Structure and Function of the LPLA2/LCAT Acyltransferase Family

LPLA2/LCAT 酰基转移酶家族的结构和功能

基本信息

批准号：
8817382
负责人：
John Tesmer
金额：
$ 56.11万
依托单位：
UNIVERSITY OF MICHIGAN AT ANN ARBOR
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-11-04 至 2018-10-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8817382
关键词：
Active Sites Acyltransferase Address Adverse effects Affect Alveolar Macrophages Amiodarone Anti-Arrhythmia Agents Apolipoprotein A-I Atherosclerosis Autoimmune Diseases Binding Biological Assay Biological Response Modifier Therapy Catabolism Catalysis Cholesterol Cholesterol Esters Complex Cryoelectron Microscopy DNA Sequence Alteration Development Disease Electron Microscopy Engineering Enzymes Eye diseases Family Fishes Future Glycerophospholipids Goals Hereditary Disease High Density Lipoproteins Human Image Infusion procedures Kidney Failure Knowledge Lead Learning Ligands Lipase Lipids Lipoprotein Binding Liposomes Liver Maps Membrane Modeling Molecular Mutate Mutation Negative Staining Outcome Study Patients Peptides Pharmaceutical Preparations Phosphatidylcholine-Sterol O-Acyltransferase Phospholipase A2 Plasma Proteins Play Positioning Attribute Proteins Pulmonary Surfactants Reaction Recombinants Regulation Reporting Resolution Role Series Serum Site-Directed Mutagenesis Somatic Mutation Structure Surface Testing Transacylase Variant acute coronary syndrome analog base design disease phenotype enzyme replacement therapy esterase familial cholesteryl ester deficiency flexibility improved insight lecithin cholesterol acyltransferase deficiency lipid metabolism macrophage meetings mimetics particle public health relevance reconstruction reverse cholesterol transport small molecule theories therapy design

项目摘要

DESCRIPTION (provided by applicant): Lysosomal phospholipase A2 (LPLA2) plays a major role in lipid degradation and is believed to underlie drug-induced phospholipidosis, which commonly occurs in patients taking cationic lipophilic drugs such as the antiarrhythmic amiodarone. Aberrant LPLA2 activity may also be involved in development of autoimmune disease and atherosclerosis. LPLA2 is 50% identical in sequence to lecithin-cholesterol acyltransferase (LCAT), a key enzyme in reverse cholesterol transport from arterial plaque macrophages via high density lipoproteins (HDL). Genetic mutations in LCAT are responsible for Familial LCAT Deficiency (FLD), a devastating disease characterized by low serum cholesterol ester levels and renal failure. There are no reported atomic models for either LPLA2 or LCAT, which do not have significant homology to other proteins of known structure. Thus, the molecular bases for their substrate selectivity, regulation, and disease phenotypes remain poorly understood. In this proposal, we address this critical gap in knowledge via functional analysis of our new 1.8 � crystal structure of LPLA2, determination of the atomic structure of LCAT, imaging LCAT bound to HDL particles by electron microscopy, mapping somatic mutations known to cause genetic disease, and investigating the structural basis for differences in acyl acceptor selectivity. In support of our aims, we provide multiple high resolution structure of LPLA2 in various ligand states, negative stained images of LCAT-HDL complexes, and a low resolution crystal structure of fully glycosylated LCAT. The expected outcome of these studies is a better mechanistic understanding of a structurally uncharacterized family of eukaryotic enzymes that play key roles in lipid metabolism. Our structural and functional studies will help explain the molecular basis for genetic disease and ultimately assist in the design of improved biotherapeutics and small molecule LCAT activators to treat lipid-related disorders such as atherosclerosis and LCAT deficiency.

描述（由应用提供）：溶酶体磷脂酶A2（LPLA2）在脂质降解中起主要作用，并且被认为是药物诱导的磷脂病的基础，通常发生在服用阳离子性亲脂性药物（例如抗心律失常胺）的患者中。异常的LPLA2活性也可能参与自身免疫性疾病和动脉粥样硬化的发展。 LPLA2的序列与卵磷脂 - 胆固醇酰基转移酶（LCAT）的顺序相同，这是一种通过高密度脂蛋白（HDL）从动脉斑块巨噬细胞（HDL）从动脉斑块巨噬细胞转移的关键酶。 LCAT中的遗传突变负责家族性LCAT缺乏症（FLD），这是一种以低血清胆固醇酯水平和肾衰竭为特征的毁灭性疾病。 LPLA2或LCAT尚无报道的原子模型，这些模型对已知结构的其他蛋白质没有显着的同源性。这，其底物选择性，调节和疾病表型的分子碱基仍然了解不足。在该提案中，我们通过对LPLA2的新1.8�晶体结构的功能分析，确定LCAT的原子结构，通过电子显微镜与HDL颗粒结合的LCAT，绘制已知的体细胞突变，并研究遗传疾病的结构基础，从而解决了与HDL颗粒的差异。为了支持我们的目标，我们在各种配体状态下提供LPLA2的多个高分辨率结构，LCAT-HDL复合物的负染色图像以及完全糖基化LCAT的低分辨率晶体结构。这些研究的预期结果是对结构未表征的真核酶的机械理解，该家族在脂质代谢中起着关键作用。我们的结构和功能研究将有助于解释遗传疾病的分子基础，并最终有助于设计改进的生物疗法和小分子LCAT活化剂，以治疗与脂质相关的疾病，例如动脉粥样硬化和LCAT诽谤。