Journal of General Physiology最新文献_第8页

Anionic omega currents from single countercharge mutants in the voltage-sensing domain of Ci-VSP. 单反电荷突变体在Ci-VSP电压传感领域的阴离子ω电流。

IF 3.3 2区医学

Journal of General Physiology Pub Date : 2024-01-01 Epub Date: 2023-11-29 DOI: 10.1085/jgp.202213311

Rong Shen, Benoît Roux, Eduardo Perozo

{"title":"Anionic omega currents from single countercharge mutants in the voltage-sensing domain of Ci-VSP.","authors":"Rong Shen, Benoît Roux, Eduardo Perozo","doi":"10.1085/jgp.202213311","DOIUrl":"10.1085/jgp.202213311","url":null,"abstract":"The S4 segment of voltage-sensing domains (VSDs) directly responds to voltage changes by reorienting within the electric field as a permion. A narrow hydrophobic \"gasket\" or charge transfer center at the core of most VSDs focuses the electric field into a narrow region and catalyzes the sequential and reversible translocation of S4 positive gating charge residues across the electric field while preventing the permeation of physiological ions. Mutating specific S4 gating charges can cause ionic leak currents through the VSDs. These gating pores or omega currents play important pathophysiological roles in many diseases of excitability. Here, we show that mutating D129, a key countercharge residue in the Ciona intestinalis voltage-sensing phosphatase (Ci-VSP), leads to the generation of unique anionic omega currents. Neutralizing D129 causes a dramatic positive shift of activation, facilitates the formation of a continuous water path through the VSD, and creates a positive electrostatic potential landscape inside the VSD that contributes to its unique anionic selectivity. Increasing the population or dwell time of the conducting state by a high external pH or an engineered Cd2+ bridge markedly increases the current magnitude. Our findings uncover a new role of countercharge residues in the impermeable VSD of Ci-VSP and offer insights into mechanisms of the conduction of anionic omega currents linked to countercharge residue mutations.","PeriodicalId":54828,"journal":{"name":"Journal of General Physiology","volume":"156 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10686229/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138453079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A dual-clock-driven model of lymphatic muscle cell pacemaking to emulate knock-out of Ano1 or IP3R. 模拟敲除Ano1或IP3R的淋巴肌细胞起搏的双时钟驱动模型。

IF 3.3 2区医学

Journal of General Physiology Pub Date : 2023-12-04 Epub Date: 2023-10-18 DOI: 10.1085/jgp.202313355

Edward J Hancock, Scott D Zawieja, Charlie Macaskill, Michael J Davis, Christopher D Bertram

{"title":"A dual-clock-driven model of lymphatic muscle cell pacemaking to emulate knock-out of Ano1 or IP3R.","authors":"Edward J Hancock, Scott D Zawieja, Charlie Macaskill, Michael J Davis, Christopher D Bertram","doi":"10.1085/jgp.202313355","DOIUrl":"10.1085/jgp.202313355","url":null,"abstract":"Lymphatic system defects are involved in a wide range of diseases, including obesity, cardiovascular disease, and neurological disorders, such as Alzheimer's disease. Fluid return through the lymphatic vascular system is primarily provided by contractions of muscle cells in the walls of lymphatic vessels, which are in turn driven by electrochemical oscillations that cause rhythmic action potentials and associated surges in intracellular calcium ion concentration. There is an incomplete understanding of the mechanisms involved in these repeated events, restricting the development of pharmacological treatments for dysfunction. Previously, we proposed a model where autonomous oscillations in the membrane potential (M-clock) drove passive oscillations in the calcium concentration (C-clock). In this paper, to model more accurately what is known about the underlying physiology, we extend this model to the case where the M-clock and the C-clock oscillators are both active but coupled together, thus both driving the action potentials. This extension results from modifications to the model's description of the IP3 receptor, a key C-clock mechanism. The synchronised dual-driving clock behaviour enables the model to match IP3 receptor knock-out data, thus resolving an issue with previous models. We also use phase-plane analysis to explain the mechanisms of coupling of the dual clocks. The model has the potential to help determine mechanisms and find targets for pharmacological treatment of some causes of lymphoedema.","PeriodicalId":54828,"journal":{"name":"Journal of General Physiology","volume":"155 12","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10585120/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41241014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Structural basis for severe pain caused by mutations in the voltage sensors of sodium channel NaV1.7. 钠通道NaV1.7的电压传感器突变引起严重疼痛的结构基础。

