scholarly journals The MDM2 Ubiquitination Signal in the DNA-Binding Domain of p53 Forms a Docking Site for Calcium Calmodulin Kinase Superfamily Members

2007 ◽  
Vol 27 (9) ◽  
pp. 3542-3555 ◽  
Author(s):  
Ashley L. Craig ◽  
Jennifer A. Chrystal ◽  
Jennifer A. Fraser ◽  
Nathalie Sphyris ◽  
Yao Lin ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Specific Activity ◽  
Phosphorylation Site ◽  
Fusion Peptide ◽  
Transactivation Domain ◽  
Docking Site ◽  
Calmodulin Kinase ◽  
Green Fluorescent

ABSTRACT Genetic and biochemical studies have shown that Ser20 phosphorylation in the transactivation domain of p53 mediates p300-catalyzed DNA-dependent p53 acetylation and B-cell tumor suppression. However, the protein kinases that mediate this modification are not well defined. A cell-free Ser20 phosphorylation site assay was used to identify a broad range of calcium calmodulin kinase superfamily members, including CHK2, CHK1, DAPK-1, DAPK-3, DRAK-1, and AMPK, as Ser20 kinases. Phosphorylation of a p53 transactivation domain fragment at Ser20 by these enzymes in vitro can be mediated in trans by a docking site peptide derived from the BOX-V domain of p53, which also harbors the ubiquitin signal for MDM2. Evaluation of these calcium calmodulin kinase superfamily members as candidate Ser20 kinases in vivo has shown that only CHK1 or DAPK-1 can stimulate p53 transactivation and induce Ser20 phosphorylation of p53. Using CHK1 as a prototypical in vivo Ser20 kinase, we demonstrate that (i) CHK1 protein depletion using small interfering RNA can attenuate p53 phosphorylation at Ser20, (ii) an enhanced green fluorescent protein (EGFP)-BOX-V fusion peptide can attenuate Ser20 phosphorylation of p53 in vivo, (iii) the EGFP-BOX-V fusion peptide can selectively bind to CHK1 in vivo, and (iv) the Δp53 spliced variant lacking the BOX-V motif is refractory to Ser20 phosphorylation by CHK1. These data indicate that the BOX-V motif of p53 has evolved the capacity to bind to enzymes that mediate either p53 phosphorylation or ubiquitination, thus controlling the specific activity of p53 as a transcription factor.

scholarly journals Pkh1/2-dependent phosphorylation of Vps27 regulates ESCRT-I recruitment to endosomes

2012 ◽  
Vol 23 (20) ◽  
pp. 4054-4064 ◽  
Author(s):  
Joëlle Morvan ◽  
Bruno Rinaldi ◽  
Sylvie Friant
Keyword(s):  
Fluorescent Protein ◽  
Phosphorylation Site ◽  
Temperature Sensitive ◽  
Endosomal Sorting ◽  
Endosomal Membrane ◽  
Surface Receptor ◽  
Escrt Complex ◽  
Green Fluorescent

Multivesicular endosomes (MVBs) are major sorting platforms for membrane proteins and participate in plasma membrane protein turnover, vacuolar/lysosomal hydrolase delivery, and surface receptor signal attenuation. MVBs undergo unconventional inward budding, which results in the formation of intraluminal vesicles (ILVs). MVB cargo sorting and ILV formation are achieved by the concerted function of endosomal sorting complex required for transport (ESCRT)-0 to ESCRT-III. The ESCRT-0 subunit Vps27 is a key player in this pathway since it recruits the other complexes to endosomes. Here we show that the Pkh1/Phk2 kinases, two yeast orthologues of the 3-phosphoinositide–dependent kinase, phosphorylate directly Vps27 in vivo and in vitro. We identify the phosphorylation site as the serine 613 and demonstrate that this phosphorylation is required for proper Vps27 function. Indeed, in pkh-ts temperature-sensitive mutant cells and in cells expressing vps27S613A, MVB sorting of the carboxypeptidase Cps1 and of the α-factor receptor Ste2 is affected and the Vps28–green fluorescent protein ESCRT-I subunit is mainly cytoplasmic. We propose that Vps27 phosphorylation by Pkh1/2 kinases regulates the coordinated cascade of ESCRT complex recruitment at the endosomal membrane.

scholarly journals Development of a Fluorescent Tool for Studying Legionella bozemanae Intracellular Infection

