scholarly journals Structural and Dynamic Determinants of Molecular Recognition in Bile Acid-Binding Proteins

2022 ◽  
Vol 23 (1) ◽  
pp. 505
Author(s):  
Orsolya Toke
Keyword(s):  
Bile Acid ◽  
Bile Salt ◽  
Bile Salts ◽  
Binding Proteins ◽  
Mammalian Species ◽  
Lipid Binding ◽  
Drug Candidates ◽  
Disease States ◽  
Bile Acid Binding ◽  
Lipid Binding Proteins

Disorders in bile acid transport and metabolism have been related to a number of metabolic disease states, atherosclerosis, type-II diabetes, and cancer. Bile acid-binding proteins (BABPs), a subfamily of intracellular lipid-binding proteins (iLBPs), have a key role in the cellular trafficking and metabolic targeting of bile salts. Within the family of iLBPs, BABPs exhibit unique binding properties including positive binding cooperativity and site-selectivity, which in different tissues and organisms appears to be tailored to the local bile salt pool. Structural and biophysical studies of the past two decades have shed light on the mechanism of bile salt binding at the atomic level, providing us with a mechanistic picture of ligand entry and release, and the communication between the binding sites. In this review, we discuss the emerging view of bile salt recognition in intestinal- and liver-BABPs, with examples from both mammalian and non-mammalian species. The structural and dynamic determinants of the BABP-bile–salt interaction reviewed herein set the basis for the design and development of drug candidates targeting the transcellular traffic of bile salts in enterocytes and hepatocytes.

scholarly journals The role of sterol carrier protein2 and other hepatic lipid-binding proteins in bile-acid biosynthesis

1986 ◽  
Vol 238 (3) ◽  
pp. 879-884 ◽  
Author(s):  
B Lidström-Olsson ◽  
K Wikvall
Keyword(s):  
Bile Acid ◽  
Binding Proteins ◽  
Glutathione Transferase ◽  
Lipid Binding ◽  
Regulatory Function ◽  
Acid Biosynthesis ◽  
Fatty Acid Binding ◽  
Bile Acid Biosynthesis ◽  
Lipid Binding Proteins

The ability of different lipid-binding proteins in liver cytosol to affect enzyme activities in bile-acid biosynthesis was studied in whole microsomes (microsomal fractions) and mitochondria and in purified enzyme systems. Sterol carrier protein2 stimulated the 7 alpha-hydroxylation of cholesterol and the 12 alpha-hydroxylation of 5 beta-cholestane-3 alpha, 7 alpha-diol in microsomes and the 26-hydroxylation of cholesterol in mitochondria 2-3-fold. It also stimulated the oxidation of 5-cholestene-3 beta, 7 alpha-diol into 7 alpha-hydroxy-4-cholesten-3-one in microsomes. The stimulatory effect of sterol carrier protein2 was much less with purified cholesterol 7 alpha- and 26-hydroxylase systems than with microsomes and mitochondria. No stimulatory effect of sterol carrier protein2 was observed with purified 12 alpha-hydroxylase and 3 beta-hydroxy-delta 5-C27-steroid oxidoreductase. Sterol carrier protein (fatty-acid-binding protein), ‘DEAE-peak I protein’ [Dempsey, McCoy, Baker, Dimitriadou-Vafiadou, Lorsbach & Howards (1981) J. Biol. Chem. 256, 1867-1873], ligandin (glutathione transferase B) and serum albumin had no marked stimulatory effects in either crude or in purified systems. The results suggest that sterol carrier protein2 facilitates the introduction of the less-polar substrates in bile-acid biosynthesis to the membrane-bound enzymes in crude systems in vitro. The broad substrate specificity appears, however, not to be consistent with a specific regulatory function for sterol carrier protein2 in bile-acid biosynthesis.

The role of dynamics in modulating ligand exchange in intracellular lipid binding proteins

2014 ◽  
Vol 1844 (7) ◽  
pp. 1268-1278 ◽  
Author(s):  
Laura Ragona ◽  
Katiuscia Pagano ◽  
Simona Tomaselli ◽  
Filippo Favretto ◽  
Alberto Ceccon ◽  
...  
Keyword(s):  
Ligand Exchange ◽  
Binding Proteins ◽  
Lipid Binding ◽  
Intracellular Lipid ◽  
Lipid Binding Proteins

scholarly journals INTRACELLULAR LIPID-BINDING PROTEINS AND THEIR GENES

1997 ◽  
Vol 17 (1) ◽  
pp. 277-303 ◽  
Author(s):  
David A. Bernlohr ◽  
Melanie A. Simpson ◽  
Ann Vogel Hertzel ◽  
Leonard J. Banaszak
Keyword(s):  
Binding Proteins ◽  
Lipid Binding ◽  
Intracellular Lipid ◽  
Lipid Binding Proteins

Abstract 583: Characterization of Cell Membrane Microdomains Facilitating HDL Biogenesis

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Hong Choi ◽  
Isabelle Ruel ◽  
Rui Hao Leo Wang ◽  
Jacques Genest
Keyword(s):  
Cell Membrane ◽  
Cell Surface ◽  
Protease Inhibitors ◽  
Binding Proteins ◽  
Lipid Binding ◽  
Cholesterol Homeostasis ◽  
Scaffolding Protein ◽  
Membrane Microdomains ◽  
Discontinuous Sucrose Gradient ◽  
Lipid Binding Proteins

High-density lipoprotein (HDL) particles, generated in the process of removing excess cellular cholesterol, play crucial roles in maintaining cholesterol homeostasis in arterial cells and in protecting the cardiovascular system from the development of atherosclerosis. Cholesterol-loaded cells increase their binding capacity to the HDL scaffolding protein, apolipoprotein A-I (ApoA-I), however, cell surface factors necessary for ApoA-I binding remains to be elucidated. To characterize cell membrane microdomains interacting with ApoA-I, primary human skin fibroblasts were incubated with ApoA-I for 1h at 4°C. After linking protein-protein interactions with a membrane-impermeable crosslinker, DTSSP, cells were subjected to homogenization. The cell homogenate was separated by a discontinuous sucrose gradient centrifugation and ten fractions were collected. ApoA-I-associated cell membrane fraction was located by immunoblotting for ApoA-I and organelle markers. Membrane-containing fractions were fragmented using sonication prior to immunoprecipitation of ApoA-I-associated microdomains using an anti-ApoA-I antibody. Major lipid classes present in the microdomains are phosphatidylcholine, phosphatidylserine, sphingomyelin and cholesterol. Two cell membrane proteins, caveolin and ABCA1, were excluded from the microdomains. These data suggest that ApoA-I bind to cholesterol-rich cell surface microdomains that are different from ABCA1 and caveolae domains. LC-MS/MS analysis identified the presence of 26 proteins in the microdomains. Among these, several desmosomal proteins, lipid binding proteins and protease inhibitors were identified. Overall, our results suggest that the initial binding of ApoA-I to cell surface occurs on the lateral sides of cell membranes where desmosomal proteins provide a binding site for ApoA-I, and that lipid binding proteins facilitate lipidation of ApoA-I while protease inhibitors protect ApoA-I and related proteins from degradation. In conclusion, we established a new method to isolate cell membrane microdomains interacting with ApoA-I. Using this method, we found that ApoA-I associates with desmosomal proteins for the formation of HDL.

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