IF 3.8 2区医学

Journal of General Physiology Pub Date : 2023-12-04 Epub Date: 2023-10-30 DOI: 10.1085/jgp.202313450

Goragot Wisedchaisri, Tamer M Gamal El-Din, Natasha M Powell, Ning Zheng, William A Catterall

{"title":"Structural basis for severe pain caused by mutations in the voltage sensors of sodium channel NaV1.7.","authors":"Goragot Wisedchaisri, Tamer M Gamal El-Din, Natasha M Powell, Ning Zheng, William A Catterall","doi":"10.1085/jgp.202313450","DOIUrl":"10.1085/jgp.202313450","url":null,"abstract":"Voltage-gated sodium channels in peripheral nerves conduct nociceptive signals from nerve endings to the spinal cord. Mutations in voltage-gated sodium channel NaV1.7 are responsible for a number of severe inherited pain syndromes, including inherited erythromelalgia (IEM). Here, we describe the negative shifts in the voltage dependence of activation in the bacterial sodium channel NaVAb as a result of the incorporation of four different IEM mutations in the voltage sensor, which recapitulate the gain-of-function effects observed with these mutations in human NaV1.7. Crystal structures of NaVAb with these IEM mutations revealed that a mutation in the S1 segment of the voltage sensor facilitated the outward movement of S4 gating charges by widening the pathway for gating charge translocation. In contrast, mutations in the S4 segments modified hydrophobic interactions with surrounding amino acid side chains or membrane phospholipids that would enhance the outward movement of the gating charges. These results provide key structural insights into the mechanisms by which these IEM mutations in the voltage sensors can facilitate outward movements of the gating charges in the S4 segment and cause hyperexcitability and severe pain in IEM. Our work gives new insights into IEM pathogenesis at the near-atomic level and provides a molecular model for mutation-specific therapy of this debilitating disease.","PeriodicalId":54828,"journal":{"name":"Journal of General Physiology","volume":"155 12","pages":""},"PeriodicalIF":3.8,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10616507/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71415334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

IP3R1 underlies diastolic ANO1 activation and pressure-dependent chronotropy in lymphatic collecting vessels. IP3R1是淋巴收集血管中舒张ANO1激活和压力依赖性时间变化的基础。

IF 3.8 2区医学

Journal of General Physiology Pub Date : 2023-12-04 Epub Date: 2023-10-18 DOI: 10.1085/jgp.202313358

Scott D Zawieja, Grace A Pea, Sarah E Broyhill, Advaya Patro, Karen H Bromert, Min Li, Charles E Norton, Jorge A Castorena-Gonzalez, Edward J Hancock, Christopher D Bertram, Michael J Davis

{"title":"IP3R1 underlies diastolic ANO1 activation and pressure-dependent chronotropy in lymphatic collecting vessels.","authors":"Scott D Zawieja, Grace A Pea, Sarah E Broyhill, Advaya Patro, Karen H Bromert, Min Li, Charles E Norton, Jorge A Castorena-Gonzalez, Edward J Hancock, Christopher D Bertram, Michael J Davis","doi":"10.1085/jgp.202313358","DOIUrl":"10.1085/jgp.202313358","url":null,"abstract":"Pressure-dependent chronotropy of murine lymphatic collecting vessels relies on the activation of the Ca2+-activated chloride channel encoded by Anoctamin 1 (Ano1) in lymphatic muscle cells. Genetic ablation or pharmacological inhibition of ANO1 results in a significant reduction in basal contraction frequency and essentially complete loss of pressure-dependent frequency modulation by decreasing the rate of the diastolic depolarization phase of the ionic pacemaker in lymphatic muscle cells (LMCs). Oscillating Ca2+ release from sarcoendoplasmic reticulum Ca2+ channels has been hypothesized to drive ANO1 activity during diastole, but the source of Ca2+ for ANO1 activation in smooth muscle remains unclear. Here, we investigated the role of the inositol triphosphate receptor 1 (Itpr1; Ip3r1) in this process using pressure myography, Ca2+ imaging, and membrane potential recordings in LMCs of ex vivo pressurized inguinal-axillary lymphatic vessels from control or Myh11CreERT2;Ip3r1fl/fl (Ip3r1ismKO) mice. Ip3r1ismKO vessels had significant reductions in contraction frequency and tone but an increased contraction amplitude. Membrane potential recordings from LMCs of Ip3r1ismKO vessels revealed a depressed diastolic depolarization rate and an elongation of the plateau phase of the action potential (AP). Ca2+ imaging of LMCs using the genetically encoded Ca2+ sensor GCaMP6f demonstrated an elongation of the Ca2+ flash associated with an AP-driven contraction. Critically, diastolic subcellular Ca2+ transients were absent in LMCs of Ip3r1ismKO mice, demonstrating the necessity of IP3R1 activity in controlling ANO1-mediated diastolic depolarization. These findings indicate a critical role for IP3R1 in lymphatic vessel pressure-dependent chronotropy and contractile regulation.","PeriodicalId":54828,"journal":{"name":"Journal of General Physiology","volume":"155 12","pages":""},"PeriodicalIF":3.8,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10585095/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41241015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A high-throughput electrophysiology assay to study the response of PIEZO1 to mechanical stimulation. 高通量电生理实验研究PIEZO1对机械刺激的反应。

