1
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Nalehua MR, Zaia J. A critical evaluation of ultrasensitive single-cell proteomics strategies. Anal Bioanal Chem 2024; 416:2359-2369. [PMID: 38358530 DOI: 10.1007/s00216-024-05171-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 01/20/2024] [Accepted: 01/23/2024] [Indexed: 02/16/2024]
Abstract
Success of mass spectrometry characterization of the proteome of single cells allows us to gain a greater understanding than afforded by transcriptomics alone but requires clear understanding of the tradeoffs between analytical throughput and precision. Recent advances in mass spectrometry acquisition techniques, including updated instrumentation and sample preparation, have improved the quality of peptide signals obtained from single cell data. However, much of the proteome remains uncharacterized, and higher throughput techniques often come at the expense of reduced sensitivity and coverage, which diminish the ability to measure proteoform heterogeneity, including splice variants and post-translational modifications, in single cell data analysis. Here, we assess the growing body of ultrasensitive single-cell approaches and their tradeoffs as researchers try to balance throughput and precision in their experiments.
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Affiliation(s)
| | - Joseph Zaia
- Bioinformatics Program, Boston University, Boston, MA, USA.
- Department of Biochemistry and Cell Biology, Boston University, Boston, MA, USA.
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2
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Brown W, Davidson LA, Deiters A. Expanding the Genetic Code of Xenopus laevis Embryos. ACS Chem Biol 2024; 19:516-525. [PMID: 38277773 PMCID: PMC10877573 DOI: 10.1021/acschembio.3c00686] [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] [Received: 11/10/2023] [Revised: 12/20/2023] [Accepted: 12/20/2023] [Indexed: 01/28/2024]
Abstract
The incorporation of unnatural amino acids into proteins through genetic code expansion has been successfully adapted to African claw-toed frog embryos. Six unique unnatural amino acids are incorporated site-specifically into proteins and demonstrate robust and reliable protein expression. Of these amino acids, several are caged analogues that can be used to establish conditional control over enzymatic activity. Using light or small molecule triggers, we exhibit activation and tunability of protein functions in live embryos. This approach was then applied to optical control over the activity of a RASopathy mutant of NRAS, taking advantage of generating explant cultures from Xenopus. Taken together, genetic code expansion is a robust approach in the Xenopus model to incorporate novel chemical functionalities into proteins of interest to study their function and role in a complex biological setting.
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Affiliation(s)
- Wes Brown
- Department
of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Lance A. Davidson
- Departments
of Bioengineering, Developmental Biology, and Computational and Systems
Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Alexander Deiters
- Department
of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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3
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Ahmadi S, Benard-Valle M, Boddum K, Cardoso FC, King GF, Laustsen AH, Ljungars A. From squid giant axon to automated patch-clamp: electrophysiology in venom and antivenom research. Front Pharmacol 2023; 14:1249336. [PMID: 37693897 PMCID: PMC10484000 DOI: 10.3389/fphar.2023.1249336] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 08/11/2023] [Indexed: 09/12/2023] Open
Abstract
Ion channels play a crucial role in diverse physiological processes, including neurotransmission and muscle contraction. Venomous creatures exploit the vital function of ion channels by producing toxins in their venoms that specifically target these ion channels to facilitate prey capture upon a bite or a sting. Envenoming can therefore lead to ion channel dysregulation, which for humans can result in severe medical complications that often necessitate interventions such as antivenom administration. Conversely, the discovery of highly potent and selective venom toxins with the capability of distinguishing between different isoforms and subtypes of ion channels has led to the development of beneficial therapeutics that are now in the clinic. This review encompasses the historical evolution of electrophysiology methodologies, highlighting their contributions to venom and antivenom research, including venom-based drug discovery and evaluation of antivenom efficacy. By discussing the applications and advancements in patch-clamp techniques, this review underscores the profound impact of electrophysiology in unravelling the intricate interplay between ion channels and venom toxins, ultimately leading to the development of drugs for envenoming and ion channel-related pathologies.