2021 ◽  
Vol 9 (2) ◽  
pp. 379
Author(s):  
Breanne M. Head ◽  
Christopher I. Graham ◽  
Teassa MacMartin ◽  
Yoav Keynan ◽  
Ann Karen C. Brassinga
Keyword(s):  
Growth Kinetics ◽  
Legionella Pneumophila ◽  
Fluorescent Protein ◽  
Disease Incidence ◽  
Acanthamoeba Castellanii ◽  
Infection Model ◽  
Intracellular Infection ◽  
Green Fluorescent

Legionnaires’ disease incidence is on the rise, with the majority of cases attributed to the intracellular pathogen, Legionella pneumophila. Nominally a parasite of protozoa, L. pneumophila can also infect alveolar macrophages when bacteria-laden aerosols enter the lungs of immunocompromised individuals. L. pneumophila pathogenesis has been well characterized; however, little is known about the >25 different Legionella spp. that can cause disease in humans. Here, we report for the first time a study demonstrating the intracellular infection of an L. bozemanae clinical isolate using approaches previously established for L. pneumophila investigations. Specifically, we report on the modification and use of a green fluorescent protein (GFP)-expressing plasmid as a tool to monitor the L. bozemanae presence in the Acanthamoeba castellanii protozoan infection model. As comparative controls, L. pneumophila strains were also transformed with the GFP-expressing plasmid. In vitro and in vivo growth kinetics of the Legionella parental and GFP-expressing strains were conducted followed by confocal microscopy. Results suggest that the metabolic burden imposed by GFP expression did not impact cell viability, as growth kinetics were similar between the GFP-expressing Legionella spp. and their parental strains. This study demonstrates that the use of a GFP-expressing plasmid can serve as a viable approach for investigating Legionella non-pneumophila spp. in real time.

scholarly journals CRISPR/Cas9-based generation of a recombinant double-reporter pseudorabies virus and its characterization in vitro and in vivo

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Peng-Fei Fu ◽  
Xuan Cheng ◽  
Bing-Qian Su ◽  
Li-Fang Duan ◽  
Cong-Rong Wang ◽  
...  
Keyword(s):  
Pseudorabies Virus ◽  
Fluorescent Protein ◽  
Antiviral Agents ◽  
Firefly Luciferase ◽  
Inhibitory Effect ◽  
Economic Losses ◽  
Green Fluorescent ◽  
Swine Herds

AbstractPseudorabies, caused by pseudorabies virus (PRV) variants, has broken out among commercial PRV vaccine-immunized swine herds and resulted in major economic losses to the pig industry in China since late 2011. However, the mechanism of virulence enhancement of variant PRV is currently unclear. Here, a recombinant PRV (rPRV HN1201-EGFP-Luc) with stable expression of enhanced green fluorescent protein (EGFP) and firefly luciferase as a double reporter virus was constructed on the basis of the PRV variant HN1201 through CRISPR/Cas9 gene-editing technology coupled with two sgRNAs. The biological characteristics of the recombinant virus and its lethality to mice were similar to those of the parental strain and displayed a stable viral titre and luciferase activity through 20 passages. Moreover, bioluminescence signals were detected in mice at 12 h after rPRV HN1201-EGFP-Luc infection. Using the double reporter PRV, we also found that 25-hydroxycholesterol had a significant inhibitory effect on PRV both in vivo and in vitro. These results suggested that the double reporter PRV based on PRV variant HN1201 should be an excellent tool for basic virology studies and evaluating antiviral agents.

scholarly journals The Great Capacity on Promoting Melanogenesis of Three Compatible Components in Vernonia anthelmintica (L.) Willd.

2021 ◽  
Vol 22 (8) ◽  
pp. 4073
Author(s):  
Yifan Lai ◽  
Qingyuan Feng ◽  
Rui Zhang ◽  
Jing Shang ◽  
Hui Zhong
Keyword(s):  
Herbal Medicine ◽  
Caffeic Acid ◽  
Fluorescent Protein ◽  
Traditional Chinese Herbal Medicine ◽  
Expression Of Genes ◽  
Proliferation And Differentiation ◽  
Green Fluorescent ◽  
Vernonia Anthelmintica