IF 3.8 2区医学

Journal of General Physiology Pub Date : 2023-12-04 Epub Date: 2023-10-06 DOI: 10.1085/jgp.202213132

Nicoletta Murciano, Maria Giustina Rotordam, Nadine Becker, Melanie J Ludlow, Gregory Parsonage, Alexis Darras, Lars Kaestner, David J Beech, Michael George, Niels Fertig, Markus Rapedius, Andrea Brüggemann

{"title":"A high-throughput electrophysiology assay to study the response of PIEZO1 to mechanical stimulation.","authors":"Nicoletta Murciano, Maria Giustina Rotordam, Nadine Becker, Melanie J Ludlow, Gregory Parsonage, Alexis Darras, Lars Kaestner, David J Beech, Michael George, Niels Fertig, Markus Rapedius, Andrea Brüggemann","doi":"10.1085/jgp.202213132","DOIUrl":"10.1085/jgp.202213132","url":null,"abstract":"PIEZO1 channels are mechanically activated cation channels that play a pivotal role in sensing mechanical forces in various cell types. Their dysfunction has been associated with numerous pathophysiological states, including generalized lymphatic dysplasia, varicose vein disease, and hereditary xerocytosis. Given their physiological relevance, investigating PIEZO1 is crucial for the pharmaceutical industry, which requires scalable techniques to allow for drug discovery. In this regard, several studies have used high-throughput automated patch clamp (APC) combined with Yoda1, a specific gating modifier of PIEZO1 channels, to explore the function and properties of PIEZO1 in heterologous expression systems, as well as in primary cells. However, a combination of solely mechanical stimulation (M-Stim) and high-throughput APC has not yet been available for the study of PIEZO1 channels. Here, we show that optimization of pipetting parameters of the SyncroPatch 384 coupled with multihole NPC-384 chips enables M-Stim of PIEZO1 channels in high-throughput electrophysiology. We used this approach to explore differences between the response of mouse and human PIEZO1 channels to mechanical and/or chemical stimuli. Our results suggest that applying solutions on top of the cells at elevated pipetting flows is crucial for activating PIEZO1 channels by M-Stim on the SyncroPatch 384. The possibility of comparing and combining mechanical and chemical stimulation in a high-throughput patch clamp assay facilitates investigations on PIEZO1 channels and thereby provides an important experimental tool for drug development.","PeriodicalId":54828,"journal":{"name":"Journal of General Physiology","volume":"155 12","pages":""},"PeriodicalIF":3.8,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10558326/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41169643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Identifiability of equilibrium constants for receptors with two to five binding sites. 具有两到五个结合位点的受体平衡常数的可识别性。

IF 3.8 2区医学

Journal of General Physiology Pub Date : 2023-12-04 Epub Date: 2023-10-26 DOI: 10.1085/jgp.202313423

