In situ dynamically monitoring the proteolytic function of the ubiquitin-proteasome system in cultured cardiac myocytes

2004 ◽  
Vol 287 (3) ◽  
pp. H1417-H1425 ◽  
Author(s):  
Xin Dong ◽  
Jinbao Liu ◽  
Hanqiao Zheng ◽  
Joseph W. Glasford ◽  
Wei Huang ◽  
...  
Keyword(s):  
Green Fluorescent Protein ◽  
Cardiac Myocytes ◽  
Fluorescent Protein ◽  
Proteasome Inhibition ◽  
Ubiquitin Proteasome System ◽  
Great Promise ◽  
Dynamic Changes ◽  
Ubiquitin Proteasome ◽  
Green Fluorescent

The ubiquitin-proteasome system (UPS) is responsible for turnover of most cellular proteins in eukaryotes. Protein degradation by the UPS serves quality control and regulatory functions. Proteasome inhibition showed great promise in effectively treating cancer and restenosis. UPS dysfunction in cardiac hypertrophy and failure has recently been suspected but remains to be investigated. A system capable of monitoring dynamic changes in proteolytic function of the UPS in cardiac myocytes in situ would no doubt benefit significantly efforts to decipher the pathogenic significance of UPS dysfunction in the heart and to evaluate the effect of proteasome inhibition on cardiac myocytes. We successfully established such a system in cultured cardiac myocytes by delivering and expressing a modified green fluorescence protein (GFPu) gene using recombinant adenoviruses. GFPu contains a ubiquitination signal sequence fused to the COOH terminus. Fluorescence microscopy and Western blots revealed that protein abundance of modified green fluorescent protein (GFPu), but not wild-type green fluorescent protein, in cultured cardiac myocytes was incrementally increased when function of the proteasomes was inhibited in various degrees by specific inhibitors. The increase in GFPu protein levels and fluorescence intensity is paralleled by a decrease in the in vitro peptidase activity of the proteasomes. Our results demonstrate that GFPu can be used as a surrogate marker to monitor dynamic changes in proteolytic function of the UPS in cardiac myocytes in situ. Application of this novel system reveals that moderate levels of H2O2, a reactive oxygen species generator, impair proteolytic function of the UPS in cultured cardiac myocytes.

scholarly journals Fate of Salmonella Typhimurium in laboratory-scale drinking water biofilms

2013 ◽  
Vol 11 (4) ◽  
pp. 629-635 ◽  
Author(s):  
L. M. Schaefer ◽  
V. S. Brözel ◽  
S. N. Venter
Keyword(s):  
Drinking Water ◽  
Green Fluorescent Protein ◽  
Health Risk ◽  
Salmonella Typhimurium ◽  
Fluorescent Protein ◽  
Laboratory Scale ◽  
Green Fluorescent ◽  
In Situ Detection

Investigations were carried out to evaluate and quantify colonization of laboratory-scale drinking water biofilms by a chromosomally green fluorescent protein (gfp)-tagged strain of Salmonella Typhimurium. Gfp encodes the green fluorescent protein and thus allows in situ detection of undisturbed cells and is ideally suited for monitoring Salmonella in biofilms. The fate and persistence of non-typhoidal Salmonella in simulated drinking water biofilms was investigated. The ability of Salmonella to form biofilms in monoculture and the fate and persistence of Salmonella in a mixed aquatic biofilm was examined. In monoculture S. Typhimurium formed loosely structured biofilms. Salmonella colonized established multi-species drinking water biofilms within 24 hours, forming micro-colonies within the biofilm. S. Typhimurium was also released at high levels from the drinking water-associated biofilm into the water passing through the system. This indicated that Salmonella could enter into, survive and grow within, and be released from a drinking water biofilm. The ability of Salmonella to survive and persist in a drinking water biofilm, and be released at high levels into the flow for recolonization elsewhere, indicates the potential for a persistent health risk to consumers once a network becomes contaminated with this bacterium.