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Affiliation(s)
- Shirin Ahmadi
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Melisa Benard-Valle
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | | | - Fernanda C. Cardoso
- Institute for Molecular Bioscience, University of Queensland, St Lucia, QLD, Australia
- Australian Research Council Centre of Excellence for Innovations in Protein and Peptide Science, University of Queensland, St Lucia, QLD, Australia
| | - Glenn F. King
- Institute for Molecular Bioscience, University of Queensland, St Lucia, QLD, Australia
- Australian Research Council Centre of Excellence for Innovations in Protein and Peptide Science, University of Queensland, St Lucia, QLD, Australia
| | - Andreas Hougaard Laustsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Anne Ljungars
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
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4
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Lüddecke T, Paas A, Harris RJ, Talmann L, Kirchhoff KN, Billion A, Hardes K, Steinbrink A, Gerlach D, Fry BG, Vilcinskas A. Venom biotechnology: casting light on nature's deadliest weapons using synthetic biology. Front Bioeng Biotechnol 2023; 11:1166601. [PMID: 37207126 PMCID: PMC10188951 DOI: 10.3389/fbioe.2023.1166601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 04/18/2023] [Indexed: 05/21/2023] Open
Abstract
Venoms are complex chemical arsenals that have evolved independently many times in the animal kingdom. Venoms have attracted the interest of researchers because they are an important innovation that has contributed greatly to the evolutionary success of many animals, and their medical relevance offers significant potential for drug discovery. During the last decade, venom research has been revolutionized by the application of systems biology, giving rise to a novel field known as venomics. More recently, biotechnology has also made an increasing impact in this field. Its methods provide the means to disentangle and study venom systems across all levels of biological organization and, given their tremendous impact on the life sciences, these pivotal tools greatly facilitate the coherent understanding of venom system organization, development, biochemistry, and therapeutic activity. Even so, we lack a comprehensive overview of major advances achieved by applying biotechnology to venom systems. This review therefore considers the methods, insights, and potential future developments of biotechnological applications in the field of venom research. We follow the levels of biological organization and structure, starting with the methods used to study the genomic blueprint and genetic machinery of venoms, followed gene products and their functional phenotypes. We argue that biotechnology can answer some of the most urgent questions in venom research, particularly when multiple approaches are combined together, and with other venomics technologies.
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Affiliation(s)
- Tim Lüddecke
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Giessen, Germany
- LOEWE Centre for Translational Biodiversity Genomics (LOEWE-TBG), Frankfurt am Main, Germany
- *Correspondence: Tim Lüddecke,
| | - Anne Paas
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Giessen, Germany
- LOEWE Centre for Translational Biodiversity Genomics (LOEWE-TBG), Frankfurt am Main, Germany
| | - Richard J. Harris
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, Brisbane, QLD, Australia
- Institute for Molecular Biosciences (IMB), The University of Queensland, Brisbane, QLD, Australia
| | - Lea Talmann
- Syngenta Crop Protection, Stein, Switzerland
| | - Kim N. Kirchhoff
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Giessen, Germany
| | - André Billion
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Giessen, Germany
| | - Kornelia Hardes
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Giessen, Germany
- LOEWE Centre for Translational Biodiversity Genomics (LOEWE-TBG), Frankfurt am Main, Germany
- BMBF Junior Research Group in Infection Research “ASCRIBE”, Giessen, Germany
| | - Antje Steinbrink
- LOEWE Centre for Translational Biodiversity Genomics (LOEWE-TBG), Frankfurt am Main, Germany
- Institute for Insect Biotechnology, Justus Liebig University of Giessen, Giessen, Germany
| | - Doreen Gerlach
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Giessen, Germany
| | - Bryan G. Fry
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Andreas Vilcinskas
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Giessen, Germany
- LOEWE Centre for Translational Biodiversity Genomics (LOEWE-TBG), Frankfurt am Main, Germany
- Institute for Insect Biotechnology, Justus Liebig University of Giessen, Giessen, Germany
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5
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Miller B, Powell A, Gutierrez BA, Limon A. Microtransplantation of Synaptic Membranes to Reactivate Human Synaptic Receptors for Functional Studies. J Vis Exp 2022:10.3791/64024. [PMID: 35938847 PMCID: PMC10729793 DOI: 10.3791/64024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Excitatory and inhibitory ionotropic receptors are the major gates of ion fluxes that determine the activity of synapses during physiological neuronal communication. Therefore, alterations in their abundance, function, and relationships with other synaptic elements have been observed as a major correlate of alterations in brain function and cognitive impairment in neurodegenerative diseases and mental disorders. Understanding how the function of excitatory and inhibitory synaptic receptors is altered by disease is of critical importance for the development of effective therapies. To gain disease-relevant information, it is important to record the electrical activity of neurotransmitter receptors that remain functional in the diseased human brain. So far this is the closest approach to assess pathological alterations in receptors' function. In this work, a methodology is presented to perform microtransplantation of synaptic membranes, which consists of reactivating synaptic membranes from snap frozen human brain tissue containing human receptors, by its injection and posterior fusion into the membrane of Xenopus laevis oocytes. The protocol also provides the methodological strategy to obtain consistent and reliable responses of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and γ-aminobutyric acid (GABA) receptors, as well as novel detailed methods that are used for normalization and rigorous data analysis.