To investigate a possible methodology of exploiting herbal medicine and design polytherapy for the treatment of skin depigmentation disorder, we have made use of Vernonia anthelmintica (L.) Willd., a traditional Chinese herbal medicine that has been proven to be effective in treating vitiligo. Here, we report that the extract of Vernonia anthelmintica (L.) Willd. effectively enhances melanogenesis responses in B16F10. In its compound library, we found three ingredients (butin, caffeic acid and luteolin) also have the activity of promoting melanogenesis in vivo and in vitro. They can reduce the accumulation of ROS induced by hydrogen peroxide and inflammatory response induced by sublethal concentrations of copper sulfate in wild type and green fluorescent protein (GFP)-labeled leukocytes zebrafish larvae. The overall objective of the present study aims to identify which compatibility proportions of the medicines may be more effective in promoting pigmentation. We utilized the D-optimal response surface methodology to optimize the ratio among three molecules. Combining three indicators of promoting melanogenesis, anti-inflammatory and antioxidant capacities, we get the best effect of butin, caffeic acid and luteolin at the ratio (butin:caffeic acid:luteolin = 7.38:28.30:64.32) on zebrafish. Moreover, the effect of melanin content recovery in the best combination is stronger than that of the monomer, which suggests that the three compounds have a synergistic effect on inducing melanogenesis. After simply verifying the result, we performed in situ hybridization on whole-mount zebrafish embryos to further explore the effects of multi-drugs combination on the proliferation and differentiation of melanocytes and the expression of genes (tyr, mitfa, dct, kit) related to melanin synthesis. In conclusion, the above three compatible compounds can significantly enhance melanogenesis and improve depigmentation in vivo.

scholarly journals Human Keratinocytes Adopt Neuronal Fates After In Utero Transplantation in the Developing Rat Brain

2021 ◽  
Vol 30 ◽  
pp. 096368972097821
Author(s):  
Andrea Tenorio-Mina ◽  
Daniel Cortés ◽  
Joel Esquivel-Estudillo ◽  
Adolfo López-Ornelas ◽  
Alejandro Cabrera-Wrooman ◽  
...  
Keyword(s):  
Green Fluorescent Protein ◽  
Fluorescent Protein ◽  
Ectopic Expression ◽  
Neural Induction ◽  
Human Keratinocytes ◽  
Differentiation Potential ◽  
Neuronal Proteins ◽  
Green Fluorescent

Human skin contains keratinocytes in the epidermis. Such cells share their ectodermal origin with the central nervous system (CNS). Recent studies have demonstrated that terminally differentiated somatic cells can adopt a pluripotent state, or can directly convert its phenotype to neurons, after ectopic expression of transcription factors. In this article we tested the hypothesis that human keratinocytes can adopt neural fates after culturing them in suspension with a neural medium. Initially, keratinocytes expressed Keratins and Vimentin. After neural induction, transcriptional upregulation of NESTIN, SOX2, VIMENTIN, SOX1, and MUSASHI1 was observed, concomitant with significant increases in NESTIN detected by immunostaining. However, in vitro differentiation did not yield the expression of neuronal or astrocytic markers. We tested the differentiation potential of control and neural-induced keratinocytes by grafting them in the developing CNS of rats, through ultrasound-guided injection. For this purpose, keratinocytes were transduced with lentivirus that contained the coding sequence of green fluorescent protein. Cell sorting was employed to select cells with high fluorescence. Unexpectedly, 4 days after grafting these cells in the ventricles, both control and neural-induced cells expressed green fluorescent protein together with the neuronal proteins βIII-Tubulin and Microtubule-Associated Protein 2. These results support the notion that in vivo environment provides appropriate signals to evaluate the neuronal differentiation potential of keratinocytes or other non-neural cell populations.

Atelocollagen Sponge as a Stem Cell Implantation Scaffold for the Treatment of Scarred Vocal Folds

2010 ◽  
Vol 119 (11) ◽  
pp. 805-810 ◽  
Author(s):  
Satoshi Ohno ◽  
Shigeru Hirano ◽  
Ichiro Tateya ◽  
Shin-Ichi Kanemaru ◽  
Hiroo Umeda ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Stromal Cells ◽  
Fluorescent Protein ◽  
In Vitro Study ◽  
Vocal Folds ◽  
Green Fluorescent ◽  
Cell Implantation

Objectives: Treatment of vocal fold scarring remains a therapeutic challenge. Our group previously reported the efficacy of treating injured vocal folds by implantation of bone marrow—derived stromal cells containing mesenchymal stem cells. Appropriate scaffolding is necessary for the stem cell implant to achieve optimal results. Terudermis is an atelocollagen sponge derived from calf dermis. It has large pores that permit cellular entry and is degraded in vivo. These characteristics suggest that this material may be a good candidate for use as scaffolding for implantation of cells. The present in vitro study investigated the feasibility of using Terudermis as such a scaffold. Methods: Bone marrow—derived stromal cells were obtained from GFP (green fluorescent protein) mouse femurs. The cells were seeded into Terudermis and incubated for 5 days. Their survival, proliferation, and expression of extracellular matrix were examined. Results: Bone marrow—derived stromal cells adhered to Terudermis and underwent significant proliferation. Immunohistochemical examination demonstrated that adherent cells were positive for expression of vimentin, desmin, fibronectin, and fsp1 and negative for beta III tubulin. These findings indicate that these cells were mesodermal cells and attached to the atelocollagen fibers biologically. Conclusions: The data suggest that Terudermis may have potential as stem cell implantation scaffolding for the treatment of scarred vocal folds.

