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Wazawa T, Ozaki-Noma R, Kai L, Fukushima SI, Matsuda T, Nagai T. Genetically-encoded temperature indicators for thermal biology. Biophys Physicobiol 2025; 22:e220008. [PMID: 40309302 PMCID: PMC12040488 DOI: 10.2142/biophysico.bppb-v22.0008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2024] [Accepted: 04/03/2025] [Indexed: 05/02/2025] Open
Abstract
Temperature crucially affects molecular processes in living organisms and thus it is one of the vital physical parameters for life. To investigate how temperature is biologically maintained and regulated and its biological impact on organisms, it is essential to measure the spatial distribution and/or temporal changes of temperature across different biological scales, from whole organism to subcellular structures. Fluorescent nanothermometers have been developed as probes for temperature measurement by fluorescence microscopy for applications in microscopic scales where macroscopic temperature sensors are inaccessible, such as embryos, tissues, cells, and organelles. Although fluorescent nanothermometers have been developed from various materials, fluorescent protein-based ones are especially of interest because they can be introduced into cells as the transgenes for expression with or without specific localization, making them suitable for less-invasive temperature observation in living biological samples. In this article, we review protein-based fluorescent nanothermometers also known as genetically-encoded temperature indicators (GETIs), covering most published GETIs, for developers, users, and researchers in thermal biology as well as interested readers. We provide overviews of the temperature sensing mechanisms and measurement methods of these protein-based fluorescent nanothermometers. We then outline key information for GETI development, focusing on unique protein engineering techniques and building blocks distinct to GETIs, unlike other fluorescent nanothermometers. Furthermore, we propose several standards for the characterization of GETIs. Additionally, we explore various issues and offer perspectives in the field of thermal biology.
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Affiliation(s)
- Tetsuichi Wazawa
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Ryohei Ozaki-Noma
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Ibaraki, Osaka 567-0047, Japan
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Lu Kai
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Shun-ichi Fukushima
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Tomoki Matsuda
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Ibaraki, Osaka 567-0047, Japan
- Department of Biosciences, School of Science, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan
| | - Takeharu Nagai
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Ibaraki, Osaka 567-0047, Japan
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
- Transdimensional Life Imaging Division, Institute for Open and Transdisciplinary Research Initiatives, Osaka University, Suita, Osaka 565-0871, Japan
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Snell NE, Rao VP, Seckinger KM, Liang J, Leser J, Mancini AE, Rizzo MA. Homotransfer of FRET Reporters for Live Cell Imaging. BIOSENSORS-BASEL 2018; 8:bios8040089. [PMID: 30314323 PMCID: PMC6316388 DOI: 10.3390/bios8040089] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 09/27/2018] [Accepted: 10/10/2018] [Indexed: 01/01/2023]
Abstract
Förster resonance energy transfer (FRET) between fluorophores of the same species was recognized in the early to mid-1900s, well before modern heterotransfer applications. Recently, homotransfer FRET principles have re-emerged in biosensors that incorporate genetically encoded fluorescent proteins. Homotransfer offers distinct advantages over the standard heterotransfer FRET method, some of which are related to the use of fluorescence polarization microscopy to quantify FRET between two fluorophores of identical color. These include enhanced signal-to-noise, greater compatibility with other optical sensors and modulators, and new design strategies based upon the clustering or dimerization of singly-labeled sensors. Here, we discuss the theoretical basis for measuring homotransfer using polarization microscopy, procedures for data collection and processing, and we review the existing genetically-encoded homotransfer biosensors.
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Affiliation(s)
- Nicole E Snell
- Department of Physiology, University of Maryland School of Medicine, 660 W Redwood St/HH525B, Baltimore, MD 21201, USA.
| | - Vishnu P Rao
- Department of Physiology, University of Maryland School of Medicine, 660 W Redwood St/HH525B, Baltimore, MD 21201, USA.
| | - Kendra M Seckinger
- Department of Physiology, University of Maryland School of Medicine, 660 W Redwood St/HH525B, Baltimore, MD 21201, USA.
| | - Junyi Liang
- Department of Physiology, University of Maryland School of Medicine, 660 W Redwood St/HH525B, Baltimore, MD 21201, USA.
| | - Jenna Leser
- Department of Physiology, University of Maryland School of Medicine, 660 W Redwood St/HH525B, Baltimore, MD 21201, USA.
| | - Allison E Mancini
- Department of Physiology, University of Maryland School of Medicine, 660 W Redwood St/HH525B, Baltimore, MD 21201, USA.
| | - M A Rizzo
- Department of Physiology, University of Maryland School of Medicine, 660 W Redwood St/HH525B, Baltimore, MD 21201, USA.
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Yasuda R. Biophysics of Biochemical Signaling in Dendritic Spines: Implications in Synaptic Plasticity. Biophys J 2017; 113:2152-2159. [PMID: 28866426 DOI: 10.1016/j.bpj.2017.07.029] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/12/2017] [Accepted: 07/20/2017] [Indexed: 11/24/2022] Open
Abstract
Dendritic spines are mushroom-shaped postsynaptic compartments that host biochemical signal cascades important for synaptic plasticity and, ultimately, learning and memory. Signaling events in spines involve a signaling network composed of hundreds of signaling proteins interacting with each other extensively. Synaptic plasticity is typically induced by Ca2+ elevation in spines, which activates a variety of signaling pathways. This leads to changes in the actin cytoskeleton and membrane dynamics, which in turn causes structural and functional changes of the spine. Recent studies have demonstrated that the activities of these proteins have a variety of spatiotemporal patterns, which orchestrate signaling activity in different subcellular compartments at different timescales. The diffusion and the decay kinetics of signaling molecules play important roles in determining the degree of their spatial spreading, and thereby the degree of the spine specificity of the signaling pathway.
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Affiliation(s)
- Ryohei Yasuda
- Max Planck Florida Institute for Neuroscience, Jupiter, Florida.
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