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Affiliation(s)
- Brice Miller
- The Mitchell Center for Neurodegenerative Diseases, Department of Neurology, University of Texas Medical Branch
| | - Ashli Powell
- The Mitchell Center for Neurodegenerative Diseases, Department of Neurology, University of Texas Medical Branch
| | - Berenice A Gutierrez
- The Mitchell Center for Neurodegenerative Diseases, Department of Neurology, University of Texas Medical Branch
| | - Agenor Limon
- The Mitchell Center for Neurodegenerative Diseases, Department of Neurology, University of Texas Medical Branch;
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6
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Abstract
The Xenopus oocyte is a specialized single cell of colossal size (>1 mm diameter) that is highly amenable for microinjection and a stalwart model for heterologous expression. Oocytes are easily obtainable, robust in vitro, and faithfully express injected constructs. Their large size translational capacity provides a huge canvas for observing and recording integrated cellular responses-from studies of single molecules within single cells to medium-throughput drug-screening applications. Most eukaryotic promoters suffice for Xenopus expression, and the oocyte can functionally express proteins from many diverse organisms. This protocol provides a basic introduction for scientists keen to perform nuclear microinjections of cDNA constructs. These are easy methods to master, do not require elaborate equipment, and make accessible a wonderful model cell system for studying signaling, transport, cell architecture, and protein function.
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7
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Aguero T, Newman K, King ML. Microinjection of Xenopus Oocytes. Cold Spring Harb Protoc 2018; 2018:pdb.prot096974. [PMID: 29321284 DOI: 10.1101/pdb.prot096974] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Microinjection of Xenopus oocytes has proven to be a valuable tool in a broad array of studies that require expression of DNA or RNA into functional protein. These studies are diverse and range from expression cloning to receptor-ligand interaction to nuclear programming. Oocytes offer a number of advantages for such studies, including their large size (∼1.2 mm in diameter), capacity for translation, and enormous nucleus (0.3-0.4 mm). They are cost effective, easily manipulated, and can be injected in large numbers in a short time period. Oocytes have a large maternal stockpile of all the essential components for transcription and translation. Consequently, the investigator needs only to introduce by microinjection the specific DNA or RNA of interest for synthesis. Oocytes translate virtually any exogenous RNA regardless of source, and the translated proteins are folded, modified, and transported to the correct cellular locations. Here we present procedures for the efficient microinjection of oocytes and their subsequent care.
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Affiliation(s)
- Tristan Aguero
- Department of Cell Biology, University of Miami School of Medicine, Miami, Florida 33136
| | - Karen Newman
- Department of Cell Biology, University of Miami School of Medicine, Miami, Florida 33136
| | - Mary Lou King
- Department of Cell Biology, University of Miami School of Medicine, Miami, Florida 33136
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8
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Yang YY, Long RK, Ferrara CT, Gitelman SE, German MS, Yang SB. A new familial form of a late-onset, persistent hyperinsulinemic hypoglycemia of infancy caused by a novel mutation in KCNJ11. Channels (Austin) 2017; 11:636-647. [PMID: 29087246 PMCID: PMC5786184 DOI: 10.1080/19336950.2017.1393131] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The ATP-sensitive potassium channel (KATP) functions as a metabo-electric transducer in regulating insulin secretion from pancreatic β-cells. The pancreatic KATP channel is composed of a pore-forming inwardly-rectifying potassium channel, Kir6.2, and a regulatory subunit, sulphonylurea receptor 1 (SUR1). Loss-of-function mutations in either subunit often lead to the development of persistent hyperinsulinemic hypoglycemia of infancy (PHHI). PHHI is a rare genetic disease and most patients present with immediate onset within the first few days after birth. In this study, we report an unusual form of PHHI, in which the index patient developed hyperinsulinemic hypoglycemia after 1 year of age. The patient failed to respond to routine medication for PHHI and underwent a complete pancreatectomy. Genotyping of the index patient and his immediate family members showed that the patient and other family members with hypoglycemic episodes carried a heterozygous novel mutation in KCNJ11 (C83T), which encodes Kir6.2 (A28V). Electrophysiological and cell biological experiments revealed that A28V hKir6.2 is a dominant-negative, loss-of-function mutation and that KATP channels carrying this mutation failed to reach the cell surface. De novo protein structure prediction indicated that this A28V mutation reoriented the ER retention motif located at the C-terminal of the hKir6.2, and this result may explain the trafficking defect caused by this point mutation. Our study is the first report of a novel form of late-onset PHHI that is caused by a dominant mutation in KCNJ11 and exhibits a defect in proper surface expression of Kir6.2.