In vitro and in vivo evaluation of a green fluorescent protein-HSV1-TK dual-function pet reporter gene

2001 ◽  
Vol 44 (S1) ◽  
pp. S339-S341
Author(s):  
K. E. Luker ◽  
G. D. Luker ◽  
C. M. Pica ◽  
J. L. Dahlheimer ◽  
T. J. Fahrner ◽  
...  
Keyword(s):  
Green Fluorescent Protein ◽  
Reporter Gene ◽  
Fluorescent Protein ◽  
Dual Function ◽  
In Vivo Evaluation ◽  
Green Fluorescent

Bax-inhibiting peptides derived from Ku70 and cell-penetrating pentapeptides

2007 ◽  
Vol 35 (4) ◽  
pp. 797-801 ◽  
Author(s):  
J.A. Gomez ◽  
V. Gama ◽  
T. Yoshida ◽  
W. Sun ◽  
P. Hayes ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Protein A ◽  
Cellular Damage ◽  
Toxic Drug ◽  
Cell Penetrating ◽  
Low Toxicity ◽  
Repair Factor ◽  
Green Fluorescent

We found that Ku70, a known DNA repair factor, has a novel function to bind and inhibit Bax (Bcl-2-associated X protein), a key mediator of apoptosis. Pentapeptides derived from the Bax-binding domain of Ku70 were cell-permeable and protected cells from Bax-mediated apoptosis. These pentapeptides were called BIPs (Bax-inhibiting peptides). BIPs may become a useful therapeutic tool to reduce cellular damage. We also generated BIP mutant pentapeptides that do not inhibit Bax, but retain their cell-penetrating activity. Since both BIPs and BIP mutants are cell-permeable, these peptides were designated CPP5s (cell-penetrating pentapeptides). Among the CPP5s discovered, VPTLK (BIP) and KLPVM (BIP mutant) were confirmed to possess protein transduction activity by examination of the delivery of GFP (green fluorescent protein) into cells by these peptides. The mechanism of cell penetration by CPP5s is not known. CPP5s enter the cell at 0 and 4°C. In preliminary studies, various inhibitors of endocytosis and pinocytosis did not show any significant suppression of CPP5 cell entry. CPP5s have very low toxicity in vitro and in vivo and so may be useful tools in order to develop non-toxic drug-delivery technologies.

scholarly journals Targeting Mucosal Sites by Polymeric Immunoglobulin Receptor-directed Peptides

2002 ◽  
Vol 196 (4) ◽  
pp. 551-555 ◽  
Author(s):  
Kendra D. White ◽  
J. Donald Capra
Keyword(s):  
Epithelial Cells ◽  
Fluorescent Protein ◽  
Secretory Component ◽  
In Vivo Studies ◽  
Polymeric Immunoglobulin Receptor ◽  
Immunoglobulin Receptor ◽  
Potential Binding Site ◽  
Green Fluorescent

Polymeric immunoglobulins provide first line humoral defense at mucosal surfaces to which they are specifically transported by the polymeric immunoglobulin receptor (pIgR) on mucosal and glandular epithelial cells. Previous studies from our laboratory suggested that amino acids 402–410 of the Cα3 domain of dimeric IgA (dIgA) represented a potential binding site for the pIgR. Here by binding human secretory component to overlapping decapeptides of Cα3, we confirm these residues and also uncover an additional site. Furthermore, we show that the Cα3 motif appears to be sufficient to direct transport of green fluorescent protein through the pIgR-specific cellular transcytosis system. An alternative approach identified phage peptides, selected from a library by the in vitro Madin Darby Canine Kidney transcytosis assay, for pIgR-mediated transport through epithelial cells. Some transcytosis-selected peptides map to the same 402–410 pIgR-binding Cα3 site. Further in vivo studies document that at least one of these peptides is transported in a rat model measuring hepatic bile transport. In addition to identifying small peptides that are both bound and transported by the pIgR, this study provides evidence that the pIgR-mediated mucosal secretion system may represent a means of targeting small molecule therapeutics and genes to mucosal epithelial cells.

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