Biophysical journal最新文献_第8页

How spatial temperature gradients modulate infrared stimulation of the ex vivo rat sciatic nerve. 空间温度梯度如何调节离体大鼠坐骨神经的红外刺激。

IF 3.2 3区生物学

Biophysical journal Pub Date : 2025-03-24 DOI: 10.1016/j.bpj.2025.03.015

Louis Vande Perre, Javier Chávez Cerda, Benoit Haut, Maxime Verstraeten, Romain Raffoul, Jean Delbeke, Riëm El Tahry, Simon-Pierre Gorza, Antoine Nonclercq

{"title":"How spatial temperature gradients modulate infrared stimulation of the ex vivo rat sciatic nerve.","authors":"Louis Vande Perre, Javier Chávez Cerda, Benoit Haut, Maxime Verstraeten, Romain Raffoul, Jean Delbeke, Riëm El Tahry, Simon-Pierre Gorza, Antoine Nonclercq","doi":"10.1016/j.bpj.2025.03.015","DOIUrl":"10.1016/j.bpj.2025.03.015","url":null,"abstract":"Infrared neural stimulation (INS) uses transient near-infrared light to activate neuronal activity, likely through heat-induced thermal gradients. However, neither the effect of basal temperature nor heat accumulation has specifically been investigated. This study examines how spatial temperature gradients, varied by different laser repetition rates and the addition of a continuous wave laser, affect the elicitation of compound nerve action potentials (CNAPs). In addition, we investigate the role of basal temperature. Overall, our results indicate that CNAP generation is more influenced by the induced spatial temperature gradients than by the increase in local or basal temperature, or temperature build-up. For instance, low-power continuous wave laser combined with low repetition rate pulsed laser stimulation successfully induced CNAPs, whereas increasing the basal nerve temperature did not facilitate CNAP generation. A heat transfer model, consistent with the experimental data, confirms that, while the volume exposed to rapid temperature changes remains constant, heat accumulation increases spatial gradients with the number of stimulation pulses. This likely explains the progressive recruitment of nerve fibers and the observed increase in CNAP amplitude. Taken together, these results highlight the critical role of spatial temperature gradients in effective infrared neural stimulation, while a temperature threshold does not appear to be the primary mechanism in CNAP triggering.","PeriodicalId":8922,"journal":{"name":"Biophysical journal","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143708310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Contradicting Markov. 矛盾马尔可夫。

IF 3.2 3区生物学

Biophysical journal Pub Date : 2025-03-22 DOI: 10.1016/j.bpj.2025.03.014

León D Islas

引用次数: 0

Solid-state NMR of membrane peptides and proteins in the lipid cubic phase. 脂质立方相中膜肽和蛋白质的固态核磁共振。

IF 3.2 3区生物学

Biophysical journal Pub Date : 2025-03-20 DOI: 10.1016/j.bpj.2025.03.012

Kiefer O Ramberg, Coilin Boland, Hamed Kooshapur, Olivier Soubias, Maciej Wiktor, Chia-Ying Huang, Jonathan Bailey, Klaus Gawrisch, Martin Caffrey

