Hydrogen peroxide stimulates ubiquitin-conjugating activity and expression of genes for specific E2 and E3 proteins in skeletal muscle myotubes

2003 ◽  
Vol 285 (4) ◽  
pp. C806-C812 ◽  
Author(s):  
Yi-Ping Li ◽  
Yuling Chen ◽  
Andrew S. Li ◽  
Michael B. Reid

Reactive oxygen species (ROS) are thought to promote muscle atrophy in chronic wasting diseases, but the underlying mechanism has not been determined. Here we show that H2O2 stimulates ubiquitin conjugation to muscle proteins through transcriptional regulation of the enzymes (E2 and E3 proteins) that conjugate ubiquitin to muscle proteins. Incubation of C2C12 myotubes with 100 μM H2O2 increased the rate of 125I-labeled ubiquitin conjugation to muscle proteins in whole cell extracts. This response required at least 4-h exposure to H2O2 and persisted for at least 24 h. Preincubating myotubes with cycloheximide or actinomycin D blocked H2O2 stimulation of ubiquitin-conjugating activity, suggesting that gene transcription is required. Northern blot analyses revealed that H2O2 upregulates expression of specific E3 and E2 proteins that are thought to regulate muscle catabolism, including atrogin1/MAFbx, MuRF1, and E214k. These results suggest that ROS stimulate protein catabolism in skeletal muscle by upregulating the ubiquitin conjugation system.

1974 ◽  
Vol 77 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Gustav Wägar

ABSTRACT Whether the short-term regulation of thyroidal protein synthesis by TSH occurs at the transcriptional or the translational level was tested by measuring the effect of actinomycin D (act D) on the TSH-induced stimulation of L-14C-leucine incorporation into the thyroidal proteins of rats. TSH was injected 6 h before the rats were killed. The thyroid glands were then removed and incubated in vitro in the presence of L-14C-leucine for 2 h. The pronounced stimulation of leucine incorporation in the TSH-treated animals was depressed as compared with controls but still significant even when the animals had been pre-treated with 100 μg act D 24 and 7 h before sacrifice. On the other hand, act D strongly decreased incorporation of 3H-uridine into RNA. Short-term regulation of thyroidal protein synthesis by TSH appears to be partly but not wholly dependent on neosynthesis of RNA. Hence regulation may partly occur at the translation level of protein synthesis.


Author(s):  
Ryan M Patrick ◽  
Xing-Qi Huang ◽  
Natalia Dudareva ◽  
Ying Li

Abstract Biosynthesis of secondary metabolites relies on primary metabolic pathways to provide precursors, energy, and cofactors, thus requiring coordinated regulation of primary and secondary metabolic networks. However, to date, it remains largely unknown how this coordination is achieved. Using Petunia hybrida flowers, which emit high levels of phenylpropanoid/benzenoid volatile organic compounds (VOCs), we uncovered genome-wide dynamic deposition of histone H3 lysine 9 acetylation (H3K9ac) during anthesis as an underlying mechanism to coordinate primary and secondary metabolic networks. The observed epigenome reprogramming is accompanied by transcriptional activation at gene loci involved in primary metabolic pathways that provide precursor phenylalanine, as well as secondary metabolic pathways to produce volatile compounds. We also observed transcriptional repression among genes involved in alternative phenylpropanoid branches that compete for metabolic precursors. We show that GNAT family histone acetyltransferase(s) (HATs) are required for the expression of genes involved in VOC biosynthesis and emission, by using chemical inhibitors of HATs, and by knocking down a specific HAT gene, ELP3, through transient RNAi. Together, our study supports that regulatory mechanisms at chromatin level may play an essential role in activating primary and secondary metabolic pathways to regulate VOC synthesis in petunia flowers.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Hu Liu ◽  
Yufei Li ◽  
Ke Ge ◽  
Binghai Du ◽  
Kai Liu ◽  
...  

Abstract Background Paenibacillus polymyxa SC2, a bacterium isolated from the rhizosphere soil of pepper (Capsicum annuum L.), promotes growth and biocontrol of pepper. However, the mechanisms of interaction between P. polymyxa SC2 and pepper have not yet been elucidated. This study aimed to investigate the interactional relationship of P. polymyxa SC2 and pepper using transcriptomics. Results P. polymyxa SC2 promotes growth of pepper stems and leaves in pot experiments in the greenhouse. Under interaction conditions, peppers stimulate the expression of genes related to quorum sensing, chemotaxis, and biofilm formation in P. polymyxa SC2. Peppers induced the expression of polymyxin and fusaricidin biosynthesis genes in P. polymyxa SC2, and these genes were up-regulated 2.93- to 6.13-fold and 2.77- to 7.88-fold, respectively. Under the stimulation of medium which has been used to culture pepper, the bacteriostatic diameter of P. polymyxa SC2 against Xanthomonas citri increased significantly. Concurrently, under the stimulation of P. polymyxa SC2, expression of transcription factor genes WRKY2 and WRKY40 in pepper was up-regulated 1.17-fold and 3.5-fold, respectively. Conclusions Through the interaction with pepper, the ability of P. polymyxa SC2 to inhibit pathogens was enhanced. P. polymyxa SC2 also induces systemic resistance in pepper by stimulating expression of corresponding transcription regulators. Furthermore, pepper has effects on chemotaxis and biofilm formation of P. polymyxa SC2. This study provides a basis for studying interactional mechanisms of P. polymyxa SC2 and pepper.