The Green Fluorescent Protein is an Efficient Biological Marker for Cardiac Myocytes

1999 ◽  
Vol 31 (12) ◽  
pp. 2155-2165 ◽  
Author(s):  
Meiwei Xian ◽  
Norman Honbo ◽  
Jianqing Zhang ◽  
Choong- Chin Liew ◽  
Joel S Karliner ◽  
...  
Keyword(s):  
Green Fluorescent Protein ◽  
Cardiac Myocytes ◽  
Fluorescent Protein ◽  
Biological Marker ◽  
Green Fluorescent

scholarly journals Complexes between Herpes Simplex Virus Glycoproteins gD, gB, and gH Detected in Cells by Complementation of Split Enhanced Green Fluorescent Protein

2007 ◽  
Vol 81 (20) ◽  
pp. 11532-11537 ◽  
Author(s):  
Elisa Avitabile ◽  
Cristina Forghieri ◽  
Gabriella Campadelli-Fiume
Keyword(s):  
Herpes Simplex Virus ◽  
Green Fluorescent Protein ◽  
Herpes Simplex ◽  
Enhanced Green Fluorescent Protein ◽  
Fluorescent Protein ◽  
Split Egfp ◽  
Green Fluorescent ◽  
Simplex Virus ◽  
In Cells

ABSTRACT The interactions between herpes simplex virus gD and its nectin1 receptor or between gD, gB, and gH were analyzed by complementation of the N and C portions of split enhanced green fluorescent protein (EGFP) fused to the glycoproteins. The gDN-NectC complex was readily detected; the gDN-gCC complex was undetectable, highlighting the specificity of the assay. Split EGFP complementation was detected between proteins designated gDN+gHC, gDN+gBC, and gHN+gBC+wtgD (gB was deleted of endocytosis motifs), both in cells transfected with two-tree glycoproteins and in syncytia. The in situ assay provides evidence that gD interacts with gH and gB independently of each other and supports a model whereby gH and gB in complex exert their activities to gD.

scholarly journals Conditional Transgenic System for Mouse Aurora A Kinase: Degradation by the Ubiquitin Proteasome Pathway Controls the Level of the Transgenic Protein

2005 ◽  
Vol 25 (12) ◽  
pp. 5270-5281 ◽  
Author(s):  
Tomokazu Fukuda ◽  
Yuji Mishina ◽  
Michael P. Walker ◽  
Richard P. DiAugustine
Keyword(s):  
Cell Cycle ◽  
Green Fluorescent Protein ◽  
Enhanced Green Fluorescent Protein ◽  
Fluorescent Protein ◽  
Aurora A ◽  
Mitotic Kinase ◽  
Mitotic Stage ◽  
Conditional Expression ◽  
Ubiquitin Proteasome ◽  
Green Fluorescent

ABSTRACT Aurora A is a mitotic kinase that localizes to centrosomes. Expression of this protein is normally limited to the mitotic stage (G2-M) of the cell cycle, whereas human cancer cells frequently exhibit overexpression of Aurora A protein regardless of the cell cycle stage. In the present study, Aurora A transgenic mouse lines were generated with a new conditional expression system (cytomegalovirus immediate early enhancer-chicken beta-actin hybrid promoter-Z-enhanced green fluorescent protein) in order to analyze the function of this protein. Although transcripts for Aurora A were elevated in multiple organs of the transgenic mice, the corresponding protein was not detected in extracts analyzed by immunoblotting. The treatment of transgenic-derived embryonic fibroblasts (MEF) with proteasome inhibitors markedly increased the protein level of transgenic Aurora A, indicating that the transgenic Aurora A protein is readily degraded in normal mouse tissues. Under the exponential growth conditions of MEF cells, transgenic Aurora A was detected within the mitotic stage of the cell cycle and localized to centrosomes. In contrast, the marker of the transgenic promoter (enhanced green fluorescent protein) was continuously expressed throughout the cell cycle, indicating the constitutive transcription of transgenic mRNA. These results indicate that transgenic Aurora A is protected from degradation within G2-M but is immediately degraded after translation in the G1-S stage of the cell cycle. The findings obtained with this transgenic model and derived cells support that the transition from protection to degradation by the ubiquitin proteasome system at the end of mitosis is an important step in controlling the level of Aurora A protein during the cell cycle.

