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Hajime Tokuda - One of the best experts on this subject based on the ideXlab platform.
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roles of the protruding loop of factor b essential for the localization of Lipoproteins lolb in the anchoring of bacterial triacylated proteins to the outer membrane
Journal of Biological Chemistry, 2014Co-Authors: Yumi Hayashi, Ryoji Tsurumizu, Jun Tsukahara, Kazuki Takeda, Shinichiro Narita, Makiko Mori, Kunio Miki, Hajime TokudaAbstract:The Lol system comprising five Lol proteins, LolA through LolE, sorts Escherichia coli Lipoproteins to outer membranes. The LolCDE complex, an ATP binding cassette transporter in inner membranes, releases outer membrane-specific Lipoproteins in an ATP-dependent manner, causing formation of the LolA-lipoprotein complex in the periplasm. LolA transports Lipoproteins through the periplasm to LolB on outer membranes. LolB is itself a lipoprotein anchored to outer membranes, although the membrane anchor is functionally dispensable. LolB then localizes Lipoproteins to outer membranes through largely unknown mechanisms. The crystal structure of LolB is similar to that of LolA, and it possesses a hydrophobic cavity that accommodates acyl chains of Lipoproteins. To elucidate the molecular function of LolB, a periplasmic version of LolB, mLolB, was mutagenized at various conserved residues. Despite the lack of acyl chains, most defective mutants were insoluble. However, a derivative with glutamate in place of leucine 68 was soluble and unable to localize Lipoproteins to outer membranes. This leucine is present in a loop protruding from mLolB into an aqueous environment, and no analogous loop is present in LolA. Thus, leucine 68 was replaced with other residues. Replacement by acidic, but not hydrophobic, residues generated for the first time mLolB derivatives that can accept but cannot localize Lipoproteins to outer membranes. Moreover, deletion of the leucine with neighboring residues impaired the lipoprotein receptor activity. Based on these observations, the roles of the protruding loop of LolB in the last step of lipoprotein sorting are discussed.
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a short helix in the c terminal region of lola is important for the specific membrane localization of Lipoproteins
FEBS Letters, 2008Co-Authors: Suguru Okuda, Shoji Watanabe, Hajime TokudaAbstract:The structures of a lipoprotein carrier, LolA, and a lipoprotein receptor, LolB, are similar except for an extra C-terminal loop containing a 310 helix and β-strand 12 in LolA. Lipoprotein release was significantly reduced when β-12 was deleted. Deletion of the 310 helix also inhibited the lipoprotein release. Furthermore, Lipoproteins were non-specifically localized to membranes when LolA lacked the 310 helix. Thus, the membrane localization of Lipoproteins with the LolA derivative lacking the 310 helix was independent of LolB whereas LolB was essential for the outer membrane localization of Lipoproteins with the wild-type LolA.
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molecular events involved in a single cycle of ligand transfer from an atp binding cassette transporter lolcde to a molecular chaperone lola
Journal of Biological Chemistry, 2008Co-Authors: Naohiro Taniguchi, Hajime TokudaAbstract:An ATP binding cassette transporter LolCDE complex releases Lipoproteins from the inner membrane of Escherichia coli in an ATP-dependent manner, leading to the formation of a complex between a lipoprotein and a periplasmic chaperone, LolA. LolA is proposed to undergo a conformational change upon the lipoprotein binding. The lipoprotein is then transferred from the LolA-lipoprotein complex to the outer membrane via LolB. Unlike most ATP binding cassette transporters mediating the transmembrane flux of substrates, the LolCDE complex catalyzes the extrusion of Lipoproteins anchored to the outer leaflet of the inner membrane. Moreover, the LolCDE complex is unique in that it can be purified as a liganded form, which is an intermediate of the lipoprotein release reaction. Taking advantage of these unique properties, we established an assay system that enabled the analysis of a single cycle of lipoprotein transfer reaction from liganded LolCDE to LolA in a detergent solution. The LolA-lipoprotein complex thus formed was physiologically functional and delivered Lipoproteins to the outer membrane in a LolB-dependent manner. Vanadate, a potent inhibitor of the lipoprotein release from proteoliposomes, was found to inhibit the release of ADP from LolCDE. However, a single cycle of lipoprotein transfer occurred from vanadate-treated LolCDE to LolA, indicating that vanadate traps LolCDE at the energized state.
