Role of PDZK1 in lipid metabolism and atherosclerosis

PDZK1在脂质代谢和动脉粥样硬化中的作用

• 批准号: 8232713
• 负责人: Olivier N. Kocher
• 金额: $ 43.5万
• 依托单位: BETH ISRAEL DEACONESS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8232713
• 关键词: Adaptor Signaling Protein; Adhesions; Adrenal Cortex; Affect; Amino Acid Sequence; Apolipoprotein E; Arterial Fatty Streak; Atherosclerosis; Binding; Biochemical; Biological Process; Cancer Biology; Cardiovascular Diseases; Carrier Proteins; Cell Surface Receptors; Cell membrane; Cholesterol; Complex; Coronary heart disease; Cytoplasm; Data; Dependence; Development; Dimerization; Evaluation; Family; Genes; Goals; Hepatic; Hepatocyte; High Density Lipoproteins; In Vitro; Individual; Ion Channel; Knockout Mice; Knowledge; Laboratories; Lead; Link; Lipoproteins; Liver; Location; Mediating; Membrane Protein Traffic; Membrane Proteins; Metabolism; Methods; Molecular; Multi-Drug Resistance; Mus; Mutate; Myocardial Infarction; Names; Organ; Ovary; PDZ protein; Phosphotyrosine; Physiological; Plasma; Play; Process; Proteins; Qualifying; Role; SR-BI receptor; Scaffolding Protein; Screening procedure; Signal Transduction; Signaling Protein; Site; Small Intestines; Structure; Techniques; Tertiary Protein Structure; Testing; Testis; Tissues; Transgenes; Transgenic Mice; Validation; X-Ray Crystallography; atheroprotective; design; high density lipoprotein receptor; hypercholesterolemia; in vivo; interest; lipid metabolism; mouse model; novel; overexpression; prevent; protein expression; receptor; research study; reverse cholesterol transport; scaffold; scavenger receptor; small molecule; therapeutic target; therapy development; three dimensional structure; uptake

DESCRIPTION (provided by applicant): Adaptor, anchoring and scaffolding proteins play an important role in signal transduction. In many situations, the interaction between signaling proteins is mediated by small amino acid sequences binding to specific protein domains, such as src homology (SH), pTyr-binding (PTB) or PDZ domains. These interactions are responsible for determining location, function and activity of receptor and transporter proteins among others. A few years ago, we isolated a novel protein that we named PDZK1. PDZK1 contains four PDZ protein-interaction domains and interacts with the carboxy-terminal portion of a number of membrane associated proteins including the high density lipoprotein (HDL) scavenger receptor SR-BI and several ion channels, one of them involved in multidrug resistance. As a result, PDZK1 is likely to play an important role in biological processes as diverse as lipid metabolism and cardiovascular disease, ion channel organization and multidrug resistance. We generated a PDZK1 knockout mouse which is characterized by increased plasma cholesterol levels and markedly reduced expression of SR-BI in the liver, resulting in impaired "reverse cholesterol transport". PDZK1 joins ARH (the product of the defective gene in autosomal recessive hypercholesterolemia) in what is likely to be a growing family of cytoplasmic adaptor proteins that control the tissue specific activity of cell surface receptors. More recently, we have determined, using a transgenic mouse model in which truncated forms of PDZK1 were overexpressed in the liver of PDZK1 KO mice, that all four PDZ domains of PDZK1 are necessary for normal SR-BI expression, localization and function, although the precise role of individual domains, PDZ2 and PDZ4 in particular, remains unknown. We have determined that SR-BI is able to interact with another site within PDZK1, in addition to the known interaction with PDZ1. In addition, we have solved the crystal structure of the first domain of PDZK1 and its interaction with SR-BI. We have also determined that PDZK1 is atheroprotective, suggesting that PDZK1 may be an attractive target for therapies in cardiovascular diseases. Our objectives are now to study the molecular organization of the PDZK1/SR-BI protein cluster. We will define the functions of the second and fourth PDZ domains (PDZ2 and PDZ4) of PDZK1 and identify their binding partners, define the complete structure of PDZK1 by X-ray crystallography to obtain a three dimensional structure of the molecule and understand how PDZK1 interacts with its binding partners. We will correlate the results obtained in vitro using a transgenic mouse model, where altered (mutated/truncated) PDZK1 transgenes will be expressed in the liver of PDZK1 KO mice. Such studies may provide the necessary background for the development of new therapies promoting reverse cholesterol transport to prevent the formation of atherosclerotic lesions and myocardial infarction. PUBLIC HEALTH RELEVANCE: A few years ago, we isolated a novel protein that we named PDZK1. PDZK1 contains four specific domains that allow it to interact with other proteins, most of them associated with the cell membrane. One of these proteins called the high density lipoprotein (HDL) scavenger receptor SR-BI participates in metabolizing the "good cholesterol" and preventing coronary heart disease. SR-BI is regulated by PDZK1. We generated a PDZK1 knockout mouse, in which PDZK1 is inactivated, and determined that PDZK1 controls the expression of SR-BI in a tissue specific fashion. More recently, we determined that PDZK1 is among the proteins that prevent atherosclerosis, suggesting that PDZK1 may be an attractive target for therapies in cardiovascular diseases. Our objectives are to study the molecular organization of the PDZK1/SR-BI protein cluster. Such studies may lead to the development of new therapies with the goal of promoting the metabolism of "good cholesterol" to prevent the formation of atherosclerotic lesions and myocardial infarction.

