scholarly journals Proteome dynamics under proteotoxic stress and disease

2021 ◽  
Author(s):  
◽  
Kevin Klann
Keyword(s):  
Protein Synthesis ◽  
Host Cell ◽  
Measurement Time ◽  
Protein Homeostasis ◽  
Dynamic Changes ◽  
Wide Scale ◽  
Viral Proliferation ◽  
Protein Synthesis And Degradation ◽  
Synthesis And Degradation

Correct cellular function is ensured by a complex network of proteins and enzymes, regulating protein synthesis and degradation. This protein network, maintaining the so-called protein homeostasis, regulates those processes on multiple levels, producing new or degrading old proteins to cope with changing intra- and extracellular environments. Disturbance of this tightly regulated machinery can have severe effects on the cell and can lead to a variety of pathologies on organism level. Diseases including cancer, neurodegeneration and infections are associated with causative or consequent alterations in protein homeostasis. To understand the pathologies of these diseases, it is therefore critical to examine how perturbations of protein homeostasis affect cellular pathways and physiology. In the recent years, analysis of protein homeostasis networks has resulted in the development of novel therapeutic approaches. However, for many factors it remains unclear how the cell is affected, if they are disturbed. Protein synthesis and degradation represent immediate responses of the cell to changes and need to be studied in the right timeframe, making them difficult to access by common methodology. In this work we developed a new mass spectrometry (MS) based method to study protein synthesis and degradation on a system-wide scale. Multiplexed enhanced protein dynamic (mePROD) MS was developed, overcoming these limitations by special sample mixing and novel data analysis protocols. MePROD thereby enables the measurement of rapid and transient (e.g. minutes) changes in protein synthesis of thousands of proteins. During responses of the cell to stressors (e.g. protein misfolding, oxidation or infection), two major pathways regulate the protein synthesis: the Integrated Stress Response (ISR) and mammalian target of rapamycin (mTOR). Both pathways have been connected with various diseases in the past and are common therapy targets. Although both pathways target protein synthesis in stress responses, the set of targets regulated by these pathways was believed to differ. Through the new mePROD MS method we could measure a comprehensive comparison of both pathways for the first time, revealing comparable system-wide patterns of regulation between the two pathways. This changed the current view on the regulation elicited by these pathways and furthermore represents a useful resource for the whole field of research. We could further develop the mePROD method and decrease MS measurement time needed to obtain an in-depth dataset. Through implementation of logic based instrument methods, it was possible to enhance the number of measured proteins by approximately three-fold within the same measurement time. The dynamics of protein synthesis and degradation are frequently modulated by pathogens infecting the cell to promote pathogen replication. At the same time, the cell counteracts the infection by modulating protein dynamics as well. To develop useful therapy approaches to fight infections, it therefore is necessary to understand the complex changes within the host cell during infections on a system-wide scale. In 2019, a novel coronavirus spread around the world, causing a world-wide health-crisis. To better understand this novel virus and its infection of the host cell we conducted a study applying the mePROD methodology and classical proteomics to characterize the dynamic changes during the infection course in vitro. We discovered that the infection remodeled a diverse set of host cell pathways (e.g. mRNA splicing, glycolysis, DNA synthesis and protein homeostasis) and thereby showed possible targets for antiviral therapy. By targeted inhibition of these pathways, we could observe that these pathways indeed are necessary for SARS-CoV-2 replication and their inhibition could reduce viral load in the cells. Another experimental approach focused on the dynamic changes of protein modification, namely phosphorylation, after infection with SARS-CoV-2. Here, we could show the very important participation of growth factor signaling pathways in viral proliferation. Both studies together revealed critical pathways that are needed for the viral proliferation and hence are promising candidates for further therapies. Subsequent targeting of these pathways by either already approved drugs (Ribavirin and Sorafenib) or drugs in clinical trials (2-deoxyglucose, Pladienolide-B, NMS-873, Pictilisib, Omipalisib, RO5126766 and Lonafarnib) could block viral replication in vitro and suggests important clinical approaches targeting SARS-COV-2 infection.

scholarly journals Comparison of protein synthesis and degradation in incubated and perfused muscle

1983 ◽  
Vol 212 (3) ◽  
pp. 649-653 ◽  
Author(s):  
A S Clark ◽  
W E Mitch
Keyword(s):  
Protein Synthesis ◽  
Protein Degradation ◽  
Insulin Treatment ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Muscle Protein Degradation ◽  
Protein Synthesis And Degradation ◽  
Synthesis And Degradation

Rates of muscle protein synthesis and degradation measured in the perfused hindquarter were compared with those in incubated epitrochlearis muscles. With fed or starved mature rats, results without insulin treatment were identical. With insulin treatment, protein synthesis in perfused hindquarters was greater, though protein degradation was the same. Thus rates of muscle protein degradation estimated by these two methods in vitro correspond closely.