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large scale preparation of the homogeneous lola lipoprotein complex and efficient in vitro transfer of Lipoproteins to the outer membrane in a lolb dependent manner
Protein Science, 2007Co-Authors: Shoji Watanabe, Yuki Oguchi, Naoko Yokota, Hajime TokudaAbstract:An ATP-binding cassette transporter LolCDE complex of Escherichia coli releases Lipoproteins destined to the outer membrane from the inner membrane as a complex with a periplasmic chaperone, LolA. Interaction of the LolA-lipoprotein complex with an outer membrane receptor, LolB, then causes localization of Lipoproteins to the outer membrane. As far as examined, formation of the LolA-lipoprotein complex strictly depends on ATP hydrolysis by the LolCDE complex in the presence of LolA. It has been speculated, based on crystallographic and biochemical observations, that LolA undergoes an ATP-dependent conformational change upon lipoprotein binding. Thus, preparation of a large amount of the LolA-lipoprotein complex is difficult. Moreover, Lipoproteins bound to LolA are heterogeneous. We report here that the coexpression of LolA and outer membrane-specific lipoprotein Pal from a very efficient plasmid causes the unusual accumulation of the LolA-Pal complex in the periplasm. The complex was purified to homogeneity and shown to be a functional intermediate of the lipoprotein localization pathway. In vitro incorporation of Pal into outer membranes revealed that a single molecule of LolB catalyzes the incorporation of more than 100 molecules of Pal into outer membranes. Moreover, the LolB-dependent incorporation of Pal was not affected by excess-free LolA, indicating that LolB specifically interacts with liganded LolA. Finally, the LolB depletion caused the accumulation of a significant amount of Pal in the periplasm, thereby establishing the conditions for preparation of the homogeneous LolA-lipoprotein complex.
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mechanisms underlying energy independent transfer of Lipoproteins from lola to lolb which have similar unclosed β barrel structures
Journal of Biological Chemistry, 2005Co-Authors: Naohiro Taniguchi, Shinichi Matsuyama, Hajime TokudaAbstract:The Lol system, comprising five Lol proteins, transfers Lipoproteins from the inner to the outer membrane of Escherichia coli. Periplasmic LolA accepts Lipoproteins from LolCDE in the inner membrane and immediately transfers them to LolB, a receptor anchored to the outer membrane. The unclosed β-barrel structures of LolA and LolB are very similar to each other and form hydrophobic cavities for Lipoproteins. The lipoprotein transfer between these similar structures is unidirectional and very efficient, but requires no energy input. To reveal the mechanisms underlying this lipoprotein transfer, Arg and Phe at positions 43 and 47, respectively, of LolA were systematically mutagenized. The two residues were previously found to affect abilities to accept and transfer Lipoproteins. Substitution of Phe-47 with polar residues inhibited the ability to accept Lipoproteins from the inner membrane. No derivatives caused periplasmic accumulation of Lipoproteins. In contrast, many Arg-43 derivatives caused unusual periplasmic accumulation of Lipoproteins to various extents. However, all derivatives, except one having Leu instead of Arg, supported the growth of cells. All Arg-43 derivatives retained the ability to accept Lipoproteins from the inner membrane, whereas their abilities to transfer associated Lipoproteins to LolB were variously reduced. Assessment of the intensity of the hydrophobic interaction between Lipoproteins and Arg-43 derivatives revealed that the LolA-lipoprotein interaction should be weak, otherwise lipoprotein transfer to LolB is inhibited, causing accumulation of Lipoproteins in the periplasm.
Jeanmichel Weber - One of the best experts on this subject based on the ideXlab platform.