{"title":"Solid-state NMR of membrane peptides and proteins in the lipid cubic phase.","authors":"Kiefer O Ramberg, Coilin Boland, Hamed Kooshapur, Olivier Soubias, Maciej Wiktor, Chia-Ying Huang, Jonathan Bailey, Klaus Gawrisch, Martin Caffrey","doi":"10.1016/j.bpj.2025.03.012","DOIUrl":"10.1016/j.bpj.2025.03.012","url":null,"abstract":"Solid-state nuclear magnetic resonance (ssNMR) is a powerful technique for studying membrane protein structure and dynamics. Ideally, measurements are performed with the protein in a lipid bilayer. However, homogenous reconstitution of functional protein into intact bilayers at sufficiently high concentrations is often difficult to achieve. In this work, we investigate the suitability of the lipid cubic phase (LCP), which incorporates a lipid bilayer, as an alternative medium for ssNMR of integral membrane peptides and proteins. The cubic mesophase has long been used to generate membrane protein crystals for use in X-ray crystallographic structure determination by the so-called in meso method and for protein functional and biophysical characterization. Preparing and handling protein-laden LCP is straightforward. LCP may therefore provide a valuable alternative to native membranes and other membrane mimetics for ssNMR. We tested this idea by conducting standard magic-angle spinning ssNMR experiments on LCP into which gramicidin, a ∼4-kDa transmembrane peptide, or bacterial lipoprotein signal peptidase II (LspA), a ∼20-kDa integral membrane enzyme, had been reconstituted. We report one- and two-dimensional ssNMR spectra for both gramicidin and LspA and the parameters for optimizing spectral quality. The high protein-carrying capacity of the cubic phase facilitated 13C ssNMR at natural abundance. Lowering temperature and raising magic-angle spinning frequency enabled significant improvements in spectral quality. One-dimensional 13C and 15N spectra were collected for LspA. Two-dimensional ssNMR experiments provided information on LspA dynamics and its interaction with the water and lipid components of the cubic phase. Solution NMR measurements carried out in parallel yielded information on the effect of the antibiotic, globomycin, on LspA structure and dynamics.","PeriodicalId":8922,"journal":{"name":"Biophysical journal","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143676787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The Rab3 GTPase cycle modulates cardiomyocyte exocytosis and atrial natriuretic peptide release. Rab3 GTPase周期调节心肌细胞胞吐和房利钠肽释放。

IF 3.2 3区生物学

Biophysical journal Pub Date : 2025-03-20 DOI: 10.1016/j.bpj.2025.03.013

Kobina Essandoh, Arasakumar Subramani, Sribharat Koripella, Matthew J Brody

{"title":"The Rab3 GTPase cycle modulates cardiomyocyte exocytosis and atrial natriuretic peptide release.","authors":"Kobina Essandoh, Arasakumar Subramani, Sribharat Koripella, Matthew J Brody","doi":"10.1016/j.bpj.2025.03.013","DOIUrl":"10.1016/j.bpj.2025.03.013","url":null,"abstract":"Natriuretic peptides are produced predominantly by atrial cardiomyocytes in response to cardiovascular stress and attenuate cardiac maladaptation by reducing blood pressure, blood volume, and cardiac workload primarily through activation of natriuretic peptide receptors in the kidney and vasculature. However, mechanisms underlying cardiomyocyte exocytosis and natriuretic peptide secretion remain poorly defined. Manipulation of Rab3a GTPase activity by Rab3gap1 was recently found to modulate atrial natriuretic peptide (ANP) release by cardiomyocytes. Here, we examined upstream signaling mechanisms and the role of the Rab3a GTPase cycle in exocytosis and ANP secretion by cardiomyocytes. Pharmacological inhibition of the heterotrimeric G protein subunit G⍺q suppressed ANP secretion at baseline and prevented GTP loading of Rab3a and ANP release in neonatal rat cardiomyocytes in response to phenylephrine (PE). Similar to agonist-induced activation of ANP secretion, genetic overexpression of a constitutively active, GTP-loaded Rab3a mutant (Q81L) in neonatal rat cardiomyocytes resulted in enhanced intracellular distribution of Rab3a at endomembranes peripheral to the Golgi and promotion of ANP release, indicating that enhancement of Rab3a activity is sufficient to elicit ANP secretion by cardiomyocytes. Collectively, these data indicate G⍺q signaling downstream of receptor activation and Rab3a-regulated secretory pathway activity and exocytosis facilitate ANP release by cardiomyocytes that could potentially be harnessed to antagonize hypertension and adverse cardiac remodeling in cardiovascular disease.","PeriodicalId":8922,"journal":{"name":"Biophysical journal","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143676756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Generalized Adder for Cell Size Homeostasis: Effects on Stochastic Clonal Proliferation. 细胞大小稳态的广义加法器：对随机克隆增殖的影响。

