Other search tools

About this data

The publication data currently available has been vetted by Vanderbilt faculty, staff, administrators and trainees. The data itself is retrieved directly from NCBI's PubMed and is automatically updated on a weekly basis to ensure accuracy and completeness.

If you have any questions or comments, please contact us.

Results: 1 to 10 of 121

Publication Record

Connections

Real-time visualization of titin dynamics reveals extensive reversible photobleaching in human induced pluripotent stem cell-derived cardiomyocytes.
Cadar AG, Feaster TK, Bersell KR, Wang L, Hong T, Balsamo JA, Zhang Z, Chun YW, Nam YJ, Gotthardt M, Knollmann BC, Roden DM, Lim CC, Hong CC
(2020) Am J Physiol Cell Physiol 318: C163-C173
MeSH Terms: Adult, Cell Differentiation, Cell Line, Connectin, Fluorescence Recovery After Photobleaching, Humans, Induced Pluripotent Stem Cells, Kinetics, Luminescent Proteins, Male, Microscopy, Fluorescence, Microscopy, Video, Myocytes, Cardiac, Recombinant Fusion Proteins, Reproducibility of Results, Sarcomeres
Show Abstract · Added March 24, 2020
Fluorescence recovery after photobleaching (FRAP) has been useful in delineating cardiac myofilament biology, and innovations in fluorophore chemistry have expanded the array of microscopic assays used. However, one assumption in FRAP is the irreversible photobleaching of fluorescent proteins after laser excitation. Here we demonstrate reversible photobleaching regarding the photoconvertible fluorescent protein mEos3.2. We used CRISPR/Cas9 genome editing in human induced pluripotent stem cells (hiPSCs) to knock-in mEos3.2 into the COOH terminus of titin to visualize sarcomeric titin incorporation and turnover. Upon cardiac induction, the titin-mEos3.2 fusion protein is expressed and integrated in the sarcomeres of hiPSC-derived cardiomyocytes (CMs). STORM imaging shows M-band clustered regions of bound titin-mEos3.2 with few soluble titin-mEos3.2 molecules. FRAP revealed a baseline titin-mEos3.2 fluorescence recovery of 68% and half-life of ~1.2 h, suggesting a rapid exchange of sarcomeric titin with soluble titin. However, paraformaldehyde-fixed and permeabilized titin-mEos3.2 hiPSC-CMs surprisingly revealed a 55% fluorescence recovery. Whole cell FRAP analysis in paraformaldehyde-fixed, cycloheximide-treated, and untreated titin-mEos3.2 hiPSC-CMs displayed no significant differences in fluorescence recovery. FRAP in fixed HEK 293T expressing cytosolic mEos3.2 demonstrates a 58% fluorescence recovery. These data suggest that titin-mEos3.2 is subject to reversible photobleaching following FRAP. Using a mouse titin-eGFP model, we demonstrate that no reversible photobleaching occurs. Our results reveal that reversible photobleaching accounts for the majority of titin recovery in the titin-mEos3.2 hiPSC-CM model and should warrant as a caution in the extrapolation of reliable FRAP data from specific fluorescent proteins in long-term cell imaging.
0 Communities
1 Members
0 Resources
16 MeSH Terms
Novel kidney dissociation protocol and image-based flow cytometry facilitate improved analysis of injured proximal tubules.
Manolopoulou M, Matlock BK, Nlandu-Khodo S, Simmons AJ, Lau KS, Phillips-Mignemi M, Ivanova A, Alford CE, Flaherty DK, Gewin LS
(2019) Am J Physiol Renal Physiol 316: F847-F855
MeSH Terms: Acute Kidney Injury, Animals, Aristolochic Acids, Biomarkers, Cell Cycle, Cell Separation, Disease Models, Animal, Epithelial Cells, Flow Cytometry, Genes, Reporter, Kidney Tubules, Proximal, Luminescent Proteins, Male, Mice, Transgenic, Polyploidy, Tissue Fixation
Show Abstract · Added March 26, 2019
Flow cytometry studies on injured kidney tubules are complicated by the low yield of nucleated single cells. Furthermore, cell-specific responses such as cell cycle dynamics in vivo have conventionally relied on indirect immunohistochemistry and proximal tubule markers that may be downregulated in injury. Here, we report a new tissue dissociation protocol for the kidney with an early fixation step that greatly enhances the yield of single cells. Genetic labeling of the proximal tubule with either mT/mG "tomato" or R26Fucci2aR (Fucci) cell cycle reporter mice allows us to follow proximal tubule-specific changes in cell cycle after renal injury. Image-based flow cytometry (FlowSight) enables gating of the cell cycle and concurrent visualization of the cells with bright field and fluorescence. We used the Fucci mouse in conjunction with FlowSight to identify a discrete polyploid population in proximal tubules after aristolochic acid injury. The tissue dissociation protocol in conjunction with genetic labeling and image-based flow cytometry is a tool that can improve our understanding of any discrete cell population after injury.
