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Chen L, Yu X, Chen W, Qiu F, Li D, Yang Z, Yang S, Lu S, Wang L, Feng S, Xiu P, Tang M, Wang H. Nanoscale detection of carbon dots-induced changes in actin skeleton of neural cells. J Colloid Interface Sci 2024; 668:293-302. [PMID: 38678885 DOI: 10.1016/j.jcis.2024.04.152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 04/08/2024] [Accepted: 04/22/2024] [Indexed: 05/01/2024]
Abstract
Understanding the cytotoxicity of fluorescent carbon dots (CDs) is crucial for their applications, and various biochemical assays have been used to study the effects of CDs on cells. Knowledge on the effects of CDs from a biophysical perspective is integral to the recognition of their cytotoxicity, however the related information is very limited. Here, we report that atomic force microscopy (AFM) can be used as an effective tool for studying the effects of CDs on cells from the biophysical perspective. We achieve this by integrating AFM-based nanomechanics with AFM-based imaging. We demonstrate the performance of this method by measuring the influence of CDs on living human neuroblastoma (SH-SY5Y) cells at the single-cell level. We find that high-dose CDs can mechanically induce elevated normalized hysteresis (energy dissipation during the cell deformation) and structurally impair actin skeleton. The nanomechanical change highly correlates with the alteration of actin filaments, indicating that CDs-induced changes in SH-SY5Y cells are revealed in-depth from the AFM-based biophysical aspect. We validate the reliability of the biophysical observations using conventional biological methods including cell viability test, fluorescent microscopy, and western blot assay. Our work contributes new and significant information on the cytotoxicity of CDs from the biophysical perspective.
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Affiliation(s)
- Ligang Chen
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China; Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China; Chongqing Engineering Research Center of High-Resolution and Three-Dimensional Dynamic Imaging Technology, Chongqing 400714, China
| | - Xiaoting Yu
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China; Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China; Chongqing Engineering Research Center of High-Resolution and Three-Dimensional Dynamic Imaging Technology, Chongqing 400714, China
| | - Wei Chen
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China; Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China; Chongqing Engineering Research Center of High-Resolution and Three-Dimensional Dynamic Imaging Technology, Chongqing 400714, China
| | - Fucheng Qiu
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China; Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China; Chongqing Engineering Research Center of High-Resolution and Three-Dimensional Dynamic Imaging Technology, Chongqing 400714, China
| | - Dandan Li
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China; Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China; Chongqing Engineering Research Center of High-Resolution and Three-Dimensional Dynamic Imaging Technology, Chongqing 400714, China
| | - Zhongbo Yang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China; Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China; Chongqing Engineering Research Center of High-Resolution and Three-Dimensional Dynamic Imaging Technology, Chongqing 400714, China
| | - Songrui Yang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China; Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China
| | - Shengjun Lu
- Department of Mechanical Engineering, University of Houston, Houston, TX 77204, USA
| | - Liang Wang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China; Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China
| | - Shuanglong Feng
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China; Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China
| | - Peng Xiu
- Department of Engineering Mechanics, Zhejiang University, Hangzhou 310027, China
| | - Mingjie Tang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China; Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China; Chongqing Engineering Research Center of High-Resolution and Three-Dimensional Dynamic Imaging Technology, Chongqing 400714, China
| | - Huabin Wang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China; Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China; Chongqing Engineering Research Center of High-Resolution and Three-Dimensional Dynamic Imaging Technology, Chongqing 400714, China.
