scholarly journals ARF‐AID: A Rapidly Inducible Protein Degradation System That Preserves Basal Endogenous Protein Levels

2020 ◽  
Vol 132 (1) ◽  
Author(s):  
Kizhakke Mattada Sathyan ◽  
Thomas G. Scott ◽  
Michael J. Guertin
Keyword(s):  
Protein Degradation ◽  
Protein Levels ◽  
Endogenous Protein ◽  
Inducible Protein

PHOTACs Enable Optical Control of Protein Degradation

2019 ◽  
Author(s):  
Martin Reynders ◽  
Bryan Matsuura ◽  
Marleen Bérouti ◽  
Daniele Simoneschi ◽  
Antonio Marzio ◽  
...  
Keyword(s):  
Protein Degradation ◽  
E3 Ligase ◽  
Optical Control ◽  
Cellular Proteins ◽  
Bifunctional Molecules ◽  
Protein Levels ◽  
Lead Compounds ◽  
Subsequent Degradation ◽  
Temporal And Spatial ◽  
Precision Therapeutics

<p><i>PROTACs (proteolysis targeting chimeras) are bifunctional molecules that tag proteins for ubiquitylation by an E3 ligase complex and subsequent degradation by the proteasome. They have emerged as powerful tools to control the levels of specific cellular proteins and are on the verge of being clinically used. We now introduce photoswitchable PROTACs that can be activated with the temporal and spatial precision that light provides. These trifunctional molecules, which we named PHOTACs, consist of a ligand for an E3 ligase, a photoswitch, and a ligand for a protein of interest. We demonstrate this concept by using PHOTACs that target either BET family proteins (BRD2,3,4) or FKBP12. Our lead compounds display little or no activity in the dark but can be reversibly activated to varying degrees with different wavelengths of light. Our modular and generalizable approach provides a method for the optical control of protein levels with photopharmacology and could lead to new types of precision therapeutics that avoid undesired systemic toxicity.</i><b></b></p>

scholarly journals Identification of Keratin 23 as a Hepatitis C Virus-Induced Host Factor in the Human Liver

Cells ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 610 ◽  
Author(s):  
Volker Kinast ◽  
Stefan L. Leber ◽  
Richard J. P. Brown ◽  
Gabrielle Vieyres ◽  
Patrick Behrendt ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Liver Disease ◽  
Hepatitis C ◽  
Ectopic Expression ◽  
Host Factor ◽  
Hcv Infection ◽  
Mrna Levels ◽  
Structural Support ◽  
Protein Levels ◽  
Inducible Protein

Keratin proteins form intermediate filaments, which provide structural support for many tissues. Multiple keratin family members are reported to be associated with the progression of liver disease of multiple etiologies. For example, keratin 23 (KRT23) was reported as a stress-inducible protein, whose expression levels correlate with the severity of liver disease. Hepatitis C virus (HCV) is a human pathogen that causes chronic liver diseases including fibrosis, cirrhosis, and hepatocellular carcinoma. However, a link between KRT23 and hepatitis C virus (HCV) infection has not been reported previously. In this study, we investigated KRT23 mRNA levels in datasets from liver biopsies of chronic hepatitis C (CHC) patients and in primary human hepatocytes experimentally infected with HCV, in addition to hepatoma cells. Interestingly, in each of these specimens, we observed an HCV-dependent increase of mRNA levels. Importantly, the KRT23 protein levels in patient plasma decreased upon viral clearance. Ectopic expression of KRT23 enhanced HCV infection; however, CRIPSPR/Cas9-mediated knockout did not show altered replication efficiency. Taken together, our study identifies KRT23 as a novel, virus-induced host-factor for hepatitis C virus.

BRCA1 modulates sensitivity to 5F-203 by regulating xenobiotic stress-inducible protein levels and EROD activity

2007 ◽  
Vol 62 (4) ◽  
pp. 689-697 ◽  
Author(s):  
Hyo Jin Kang ◽  
Hee Jeong Kim ◽  
Sang Hoon Kwon ◽  
Brian DongHoon Kang ◽  
Thomas E. Eling ◽  
...  
Keyword(s):  
Erod Activity ◽  
Xenobiotic Stress ◽  
Protein Levels ◽  
Inducible Protein

Abstract WP265: Interferon-inducible Protein 10 Increases following Stroke

Stroke ◽  
2013 ◽  
Vol 44 (suppl_1) ◽  
Author(s):  
Hilary A Seifert ◽  
Lisa A Collier ◽  
Stanley A Benkovic ◽  
Alison E Willing ◽  
Keith R Pennypacker
Keyword(s):  
Time Course ◽  
Neutralizing Antibody ◽  
Artery Occlusion ◽  
T Helper ◽  
Protein Levels ◽  
Organ Systems ◽  
Inducible Protein ◽  
Cerebral Artery Occlusion ◽  
The Brain ◽  
Interferon Inducible Protein

