scholarly journals Interactions between CLIP-170, Tubulin, and Microtubules: Implications for the Mechanism of CLIP-170 Plus-End Tracking Behavior

2005 ◽  
Vol 16 (11) ◽  
pp. 5373-5384 ◽  
Author(s):  
Eric S. Folker ◽  
Brian M. Baker ◽  
Holly V. Goodson
Keyword(s):  
Live Cell Imaging ◽  
Cell Imaging ◽  
Previous Analysis ◽  
Microtubule Dynamics ◽  
Release Mechanism ◽  
Tubulin Dimer ◽  
Tracking Behavior

CLIP-170 belongs to a group of proteins (+TIPs) with the enigmatic ability to dynamically track growing microtubule plus-ends. CLIP-170 regulates microtubule dynamics in vivo and has been implicated in cargo-microtubule interactions in vivo and in vitro. Though plus-end tracking likely has intimate connections to +TIP function, little is known about the mechanism(s) by which this dynamic localization is achieved. Using a combination of biochemistry and live cell imaging, we provide evidence that CLIP-170 tracks microtubule plus-ends by a preassociation, copolymerization, and regulated release mechanism. As part of this analysis, we find that CLIP-170 has a stronger affinity for tubulin dimer than for polymer, and that CLIP-170 can distinguish between GTP- and GDP-like polymer. This work extends the previous analysis of CLIP-170 behavior in vivo and complements the existing fluorescence microscope characterization of CLIP-170 interactions with microtubules in vitro. In particular, these data explain observations that CLIP-170 localizes to newly polymerized microtubules in vitro but cannot track microtubule plus-ends in vitro. These observations have implications for the functions of CLIP-170 in regulating microtubule dynamics.

A new visible-light-excitable ICT-CHEF-mediated fluorescence ‘turn-on’ probe for the selective detection of Cd2+ in a mixed aqueous system with live-cell imaging

2015 ◽  
Vol 44 (12) ◽  
pp. 5763-5770 ◽  
Author(s):  
Shyamaprosad Goswami ◽  
Krishnendu Aich ◽  
Sangita Das ◽  
Chitrangada Das Mukhopadhyay ◽  
Deblina Sarkar ◽  
...  
Keyword(s):  
Visible Light ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Aqueous System ◽  
Live Cell ◽  
Selective Detection ◽  
Turn On ◽  
Fluorescence Turn On

A new quinoline based sensor was developed and applied for the selective detection of Cd2+ both in vitro and in vivo.

scholarly journals Detection and Characterization of Protein Interactions In Vivo by a Simple Live-Cell Imaging Method

PLoS ONE ◽  
2013 ◽  
Vol 8 (5) ◽  
pp. e62195 ◽  
Author(s):  
Oriol Gallego ◽  
Tanja Specht ◽  
Thorsten Brach ◽  
Arun Kumar ◽  
Anne-Claude Gavin ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Live Cell ◽  
Imaging Method

scholarly journals Identification and characterization of T reg–like cells in zebrafish

2017 ◽  
Vol 214 (12) ◽  
pp. 3519-3530 ◽  
Author(s):  
Melissa Kasheta ◽  
Corrie A. Painter ◽  
Finola E. Moore ◽  
Riadh Lobbardi ◽  
Alysia Bryll ◽  
...  
Keyword(s):  
T Lymphocytes ◽  
Live Cell Imaging ◽  
Genetic Ablation ◽  
Functional Studies ◽  
Normal Functions ◽  
Inflammatory Phenotype ◽  
Identification And Characterization

Regulatory T (T reg) cells are a specialized sublineage of T lymphocytes that suppress autoreactive T cells. Functional studies of T reg cells in vitro have defined multiple suppression mechanisms, and studies of T reg–deficient humans and mice have made clear the important role that these cells play in preventing autoimmunity. However, many questions remain about how T reg cells act in vivo. Specifically, it is not clear which suppression mechanisms are most important, where T reg cells act, and how they get there. To begin to address these issues, we sought to identify T reg cells in zebrafish, a model system that provides unparalleled advantages in live-cell imaging and high-throughput genetic analyses. Using a FOXP3 orthologue as a marker, we identified CD4-enriched, mature T lymphocytes with properties of T reg cells. Zebrafish mutant for foxp3a displayed excess T lymphocytes, splenomegaly, and a profound inflammatory phenotype that was suppressed by genetic ablation of lymphocytes. This study identifies T reg–like cells in zebrafish, providing both a model to study the normal functions of these cells in vivo and mutants to explore the consequences of their loss.