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the fibrate drug gemfibrozil disrupts lipoprotein metabolism in rainbow trout
Toxicology and Applied Pharmacology, 2011Co-Authors: John S Prindiville, Jan A Mennigen, Jake M Zamora, Thomas W Moon, Jeanmichel WeberAbstract:Gemfibrozil (GEM) is a fibrate drug consistently found in effluents from sewage treatment plants. This study characterizes the pharmacological effects of GEM on the plasma Lipoproteins of rainbow trout (Oncorhynchus mykiss). Our goals were to quantify the impact of the drug on: 1) lipid constituents of Lipoproteins (phospholipids (PL), triacylglycerol (TAG), and cholesterol), 2) lipoprotein classes (high, low and very low density Lipoproteins), and 3) fatty acid composition of Lipoproteins. Potential mechanisms of GEM action were investigated by measuring lipoprotein lipase activity (LPL) and the hepatic gene expression of LPL and of the peroxisome proliferator-activated receptor (PPAR) {alpha}, {beta}, and {gamma} isoforms. GEM treatment resulted in decreased plasma lipoprotein levels (- 29%) and a reduced size of all lipoprotein classes (lower PL:TAG ratios). However, the increase in HDL-cholesterol elicited by GEM in humans failed to be observed in trout. Therefore, HDL-cholesterol cannot be used to assess the impact of the drug on fish. GEM also modified lipoprotein composition by reducing the abundance of long-chain n-3 fatty acids, thereby potentially reducing the nutritional quality of exposed fish. The relative gene expression of LPL was increased, but the activity of the enzyme was not, and we found no evidence for the activationmore » of PPAR pathways. The depressing effects of GEM on fish Lipoproteins demonstrated here may be a concern in view of the widespread presence of fibrates in aquatic environments. Work is needed to test whether exposure to environmental concentrations of these drugs jeopardizes the capacity of fish for reproduction, temperature acclimation or migratory behaviors.« less
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the fibrate drug gemfibrozil disrupts lipoprotein metabolism in rainbow trout
Toxicology and Applied Pharmacology, 2011Co-Authors: John S Prindiville, Jan A Mennigen, Jake M Zamora, Thomas W Moon, Jeanmichel WeberAbstract:Gemfibrozil (GEM) is a fibrate drug consistently found in effluents from sewage treatment plants. This study characterizes the pharmacological effects of GEM on the plasma Lipoproteins of rainbow trout (Oncorhynchus mykiss). Our goals were to quantify the impact of the drug on: 1) lipid constituents of Lipoproteins (phospholipids (PL), triacylglycerol (TAG), and cholesterol), 2) lipoprotein classes (high, low and very low density Lipoproteins), and 3) fatty acid composition of Lipoproteins. Potential mechanisms of GEM action were investigated by measuring lipoprotein lipase activity (LPL) and the hepatic gene expression of LPL and of the peroxisome proliferator-activated receptor (PPAR) α, β, and γ isoforms. GEM treatment resulted in decreased plasma lipoprotein levels (-29%) and a reduced size of all lipoprotein classes (lower PL:TAG ratios). However, the increase in HDL-cholesterol elicited by GEM in humans failed to be observed in trout. Therefore, HDL-cholesterol cannot be used to assess the impact of the drug on fish. GEM also modified lipoprotein composition by reducing the abundance of long-chain n-3 fatty acids, thereby potentially reducing the nutritional quality of exposed fish. The relative gene expression of LPL was increased, but the activity of the enzyme was not, and we found no evidence for the activation of PPAR pathways. The depressing effects of GEM on fish Lipoproteins demonstrated here may be a concern in view of the widespread presence of fibrates in aquatic environments. Work is needed to test whether exposure to environmental concentrations of these drugs jeopardizes the capacity of fish for reproduction, temperature acclimation or migratory behaviors.
Hideaki Bujo - One of the best experts on this subject based on the ideXlab platform.