IF 3.2 3区生物学

Biophysical journal Pub Date : 2025-03-20 DOI: 10.1016/j.bpj.2025.03.011

César Nieto, César Augusto Vargas-García, Abhyudai Singh

{"title":"A Generalized Adder for Cell Size Homeostasis: Effects on Stochastic Clonal Proliferation.","authors":"César Nieto, César Augusto Vargas-García, Abhyudai Singh","doi":"10.1016/j.bpj.2025.03.011","DOIUrl":"https://doi.org/10.1016/j.bpj.2025.03.011","url":null,"abstract":"Measurements of cell size dynamics have revealed phenomenological principles by which individual cells control their size across diverse organisms. One of the emerging paradigms of cell size homeostasis is the adder, where the cell cycle duration is established such that the cell size increase from birth to division is independent of the newborn cell size. We provide a mechanistic formulation of the adder considering that cell size follows any arbitrary non-exponential growth law. Our results show that the main requirement to obtain an adder regardless of the growth law (the time derivative of cell size) is that cell cycle regulators are produced at a rate proportional to the growth law and cell division is triggered when these molecules reach a prescribed threshold level. Among the implications of this generalized adder, we investigate fluctuations in the proliferation of single-cell derived colonies. Considering exponential cell size growth, random fluctuations in clonal size show a transient increase and then eventually decay to zero over time (i.e., clonal populations become asymptotically more similar). In contrast, several forms of non-exponential cell size dynamics (with adder-based cell size control) yield qualitatively different results: clonal size fluctuations monotonically increase over time reaching a non-zero value. These results characterize the interplay between cell size homeostasis at the single-cell level and clonal proliferation at the population level, explaining the broad fluctuations in clonal sizes seen in barcoded human cell lines.","PeriodicalId":8922,"journal":{"name":"Biophysical journal","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143676785","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Receptor binding and tortuosity explain morphogen local-to-global diffusion coefficient transition. 受体结合和迂回解释了形态发生器局部到整体扩散系数的转变。

IF 3.2 3区生物学

Biophysical journal Pub Date : 2025-03-18 Epub Date: 2024-07-24 DOI: 10.1016/j.bpj.2024.07.024

Shiwen Zhu, Yi Ting Loo, Sapthaswaran Veerapathiran, Tricia Y J Loo, Bich Ngoc Tran, Cathleen Teh, Jun Zhong, Paul Matsudaira, Timothy E Saunders, Thorsten Wohland

{"title":"Receptor binding and tortuosity explain morphogen local-to-global diffusion coefficient transition.","authors":"Shiwen Zhu, Yi Ting Loo, Sapthaswaran Veerapathiran, Tricia Y J Loo, Bich Ngoc Tran, Cathleen Teh, Jun Zhong, Paul Matsudaira, Timothy E Saunders, Thorsten Wohland","doi":"10.1016/j.bpj.2024.07.024","DOIUrl":"10.1016/j.bpj.2024.07.024","url":null,"abstract":"Morphogens are intercellular signaling molecules providing spatial information to cells in developing tissues to coordinate cell fate decisions. The spatial information is encoded within long-ranged concentration gradients of the morphogen. Direct measurement of morphogen dynamics in a range of systems suggests that local and global diffusion coefficients can differ by orders of magnitude. Further, local diffusivity can be large, which would potentially abolish any concentration gradient rapidly. Such observations have led to alternative transport models being proposed, including transcytosis and cytonemes. Here, we show that accounting for tissue architecture combined with receptor binding is sufficient to hinder the diffusive dynamics of morphogens, leading to an order of magnitude decrease in the effective diffusion coefficient from local to global scales. In particular, we built a realistic in silico architecture of the extracellular spaces of the zebrafish brain using light and electron microscopy data. Simulations on realistic architectures demonstrate that tortuosity and receptor binding within these spaces are sufficient to reproduce experimentally measured morphogen dynamics. Importantly, this work demonstrates that hindered diffusion is a viable mechanism for gradient formation, without requiring additional regulatory control.","PeriodicalId":8922,"journal":{"name":"Biophysical journal","volume":" ","pages":"963-979"},"PeriodicalIF":3.2,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11947475/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141756971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Cell-to-cell signaling in cell populations with large cell size variability. 细胞大小差异较大的细胞群中的细胞间信号传递。