Function ◽  
2021 ◽  
Author(s):  
Leslie M Baehr ◽  
David C Hughes ◽  
Sarah A Lynch ◽  
Delphi Van Haver ◽  
Teresa Mendes Maia ◽  
...  

Abstract MuRF1 (TRIM63) is a muscle-specific E3 ubiquitin ligase and component of the ubiquitin proteasome system. MuRF1 is transcriptionally upregulated under conditions that cause muscle loss, in both rodents and humans, and is a recognized marker of muscle atrophy. In this study, we used in vivo electroporation to determine if MuRF1 overexpression alone can cause muscle atrophy and, in combination with ubiquitin proteomics, identify the endogenous MuRF1 substrates in skeletal muscle. Overexpression of MuRF1 in adult mice increases ubiquitination of myofibrillar and sarcoplasmic proteins, increases expression of genes associated with neuromuscular junction instability, and causes muscle atrophy. A total of 169 ubiquitination sites on 56 proteins were found to be regulated by MuRF1. MuRF1-mediated ubiquitination targeted both thick and thin filament contractile proteins, as well as, glycolytic enzymes, deubiquitinases, p62, and VCP. These data reveal a potential role for MuRF1 in not only the breakdown of the sarcomere, but also the regulation of metabolism and other proteolytic pathways in skeletal muscle.


1973 ◽  
Vol 134 (4) ◽  
pp. 1103-1113 ◽  
Author(s):  
A. Betteridge ◽  
M. Wallis

The effect of insulin on the incorporation of radioactive leucine into growth hormone was investigated by using rat anterior pituitary glands incubated in vitro. A 50% stimulation over control values was observed at insulin concentrations above 2μm (280munits/ml). The effect was specific for growth hormone biosynthesis, over the range 1–5μm-insulin (140–700munits/ml). Lower more physiological concentrations had no significant effect in this system. Above 10μm (1.4 units/ml) total protein synthesis was also increased. The stimulation of growth hormone synthesis could be partially blocked by the addition of actinomycin D, suggesting that RNA synthesis was involved. Insulin was found to stimulate the rate of glucose utilization in a similar way to growth hormone synthesis. 2-Deoxyglucose and phloridzin, which both prevented insulin from stimulating glucose utilization, also prevented the effect of insulin on growth hormone synthesis. If glucose was replaced by fructose in the medium, the effect of insulin on growth hormone synthesis was decreased. We conclude that the rate of utilization of glucose may be an important step in mediating the effect of insulin on growth hormone synthesis.


2004 ◽  
Vol 100 (6) ◽  
pp. 997-1001 ◽  
Author(s):  
Mitsuhiro Ogura ◽  
Naoyuki Nakao ◽  
Ekini Nakai ◽  
Yuji Uematsu ◽  
Toru Itakura

Object. Although chronic electrical stimulation of the globus pallidus (GP) has been shown to ameliorate motor disabilities in Parkinson disease (PD), the underlying mechanism remains to be clarified. In this study the authors explored the mechanism for the effects of deep brain stimulation of the GP by investigating the changes in neurotransmitter levels in the cerebrospinal fluid (CSF) during the stimulation. Methods. Thirty patients received chronic electrical stimulation of the GP internus (GPi). Clinical effects were assessed using the Unified PD Rating Scale (UPDRS) and the Hoehn and Yahr Staging Scale at 1 week before surgery and at 6 and 12 months after surgery. One day after surgery, CSF samples were collected through a ventricular tube before and 1 hour after GPi stimulation. The concentration of neurotransmitters such as γ-aminobutyric acid (GABA), noradrenaline, dopamine, and homovanillic acid (HVA) in the CSF was measured using high-performance liquid chromatography. The treatment was effective for tremors, rigidity, and drug-induced dyskinesia. The concentration of GABA in the CSF increased significantly during stimulation, although there were no significant changes in the level of noradrenaline, dopamine, and HVA. A comparison between an increased rate of GABA concentration and a lower UPDRS score 6 months postimplantation revealed that the increase in the GABA level correlated with the stimulation-induced clinical effects. Conclusions. Stimulation of the GPi substantially benefits patients with PD. The underlying mechanism of the treatment may involve activation of GABAergic afferents in the GP.


FEBS Letters ◽  
1990 ◽  
Vol 259 (2) ◽  
pp. 269-272 ◽  
Author(s):  
F.Norman Briggs ◽  
K.Francis Lee ◽  
Joseph J. Feher ◽  
Andrew S. Wechsler ◽  
Kay Ohiendieck ◽  
...  

1998 ◽  
Vol 55 (8) ◽  
pp. 1309-1314 ◽  
Author(s):  
John N. Fain ◽  
Suleiman W. Bahouth

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