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lipoprotein subfractions highly associated with renal damage in familial lecithin cholesterol acyltransferase deficiency
Arteriosclerosis Thrombosis and Vascular Biology, 2014Co-Authors: Masayuki Kuroda, Adriaan G Holleboom, E S Stroes, Sakiyo Asada, Yasuyuki Aoyagi, Kouju Kamata, Shizuya Yamashita, Shun Ishibashi, Yasushi Saito, Hideaki BujoAbstract:Objective In familial lecithin:cholesterol acyltransferase (LCAT) deficiency (FLD), deposition of abnormal Lipoproteins in the renal stroma ultimately leads to renal failure. However, fish-eye disease (FED) does not lead to renal damage although the causative mutations for both FLD and FED lie within the same LCAT gene. This study was performed to identify the Lipoproteins important for the development of renal failure in genetically diagnosed FLD in comparison with FED, using high-performance liquid chromatography with a gel filtration column. Approach and results Lipoprotein profiles of 9 patients with LCAT deficiency were examined. Four lipoprotein fractions specific to both FLD and FED were identified: (1) large Lipoproteins (>80 nm), (2) Lipoproteins corresponding to large low-density lipoprotein (LDL), (3) Lipoproteins corresponding to small LDL to large high-density lipoprotein, and (4) to small high-density lipoprotein. Contents of cholesteryl ester and triglyceride of the large LDL in FLD (below detection limit and 45.8±3.8%) and FED (20.7±6.4% and 28.0±6.5%) were significantly different, respectively. On in vitro incubation with recombinant LCAT, content of cholesteryl ester in the large LDL in FLD, but not in FED, was significantly increased (to 4.2±1.4%), whereas dysfunctional high-density lipoprotein was diminished in both FLD and FED. Conclusions Our novel analytic approach using high-performance liquid chromatography with a gel filtration column identified large LDL and high-density lipoprotein with a composition specific to FLD, but not to FED. The abnormal Lipoproteins were sensitive to treatment with recombinant LCAT and thus may play a causal role in the renal pathology of FLD.
John S Prindiville - One of the best experts on this subject based on the ideXlab platform.
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the fibrate drug gemfibrozil disrupts lipoprotein metabolism in rainbow trout
Toxicology and Applied Pharmacology, 2011Co-Authors: John S Prindiville, Jan A Mennigen, Jake M Zamora, Thomas W Moon, Jeanmichel WeberAbstract:Gemfibrozil (GEM) is a fibrate drug consistently found in effluents from sewage treatment plants. This study characterizes the pharmacological effects of GEM on the plasma Lipoproteins of rainbow trout (Oncorhynchus mykiss). Our goals were to quantify the impact of the drug on: 1) lipid constituents of Lipoproteins (phospholipids (PL), triacylglycerol (TAG), and cholesterol), 2) lipoprotein classes (high, low and very low density Lipoproteins), and 3) fatty acid composition of Lipoproteins. Potential mechanisms of GEM action were investigated by measuring lipoprotein lipase activity (LPL) and the hepatic gene expression of LPL and of the peroxisome proliferator-activated receptor (PPAR) {alpha}, {beta}, and {gamma} isoforms. GEM treatment resulted in decreased plasma lipoprotein levels (- 29%) and a reduced size of all lipoprotein classes (lower PL:TAG ratios). However, the increase in HDL-cholesterol elicited by GEM in humans failed to be observed in trout. Therefore, HDL-cholesterol cannot be used to assess the impact of the drug on fish. GEM also modified lipoprotein composition by reducing the abundance of long-chain n-3 fatty acids, thereby potentially reducing the nutritional quality of exposed fish. The relative gene expression of LPL was increased, but the activity of the enzyme was not, and we found no evidence for the activationmore » of PPAR pathways. The depressing effects of GEM on fish Lipoproteins demonstrated here may be a concern in view of the widespread presence of fibrates in aquatic environments. Work is needed to test whether exposure to environmental concentrations of these drugs jeopardizes the capacity of fish for reproduction, temperature acclimation or migratory behaviors.« less