scholarly journals Green Fluorescent Protein in the sea urchin: new experimental approaches to transcriptional regulatory analysis in embryos and larvae

Development ◽  
1997 ◽  
Vol 124 (22) ◽  
pp. 4649-4659 ◽  
Author(s):  
M.I. Arnone ◽  
L.D. Bogarad ◽  
A. Collazo ◽  
C.V. Kirchhamer ◽  
R.A. Cameron ◽  
...  
Keyword(s):  
Green Fluorescent Protein ◽  
Sea Urchin ◽  
Fluorescent Protein ◽  
Regulatory Systems ◽  
Transcriptional Regulatory ◽  
Experimental Approaches ◽  
Regulatory Analysis ◽  
Green Fluorescent ◽  
First Time

The use of Green Fluorescent Protein (GFP) as a reporter for expression transgenes opens the way to several new experimental strategies for the study of gene regulation in sea urchin development. A GFP coding sequence was associated with three different previously studied cis-regulatory systems, viz those of the SM50 gene, expressed in skeletogenic mesenchyme, the CyIIa gene, expressed in archenteron, skeletogenic and secondary mesenchyme, and the Endo16 gene, expressed in vegetal plate, archenteron and midgut. We demonstrate that the sensitivity with which expression can be detected is equal to or greater than that of whole-mount in situ hybridization applied to detection of CAT mRNA synthesized under the control of the same cis-regulatory systems. However, in addition to the important feature that it can be visualized nondestructively in living embryos, GFP has other advantages. First, it freely diffuses even within fine cytoplasmic cables, and thus reveals connections between cells, which in sea urchin embryos is particularly useful for observations on regulatory systems that operate in the syncytial skeletogenic mesenchyme. Second, GFP expression can be dramatically visualized in postembryonic larval tissues. This brings postembryonic larval developmental processes for the first time within the easy range of gene transfer analyses. Third, GFP permits identification and segregation of embryos in which the clonal incorporation of injected DNA has occurred in any particular desired region of the embryo. Thus, we show explicitly that, as expected, GFP transgenes are incorporated in the same nuclei together with other transgenes with which they are co-injected.

scholarly journals Mode of Targeting to the Proteasome Determines GFP Fate

2020 ◽  
Author(s):  
Christopher E. Bragança ◽  
Daniel A. Kraut
Keyword(s):  
Fluorescent Protein ◽  
Ubiquitin Proteasome System ◽  
Eukaryotic Cells ◽  
Polyubiquitin Chains ◽  
Ubiquitin Proteasome ◽  
Targeting Signal ◽  
Green Fluorescent ◽  
Ubiquitin Receptors ◽  
Multiple Variants ◽  
Domain Stability

ABSTRACTThe Ubiquitin-proteasome system (UPS) is the canonical pathway for protein degradation in eukaryotic cells. Green fluorescent protein (GFP) is frequently used as a reporter in proteasomal degradation assays. However, there are multiple variants of GFP in use, and these variants have different stabilities. We previously found that the proteasome’s ability to unfold and degrade substrates is enhanced by polyubiquitin chains on the substrate, and that proteasomal ubiquitin receptors mediate this activation. Herein we investigate how the fate of GFP variants of differing stabilities is determined by the mode of targeting to the proteasome. We compared two targeting systems: linear Ub4 degrons and the UBL domain from yeast Rad23, both of which are commonly used in degradation experiments. Surprisingly, the UBL degron allows for degradation of the most stable sGFP-containing substrates, while the Ub4 degron does not. Destabilizing the GFP by circular permutation allows degradation with either targeting signal, indicating that domain stability and mode of targeting combine to determine substrate fate. Finally, we show that the ubiquitin receptor Rpn13 is primarily responsible for the enhanced ability of the proteasome to degrade stable UBL-tagged substrates.

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