-
Expert Opinion on Therapeutic Patents Aug 2020The peptide hormone ghrelin regulates physiological processes associated with energy homeostasis such as appetite, insulin signaling, glucose metabolism, and adiposity.... (Review)
Review
INTRODUCTION
The peptide hormone ghrelin regulates physiological processes associated with energy homeostasis such as appetite, insulin signaling, glucose metabolism, and adiposity. Ghrelin has also been implicated in a growing number of neurological pathways involved in stress response and addiction behavior. For ghrelin to bind the growth hormone secretagogue receptor 1a (GHS-R1a) and activate signaling, the hormone must first be octanoylated on a specific serine side chain. This key transformation is performed by the enzyme ghrelin -acyltransferase (GOAT), and therefore GOAT inhibitors may be useful in treating disorders related to ghrelin signaling such as diabetes, obesity, and related metabolic syndromes.
AREAS COVERED
This report covers ghrelin and GOAT as potential therapeutic targets and summarizes work on GOAT inhibitors through the end of 2019, highlighting recent successes with both peptidomimetics and small molecule GOAT inhibitors as potent modulators of GOAT-catalyzed ghrelin octanoylation.
EXPERT OPINION
A growing body of biochemical and structural knowledge regarding the ghrelin/GOAT system now enables multiple avenues for identifying and optimizing GOAT inhibitors. We are at the beginning of a new era with increased opportunities for leveraging ghrelin and GOAT in the understanding and treatment of multiple health conditions including diabetes, obesity, and addiction.
Topics: Acyltransferases; Diabetes Mellitus; Drug Development; Enzyme Inhibitors; Ghrelin; Humans; Metabolic Syndrome; Obesity; Patents as Topic
PubMed: 32564644
DOI: 10.1080/13543776.2020.1776263 -
Molecular Membrane Biology Jan 2009Palmitoylated proteins have been implicated in several disease states including Huntington's, cardiovascular, T-cell mediated immune diseases, and cancer. To proceed... (Review)
Review
Palmitoylated proteins have been implicated in several disease states including Huntington's, cardiovascular, T-cell mediated immune diseases, and cancer. To proceed with drug discovery efforts in this area, it is necessary to: identify the target enzymes, establish efficient assays for palmitoylation, and conduct high-throughput screening to identify inhibitors. The primary objectives of this review are to examine the types of assays used to study protein palmitoylation and to discuss the known inhibitors of palmitoylation. Six main palmitoylation assays are currently in use. Four assays, radiolabeled palmitate incorporation, fatty acyl exchange chemistry, MALDI-TOF MS and azido-fatty acid labeling are useful in the identification of palmitoylated proteins and palmitoyl acyltransferase (PAT) enzymes. Two other methods, the in vitro palmitoylation (IVP) assay and a cell-based peptide palmitoylation assay, are useful in the identification of PAT enzymes and are more amenable to screening for inhibitors of palmitoylation. To date, two general types of palmitoylation inhibitors have been identified. Lipid-based palmitoylation inhibitors broadly inhibit the palmitoylation of proteins; however, the mechanism of action of these compounds is unknown, and each also has effects on fatty acid biosynthesis. Conversely, several non-lipid palmitoylation inhibitors have been shown to selectively inhibit the palmitoylation of different PAT recognition motifs. The selective nature of these compounds suggests that they may act as protein substrate competitors, and may produce fewer non-specific effects. Therefore, these molecules may serve as lead compounds for the further development of selective inhibitors of palmitoylation, which may lead to new therapeutics for cancer and other diseases.
Topics: Acyltransferases; Drug Discovery; Enzyme Inhibitors; Humans; Lipoylation
PubMed: 19152182
DOI: 10.1080/09687680802683839 -
Nature Communications May 2023Inhibitors of triacylglycerol (TG) synthesis have been developed to treat metabolism-related diseases, but we know little about their mechanisms of action. Here, we...
Inhibitors of triacylglycerol (TG) synthesis have been developed to treat metabolism-related diseases, but we know little about their mechanisms of action. Here, we report cryo-EM structures of the TG-synthesis enzyme acyl-CoA:diacylglycerol acyltransferase 1 (DGAT1), a membrane bound O-acyltransferase (MBOAT), in complex with two different inhibitors, T863 and DGAT1IN1. Each inhibitor binds DGAT1's fatty acyl-CoA substrate binding tunnel that opens to the cytoplasmic side of the ER. T863 blocks access to the tunnel entrance, whereas DGAT1IN1 extends further into the enzyme, with an amide group interacting with more deeply buried catalytic residues. A survey of DGAT1 inhibitors revealed that this amide group may serve as a common pharmacophore for inhibition of MBOATs. The inhibitors were minimally active against the related MBOAT acyl-CoA:cholesterol acyltransferase 1 (ACAT1), yet a single-residue mutation sensitized ACAT1 for inhibition. Collectively, our studies provide a structural foundation for developing DGAT1 and other MBOAT inhibitors.