0 Communities
1 Members
0 Resources
16 MeSH Terms
The C-terminal region of A-kinase anchor protein 350 (AKAP350A) enables formation of microtubule-nucleation centers and interacts with pericentriolar proteins.
Kolobova E, Roland JT, Lapierre LA, Williams JA, Mason TA, Goldenring JR
(2017) J Biol Chem 292: 20394-20409
MeSH Terms: A Kinase Anchor Proteins, Biomarkers, Cell Cycle Proteins, Cell Line, Centrosome, Cytoskeletal Proteins, Humans, Imaging, Three-Dimensional, Intracellular Signaling Peptides and Proteins, Luminescent Proteins, Microscopy, Electron, Transmission, Microtubule-Associated Proteins, Microtubule-Organizing Center, Models, Molecular, Nerve Tissue Proteins, Peptide Fragments, Phosphoproteins, Protein Interaction Domains and Motifs, Protein Interaction Mapping, Protein Multimerization, Proteomics, RNA Interference, Recombinant Fusion Proteins, Recombinant Proteins, Two-Hybrid System Techniques
Show Abstract · Added April 3, 2018
Microtubules in animal cells assemble (nucleate) from both the centrosome and the cis-Golgi cisternae. A-kinase anchor protein 350 kDa (AKAP350A, also called AKAP450/CG-NAP/AKAP9) is a large scaffolding protein located at both the centrosome and Golgi apparatus. Previous findings have suggested that AKAP350 is important for microtubule dynamics at both locations, but how this scaffolding protein assembles microtubule nucleation machinery is unclear. Here, we found that overexpression of the C-terminal third of AKAP350A, enhanced GFP-AKAP350A(2691-3907), induces the formation of multiple microtubule-nucleation centers (MTNCs). Nevertheless, these induced MTNCs lacked "true" centriole proteins, such as Cep135. Mapping analysis with AKAP350A truncations demonstrated that AKAP350A contains discrete regions responsible for promoting or inhibiting the formation of multiple MTNCs. Moreover, GFP-AKAP350A(2691-3907) recruited several pericentriolar proteins to MTNCs, including γ-tubulin, pericentrin, Cep68, Cep170, and Cdk5RAP2. Proteomic analysis indicated that Cdk5RAP2 and Cep170 both interact with the microtubule nucleation-promoting region of AKAP350A, whereas Cep68 interacts with the distal C-terminal AKAP350A region. Yeast two-hybrid assays established a direct interaction of Cep170 with AKAP350A. Super-resolution and deconvolution microscopy analyses were performed to define the association of AKAP350A with centrosomes, and these studies disclosed that AKAP350A spans the bridge between centrioles, co-localizing with rootletin and Cep68 in the linker region. siRNA-mediated depletion of AKAP350A caused displacement of both Cep68 and Cep170 from the centrosome. These results suggest that AKAP350A acts as a scaffold for factors involved in microtubule nucleation at the centrosome and coordinates the assembly of protein complexes associating with the intercentriolar bridge.
0 Communities
1 Members
0 Resources
25 MeSH Terms
Quantitative assessment of fluorescent proteins.
Cranfill PJ, Sell BR, Baird MA, Allen JR, Lavagnino Z, de Gruiter HM, Kremers GJ, Davidson MW, Ustione A, Piston DW
(2016) Nat Methods 13: 557-62
MeSH Terms: Fluorescence, HeLa Cells, Humans, Luminescent Proteins, Microscopy, Fluorescence, Recombinant Fusion Proteins, Spectrometry, Fluorescence
Show Abstract · Added May 5, 2017
The advent of fluorescent proteins (FPs) for genetic labeling of molecules and cells has revolutionized fluorescence microscopy. Genetic manipulations have created a vast array of bright and stable FPs spanning blue to red spectral regions. Common to autofluorescent FPs is their tight β-barrel structure, which provides the rigidity and chemical environment needed for effectual fluorescence. Despite the common structure, each FP has unique properties. Thus, there is no single 'best' FP for every circumstance, and each FP has advantages and disadvantages. To guide decisions about which FP is right for a given application, we have quantitatively characterized the brightness, photostability, pH stability and monomeric properties of more than 40 FPs to enable straightforward and direct comparison between them. We focus on popular and/or top-performing FPs in each spectral region.