IF 3.2 3区生物学

Biophysical journal Pub Date : 2025-03-18 Epub Date: 2024-08-12 DOI: 10.1016/j.bpj.2024.07.017

Yukihisa Hayashida, Chikoo Oosawa, Takuo Yasunaga, Yusuke V Morimoto

引用次数: 0

Membrane extraction in native lipid nanodiscs reveals dynamic regulation of Cdc42 complexes during cell polarization. 天然脂质纳米圆盘的膜提取揭示了Cdc42复合物在细胞极化过程中的动态调控。

IF 3.2 3区生物学

Biophysical journal Pub Date : 2025-03-18 Epub Date: 2023-11-23 DOI: 10.1016/j.bpj.2023.11.021

Lars N Deutz, Sena Sarıkaya, Daniel J Dickinson

{"title":"Membrane extraction in native lipid nanodiscs reveals dynamic regulation of Cdc42 complexes during cell polarization.","authors":"Lars N Deutz, Sena Sarıkaya, Daniel J Dickinson","doi":"10.1016/j.bpj.2023.11.021","DOIUrl":"10.1016/j.bpj.2023.11.021","url":null,"abstract":"Embryonic development requires the establishment of cell polarity to enable cell fate segregation and tissue morphogenesis. This process is regulated by Par complex proteins, which partition into polarized membrane domains and direct downstream polarized cell behaviors. The kinase aPKC (along with its cofactor Par6) is a key member of this network and can be recruited to the plasma membrane by either the small GTPase Cdc42 or the scaffolding protein Par3. Although in vitro interactions among these proteins are well established, much is still unknown about the complexes they form during development. Here, to enable the study of membrane-associated complexes ex vivo, we used a maleic acid copolymer to rapidly isolate membrane proteins from single C. elegans zygotes into lipid nanodiscs. We show that native lipid nanodisc formation enables detection of endogenous complexes involving Cdc42, which are undetectable when cells are lysed in detergent. We found that Cdc42 interacts more strongly with aPKC/Par6 during polarity maintenance than polarity establishment, two developmental stages that are separated by only a few minutes. We further show that Cdc42 and Par3 do not bind aPKC/Par6 simultaneously, confirming recent in vitro findings in an ex vivo context. Our findings establish a new tool for studying membrane-associated signaling complexes and reveal an unexpected mode of polarity regulation via Cdc42.","PeriodicalId":8922,"journal":{"name":"Biophysical journal","volume":" ","pages":"876-890"},"PeriodicalIF":3.2,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11947473/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138433153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Auxin-mediated stress relaxation in pericycle and endoderm remodeling drives lateral root initiation. 灌浆素介导的周皮应力松弛和内胚层重塑驱动侧根萌发

IF 3.2 3区生物学

Biophysical journal Pub Date : 2025-03-18 Epub Date: 2024-06-20 DOI: 10.1016/j.bpj.2024.06.017