Objective: The splenic response to injury furthers cellular degeneration as its removal is protective in ischemic injuries to several organ systems including the brain. Previously, we have shown that the proinflammatory cytokine interferon gamma (IFNg), which activates microglia/macrophages, is elevated in the spleen and the brain following permanent middle cerebral artery occlusion (MCAO). IFNg induces the production of interferon-inducible protein 10 (IP-10) which further propagates the inflammatory response. Therefore, we investigated the expression of IP-10 in the brain and spleen following ischemic stroke. Hypothesis: IFNg production in the brain and the spleen results in elevated levels of IP-10 in the same tissues post-MCAO. Methods: A time course was conducted to investigate splenic and brain protein levels of IP-10 in rats over time following MCAO and sham-MCAO (n≥3). In a second experiment, rats were administered an IFNg neutralizing antibody following MCAO with a survival time of 96 h: vehicle control (n=4), goat IgG 5μg (n=7), and IFNg antibody 5μg (n=7). Spleens and brains were collected for all groups. Results: IP-10 levels were significantly elevated in the brain at 72 and 96 h post-MCAO (p<0.01) compared to naïve brains. In the spleen IP-10 levels become significantly elevated at 24 h and remain elevated out to 96 h post-MCAO (p<0.0007) compared to naïve spleens. Administration of a neutralizing antibody directed against IFNg significantly decreased IP-10 levels in the brain (p<0.009) but did not affect IP-10 levels in the spleen. Conclusion: These results demonstrate that increased production of IFNg results in elevated levels of IP-10 in both the spleen and the brain following stroke. However, administration of a neutralizing antibody against IFNg decreased the amount of IP-10 in the brain. Levels of IFNg and IP-10 in the brain increase at the same time following stroke. Based on these data, IFNg propagates a proinflammatory T helper cell response to stroke through IP-10. Inhibition of this signaling could reduce neuroinflammation thereby improving stroke outcome.

scholarly journals MAP1B Interaction with the FW Domain of the Autophagic Receptor Nbr1 Facilitates Its Association to the Microtubule Network

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Katie Marchbank ◽  
Sarah Waters ◽  
Roland G. Roberts ◽  
Ellen Solomon ◽  
Caroline A. Whitehouse
Keyword(s):  
Protein Degradation ◽  
Microtubule Network ◽  
Protein Levels ◽  
Ubiquitinated Proteins ◽  
Autophagy Induction ◽  
Evolutionarily Conserved ◽  
Cargo Proteins ◽  
Autophagic Degradation ◽  
Membrane Bound ◽  
Lysosomal Acidification

Selective autophagy is a process whereby specific targeted cargo proteins, aggregates, or organelles are sequestered into double-membrane-bound phagophores before fusion with the lysosome for protein degradation. It has been demonstrated that the microtubule network is important for the formation and movement of autophagosomes. Nbr1 is a selective cargo receptor that through its interaction with LC3 recruits ubiquitinated proteins for autophagic degradation. This study demonstrates an interaction between the evolutionarily conserved FW domain of Nbr1 with the microtubule-associated protein MAP1B. Upon autophagy induction, MAP1B localisation is focused into discrete vesicles with Nbr1. This colocalisation is dependent upon an intact microtubule network as depolymerisation by nocodazole treatment abolishes starvation-induced MAP1B recruitment to these vesicles. MAP1B is not recruited to autophagosomes for protein degradation as blockage of lysosomal acidification does not result in significant increased MAP1B protein levels. However, the protein levels of phosphorylated MAP1B are significantly increased upon blockage of autophagic degradation. This is the first evidence that links the ubiquitin receptor Nbr1, which shuttles ubiquitinated proteins to be degraded by autophagy, to the microtubule network.

Potassium channel KCNJ15 is required for histamine-stimulated gastric acid secretion

2015 ◽  
Vol 309 (4) ◽  
pp. C264-C270 ◽  
Author(s):  
Jianye Yuan ◽  
Wensheng Liu ◽  
Serhan Karvar ◽  
Susan S. Baker ◽  
Wenjun He ◽  
...  
Keyword(s):  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Apical Membrane ◽  
Imaging System ◽  
Parietal Cells ◽  
Live Cells ◽  
Protein Levels ◽  
Endogenous Protein ◽  
Luminal Side

Gastric acid secretion is mediated by the K+-dependent proton pump (H+,K+-ATPase), which requires a continuous supply of K+ at the luminal side of the apical membrane. Several K+ channels are implicated in gastric acid secretion. However, the identity of the K+ channel(s) responsible for apical K+ supply is still elusive. Our previous studies have shown the translocation of KCNJ15 from cytoplasmic vesicles to the apical membrane on stimulation, indicating its involvement in gastric acid secretion. In this study, the stimulation associated trafficking of KCNJ15 was observed in a more native context with a live cell imaging system. KCNJ15 molecules in resting live cells were scattered in cytoplasm but exhibited apical localization after stimulation. Furthermore, knocking down KCNJ15 expression with a short hairpin RNA adenoviral construct abolished histamine-stimulated acid secretion in rabbit primary parietal cells. Moreover, KCNJ15, like H+,K+-ATPase, was detected in all of the parietal cells by immunofluorescence staining, whereas only about half of the parietal cells were positive for KCNQ1 under the same condition. Consistently, the endogenous protein levels of KCNJ15, analyzed by Western blotting, were higher than those of KCNQ1 in the gastric mucosa of human, mouse, and rabbit. These results provide evidence for a major role of KCNJ15 in apical K+ supply during stimulated acid secretion.

Influence of NH4CI on Polarized Release of Endogenous Protein Degradation Products and on Morphology in LLC-PK1 Cells

2000 ◽  
Vol 20 (1) ◽  
pp. 74-81 ◽  
Author(s):  
Eva Wardelmann ◽  
Hong Ling ◽  
Inge Heim ◽  
Harald Schlebusch ◽  
August Heidland ◽  
...  
Keyword(s):  
Protein Degradation ◽  
Degradation Products ◽  
Endogenous Protein
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