scholarly journals An autonomous, but INSIG-modulated, role for the Sterol Sensing Domain in mallostery-regulated ERAD of yeast HMG-CoA reductase

2020 ◽  
Author(s):  
Margaret A Wangeline ◽  
Randolph Y Hampton
Keyword(s):  
Protein Quality ◽  
Quaternary Structure ◽  
Limited Proteolysis ◽  
Hmg Coa Reductase ◽  
Autonomous Action ◽  
Pathway Regulation ◽  
Coa Reductase ◽  
Related Proteins

AbstractHMG-CoA reductase (HMGR) undergoes feedback regulated degradation as part of sterol pathway control. Degradation of the yeast HMGR isozyme Hmg2 is controlled by the sterol pathway intermediate GGPP, which causes misfolding of Hmg2 to enhance its ERAD by the HRD pathway. GGPP-dependent reversible misfolding of Hmg2 is remarkably similar to classic allosteric control; we recently labeled this process mallostery to fuse the ideas of misfolding and allostery. We have evaluated the role of the Hmg2 sterol sensing domain (SSD) in mallostery, and the involvement of highly conserved INSIG proteins in SSD function. The SSD is a membrane-embedded motif found in many sterol-related proteins. The Hmg2 SSD was critical for in vivo regulated degradation of Hmg2, and required for mallosteric misfolding of GGPP as studied by in vitro limited proteolysis. The Hmg2 SSD functions in mallostery independently of conserved yeast INSIG proteins. However, this autonomous action of the SSD was modulated by INSIG, thus imposing a second layer of control on Hmg2 regulation. SSD-mediated mallostery occurs prior to HRD dependent ubiquitination, defining a pathway regulation involving SSD-mediated misfolding followed by HRD dependent ubiquitination. GGPP dependent misfolding occurred at a much slower rate in the absence of a functional SSD, indicating that the SSD functions to allow physiologically useful rate of GGPP response, and implying that the SSD is not a binding site for GGPP. We used unresponsive Hmg2 SSD mutants to test the importance of quaternary structure in mallosteric regulation: the presence of a non-responsive Hmg2 mutant strongly suppressed regulation of a co-expressed, normal Hmg2. Finally, we have found that GGPP regulated misfolding occurred in detergent solubilized Hmg2, indicating that the mallosteric response is an intrinsic feature of the Hmg2 multimer. The preserved response of Hmg2 when in micellar solution will allow next-level studies on the structural and biophysical features of this novel fusion of regulation and protein quality control.

scholarly journals An autonomous, but INSIG-modulated, role for the Sterol Sensing Domain in mallostery-regulated ERAD of yeast HMG-CoA reductase

2020 ◽  
pp. jbc.RA120.015910
Author(s):  
Margaret A Wangeline ◽  
Randolph Y Hampton
Keyword(s):  
Binding Site ◽  
Quaternary Structure ◽  
Limited Proteolysis ◽  
Hmg Coa Reductase ◽  
Coa Reductase ◽  
Level Analysis

HMG-CoA reductase (HMGR) undergoes feedback-regulated degradation as part of sterol pathway control. Degradation of the yeast HMGR isozyme Hmg2 is controlled by the sterol pathway intermediate GGPP, which causes misfolding of Hmg2, leading to degradation by the HRD pathway; we call this process mallostery. We evaluated the role of the Hmg2 sterol sensing domain (SSD) in mallostery, as well as the involvement of the highly conserved INSIG proteins. We show that the Hmg2 SSD is critical for regulated degradation of Hmg2 and required for mallosteric misfolding of GGPP as studied by in vitro limited proteolysis. The Hmg2 SSD functions independently of conserved yeast INSIG proteins, but its function was modulated by INSIG, thus imposing a second layer of control on Hmg2 regulation. Mutant analyses indicated that SSD-mediated mallostery occurred prior to and independent of HRD-dependent ubiquitination. GGPP-dependent misfolding was still extant but occurred at a much slower rate in the absence of a functional SSD, indicating that the SSD facilitates a physiologically useful rate of GGPP response, and implying that the SSD is not a binding site for GGPP. Non-functional SSD mutants allowed us to test the importance of Hmg2 quaternary structure in mallostery:  a non-responsive Hmg2 SSD mutant strongly suppressed regulation of a co-expressed, normal Hmg2. Finally, we have found that GGPP-regulated misfolding occurred in detergent-solubilized Hmg2, a feature that will allow next-level analysis of the mechanism of this novel tactic of ligand-regulated misfolding.

scholarly journals An HMG-CoA Reductase Inhibitor, Cerivastatin, Suppresses Growth of Macrophages Expressing Matrix Metalloproteinases and Tissue Factor In Vivo and In Vitro

