, a Homodimer in a Head-to-Tail Conformation

Griffon

Jin²,

Petty

et al. 2009

Journal of Biological Chemistry

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Endothelial lipase (EL) is a member of a subfamily of lipases that act on triglycerides and phospholipids in plasma lipoproteins, which also includes lipoprotein lipase and hepatic lipase. EL has a tropism for high density lipoprotein, and its level of phospholipase activity is similar to its level of triglyceride lipase activity. Inhibition or loss-of-function of EL in mice results in an increase in high density lipoprotein cholesterol, making it a potential therapeutic target. Although hepatic lipase and lipoprotein lipase have been shown to function as homodimers, the active form of EL is not known. In these studies, the size and conformation of the active form of EL were determined. Immunoprecipitation experiments suggested oligomerization. Ultracentrifugation experiments showed that the active form of EL had a molecular weight higher than the molecular weight of a simple monomer but less than a dimer. A construct encoding a covalent head-to-tail homodimer of EL (EL-EL) was expressed and had similar lipolytic activity to EL. The functional molecular weights determined by radiation inactivation were similar for EL and the covalent homodimer EL-EL. We previously showed that EL could be cleaved by proprotein convertases, such as PC5, resulting in loss of activity. In cells overexpressing PC5, the covalent homodimeric EL-EL appeared to be more stable, with reduced cleavage and conserved lipolytic activity. A comparative model obtained using other lipase structures suggests a structure for the head-to-tail EL homodimer that is consistent with the experimental findings. These data confirm the hypothesis that EL is active as a homodimer in head-to-tail conformation.Three members of the triglyceride lipase family, lipoprotein lipase (LPL), 3 hepatic lipase (HL), and endothelial lipase (EL), contribute to lipoprotein catabolism in the plasma compartment. They are all secreted proteins that bind to heparan sulfate proteoglycans on the luminal side of endothelial cells where they interact with their lipoprotein substrates. They have different specificities for lipoproteins, and all hydrolyze triglycerides and phosphatidylcholine at the sn-1 position, albeit with widely differing efficiencies (1). The preferred lipoprotein substrates for LPL are the triglyceride-rich lipoproteins, chylomicrons, and very low density lipoproteins; the triglyceride lipase activity of LPL is more than 100-fold greater than its phospholipase activity. The primary lipoprotein substrates for HL are chylomicron remnants, intermediate density lipoproteins, and large triglyceridase-enriched HDL; its triglyceride lipase activity is about 20-fold higher than its phospholipase activity. EL is much more active on HDL, and its phospholipase activity is quite similar to its triglyceride lipase activity. These three lipolytic enzymes share a number of structural features. By analogy to the crystal structure of pancreatic lipase (2), another member of the triglyceride lipase family, each has a clearly defined N-terminal and C-terminal structural domain, ...

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“…Active LPL is known as a noncovalent homodimer. Dissociation of the dimer to the monomeric form renders the lipase inactive (Osborne et al, 1985). These maturation steps are important for the post-translational regulation of enzyme activity (Braun and Severson, 1992;Park et al, 1995;Scow et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

Effect of Nordihydroguaiaretic Acid on the Secretion of Lipoprotein Lipase

Kim

Park²,

Park³

2002

BMB Reports

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Nordihydroguaiaretic acid (NDGA), an inhibitor of lipoxygenase, inhibits the secretion of proteins and causes the redistribution of resident Golgi proteins into the endoplasmic reticulum (ER). In this study, the effect of NDGA on lipoprotein lipase (LPL) secretion was investigated in 3T3-L1 adipocytes, and compared with those of brefeldin A (BFA), a well-known fungal metabolite that exhibits similar ER-Golgi redistribution. Both BFA and NDGA blocked secretions of LPL. In the presence of BFA, the active and dimeric LPL was accumulated in adipocytes. After endoglycosidase H (endo H) digestion, the proportion of LPL subunits with partially endo Hsensitive oligosaccharide was significantly increased with BFA. However, in the presence of NDGA, the cellular LPL became inactive, and only the endo H-sensitive fraction of the LPL subunit was observed. An increase of the aggregated forms was observed in the fractions of the sucrose-density gradient ultracentrifugation. These properties of LPL in the NDGA-treated cells were similar to those of LPL that is retained in ER, and the effects of NDGA could not be reversed by BFA. These results indicate that the inhibitory mechanism of NDGA on the LPL secretion is functionally different from the ER-Golgi redistribution that is induced by BFA.

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Studies on inactivation of lipoprotein lipase: role of the dimer to monomer dissociation

Cited by 168 publications

References 20 publications

Chymotryptic cleavage of lipoprotein lipase

Chymotryptic cleavage of lipoprotein lipase

Identification of the Active Form of Endothelial Lipase, a Homodimer in a Head-to-Tail Conformation

Effect of Nordihydroguaiaretic Acid on the Secretion of Lipoprotein Lipase

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