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Affiliation(s)
- Yen-Yu Yang
- a Institute of Biomedical Sciences, Academia Sinica , Taipei , Taiwan
| | - Roger K Long
- b Department of Pediatrics , University of California San Francisco , USA
| | | | - Stephen E Gitelman
- b Department of Pediatrics , University of California San Francisco , USA.,c Diabetes Center , University of California San Francisco , USA
| | - Michael S German
- c Diabetes Center , University of California San Francisco , USA.,d Department of Medicine and Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research , University of California San Francisco , USA
| | - Shi-Bing Yang
- a Institute of Biomedical Sciences, Academia Sinica , Taipei , Taiwan
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9
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Schneider M, Prudic K, Pippel A, Klapperstück M, Braam U, Müller CE, Schmalzing G, Markwardt F. Interaction of Purinergic P2X4 and P2X7 Receptor Subunits. Front Pharmacol 2017; 8:860. [PMID: 29213241 PMCID: PMC5702805 DOI: 10.3389/fphar.2017.00860] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 11/09/2017] [Indexed: 11/13/2022] Open
Abstract
P2X4 and P2X7 are members of the P2X receptor family, comprising seven isoforms (P2X1–P2X7) that form homo- and heterotrimeric non-specific cation channels gated by extracellular ATP. P2X4 and P2X7 are widely coexpressed, particularly in secretory epithelial cells and immune and inflammatory cells, and regulate inflammation and nociception. Although functional heteromerization has been established for P2X2 and P2X3 subunits expressed in sensory neurons, there are contradictory reports regarding a functional interaction between P2X4 and P2X7 subunits. To resolve this issue, we coexpressed P2X4 and P2X7 receptor subunits labeled with green (EGFP) and red (TagRFP) fluorescent proteins in Xenopus laevis oocytes and investigated a putative physical interaction between the fusion proteins by Förster resonance energy transfer (FRET). Coexpression of P2X4 and P2X7 subunits with EGFP and TagRFP located in the extracellular receptor domains led to significant FRET signals. Significant FRET signals were also measured between C-terminally fluorophore-labeled full-length P2X41-384 and C-terminally truncated fluorescent P2X71-408 subunits. We furthermore used the two-electrode voltage clamp technique to investigate whether human P2X4 and P2X7 receptors (hP2X4, hP2X7) functionally interact at the level of ATP-induced whole-cell currents. Concentration–response curves and effects of ivermectin (P2X4-potentiating drug) or BzATP (P2X7-specific agonist) were consistent with a model in which coexpressed hP2X4 and hP2X7 do not interact. Similarly, the effect of adding specific inhibitors of P2X4 (PSB-15417) or P2X7 (oATP, A438079) could be explained by a model in which only homomers exist, and that these are blocked by the respective antagonist. In conclusion, we show that P2X4 and P2X7 subunits can form heterotrimeric P2X4/P2X7 receptors. However, unlike observations for P2X2 and P2X3, coexpression of P2X4 and P2X7 subunits does not result in a novel electrophysiologically discriminable P2X receptor phenotype.
