Mechanisms of voltage regulation of membrane transport

膜运输的电压调节机制

• 批准号: 10417430
• 负责人: Sandipan Chowdhury
• 金额: $ 34.33万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-04-01 至 2027-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10417430
• 关键词: Action Potentials; Activities of Daily Living; Address; Affect; Angelman Syndrome; Architecture; Attention deficit hyperactivity disorder; Binding; Biochemical; Biological Assay; Biophysical Process; C-terminal; CCL21 gene; Cardiac; Cations; Cell Proliferation; Cells; Charge; Chemicals; Choline; Complement; Couples; Cryoelectron Microscopy; Cues; Cyclic AMP; Cyclic GMP; Cyclic Nucleotides; Cytoplasmic Tail; DNA Sequence Alteration; Data; Dependence; Detergents; Development; Diabetes Mellitus; Digestive System Disorders; Disease; Drug Design; Electrophysiology (science); Enzymes; Epilepsy; Exhibits; Family; Family member; Fluorescence; Foundations; Health; Heart failure; Homeostasis; Human; Hydrogen; Hypertension; Intervention; Investigation; Ion Channel Gating; Ion Exchange; Ion Transport; Ions; Length; Ligands; Link; Liposomes; Male Infertility; Malignant Neoplasms; Maps; Measures; Mediating; Membrane; Membrane Proteins; Membrane Transport Proteins; Methods; Micelles; Modeling; Molecular; Molecular Conformation; Movement; Mus; Muscular Dystrophies; Orthologous Gene; Pathologic; Peptide Hydrolases; Ph+ ALL; Pharmacology; Phosphoric Monoester Hydrolases; Photobleaching; Physiological Processes; Play; Point Mutation; Protein Family; Proteins; Protons; Regulation; Reperfusion Injury; Resolution; Role; Sea Urchins; Sodium; Sodium Chloride; Sperm Capacitation; Sperm Motility; Stimulus; Structure; System; Techniques; Testing; Thermodynamics; Transmembrane Transport; Variant; autism spectrum disorder; base; density; design; dimer; electric field; experimental study; innovation; insight; interfacial; member; mutant; novel; particle; polypeptide; reconstitution; reconstruction; single molecule; sodium ion; sperm cell; therapy design; voltage

Mechanisms of voltage regulation of membrane transport SLC9 family of membrane transporters couple the import of sodium ions to export of protons. They are vital for regulation of cytoplasmic and endosomal pH, which in turn affect several physiological processes. Their disfunction has been linked to many diseases such as diabetes, hypertension, heart failure and cancer. Genetic mutations in specific SLC9 members have also been associated with Angelman-syndrome like disorders, ADHD, familial autism, epilepsies and male infertility. The SLC9C1 is a unique member of the SLC9 family. Unlike other SLC9s which feature a membrane delimited sodium-hydrogen exchange (NHE) domain and a usually short and relatively unstructured C-terminal soluble domain, SLC9C1 combines an NHE, a voltage-sensing domain (VSD) and a cyclic nucleotide binding domain (CNBD), interconnected via long, structured linkers, in a single polypeptide. Recent foundational experiments have revealed that membrane hyperpolarization and binding of cyclic nucleotides potentiates ion transport via SLC9C1. Its unique design makes it impossible to predict how voltage and ligand regulation of this protein is manifested at a structural level. SLC9C1 exhibits sperm-specific expression and has been shown to be critical for sperm motility in mouse and humans. Sperm motility is robustly modulated by changes in membrane voltage, intracellular cAMP levels and pH and all these stimuli influence SLC9C1 mediated ion exchange directly, making it vital to understand the molecular underpinnings of such diverse regulation. To this end, in this proposal we will integrate single- particle cryo-electron microscopy and reconstruction techniques with biochemical and electrophysiological methods to explore key biophysical mechanisms of SLC9C1. In Aim 1, we will determine the first high-resolution structure of SLC9C1 and identify the key interactions governing its organization. In Aim 2, we will elucidate the structural rearrangements in SLC9C1 triggered by cyclic nucleotide binding and use electrophysiology to test the role of a key interface in mediating the regulatory effects of the CNBD. In Aim 3, we will determine how pH and permeant ions affect the structure and function of SLC9C1. The proposal has a strong scientific foundation built on our rigorous preliminary studies. It is innovative as it will provide the first snapshots of a novel membrane protein in different conformations and test provocative hypotheses on the mechanisms of voltage and cyclic nucleotide regulation of a transporter. The insights obtained from our studies will aid structure-based drug design for treatment of male infertility. It will also have broad implications on the structural and functional mechanisms of SLC9 regulation by their cytoplasmic domains further underscoring its importance for human health.

膜传输的电压调节机制