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Tamilselvan E, Sotomayor M. CELSR1, a core planar cell polarity protein, features a weakly adhesive and flexible cadherin ectodomain. Structure 2024; 32:476-491.e5. [PMID: 38307021 DOI: 10.1016/j.str.2024.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 09/30/2023] [Accepted: 01/08/2024] [Indexed: 02/04/2024]
Abstract
Planar cell polarity (PCP), essential to multicellular developmental processes, arises when cells polarize and align across tissues. Central to PCP is CELSR1, an atypical cadherin featuring a long ectodomain with nine extracellular cadherin (EC) repeats, a membrane adjacent domain (MAD10), and several characteristic adhesion GPCR domains. Cell-based aggregation assays have demonstrated CELSR1's homophilic adhesive nature, but mechanistic details are missing. Here, we investigate the possible adhesive properties and structures of CELSR1 EC repeats. Our bead aggregation assays do not support strong adhesion by EC repeats alone. Consistently, EC1-4 only dimerizes at high concentration in solution. Crystal structures of human CELSR1 EC1-4 and EC4-7 reveal typical folds and a non-canonical linker between EC5 and EC6. Simulations and experiments using EC4-7 indicate flexibility at EC5-6, and solution experiments show EC7-MAD10-mediated dimerization. Our results suggest weak homophilic adhesion by CELSR1 cadherin repeats and provide mechanistic insights into the structural determinants of CELSR1 function.
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Affiliation(s)
- Elakkiya Tamilselvan
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; Biophysics Program, The Ohio State University, Columbus, OH 43210, USA
| | - Marcos Sotomayor
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; Biophysics Program, The Ohio State University, Columbus, OH 43210, USA.
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Bandekar SJ, Garbett K, Kordon SP, Dintzner E, Shearer T, Sando RC, Araç D. Structure of the extracellular region of the adhesion GPCR CELSR1 reveals a compact module which regulates G protein-coupling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.26.577439. [PMID: 38328199 PMCID: PMC10849658 DOI: 10.1101/2024.01.26.577439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Cadherin EGF Laminin G seven-pass G-type receptors (CELSRs or ADGRCs) are conserved adhesion G protein-coupled receptors which are essential for animal development. CELSRs have extracellular regions (ECRs) containing 23 adhesion domains which couple adhesion to intracellular signaling. However, molecular-level insight into CELSR function is sparsely available. We report the 4.3 Å cryo-EM reconstruction of the mCELSR1 ECR with 13 domains resolved in the structure. These domains form a compact module mediated by interdomain interactions with contact between the N- and C-terminal domains. We show the mCELSR1 ECR forms an extended species in the presence of Ca 2+ , which we propose represents the antiparallel cadherin repeat dimer. Using assays for adhesion and G protein-coupling, we assign the N-terminal CADH1-8 module as necessary for cell adhesion and we show the C-terminal CAHD9-GAIN module regulates signaling. Our work provides important molecular context to the literature on CELSR function and opens the door towards further mechanistic studies.
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Devenport D. Cell polarity: How to build an asymmetric bridge. Curr Biol 2023; 33:R1306-R1309. [PMID: 38113846 DOI: 10.1016/j.cub.2023.11.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
A new study provides key insights into planar cell polarity (PCP) establishment through the discovery of molecular asymmetries in the homotypic adhesive interactions of the PCP cadherin, Flamingo, resulting in the formation of asymmetric, intercellular bridges.