Klaus Benndorf, Eckhard Schulz

{"title":"Identifiability of equilibrium constants for receptors with two to five binding sites.","authors":"Klaus Benndorf, Eckhard Schulz","doi":"10.1085/jgp.202313423","DOIUrl":"10.1085/jgp.202313423","url":null,"abstract":"Ligand-gated ion channels (LGICs) are regularly oligomers containing between two and five binding sites for ligands. Neither in homomeric nor heteromeric LGICs the activation process evoked by the ligand binding is fully understood. Here, we show on theoretical grounds that for LGICs with two to five binding sites, the cooperativity upon channel activation can be determined in considerable detail. The main requirements for our strategy are a defined number of binding sites in a channel, which can be achieved by concatenation, a systematic mutation of all binding sites and a global fit of all concentration-activation relationships (CARs) with corresponding intimately coupled Markovian state models. We take advantage of translating these state models to cubes with dimensions 2, 3, 4, and 5. We show that the maximum possible number of CARs for these LGICs specify all 7, 13, 23, and 41 independent model parameters, respectively, which directly provide all equilibrium constants within the respective schemes. Moreover, a fit that uses stochastically varied scaled unitary start vectors enables the determination of all parameters, without any bias imposed by specific start vectors. A comparison of the outcome of the analyses for the models with 2 to 5 binding sites showed that the identifiability of the parameters is best for a case with 5 binding sites and 41 parameters. Our strategy can be used to analyze experimental data of other LGICs and may be applicable to voltage-gated ion channels and metabotropic receptors.","PeriodicalId":54828,"journal":{"name":"Journal of General Physiology","volume":"155 12","pages":""},"PeriodicalIF":3.8,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10602793/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50163819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Changing face of contractile activation in striated muscle at physiological temperature. 生理温度下横纹肌收缩激活的变化面。

IF 3.8 2区医学

Journal of General Physiology Pub Date : 2023-12-04 Epub Date: 2023-11-07 DOI: 10.1085/jgp.202313494

Alf Månsson

引用次数: 0

Examining the calcium sensitivity of skeletal muscle thick filaments. 骨骼肌粗丝钙敏感性的研究。

IF 3.8 2区医学

Journal of General Physiology Pub Date : 2023-12-04 Epub Date: 2023-11-15 DOI: 10.1085/jgp.202313501

Ben Short

引用次数: 0

Dependence of myosin filament structure on intracellular calcium concentration in skeletal muscle. 肌球蛋白丝结构对骨骼肌细胞内钙浓度的依赖性。

IF 3.3 2区医学

Journal of General Physiology Pub Date : 2023-12-04 Epub Date: 2023-09-27 DOI: 10.1085/jgp.202313393

Marco Caremani, Luca Fusi, Massimo Reconditi, Gabriella Piazzesi, Theyencheri Narayanan, Malcolm Irving, Vincenzo Lombardi, Marco Linari, Elisabetta Brunello

{"title":"Dependence of myosin filament structure on intracellular calcium concentration in skeletal muscle.","authors":"Marco Caremani, Luca Fusi, Massimo Reconditi, Gabriella Piazzesi, Theyencheri Narayanan, Malcolm Irving, Vincenzo Lombardi, Marco Linari, Elisabetta Brunello","doi":"10.1085/jgp.202313393","DOIUrl":"10.1085/jgp.202313393","url":null,"abstract":"Contraction of skeletal muscle is triggered by an increase in intracellular calcium concentration that relieves the structural block on actin-binding sites in resting muscle, potentially allowing myosin motors to bind and generate force. However, most myosin motors are not available for actin binding because they are stabilized in folded helical tracks on the surface of myosin-containing thick filaments. High-force contraction depends on the release of the folded motors, which can be triggered by stress in the thick filament backbone, but additional mechanisms may link the activation of the thick filaments to that of the thin filaments or to intracellular calcium concentration. Here, we used x-ray diffraction in combination with temperature-jump activation to determine the steady-state calcium dependence of thick filament structure and myosin motor conformation in near-physiological conditions. We found that x-ray signals associated with the perpendicular motors characteristic of isometric force generation had almost the same calcium sensitivity as force, but x-ray signals associated with perturbations in the folded myosin helix had a much higher calcium sensitivity. Moreover, a new population of myosin motors with a longer axial periodicity became prominent at low levels of calcium activation and may represent an intermediate regulatory state of the myosin motors in the physiological pathway of filament activation.","PeriodicalId":54828,"journal":{"name":"Journal of General Physiology","volume":"155 12","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10533363/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41172532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Myosin and tropomyosin-troponin complementarily regulate thermal activation of muscles. 肌球蛋白和原肌球蛋白肌钙蛋白互补调节肌肉的热激活。

IF 3.8 2区医学

Journal of General Physiology Pub Date : 2023-12-04 Epub Date: 2023-10-23 DOI: 10.1085/jgp.202313414

Shuya Ishii, Kotaro Oyama, Fuyu Kobirumaki-Shimozawa, Tomohiro Nakanishi, Naoya Nakahara, Madoka Suzuki, Shin'ichi Ishiwata, Norio Fukuda

引用次数: 1