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Affiliation(s)
- Markus Schneider
- Julius-Bernstein-Institute for Physiology, Martin-Luther-University, Halle, Germany
| | - Kirsten Prudic
- Julius-Bernstein-Institute for Physiology, Martin-Luther-University, Halle, Germany
| | - Anja Pippel
- Julius-Bernstein-Institute for Physiology, Martin-Luther-University, Halle, Germany
| | - Manuela Klapperstück
- Julius-Bernstein-Institute for Physiology, Martin-Luther-University, Halle, Germany
| | - Ursula Braam
- Molecular Pharmacology, RWTH Aachen University, Aachen, Germany
| | - Christa E Müller
- Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, Bonn, Germany
| | | | - Fritz Markwardt
- Julius-Bernstein-Institute for Physiology, Martin-Luther-University, Halle, Germany
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10
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Virant-Klun I, Leicht S, Hughes C, Krijgsveld J. Identification of Maturation-Specific Proteins by Single-Cell Proteomics of Human Oocytes. Mol Cell Proteomics 2016; 15:2616-27. [PMID: 27215607 DOI: 10.1074/mcp.m115.056887] [Citation(s) in RCA: 139] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Indexed: 12/25/2022] Open
Abstract
Oocytes undergo a range of complex processes via oogenesis, maturation, fertilization, and early embryonic development, eventually giving rise to a fully functioning organism. To understand proteome composition and diversity during maturation of human oocytes, here we have addressed crucial aspects of oocyte collection and proteome analysis, resulting in the first proteome and secretome maps of human oocytes. Starting from 100 oocytes collected via a novel serum-free hanging drop culture system, we identified 2,154 proteins, whose function indicate that oocytes are largely resting cells with a proteome that is tailored for homeostasis, cellular attachment, and interaction with its environment via secretory factors. In addition, we have identified 158 oocyte-enriched proteins (such as ECAT1, PIWIL3, NLRP7)(1) not observed in high-coverage proteomics studies of other human cell lines or tissues. Exploiting SP3, a novel technology for proteomic sample preparation using magnetic beads, we scaled down proteome analysis to single cells. Despite the low protein content of only ∼100 ng per cell, we consistently identified ∼450 proteins from individual oocytes. When comparing individual oocytes at the germinal vesicle (GV) and metaphase II (MII) stage, we found that the Tudor and KH domain-containing protein (TDRKH) is preferentially expressed in immature oocytes, while Wee2, PCNA, and DNMT1 were enriched in mature cells, collectively indicating that maintenance of genome integrity is crucial during oocyte maturation. This study demonstrates that an innovative proteomics workflow facilitates analysis of single human oocytes to investigate human oocyte biology and preimplantation development. The approach presented here paves the way for quantitative proteomics in other quantity-limited tissues and cell types. Data associated with this study are available via ProteomeXchange with identifier PXD004142.
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Affiliation(s)
- Irma Virant-Klun
- From the ‡Reproductive Unit, Department of Obstetrics and Gynecology, University Medical Centre Ljubljana, Slajmerjeva 3, 1000 Ljubljana, Slovenia
| | - Stefan Leicht
- §European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Christopher Hughes
- ¶British Columbia Cancer Research Agency, 675 West 10th Avenue, Vancouver, Canada
| | - Jeroen Krijgsveld
- §European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany; ‖German Cancer Research Center and Heidelberg University, Im Neuenheimer Feld 581, 69120, Heidelberg, Germany
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11
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Lin-Moshier Y, Marchant JS. A rapid Western blotting protocol for the Xenopus oocyte. Cold Spring Harb Protoc 2013; 2013:2013/3/pdb.prot072793. [PMID: 23457341 PMCID: PMC4017335 DOI: 10.1101/pdb.prot072793] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Often experimentalists require a quantitative assessment of the levels of heterologously expressed proteins to best interpret changed Ca(2+) signaling patterns. Here, we detail a rapid and convenient western blotting method for individual Xenopus oocytes. The method exploits recently introduced rapid blotting systems, commercially available from Invitrogen (iBlot) or Bio-Rad (Trans-Blot Turbo). The key advantage is speed: from live cell to transferred membrane in <1 h. Therefore, oocytes can be conveniently processed for western blotting to assess relative expression levels, even after a long day of Ca(2+) imaging experiments.
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12
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Lin-Moshier Y, Marchant JS. Nuclear microinjection to assess how heterologously expressed proteins impact Ca2+ signals in Xenopus oocytes. Cold Spring Harb Protoc 2013; 2013:2013/3/pdb.prot072785. [PMID: 23457340 DOI: 10.1101/pdb.prot072785] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The Xenopus oocyte is frequently used for heterologous expression and for studying the spatiotemporal patterning of Ca(2+) signals. Here, we outline a protocol for nuclear microinjection of the Xenopus oocyte for the purpose of studying how subsequently expressed proteins impact intracellular Ca(2+) signals evoked by inositol trisphosphate (InsP3). Injected oocytes can easily be identified by reporter technologies and the impact of heterologously expressed proteins on the generation and properties of InsP3-evoked Ca(2+) signals can be resolved using caged InsP3 and fluorescent Ca(2+) indicators.
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Affiliation(s)
- Yaping Lin-Moshier
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
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