Topics: Acyltransferases; Diacylglycerol O-Acyltransferase; Lipogenesis; Sterol O-Acyltransferase; Triglycerides
PubMed: 37248213
DOI: 10.1038/s41467-023-38934-3 -
The Journal of Biological Chemistry Oct 2020The human zDHHC -acyltransferase family comprises 23 enzymes that mediate the -acylation of a multitude of cellular proteins, including channels, receptors,... (Review)
Review
The human zDHHC -acyltransferase family comprises 23 enzymes that mediate the -acylation of a multitude of cellular proteins, including channels, receptors, transporters, signaling molecules, scaffolds, and chaperones. This reversible post-transitional modification (PTM) involves the attachment of a fatty acyl chain, usually derived from palmitoyl-CoA, to specific cysteine residues on target proteins, which affects their stability, localization, and function. These outcomes are essential to control many processes, including synaptic transmission and plasticity, cell growth and differentiation, and infectivity of viruses and other pathogens. Given the physiological importance of -acylation, it is unsurprising that perturbations in this process, including mutations in genes, have been linked to different neurological pathologies and cancers, and there is growing interest in zDHHC enzymes as novel drug targets. Although zDHHC enzymes control a diverse array of cellular processes and are associated with major disorders, our understanding of these enzymes is surprisingly incomplete, particularly with regard to the regulatory mechanisms controlling these enzymes. However, there is growing evidence highlighting the role of different PTMs in this process. In this review, we discuss how PTMs, including phosphorylation, -acylation, and ubiquitination, affect the stability, localization, and function of zDHHC enzymes and speculate on possible effects of PTMs that have emerged from larger screening studies. Developing a better understanding of the regulatory effects of PTMs on zDHHC enzymes will provide new insight into the intracellular dynamics of -acylation and may also highlight novel approaches to modulate -acylation for clinical gain.
Topics: Acylation; Acyltransferases; Animals; Humans; Lipoylation; Methylation; Phosphorylation; Protein Processing, Post-Translational; Substrate Specificity; Ubiquitination
PubMed: 32817054
DOI: 10.1074/jbc.REV120.014717 -
Chemical Reviews Apr 2017The enzymology of 135 assembly lines containing primarily cis-acyltransferase modules is comprehensively analyzed, with greater attention paid to less common phenomena.... (Review)
Review
The enzymology of 135 assembly lines containing primarily cis-acyltransferase modules is comprehensively analyzed, with greater attention paid to less common phenomena. Diverse online transformations, in which the substrate and/or product of the reaction is an acyl chain bound to an acyl carrier protein, are classified so that unusual reactions can be compared and underlying assembly-line logic can emerge. As a complement to the chemistry surrounding the loading, extension, and offloading of assembly lines that construct primarily polyketide products, structural aspects of the assembly-line machinery itself are considered. This review of assembly-line phenomena, covering the literature up to 2017, should thus be informative to the modular polyketide synthase novice and expert alike.
Topics: Acyltransferases; Polyketide Synthases; Polyketides; Substrate Specificity
PubMed: 28394118
DOI: 10.1021/acs.chemrev.6b00683 -
Biochemical Society Transactions Apr 2015The discovery of the zDHHC family of S-acyltransferase enzymes has been one of the major breakthroughs in the S-acylation field. Now, more than a decade since their... (Review)
Review
The discovery of the zDHHC family of S-acyltransferase enzymes has been one of the major breakthroughs in the S-acylation field. Now, more than a decade since their discovery, major questions centre on profiling the substrates of individual zDHHC enzymes (there are 24 ZDHHC genes and several hundred S-acylated proteins), defining the mechanisms of enzyme-substrate specificity and unravelling the importance of this enzyme family for cellular physiology and pathology.
Topics: Acylation; Acyltransferases; Humans; Multigene Family; Substrate Specificity
PubMed: 25849920
DOI: 10.1042/BST20140270 -
Progress in Lipid Research Jan 2011A phospholipase A₂ was identified from MDCK cell homogenates with broad specificity toward glycerophospholipids including phosphatidylcholine,... (Review)
Review
A phospholipase A₂ was identified from MDCK cell homogenates with broad specificity toward glycerophospholipids including phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and phosphatidylglycerol. The phospholipase has the unique ability to transacylate short chain ceramides. This phospholipase is calcium-independent, localized to lysosomes, and has an acidic pH optimum. The enzyme was purified from bovine brain and found to be a water-soluble glycoprotein consisting of a single peptide chain with a molecular weight of 45 kDa. The primary structure deduced from the DNA sequences is highly conserved between chordates. The enzyme was named lysosomal phospholipase A₂ (LPLA₂) and subsequently designated group XV phospholipase A₂. LPLA₂ has 49% of amino acid sequence identity to lecithin-cholesterol acyltransferase and is a member of the αβ-hydrolase superfamily. LPLA₂ is highly expressed in alveolar macrophages. A marked accumulation of glycerophospholipids and extensive lamellar inclusion bodies, a hallmark of cellular phospholipidosis, is observed in alveolar macrophages in LPLA₂(-/-) mice. This defect can also be reproduced in macrophages that are exposed to cationic amphiphilic drugs such as amiodarone. In addition, older LPLA₂(-/-) mice develop a phenotype similar to human autoimmune disease. These observations indicate that LPLA₂ may play a primary role in phospholipid homeostasis, drug toxicity, and host defense.