Fluorogenic Protein Probes with Red or Near-Infrared Emission for Genetically Targeted Live-Cell Imaging

2020 ◽  
Author(s):  
Sylvestre P. J. T. Bachollet ◽  
Cyril Addi ◽  
Jean-Maurice Mallet ◽  
Blaise Dumat
Keyword(s):  
Live Cell Imaging ◽  
Near Infrared ◽  
Cell Imaging ◽  
Infrared Emission ◽  
Live Cell ◽  
Molecular Rotor ◽  
Model Protein ◽  
Near Infrared Emission

A series of red-emitting and near-infrared fluorogenic protein probes based on push-pull molecular rotor structures was developed. After characterization of their optical properties using Bovine Serum Albumin as a model protein, they were conjugated to a halogenoalkane ligand in order to target the protein self-labeling tag HaloTag. The interaction with HaloTag was investigated in vitro and then the most promising probes were applied to live-cell imaging in wash-free conditions using fluorogenic and chemogenetic targeting of HaloTag fusion proteins.<br>

CBIO-17. A NOVEL ROLE FOR ATR KINASE DETERMINES GLIOBLASTOMA TUMOUR CELL INVASION

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi30-vi30
Author(s):  
ross carruthers ◽  
Sarah Derby ◽  
Karen Strathdee ◽  
Anthony Chalmers ◽  
Jim Norman ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Invasion ◽  
Tumour Cell ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Live Cell ◽  
Tumour Cell Invasion ◽  
Atr Kinase

Abstract BACKGROUND: Widespread contamination of the brain with malignant cells is a predominant feature of glioblastoma (GBM) and fatal brainstem infiltration is frequently observed at autopsy. Whilst radiotherapy improves survival, irradiation increases GBM cell invasion, resulting in sublethal dose to cells migrating outside the irradiated volume. Tumour cell invasion should be a therapeutic priority if survival is to be improved. The responsible molecular mechanisms are key to improving outcomes but remain enigmatic. Ataxia telangiectasia and rad3-related (ATR) is a DNA damage response (DDR) kinase involved in DNA replication stress (RS) response and is an established therapeutic target for GBM. In this study we demonstrate a novel role for ATR kinase in facilitating malignant cell invasion. METHODS AND RESULTS: Invading margins of human GBM samples demonstrated increased pATR expression relative to core. Live cell imaging demonstrated a reduction in cell velocity following ATR inhibition (ATRi; VE822) or ATR siRNA, and a retraction defect was evident in vitro. Extensive cytoplasmic vacuolation occurred following ATRi or siRNA which were single walled structures on electron microscopy which could engulf high molecular weight dextran, suggesting blockade of macropinosome processing. Live cell imaging with GFP-integrin α5 and integrin recycling assays showed integrin sequestration within macropinosomes and reduced integrin internalisation respectively. Interrogation of a published ‘ATR interactome’ revealed ATR targets with functions in endocytic vesicle trafficking. Intravital in vivo imaging of murine xenograft tumours confirmed vacuolation and dextran uptake following ATRi, whilst a further study demonstrated reduced invading tumour cells following ATRi in intracranial xenografts. CONCLUSION: We demonstrate a novel role for ATR in facilitating macropinocytic vesicle trafficking and integrin internalisation. ATRi results in a profound motility defect in vitro and in vivo. ATR inhibitors are entering early phase trials as radiation sensitisers and we propose that therapeutic benefit will extend beyond DNA damage potentiation.

scholarly journals Tubulin cofactors and Arl2 are cage-like chaperones that regulate the soluble αβ-tubulin pool for microtubule dynamics

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Stanley Nithianantham ◽  
Sinh Le ◽  
Elbert Seto ◽  
Weitao Jia ◽  
Julie Leary ◽  
...  
Keyword(s):  
Ternary Complex ◽  
Microtubule Dynamics ◽  
Gtp Hydrolysis ◽  
Tubulin Dimer ◽  
Physical Mechanisms ◽  
Biochemical Assays ◽  
Sequential Binding ◽  
Β Tubulin