0 Communities
1 Members
0 Resources
7 MeSH Terms
The Ste20 kinases SPAK and OSR1 travel between cells through exosomes.
Koumangoye R, Delpire E
(2016) Am J Physiol Cell Physiol 311: C43-53
MeSH Terms: Cell Communication, Cell Membrane, Coculture Techniques, Culture Media, Conditioned, Exosomes, HEK293 Cells, HeLa Cells, Humans, Luminescent Proteins, Microscopy, Fluorescence, Particle Size, Phosphorylation, Protein Transport, Protein-Serine-Threonine Kinases, Recombinant Proteins, Solute Carrier Family 12, Member 2, Tetraspanin 30, Time Factors, Transfection
Show Abstract · Added May 3, 2017
Proteomics studies have identified Ste20-related proline/alanine-rich kinase (SPAK) and oxidative stress response 1 (OSR1) in exosomes isolated from body fluids such as blood, saliva, and urine. Because proteomics studies likely overestimate the number of exosome proteins, we sought to confirm and extend this observation using traditional biochemical and cell biology methods. We utilized HEK293 cells in culture to verify the packaging of these Ste20 kinases in exosomes. Using a series of centrifugation and filtration steps of conditioned culture medium isolated from HEK293 cells, we isolated nanovesicles in the range of 40-100 nm. We show that these small vesicles express the tetraspanin protein CD63 and lack endoplasmic reticulum and Golgi markers, consistent with these being exosomes. We show by Western blot and immunogold analyses that these exosomes express SPAK, OSR1, and Na-K-Cl cotransporter 1 (NKCC1). We show that exosomes are not only secreted by cells, but also accumulated by adjacent cells. Indeed, exposing cultured cells to exosomes produced by other cells expressing a fluorescently labeled kinase resulted in the kinase finding its way into the cytoplasm of these cells, consistent with the idea of exosomes serving as cell-to-cell communication vessels. Similarly, coculturing cells expressing different fluorescently tagged proteins resulted in the exchange of proteins between cells. In addition, we show that both SPAK and OSR1 kinases entering cells through exosomes are preferentially expressed at the plasma membrane and that the kinases in exosomes are functional and maintain NKCC1 in a phosphorylated state.
Copyright © 2016 the American Physiological Society.
0 Communities
1 Members
0 Resources
19 MeSH Terms
Advanced Intestinal Cancers often Maintain a Multi-Ancestral Architecture.
Zahm CD, Szulczewski JM, Leystra AA, Paul Olson TJ, Clipson L, Albrecht DM, Middlebrooks M, Thliveris AT, Matkowskyj KA, Washington MK, Newton MA, Eliceiri KW, Halberg RB
(2016) PLoS One 11: e0150170
MeSH Terms: Adenocarcinoma, Adenoma, Animals, Carcinoma in Situ, Cell Lineage, Cell Transformation, Neoplastic, Clone Cells, Disease Models, Animal, Disease Progression, Evolution, Molecular, Fatty Acid-Binding Proteins, Female, Gene Expression Regulation, Neoplastic, Genes, APC, Genes, Reporter, Integrases, Intestinal Mucosa, Intestinal Neoplasms, Luminescent Proteins, Male, Mice, Mice, Inbred C57BL, Models, Biological, Mosaicism, Neoplasm Invasiveness, Neoplastic Stem Cells, RNA, Untranslated, Rats, Transgenes, Tumor Microenvironment
Show Abstract · Added April 12, 2016
A widely accepted paradigm in the field of cancer biology is that solid tumors are uni-ancestral being derived from a single founder and its descendants. However, data have been steadily accruing that indicate early tumors in mice and humans can have a multi-ancestral origin in which an initiated primogenitor facilitates the transformation of neighboring co-genitors. We developed a new mouse model that permits the determination of clonal architecture of intestinal tumors in vivo and ex vivo, have validated this model, and then used it to assess the clonal architecture of adenomas, intramucosal carcinomas, and invasive adenocarcinomas of the intestine. The percentage of multi-ancestral tumors did not significantly change as tumors progressed from adenomas with low-grade dysplasia [40/65 (62%)], to adenomas with high-grade dysplasia [21/37 (57%)], to intramucosal carcinomas [10/23 (43%]), to invasive adenocarcinomas [13/19 (68%)], indicating that the clone arising from the primogenitor continues to coexist with clones arising from co-genitors. Moreover, neoplastic cells from distinct clones within a multi-ancestral adenocarcinoma have even been observed to simultaneously invade into the underlying musculature [2/15 (13%)]. Thus, intratumoral heterogeneity arising early in tumor formation persists throughout tumorigenesis.
