Functional interactions among retinoschisin and its binding partners

视黄体素及其结合伙伴之间的功能相互作用

基本信息

批准号：
8485191
负责人：
GLADYS Y KO
金额：
$ 21.51万
依托单位：
TEXAS A&M AGRILIFE RESEARCH
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-05-01 至 2015-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8485191
关键词：
Adhesions Adolescent Amino Acid Sequence Amino Acids Binding Biological Assay Blindness Ca(2+)-Transporting ATPase Calcium Channel Cell membrane Cell physiology Cells Chickens Clinical Complex Data Diagnosis Disease Early Diagnosis Electroretinography Future Gene Mutation Genes Goals Homeostasis Human Impairment Intervention Knowledge Link Macular degeneration Membrane Mission Molecular Mutation N-terminal Na(+)-K(+)-Exchanging ATPase National Eye Institute Nature Night Blindness Outcome Patients Phenotype Photoreceptors Physiology Play Point Mutation Prevalence Prevention Protein Fragment Proteins Public Health Pump Regulation Research Retina Retinal Retinal Cone Role Severities Structure United States National Institutes of Health Variant Vision Visual Acuity Work X-Linked Retinoschisis XLRS1 protein base extracellular hybrid protein loss of function loss of function mutation male neurotransmitter release novel programs public health relevance response retinal neuron voltage yeast two hybrid system

项目摘要

DESCRIPTION (provided by applicant): X-linked juvenile retinoschisis (XLRS) is a leading cause of macular degeneration in juvenile males, with a worldwide prevalence from 1:5000 to 1:20,000. The phenotypes of XLRS are caused by mutations of RS1, the gene encoding retinoschisin, an extracellular octameric protein that participates in retinal cell organization an adhesion. Because XLRS progression and severity is highly variable, early diagnosis and potential clinical intervention is very challenging. Retinoschisin is known to interact with variou molecules in the plasma membrane, including the L-type voltage-gated calcium channel ¿1D subunit (L-VGCC¿1D). However, how retinoschisin interacts with its binding partners and its functional roles in the retina are not completely clear. Understanding the molecular nature of the components that interact with retinoschisin will allow us to more fully understand the roles of retinoschisin in retinal cell physiology and function, which will provide new information for making early diagnosis and potential clinical intervention possible. Previously, we demonstrated that L- VGCC¿1D is a binding partner of retinoschisin in the chick retina. The L-VGCCs are essential for neurotransmitter release and intracellular Ca2+ homeostasis in photoreceptors and other retinal neurons. Retinoschisin binds a 500 amino acid N-terminal region of chicken L-VGCC¿1D, which is highly conserved with human L-VGCC¿1D and L-VGCC¿1F subunits. In humans, mutations of L-VGCC¿1F cause incomplete congenital stationary night blindness (CSNB2). Our finding may explain why both XLRS and CSNB2 patients share a similar loss of cone responses. We have further identified a new binding partner of retinoschisin, the plasma membrane Ca2+-ATPase (PMCA1), a Ca2+ pump that is important in excreting excessive intracellular Ca2+ from photoreceptors. Our central hypothesis is that retinoschisin is necessary for plasma membrane retention of PMCA1, and there is a functional interaction among retinoschisin, L-VGCC, and PMCA1 to regulate intracellular Ca2+ homeostasis in photoreceptors. Our research goal is to understand how retinoschisin interacts with L-VGCCs and PMCA1, and how this dynamic trio regulates intracellular Ca2+ homeostasis through the following specific aims: Aim 1. Determine the functional interaction between retinoschisin (RS1) and PMCA1; Aim 2. Determine the molecular sequences responsible for the physical interactions between RS1 and PMCA1 / L-VGCC¿1D; Aim 3. Determine the functional interaction among RS1, L-VGCC1D, and PMCA1 in intracellular Ca2+ homeostasis. We expect to demonstrate: 1. Loss-of- function mutations of RS1 will decrease PMCA1 membrane retention; 2. Specific molecular sequences of RS1, L-VGCC¿1D, and PMCA1 responsible for their physical interactions; 3. Interactions among RS1, L-VGCC1D, and PMCA1 contribute to intracellular Ca2+ homeostasis. Impact: This research program will reveal how retinoschisin interacts with its binding partners, specifically L-VGCCs and PMCA1, and new roles of retinoschisin in photoreceptor physiology and function.

描述（由适用提供）：X连锁的少年视网膜（XLR）是少年男性黄斑变性的主要原因，全球患病率从1：5000到1：20,000。 XLR的表型是由RS1的突变引起的，RS1的突变是编码视网膜气概的基因，这是一种参与视网膜细胞组织的细胞外八度蛋白质。由于XLR的进展和严重程度高度可变，因此早期诊断和潜在的临床干预措施非常挑战。已知视网膜气概会与质膜中的variou分子相互作用，包括L型电压门控钙通道»1D亚基（L-VGCCC。1D）。但是，视网膜气概如何与其结合伙伴及其在视网膜中的功能作用相互作用并不完全清楚。了解与视视视网膜相互作用的成分的分子性质将使我们能够更充分地了解视网膜细胞生理和功能中视网膜感染的作用，这将为早期诊断和潜在的临床干预提供新的信息。以前，我们证明了l-vgcc¿1d是小鸡视网膜中视网膜感染蛋白的结合伴侣。 L-VGCC对于感光体和其他视网膜神经元中的神经递质释放和细胞内Ca2+稳态至关重要。视网膜气概结合了鸡L-VGCC。1D的500氨基酸N末端区域，该区域与人L-VGCCCC. 1D和L-VGCCC。1F亚基高度保守。在人类中，l-vgcc¿1f的突变会导致先天性固定的夜间失明（CSNB2）。我们的发现可以解释为什么XLR和CSNB2患者均具有相似的锥反应损失。我们进一步确定了视网膜膜CA2+ -ATPase（PMCA1）的新结合伴侣，这是一种Ca2+泵，对来自光感受器的细胞内Ca2+很重要。我们的中心假设是，视网膜气概对于PMCA1的质膜保留是必不可少的，并且视网膜气旋，L-VGCC和PMCA1之间存在功能相互作用，以调节光感受器中细胞内Ca2+稳态。我们的研究目标是了解视网膜感染素如何与L-VGCC和PMCA1相互作用，以及该动态三重奏如何通过以下特定目的调节细胞内Ca2+稳态。 AIM 2。确定负责RS1和PMCA1 / L-VGCCC之间物理相互作用的分子序列； AIM 3。确定细胞内Ca2+稳态中RS1，L-VGCCC1D和PMCA1之间的功能相互作用。我们期望证明：1。rs1的功能丧失突变将减少PMCA1膜的保留； 2。rs1，l-vgcc¿1D和PMCA1的特定分子序列负责其物理相互作用； 3。RS1，L-VGCC1D和PMCA1之间的相互作用有助于细胞内Ca2+稳态。影响：该研究计划将揭示视网膜气概如何与其结合伙伴（特别是L-VGCC和PMCA1）相互作用，以及视网膜感染素在光感受器生理和功能中的新作用。