Circulation ◽  
2001 ◽  
Vol 103 (2) ◽  
pp. 276-283 ◽  
Author(s):  
Masanori Aikawa ◽  
Elena Rabkin ◽  
Seigo Sugiyama ◽  
Sami J. Voglic ◽  
Yoshihiro Fukumoto ◽  
...  
Keyword(s):  
Matrix Metalloproteinases ◽  
Tissue Factor ◽  
Reductase Inhibitor ◽  
Hmg Coa Reductase ◽  
Hmg Coa Reductase Inhibitor ◽  
Coa Reductase

scholarly journals Ameliorations in the Biomarker Indices of Dyslipidemia and Atherosclerotic Plaque by the Inhibition of HMG – CoA Reductase and Antioxidant Potential of Phytoconstituents of an Aqueous Seed Extract of Acacia Senegal (L.) Willd in Rabbits

2021 ◽  
Author(s):  
Jaykaran Charan ◽  
Priyanka Riyad ◽  
Heera Ram ◽  
Ashok Purohit ◽  
Sneha Ambwani ◽  
...  
Keyword(s):  
Atherosclerotic Plaque ◽  
In Silico ◽  
Risk Index ◽  
Seed Extract ◽  
Atherogenic Index ◽  
Acacia Senegal ◽  
Hmg Coa Reductase ◽  
Coa Reductase

Abstract Background: The HMG-CoA inhibitor are used to control adverse cardiovascular event caused by Hypercholesterolemia and dyslipidaemia. The current study was aimed to evaluate the ability of phytoconstituents of an aqueous seed extract of Acacia senegal (L.) Willd to inhibit HMG-CoA reductase and regress the formation of atherosclerotic plaque. Methods: The chemical fingerprinting of the test extract was assessed by LC-MS. Consequently, the assessments of in-vitro, in-vivo, and in-silico were performed by following the standard methods.Results: The in-vitro assessment of the test extract revealed 74.1 % inhibition potential of HMG-CoA reductase. In-vivo evaluations of the test extract indicated that treated hypercholesterolemic rabbits exhibited a significant (𝑃 ≤ 0.001) ameliorations in the biomarker indices of the dyslipidaemia, such as the atherogenic index, Castelli risk index (I&II), atherogenic coefficient along with lipid profile. Concomitantly, significant reductions were observed in the atherosclerotic plaque area and antioxidants. The in-silico study of molecular docking shown interactions capabilities of key phytoconstituents of the test extract with target protein of HMG-CoA reductase which further validated by the molecular dynamics through potentail energy, NPT, NVT, RSMD and others. Subsequently, the ADMET analysis shown ideal druggability. Conclusion: The results indicate that phytoconstituents of an aqueous seed extract of Acacia senegal (L.) Willd. could inhibit HMG-CoA reductase and improve the levels of antioxidants activity that may reduce symptoms associated with hypercholesterolemia.

scholarly journals The Cholesterol-Lowering Effect of Alisol Acetates Based on HMG-CoA Reductase and Its Molecular Mechanism

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Fei Xu ◽  
Hui Yu ◽  
Cai Lu ◽  
Jun Chen ◽  
Wei Gu
Keyword(s):  
Molecular Simulation ◽  
Reductase Activity ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Lipoprotein Cholesterol ◽  
Hmg Coa Reductase ◽  
Coa Reductase ◽  
The Impact

This study measured the impact of alisol B 23-acetate and alisol A 24-acetate, the main active ingredients of the traditional Chinese medicine Alismatis rhizoma, on total cholesterol (TC), triglyceride (TG), high density lipoprotein-cholesterol (HDL-C), and low density lipoprotein-cholesterol (LDL-C) levels of hyperlipidemic mice. The binding of alisol B 23-acetate and alisol A 24-acetate to the key enzyme involved in the metabolism of TC, 3-hydroxy-3-methylglutary-coenzyme A (HMG-CoA) reductase, was studied using the reagent kit method and the western blotting technique combined with a molecular simulation technique. According to the results, alisol acetates significantly lower the TC, TG, and LDL-C concentrations of hyperlipidemic mice, while raising HDL-C concentrations. Alisol acetates lower HMG-CoA reductase activity in a dose-dependent fashion, both in vivo and in vitro. Neither of these alisol acetates significantly lower the protein expression of HMG-CoA. This suggests that alisol acetates lower the TC level via inhibiting the activity of HMG-CoA reductase by its prototype drug, which may exhibit an inhibition effect via directly and competitively binding to HMG-CoA. The side chain of the alisol acetate was the steering group via molecular simulation.

Stimulation of inflammatory responses in vitro and in vivo by lipophilic HMG-CoA reductase inhibitors

2001 ◽  
Vol 1 (1) ◽  
pp. 105-118 ◽  
Author(s):  
Peter A Kiener ◽  
Patricia M Davis ◽  
Judy L Murray ◽  
Sonia Youssef ◽  
Bruce M Rankin ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Hmg Coa Reductase ◽  
Reductase Inhibitors ◽  
Hmg Coa Reductase Inhibitors ◽  
Coa Reductase ◽  
Stimulation Of

scholarly journals Apomine™, an inhibitor of HMG-CoA-reductase, promotes apoptosis of myeloma cells in vitro and is associated with a modulation of myeloma in vivo

2007 ◽  
Vol 120 (8) ◽  
pp. 1657-1663 ◽  
Author(s):  
Claire M. Edwards ◽  
Gabrielle Mueller ◽  
Anke J. Roelofs ◽  
Andrew Chantry ◽  
Mark Perry ◽  
...  
Keyword(s):  
Hmg Coa Reductase ◽  
Myeloma Cells ◽  
Coa Reductase