0 Communities
1 Members
0 Resources
30 MeSH Terms
Fluorescent Protein Approaches in Alpha Herpesvirus Research.
Hogue IB, Bosse JB, Engel EA, Scherer J, Hu JR, Del Rio T, Enquist LW
(2015) Viruses 7: 5933-61
MeSH Terms: Alphaherpesvirinae, Biomedical Research, Host-Pathogen Interactions, Luminescent Proteins, Recombinant Fusion Proteins, Staining and Labeling, Virology
Show Abstract · Added April 6, 2019
In the nearly two decades since the popularization of green fluorescent protein (GFP), fluorescent protein-based methodologies have revolutionized molecular and cell biology, allowing us to literally see biological processes as never before. Naturally, this revolution has extended to virology in general, and to the study of alpha herpesviruses in particular. In this review, we provide a compendium of reported fluorescent protein fusions to herpes simplex virus 1 (HSV-1) and pseudorabies virus (PRV) structural proteins, discuss the underappreciated challenges of fluorescent protein-based approaches in the context of a replicating virus, and describe general strategies and best practices for creating new fluorescent fusions. We compare fluorescent protein methods to alternative approaches, and review two instructive examples of the caveats associated with fluorescent protein fusions, including describing several improved fluorescent capsid fusions in PRV. Finally, we present our future perspectives on the types of powerful experiments these tools now offer.
0 Communities
1 Members
0 Resources
MeSH Terms
Extracellular rigidity sensing by talin isoform-specific mechanical linkages.
Austen K, Ringer P, Mehlich A, Chrostek-Grashoff A, Kluger C, Klingner C, Sabass B, Zent R, Rief M, Grashoff C
(2015) Nat Cell Biol 17: 1597-606
MeSH Terms: Actin Cytoskeleton, Actins, Animals, Biosensing Techniques, Blotting, Western, Cell Adhesion, Cells, Cultured, Extracellular Matrix, Fibroblasts, Fluorescence Resonance Energy Transfer, Focal Adhesions, Luminescent Proteins, Mechanical Phenomena, Mice, Knockout, Mice, Transgenic, Microfilament Proteins, Microscopy, Confocal, Microscopy, Fluorescence, Optical Tweezers, Peptides, Protein Binding, Talin, Vinculin
Show Abstract · Added February 4, 2016
The ability of cells to adhere and sense differences in tissue stiffness is crucial for organ development and function. The central mechanisms by which adherent cells detect extracellular matrix compliance, however, are still unknown. Using two single-molecule-calibrated biosensors that allow the analysis of a previously inaccessible but physiologically highly relevant force regime in cells, we demonstrate that the integrin activator talin establishes mechanical linkages following cell adhesion, which are indispensable for cells to probe tissue stiffness. Talin linkages are exposed to a range of piconewton forces and bear, on average, 7-10 pN during cell adhesion depending on their association with F-actin and vinculin. Disruption of talin's mechanical engagement does not impair integrin activation and initial cell adhesion but prevents focal adhesion reinforcement and thus extracellular rigidity sensing. Intriguingly, talin mechanics are isoform specific so that expression of either talin-1 or talin-2 modulates extracellular rigidity sensing.
1 Communities
1 Members
0 Resources
23 MeSH Terms
Nkx2.2 is expressed in a subset of enteroendocrine cells with expanded lineage potential.