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the fibrate drug gemfibrozil disrupts lipoprotein metabolism in rainbow trout
Toxicology and Applied Pharmacology, 2011Co-Authors: John S Prindiville, Jan A Mennigen, Jake M Zamora, Thomas W Moon, Jeanmichel WeberAbstract:Gemfibrozil (GEM) is a fibrate drug consistently found in effluents from sewage treatment plants. This study characterizes the pharmacological effects of GEM on the plasma Lipoproteins of rainbow trout (Oncorhynchus mykiss). Our goals were to quantify the impact of the drug on: 1) lipid constituents of Lipoproteins (phospholipids (PL), triacylglycerol (TAG), and cholesterol), 2) lipoprotein classes (high, low and very low density Lipoproteins), and 3) fatty acid composition of Lipoproteins. Potential mechanisms of GEM action were investigated by measuring lipoprotein lipase activity (LPL) and the hepatic gene expression of LPL and of the peroxisome proliferator-activated receptor (PPAR) α, β, and γ isoforms. GEM treatment resulted in decreased plasma lipoprotein levels (-29%) and a reduced size of all lipoprotein classes (lower PL:TAG ratios). However, the increase in HDL-cholesterol elicited by GEM in humans failed to be observed in trout. Therefore, HDL-cholesterol cannot be used to assess the impact of the drug on fish. GEM also modified lipoprotein composition by reducing the abundance of long-chain n-3 fatty acids, thereby potentially reducing the nutritional quality of exposed fish. The relative gene expression of LPL was increased, but the activity of the enzyme was not, and we found no evidence for the activation of PPAR pathways. The depressing effects of GEM on fish Lipoproteins demonstrated here may be a concern in view of the widespread presence of fibrates in aquatic environments. Work is needed to test whether exposure to environmental concentrations of these drugs jeopardizes the capacity of fish for reproduction, temperature acclimation or migratory behaviors.
Masayuki Kuroda - One of the best experts on this subject based on the ideXlab platform.
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lipoprotein subfractions highly associated with renal damage in familial lecithin cholesterol acyltransferase deficiency
Arteriosclerosis Thrombosis and Vascular Biology, 2014Co-Authors: Masayuki Kuroda, Adriaan G Holleboom, E S Stroes, Sakiyo Asada, Yasuyuki Aoyagi, Kouju Kamata, Shizuya Yamashita, Shun Ishibashi, Yasushi Saito, Hideaki BujoAbstract:Objective In familial lecithin:cholesterol acyltransferase (LCAT) deficiency (FLD), deposition of abnormal Lipoproteins in the renal stroma ultimately leads to renal failure. However, fish-eye disease (FED) does not lead to renal damage although the causative mutations for both FLD and FED lie within the same LCAT gene. This study was performed to identify the Lipoproteins important for the development of renal failure in genetically diagnosed FLD in comparison with FED, using high-performance liquid chromatography with a gel filtration column. Approach and results Lipoprotein profiles of 9 patients with LCAT deficiency were examined. Four lipoprotein fractions specific to both FLD and FED were identified: (1) large Lipoproteins (>80 nm), (2) Lipoproteins corresponding to large low-density lipoprotein (LDL), (3) Lipoproteins corresponding to small LDL to large high-density lipoprotein, and (4) to small high-density lipoprotein. Contents of cholesteryl ester and triglyceride of the large LDL in FLD (below detection limit and 45.8±3.8%) and FED (20.7±6.4% and 28.0±6.5%) were significantly different, respectively. On in vitro incubation with recombinant LCAT, content of cholesteryl ester in the large LDL in FLD, but not in FED, was significantly increased (to 4.2±1.4%), whereas dysfunctional high-density lipoprotein was diminished in both FLD and FED. Conclusions Our novel analytic approach using high-performance liquid chromatography with a gel filtration column identified large LDL and high-density lipoprotein with a composition specific to FLD, but not to FED. The abnormal Lipoproteins were sensitive to treatment with recombinant LCAT and thus may play a causal role in the renal pathology of FLD.