Type II HMG-CoA Reductase Inhibitors (Statins) Provide Acute-Graft-Versus-Host Disease Protection by Th-2 Cytokine Induction While Sparing Graft-Versus-Leukemia Activity.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 189-189
Author(s):  
Robert Zeiser ◽  
Sawsan Youssef ◽  
Jeanette Baker ◽  
Lawrence Steinman ◽  
Robert Negrin
Keyword(s):  
T Cells ◽  
Cell Lymphoma ◽  
Type Ii ◽  
Hmg Coa Reductase ◽  
Cytokine Induction ◽  
Reductase Inhibitors ◽  
Hmg Coa Reductase Inhibitors ◽  
Coa Reductase

Abstract Recent studies have shown the beneficial impact of 3-hydroxy-3-methyl-CoA (HMG-CoA) reductase inhibitors (statins) on autoimmunity and allograft rejection. To investigate whether statins are capable of protecting from acute graft vs host disease (aGVHD) we utilized an established murine model (FVB/N->Balb/c) across major MHC barriers. Type II statins were potent inducers of a T-helper cell (Th)-2 cytokine profile in the adoptively transferred T cells upon exposure in vitro or in vivo. Expansion of alloreactive luciferase transgenic T cells as measured by total body light emission was significantly reduced by donor pre-treatment (10mg/kg bodyweight) or in vitro T cell treatment (10nM) with atorvastatin (AT vs PBS; p=0.0008) and fluvastatin (FLU vs PBS; p=0.0007). The beneficial effect of statin treatment translated into significantly reduced aGvHD lethality in statin as compared to PBS treated animals. Th-2 biased donor T cells could be tracked until day 15 after BMT by intracellular cytokine staining and FACS analysis. Host treatment prior to transplantation induced down-regulation of the costimulatory molecules CD40, CD80 and CD86 and MHC class II on recipient APCs and enhanced the protective statin effect when donor and recipient were treated (survival AT vs PBS, p=0.0012). Induction of the Th-2 cytokine profile was still permissive for in vivo graft vs leukemia effects by cytolytic effector function of CD8+ T cells against A20 B-cell lymphoma cells as assessed by bioluminescence imaging, FACS, histology and survival. In vitro CD8+ T cells derived from AT treated animals displayed equal cytolytic activity against Yac1 T-cell lymphoma cells as compared to T cells derived from PBS treated animals. Mechanistically we identified a role for the STAT-6 pathway in statin induced Th-2 induction as aGvHD protection was partially reversed with STAT-6−/− donors. The in vivo statin effect could be antagonized by L-mevalonate indicating the relevance of the mevalonate pathway for statin mediated aGvHD protection. Since L-mevalonate produced by the HMG-CoA reductase is the precursor of non steroidal isoprenoid compounds, such as farnesyl pyrophosphate and geranylgeranyl pyrophosphate, the statin impact on prenylation status of critical signaling proteins in alloreactive T cells was determined by Western blot. In vitro AT treatment reduced the levels of RAP-1, RhoB and Ras prenylation in allo-antigen exposed T cells and abrogated expression of T-bet which is critical for Th1 induction. We conclude that type II statins have significant protective impact on aGvHD lethality by Th-2 cytokine induction and inhibition of an uncontrolled Th-1 response, which is of great clinical relevance given the widespread use and well defined toxicity profile of these agents.

scholarly journals Solubility and Bioavailability Enhancement of Poorly Aqueous Soluble Atorvastatin:In Vitro,Ex Vivo, andIn VivoStudies

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Madhuri S. Rodde ◽  
Ganesh T. Divase ◽  
Tejas B. Devkar ◽  
Avinash R. Tekade
Keyword(s):  
Drug Release ◽  
Dissolution Rate ◽  
Ex Vivo ◽  
Reductase Activity ◽  
Polymer Concentration ◽  
Water Soluble ◽  
Hmg Coa Reductase ◽  
Coa Reductase

The objective of this investigation was to improve the solubility of the poorly water soluble drug atorvastatin (ATR), using solid dispersion (SD) techniques, with Neem Gum (NG) as a hydrophilic carrier. The effects of the polymer concentration and method of preparation on the solubility and dissolution rate were studied. The results showed that the solubility of ATR increases with increasing NG concentration. However, dissolution rate of ATR from its SD was dependent on the method used to prepare SD. Anin vitrodrug release study revealed that the solvent evaporation technique is a more convenient and effective method of preparing SD than kneading method. The SD was characterized using DSC, SEM, and XRD study. Anin vivostudy was performed in which the 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG CoA) reductase inhibition activity was measured. A significant reduction in HMG CoA reductase activity was observed with SD of ATR compared with the plain drug. Anex vivoabsorption study was carried out using modified apparatus developed in our laboratory. Thein vitrodrug release andin vivoandex vivostudies clearly demonstrated the potential of hydrophilic NG in enhancing the solubility, dissolution rate, and bioavailability of ATR.

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