Microtubule dynamics and polarity stem from the polymerization of αβ-tubulin heterodimers. Five conserved tubulin cofactors/chaperones and the Arl2 GTPase regulate α- and β-tubulin assembly into heterodimers and maintain the soluble tubulin pool in the cytoplasm, but their physical mechanisms are unknown. Here, we reconstitute a core tubulin chaperone consisting of tubulin cofactors TBCD, TBCE, and Arl2, and reveal a cage-like structure for regulating αβ-tubulin. Biochemical assays and electron microscopy structures of multiple intermediates show the sequential binding of αβ-tubulin dimer followed by tubulin cofactor TBCC onto this chaperone, forming a ternary complex in which Arl2 GTP hydrolysis is activated to alter αβ-tubulin conformation. A GTP-state locked Arl2 mutant inhibits ternary complex dissociation in vitro and causes severe defects in microtubule dynamics in vivo. Our studies suggest a revised paradigm for tubulin cofactors and Arl2 functions as a catalytic chaperone that regulates soluble αβ-tubulin assembly and maintenance to support microtubule dynamics.

A quinoline-based probe for effective and selective sensing of aspartic acid in aqueous medium: in vitro and in vivo live cell imaging

2019 ◽  
Vol 6 (11) ◽  
pp. 3237-3244 ◽  
Author(s):  
C. Elamathi ◽  
R. J. Butcher ◽  
A. Mohankumar ◽  
P. Sundararaj ◽  
A. Madankumar ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Aspartic Acid ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Live Cell ◽  
C Elegans ◽  
Highly Sensitive ◽  
Mcf 7

A highly sensitive and selective “on–off–on” chemosensor for aspartic acid in aqueous solution was established. In vitro live cell imaging against MCF 7 cells and in vivo imaging using C. elegans were successfully demonstrated.

FRET based ‘red-switch’ for Al3+ over ESIPT based ‘green-switch’ for Zn2+: dual channel detection with live-cell imaging on a dyad platform

RSC Advances ◽  
2014 ◽  
Vol 4 (65) ◽  
pp. 34572-34576 ◽  
Author(s):  
Shyamaprosad Goswami ◽  
Abhishek Manna ◽  
Sima Paul ◽  
Anup Kumar Maity ◽  
Partha Saha ◽  
...  
Keyword(s):  
Live Cell Imaging ◽  
Cell Imaging ◽  
Live Cell ◽  
Channel Detection ◽  
Dual Channel

Our designed chemosensor, rhodamine-HBT-dyad (RHD), selectively detects two biologically important ions (Al3+ and Zn2+) at two different wavelengths (red and green, respectively) through FRET and ESIPT in vitro and in vivo.

scholarly journals Live-cell imaging with Aspergillus fumigatus-specific fluorescent siderophore conjugates

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Joachim Pfister ◽  
Alexander Lichius ◽  
Dominik Summer ◽  
Hubertus Haas ◽  
Thines Kanagasundaram ◽  
...  
Keyword(s):  
Aspergillus Fumigatus ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Fluorescent Dyes ◽  
Iron Acquisition ◽  
Live Cell ◽  
Subcellular Localisation ◽  
Gallium 68

Abstract Live-cell imaging allows the in vivo analysis of subcellular localisation dynamics of physiological processes with high spatial–temporal resolution. However, only few fluorescent dyes have been custom-designed to facilitate species-specific live-cell imaging approaches in filamentous fungi to date. Therefore, we developed fluorescent dye conjugates based on the sophisticated iron acquisition system of Aspergillus fumigatus by chemical modification of the siderophore triacetylfusarinine C (TAFC). Various fluorophores (FITC, NBD, Ocean Blue, BODIPY 630/650, SiR, TAMRA and Cy5) were conjugated to diacetylfusarinine C (DAFC). Gallium-68 labelling enabled in vitro and in vivo characterisations. LogD, uptake assays and growth assays were performed and complemented by live-cell imaging in different Aspergillus species. Siderophore conjugates were specifically recognised by the TAFC transporter MirB and utilized as an iron source in growth assays. Fluorescence microscopy revealed uptake dynamics and differential subcellular accumulation patterns of all compounds inside fungal hyphae.[Fe]DAFC-NBD and -Ocean Blue accumulated in vacuoles, whereas [Fe]DAFC-BODIPY, -SiR and -Cy5 localised to mitochondria. [Fe]DAFC -FITC showed a uniform cytoplasmic distribution, whereas [Fe]DAFC-TAMRA was not internalised at all. Co-staining experiments with commercially available fluorescent dyes confirmed these findings. Overall, we developed a new class of fluorescent dyes that vary in intracellular fungal targeting , thereby providing novel tools for live-cell imaging applications for Aspergillus fumigatus.

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