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Affiliation(s)
- Danelle Devenport
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
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Strutt H, Warrington S, Madathil ACK, Langenhan T, Strutt D. Molecular symmetry breaking in the Frizzled-dependent planar polarity pathway. Curr Biol 2023; 33:5340-5354.e6. [PMID: 37995695 PMCID: PMC7616066 DOI: 10.1016/j.cub.2023.10.071] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 10/03/2023] [Accepted: 10/31/2023] [Indexed: 11/25/2023]
Abstract
The core planar polarity pathway consists of six proteins that form asymmetric intercellular complexes that segregate to opposite cell ends in developing tissues and specify polarized cell structures or behaviors. Within these complexes, the atypical cadherin Flamingo localizes on both sides of intercellular junctions, where it interacts homophilically in trans via its cadherin repeats, whereas the transmembrane proteins Frizzled and Strabismus localize to the opposite sides of apposing junctions. However, the molecular mechanisms underlying the formation of such asymmetric complexes are poorly understood. Using a novel tissue culture system, we determine the minimum requirements for asymmetric complex assembly in the absence of confounding feedback mechanisms. We show that complexes are intrinsically asymmetric and that an interaction of Frizzled and Flamingo in one cell with Flamingo in the neighboring cell is the key symmetry-breaking step. In contrast, Strabismus is unable to promote homophilic Flamingo trans binding and is only recruited into complexes once Frizzled has entered on the opposite side. This interaction with Strabismus requires intact intracellular loops of the seven-pass transmembrane domain of Flamingo. Once recruited, Strabismus stabilizes the intercellular complexes together with the three cytoplasmic core proteins. We propose a model whereby Flamingo exists in a closed conformation and binding of Frizzled in one cell results in a conformational change that allows its cadherin repeats to interact with a Flamingo molecule in the neighboring cell. Flamingo in the adjacent cell then undergoes a further change in the seven-pass transmembrane region that promotes the recruitment of Strabismus.
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Affiliation(s)
- Helen Strutt
- School of Biosciences, University of Sheffield, Firth Court, Sheffield S10 2TN, UK.
| | - Samantha Warrington
- School of Biosciences, University of Sheffield, Firth Court, Sheffield S10 2TN, UK
| | | | - Tobias Langenhan
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, 04103 Leipzig, Germany
| | - David Strutt
- School of Biosciences, University of Sheffield, Firth Court, Sheffield S10 2TN, UK.
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Nishiguchi S, Kasai RS, Uchihashi T. Antiparallel dimer structure of CELSR cadherin in solution revealed by high-speed atomic force microscopy. Proc Natl Acad Sci U S A 2023; 120:e2302047120. [PMID: 37094146 PMCID: PMC10160967 DOI: 10.1073/pnas.2302047120] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 04/03/2023] [Indexed: 04/26/2023] Open
Abstract
Cadherin EGF LAG seven-pass G-type receptors (CELSR) cadherins, members of the cadherin superfamily, and adhesion G-protein-coupled receptors, play a vital role in cell-cell adhesion. The mutual binding of the extracellular domains (ectodomains) of CELSR cadherins between cells is crucial for tissue formation, including the establishment of planar cell polarity, which directs the proper patterning of cells. CELSR cadherins possess nine cadherin ectodomains (EC1-EC9) and noncadherin ectodomains. However, the structural and functional mechanisms of the binding mode of CELSR cadherins have not been determined. In this study, we investigated the binding mode of CELSR cadherins using single-molecule fluorescence microscopy, high-speed atomic force microscopy (HS-AFM), and bead aggregation assay. The fluorescence microscopy analysis results indicated that the trans-dimer of the CELSR cadherin constitutes the essential adhesive unit between cells. HS-AFM analysis and bead aggregation assay results demonstrated that EC1-EC8 entirely overlap and twist to form antiparallel dimer conformations and that the binding of EC1-EC4 is sufficient to sustain bead aggregation. The interaction mechanism of CELSR cadherin may elucidate the variation of the binding mechanism within the cadherin superfamily and physiological role of CELSR cadherins in relation to planar cell polarity.
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Affiliation(s)
- Shigetaka Nishiguchi
- Exploratory Research Center on Life and Living Systems, National Institutes of Natural Sciences, Okazaki444-8787, Japan
| | - Rinshi S. Kasai
- Institute for Life and Medical Sciences, Kyoto University, Kyoto606-8507, Japan
- Institute for Glyco-core Research, Gifu University, Gifu501-1193, Japan
| | - Takayuki Uchihashi
- Exploratory Research Center on Life and Living Systems, National Institutes of Natural Sciences, Okazaki444-8787, Japan
- Department of Physics, Nagoya University, Nagoya464-8602, Japan
- Institute for Glyco-core Research, Nagoya University, Nagoya464-8602, Japan
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