Topics: Acyltransferases; Amino Acid Sequence; Animals; Ceramides; Humans; Lysosomes; Molecular Sequence Data; Phospholipases A2
PubMed: 21074554
DOI: 10.1016/j.plipres.2010.10.006 -
The Ocular Surface Jan 2022Previously, we showed that Acyl-CoA wax-alcohol acyltransferase 2 (AWAT2), an essential enzyme required for meibum wax ester synthesis, was not expressed by immortalized...
PURPOSE
Previously, we showed that Acyl-CoA wax-alcohol acyltransferase 2 (AWAT2), an essential enzyme required for meibum wax ester synthesis, was not expressed by immortalized human meibomian gland epithelial cells (hMGEC) in culture. To begin to understand the mechanisms controlling AWAT2 expression, we have analyzed its expression in human and rabbit meibomian glands and cultured meibocytes.
METHODS
Rabbit meibocyte progenitor cells (rMPC) were first grown in Cnt-BM.1 basal medium (Cellntec) supplemented with rhEGF, FGF10, and ROCK inhibitor (Y-27632 dihydrochloride), and then passed at 70-80% confluency with Accutase. Differentiation of rMPC to meibocytes (rMC) was induced by removal of Y-27632 and addition of 1 mM calcium with and without PPARγ agonists. RNA from the tissue, primary, passaged rMPC and differentiated rMC were obtained for AWAT2 qPCR analysis. Proteins and cells were evaluated for western blotting and neutral lipid synthesis, respectively. For comparison, human meibomian glands were separated for RNA and protein analysis. hMGEC was cultured to collect RNA and protein.
RESULTS
Rabbit rMPCs were successfully grown, passaged, and differentiated, showing a significant increase in lipid droplet accumulation. AWAT2 RNA was highly expressed in tissue but showed a -16.9 log2 fold decrease in primary and passaged rMPCs and was not induced by differentiation to rMC. By comparison, human meibomian glands showed high expression of AWAT2, and hMGEC expressed non-detectable levels of AWAT2 transcripts or protein.
CONCLUSIONS
AWAT2 expression is lost in cultured rMPC and rMC suggesting that cells in culture do not undergo complete meibocyte differentiation and require yet to be identified culture conditions.
Topics: Acyltransferases; Animals; Humans; Meibomian Glands; RNA; Rabbits
PubMed: 34838721
DOI: 10.1016/j.jtos.2021.11.010 -
Journal of Lipid Research Apr 2017
Topics: Acyltransferases; Color Vision; Diacylglycerol O-Acyltransferase; Substrate Specificity
PubMed: 28232616
DOI: 10.1194/jlr.C075838 -
Journal of Lipid Research Sep 2008Phospholipid biosynthesis is a vital facet of bacterial physiology that begins with the synthesis of the fatty acids by a soluble type II fatty acid synthase. The... (Review)
Review
Phospholipid biosynthesis is a vital facet of bacterial physiology that begins with the synthesis of the fatty acids by a soluble type II fatty acid synthase. The bacterial glycerol-phosphate acyltransferases utilize the completed fatty acid chains to form the first membrane phospholipid and thus play a critical role in the regulation of membrane biogenesis. The first bacterial acyltransferase described was PlsB, a glycerol-phosphate acyltransferase. PlsB is a key regulatory point that coordinates membrane phospholipid formation with cell growth and macromolecular synthesis. Phosphatidic acid is then produced by PlsC, a 1-acylglycerol-phosphate acyltransferase. These two acyltransferases use thioesters of either CoA or acyl carrier protein (ACP) as the acyl donors and have homologs that perform the same reactions in higher organisms. However, the most prevalent glycerol-phosphate acyltransferase in the bacterial world is PlsY, which uses a recently discovered acyl-phosphate fatty acid intermediate as an acyl donor. This unique activated fatty acid is formed from the acyl-ACP end products of the fatty acid biosynthetic pathway by PlsX, an acyl-ACP:phosphate transacylase.
Topics: 1-Acylglycerol-3-Phosphate O-Acyltransferase; Acetyltransferases; Acyl Carrier Protein; Acyltransferases; Bacteria; Bacterial Proteins; Escherichia coli Proteins; Fatty Acid Synthase, Type II; Glycerol-3-Phosphate O-Acyltransferase; Glycerophospholipids; Phylogeny
PubMed: 18369234
DOI: 10.1194/jlr.R800005-JLR200