Gross S, Balderes D, Liu J, Asfaha S, Gu G, Wang TC, Sussel L
(2015) Am J Physiol Gastrointest Liver Physiol 309: G975-87
MeSH Terms: Animals, Basic Helix-Loop-Helix Transcription Factors, Biomarkers, Cell Differentiation, Cell Lineage, Cell Proliferation, Cells, Cultured, Enteroendocrine Cells, Genotype, Homeodomain Proteins, Intestinal Mucosa, Luminescent Proteins, Mice, Inbred C57BL, Mice, Transgenic, Nerve Tissue Proteins, Phenotype, Pluripotent Stem Cells, Polycomb Repressive Complex 1, Proto-Oncogene Proteins, Receptors, G-Protein-Coupled, Transcription Factors, Whole-Body Irradiation, Zebrafish Proteins
Show Abstract · Added February 3, 2017
There are two major stem cell populations in the intestinal crypt region that express either Bmi1 or Lgr5; however, it has been shown that other populations in the crypt can regain stemness. In this study, we demonstrate that the transcription factor NK2 homeobox 2 (Nkx2.2) is expressed in enteroendocrine cells located in the villus and crypt of the intestinal epithelium and is coexpressed with the stem cell markers Bmi1 and Lgr5 in a subset of crypt cells. To determine whether Nkx2.2-expressing enteroendocrine cells display cellular plasticity and stem cell potential, we performed genetic lineage tracing of the Nkx2.2-expressing population using Nkx2.2(Cre/+);R26RTomato mice. These studies demonstrated that Nkx2.2+ cells are able to give rise to all intestinal epithelial cell types in basal conditions. The proliferative capacity of Nkx2.2-expressing cells was also demonstrated in vitro using crypt organoid cultures. Injuring the intestine with irradiation, systemic inflammation, and colitis did not enhance the lineage potential of Nkx2.2-expressing cells. These findings demonstrate that a rare mature enteroendocrine cell subpopulation that is demarcated by Nkx2.2 expression display stem cell properties during normal intestinal epithelial homeostasis, but is not easily activated upon injury.
Copyright © 2015 the American Physiological Society.
2 Communities
0 Members
0 Resources
23 MeSH Terms
Heterogeneous transgene expression in the retinas of the TH-RFP, TH-Cre, TH-BAC-Cre and DAT-Cre mouse lines.
Vuong HE, Pérez de Sevilla Müller L, Hardi CN, McMahon DG, Brecha NC
(2015) Neuroscience 307: 319-37
MeSH Terms: Animals, Biotin, Calbindin 2, Choline O-Acetyltransferase, Chromosomes, Artificial, Bacterial, Dopamine Plasma Membrane Transport Proteins, Female, Gene Expression Regulation, Glycine, Integrases, Luminescent Proteins, Male, Mice, Mice, Inbred C57BL, Mice, Transgenic, RNA-Binding Proteins, Retina, Tyrosine 3-Monooxygenase, Visual Pathways, gamma-Aminobutyric Acid
Show Abstract · Added February 3, 2017
Transgenic mouse lines are essential tools for understanding the connectivity, physiology and function of neuronal circuits, including those in the retina. This report compares transgene expression in the retina of a tyrosine hydroxylase (TH)-red fluorescent protein (RFP) mouse line with three catecholamine-related Cre recombinase mouse lines [TH-bacterial artificial chromosome (BAC)-, TH-, and dopamine transporter (DAT)-Cre] that were crossed with a ROSA26-tdTomato reporter line. Retinas were evaluated and immunostained with commonly used antibodies including those directed to TH, GABA and glycine to characterize the RFP or tdTomato fluorescent-labeled amacrine cells, and an antibody directed to RNA-binding protein with multiple splicing to identify ganglion cells. In TH-RFP retinas, types 1 and 2 dopamine (DA) amacrine cells were identified by their characteristic cellular morphology and type 1 DA cells by their expression of TH immunoreactivity. In the TH-BAC-, TH-, and DAT-tdTomato retinas, less than 1%, ∼ 6%, and 0%, respectively, of the fluorescent cells were the expected type 1 DA amacrine cells. Instead, in the TH-BAC-tdTomato retinas, fluorescently labeled AII amacrine cells were predominant, with some medium diameter ganglion cells. In TH-tdTomato retinas, fluorescence was in multiple neurochemical amacrine cell types, including four types of polyaxonal amacrine cells. In DAT-tdTomato retinas, fluorescence was in GABA immunoreactive amacrine cells, including two types of bistratified and two types of monostratified amacrine cells. Although each of the Cre lines was generated with the intent to specifically label DA cells, our findings show a cellular diversity in Cre expression in the adult retina and indicate the importance of careful characterization of transgene labeling patterns. These mouse lines with their distinctive cellular labeling patterns will be useful tools for future studies of retinal function and visual processing.
Published by Elsevier Ltd.
1 Communities
1 Members
0 Resources
20 MeSH Terms