描述（由申请人提供）：衔接蛋白、锚定蛋白和支架蛋白在信号转导中起重要作用。在许多情况下，信号传导蛋白之间的相互作用是由与特定蛋白结构域结合的小氨基酸序列介导的，所述特定蛋白结构域例如src同源性（SH）、pTyr结合（PTB）或PDZ结构域。这些相互作用负责确定受体和转运蛋白等的位置、功能和活性。几年前，我们分离出一种新的蛋白质，我们命名为PDZK 1。PDZK 1含有四个PDZ蛋白相互作用结构域，并与许多膜相关蛋白的羧基末端部分相互作用，包括高密度脂蛋白（HDL）清道夫受体SR-BI和几个离子通道，其中一个涉及多药耐药性。因此，PDZK 1可能在脂质代谢和心血管疾病、离子通道组织和多药耐药性等多种生物过程中发挥重要作用。 我们产生了PDZK 1基因敲除小鼠，其特征在于血浆胆固醇水平升高和肝脏中SR-BI表达显著降低，导致“胆固醇逆向转运”受损。PDZK 1加入ARH（常染色体隐性高胆固醇血症缺陷基因的产物），可能是一个不断增长的细胞质衔接蛋白家族，控制细胞表面受体的组织特异性活性。 最近，我们已经确定，使用转基因小鼠模型，其中截短形式的PDZK 1在PDZK 1 KO小鼠的肝脏中过表达，PDZK 1的所有四个PDZ结构域是正常SR-BI表达，定位和功能所必需的，尽管单个结构域，特别是PDZ 2和PDZ 4的确切作用仍然未知。我们已经确定，SR-BI能够与PDZK 1内的另一个位点相互作用，除了已知的与PDZ 1的相互作用。此外，我们还研究了PDZK 1第一结构域的晶体结构及其与SR-BI的相互作用。我们还确定PDZK 1具有动脉粥样硬化保护作用，这表明PDZK 1可能是心血管疾病治疗的有吸引力的靶点。 我们的目标是研究PDZK 1/SR-BI蛋白簇的分子结构。我们将定义PDZK 1的第二和第四个PDZ结构域（PDZ 2和PDZ 4）的功能，并确定它们的结合伴侣，通过X射线晶体学确定PDZK 1的完整结构，以获得分子的三维结构，并了解PDZK 1如何与其结合伴侣相互作用。我们将使用转基因小鼠模型将体外获得的结果相关联，其中改变的（突变/截短的）PDZK 1转基因将在PDZK 1 KO小鼠的肝脏中表达。这些研究可能为开发促进胆固醇逆向转运的新疗法以预防动脉粥样硬化病变和心肌梗死的形成提供必要的背景。 公共卫生相关性：几年前，我们分离出一种新的蛋白质，我们命名为PDZK 1。PDZK 1包含四个特定的结构域，使其能够与其他蛋白质相互作用，其中大多数与细胞膜相关。其中一种蛋白质称为高密度脂蛋白（HDL）清道夫受体SR-BI，参与代谢“好胆固醇”和预防冠心病。SR-BI受PDZK 1调节。我们产生了PDZK 1敲除小鼠，其中PDZK 1失活，并确定PDZK 1以组织特异性方式控制SR-BI的表达。最近，我们确定PDZK 1是预防动脉粥样硬化的蛋白质之一，这表明PDZK 1可能是心血管疾病治疗的一个有吸引力的靶点。我们的目标是研究PDZK 1/SR-BI蛋白簇的分子结构。这些研究可能会导致新疗法的发展，其目标是促进“好胆固醇”的代谢，以防止动脉粥样硬化病变和心肌梗死的形成。