Sodium Ions and Calcium Signaling in Neurons and Glia

神经元和神经胶质细胞中的钠离子和钙信号传导

• 批准号: 7849123
• 负责人: MORDECAI P BLAUSTEIN
• 金额: $ 1.6万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 依托单位国家: 美国
• 财政年份: 1979
• 资助国家: 美国
• 起止时间: 1979-08-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7849123
• 关键词: Amino Acid Sequence; Amino Acids; Ankyrins; Astrocytes; Binding; Biological; Brain Hypoxia-Ischemia; Brain Pathology; C-terminal; Calcium; Camping; Cell membrane; Cells; Chimera organism; Complex; Coupled; Coupling; Dendrites; Destinations; Diffusion; Endoplasmic Reticulum; G-substrate; Goals; Homeostasis; Immunoprecipitation; Knockout Mice; Light; Location; Measures; Membrane; Membrane Microdomains; Molecular; Mutant Strains Mice; Mutate; N-terminal; Na(+)-K(+)-Exchanging ATPase; Nerve; Neuroglia; Neurons; Process; Protein Engineering; Protein Isoforms; Regulation; Research; Role; Signal Transduction; Sorting - Cell Movement; Testing; base; novel; sodium ion; tool

The goal of this research is to elucidate the fundamental mechanisms by which Na+ transport influences Ca2+ homeostasis and signaling, in neurons and glia. Neurons and glia both express Na+ pumps with the a1 isoform of the catalytic (a) subunit and Na+ pumps with either the ot2 (glia) or a3 (neurons) isoform. Na+ pumps with a2 or a3 isoforms are localized to plasma membrane-endoplasmic reticulum (PM-ER) junctional complexes ("PLasmERosomes") and are coupled to PM Na/Ca exchangers (NCX) and, thus, to cytosolic ([Ca2+]CYr) and ER Ca2+ concentration and Ca2+ signal regulation in these cells. Critical questions are: How are the a2 and oc3 Na+ pumps sorted and tethered to their appropriate PM destinations? And, what are the local and global functional consequences of this special organization? There are four Specific Aims: Aim 1. To determine how Na+ pump a2 and a3 subunits are targeted and tethered to their appropriate PM locations, a subunit chimeras (e.g., part a2 and part a1, and vice-versa), WT and mutated a truncations, and ankyrin B knockout mice will be used to test the hypothesis that ot2and a3 subunits are targeted to PLasmERosomes by specific N-terminal amino acid (AA) sequences and are tethered by ankyrin B. Aim 2. To determine whether the sub-PM Ca2+ concentration at PM-ER junctions is controlled independently of "bulk" [Ca2+]CYT- Novel near-membrane Ca2+ indicators (FFP-18 and G-CaMP-2, an engineered protein targeted to the PM- ER junction) will be used to test, directly, the idea that PM-ER junctional space Ca2+ is regulated by oc2/a3 Na+ pumps and NCX1 in astrocytes and neurons. Aim 3. To determine how linkage of the Na+ pump a2 subunit isoform, NCX1, and ankyrin B contributes to their central roles in local Ca2+ regulation and global Ca2+ signaling in astrocytes. Aim 4. To determine the roles of the Na+ pump and NCX in Ca2+ efflux from neuronal dendrites and nerve terminals and how these processes influence neuronal function. For Aims 3 and 4, null mutant mice, and molecular biological and pharmacological tools will be used to test the hypothesis that structural linkage of key PM Na+ and Ca2+ transporters in PLasmERosomes enables them to serve critical functionally-coupled roles in Ca2+ regulation and signaling in neurons (Aim 4) and in astrocytes (Aim 3). These studies will shed new light on specific mechanisms that regulate normal Ca2+ homeostasis and signaling, and that may go awry during hypoxia/ischemia and other brain pathologies.

本研究的目的是阐明Na+转运影响Ca2+的基本机制