João R D Ramos, Blanca Jazmin Reyes-Hernández, Karen Alim, Alexis Maizel

{"title":"Auxin-mediated stress relaxation in pericycle and endoderm remodeling drives lateral root initiation.","authors":"João R D Ramos, Blanca Jazmin Reyes-Hernández, Karen Alim, Alexis Maizel","doi":"10.1016/j.bpj.2024.06.017","DOIUrl":"10.1016/j.bpj.2024.06.017","url":null,"abstract":"Plant development relies on the precise coordination of cell growth, which is influenced by the mechanical constraints imposed by rigid cell walls. The hormone auxin plays a crucial role in regulating this growth by altering the mechanical properties of cell walls. During the postembryonic formation of lateral roots, pericycle cells deep within the main root are triggered by auxin to resume growth and divide to form a new root. This growth involves a complex interplay between auxin, growth, and the resolution of mechanical conflicts with the overlying endodermis. However, the exact mechanisms by which this coordination is achieved are still unknown. Here, we propose a model that integrates tissue mechanics and auxin transport, revealing a connection between the auxin-induced relaxation of mechanical stress in the pericycle and auxin signaling in the endodermis. We show that the endodermis initially limits the growth of pericycle cells, resulting in a modest initial expansion. However, the associated stress relaxation is sufficient to redirect auxin to the overlying endodermis, which then actively accommodates the growth, allowing for the subsequent development of the lateral root. Our model uncovers that increased pericycle turgor and decreased endodermal resistance license expansion of the pericycle and how the topology of the endodermis influences the formation of the new root. These findings highlight the interconnected relationship between mechanics and auxin flow during lateral root initiation, emphasizing the vital role of the endodermis in shaping root development through mechanotransduction and auxin signaling.","PeriodicalId":8922,"journal":{"name":"Biophysical journal","volume":" ","pages":"942-953"},"PeriodicalIF":3.2,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11947471/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141431200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Fat4 intracellular domain controls internalization of Fat4/Dchs1 planar polarity membrane complexes. Fat4胞内结构域控制Fat4/Dchs1平面极性膜复合物的内化。

IF 3.2 3区生物学

Biophysical journal Pub Date : 2025-03-18 Epub Date: 2025-02-14 DOI: 10.1016/j.bpj.2025.02.012

Yathreb Easa, Olga Loza, Roie Cohen, David Sprinzak

{"title":"Fat4 intracellular domain controls internalization of Fat4/Dchs1 planar polarity membrane complexes.","authors":"Yathreb Easa, Olga Loza, Roie Cohen, David Sprinzak","doi":"10.1016/j.bpj.2025.02.012","DOIUrl":"10.1016/j.bpj.2025.02.012","url":null,"abstract":"The Fat/Dachsous (Ft/Ds) pathway is a highly conserved pathway regulating planar cell polarity (PCP) across different animal species. Proteins from the Ft and Ds family are large transmembrane protocadherins that form heterophilic complexes on the boundaries between cells. Fat4 and Dchs1, the main mammalian homologs of this pathway, have been implicated in PCP in various epithelial tissues and were shown to form extremely stable complexes at the boundaries between cells. It is unclear, however, what are the dynamics controlling such stable boundary complexes, and how the formation and internalization of these complexes is regulated. Here, we use quantitative live imaging to elucidate the role of the intracellular domains (ICDs) of Fat4 and Dchs1 in regulating Fat4/Dchs1 complex dynamics. We show that removing the ICD of Fat4 results in a reduction of both trans-endocytosis of Dchs1 into the Fat4 cells and boundary accumulation of Fat4/Dchs1 complexes, but does not affect the diffusion of the complexes at the boundary. We further show that the ICD of Fat4 controls the internalization rate of Fat4/Dchs1 complexes. Finally, we find that while actin polymerization is required for the accumulation at the boundary of Fat4/Dchs1 complexes, we do not identify correlations between Fat4/Dchs1 complexes and local actin accumulation. Overall, we suggest that the Fat4 ICD is important for the internalization and plasticity of the highly stable Fat4/Dchs1 complexes associated with PCP.","PeriodicalId":8922,"journal":{"name":"Biophysical journal","volume":" ","pages":"1024-1033"},"PeriodicalIF":3.2,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11947466/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143424930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0