scholarly journals The effects of cutting or of stretching skeletal muscle in vitro on the rates of protein synthesis and degradation

1980 ◽  
Vol 188 (1) ◽  
pp. 247-254 ◽  
Author(s):  
M J Seider ◽  
R Kapp ◽  
C P Chen ◽  
F W Booth
Keyword(s):  
Protein Synthesis ◽  
Protein Degradation ◽  
Extensor Digitorum Longus ◽  
High Energy ◽  
Extensor Digitorum ◽  
Muscle Fibres ◽  
High Energy Phosphates ◽  
Protein Synthesis And Degradation ◽  
Synthesis And Degradation

Rates of protein synthesis were significantly lower in the cut soleus and extensor digitorum longus muscles than in their uncut counterparts. Rates of protein degradation were significantly higher in cut soleus muscles, but not in cut extensor digitorum longus muscles as compared with their uncut controls. Concentrations of ATP and phosphocreatine were significantly lower in cut soleus and extensor digitorum longus muscles after incubation in vitro in contrast with respective control uncut muscles. These data indicate that cutting of muscle fibres alters rates of protein synthesis and degradation, in addition to altering concentrations of high-energy phosphates. Since these findings stressed the importance of using intact muscles to study protein metabolism, additional studies were made on intact muscles in vitro. Stretched soleus muscles had higher concentrations of high-energy phosphates at the end of an incubation period than did unstretched muscles. However, the length of the soleus, extensor digitorum longus and diaphragm muscles during incubation did not affect rates of protein degradation.

scholarly journals Response of muscle protein turnover to insulin after acute exercise and training

1986 ◽  
Vol 240 (3) ◽  
pp. 651-657 ◽  
Author(s):  
T A Davis ◽  
I E Karl
Keyword(s):  
Protein Synthesis ◽  
Exercise Training ◽  
Protein Turnover ◽  
Acute Exercise ◽  
Muscle Protein ◽  
Muscle Protein Turnover ◽  
Exercise And Training ◽  
Protein Synthesis And Degradation ◽  
Synthesis And Degradation

To determine whether the enhanced insulin-sensitivity of glucose metabolism in muscle after acute exercise also extends to protein metabolism, untrained and exercise-trained rats were subjected to an acute bout of exercise, and the responses of protein synthesis and degradation to insulin were measured in epitrochlearis muscles in vitro. Acute exercise of both untrained and trained rats decreased protein synthesis in muscle in the absence or presence of insulin, but protein degradation was not altered. Exercise training alone had no effect on protein synthesis or degradation in muscle in the absence or presence of insulin. Acute exercise or training alone enhanced the sensitivities of both protein synthesis and degradation to insulin, but the enhanced insulin-sensitivities from training alone were not additive to those after acute exercise. These results indicate that: a decrease in protein synthesis is the primary change in muscle protein turnover after acute exercise and is not altered by prior exercise training, and the enhanced insulin-sensitivities of metabolism of both glucose and protein after either acute exercise or training suggest post-binding receptor events.

scholarly journals A comparison of rates of protein turnover in rat diaphragm in vivo and in vitro

1986 ◽  
Vol 233 (1) ◽  
pp. 279-282 ◽  
Author(s):  
V R Preedy ◽  
D M Smith ◽  
P H Sugden
Keyword(s):  
Protein Synthesis ◽  
Protein Turnover ◽  
Rat Diaphragm ◽  
Degradation Rates ◽  
Protein Synthesis And Degradation ◽  
Synthesis And Degradation

Protein synthesis and degradation rates in diaphragms from fed or starved rats were compared in vivo and in vitro. For fed rats, synthesis rates in vivo were approximately twice those in vitro, but for starved rats rates were similar. Degradation rates were less in vivo than in vitro in diaphragms from either fed or starved rats.

scholarly journals Pentoxifylline improves insulin action limiting skeletal muscle catabolism after infection

1999 ◽  
Vol 163 (1) ◽  
pp. 15-24 ◽  
Author(s):  
T Vary ◽  
D Dardevet ◽  
J Grizard ◽  
L Voisin ◽  
C Buffiere ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Protein Degradation ◽  
Muscle Protein ◽  
Plasma Concentrations ◽  
Skeletal Muscle Protein ◽  
Muscle Protein Metabolism ◽  
Protein Synthesis And Degradation ◽  
Synthesis And Degradation

We investigated the ability of pentoxifylline (PTX) to modulate protein synthesis and degradation in the presence and absence of insulin during incubation of epitrochlearis muscle, 2 or 6 days after injection of Escherichia coli. On days 2 and 6 after infection, protein synthesis was inhibited by 25%, whereas proteolysis was enhanced by 75%. Insulin (2 nM) in vitro stimulated protein synthesis in muscles from infected rats to the same extent as in controls. The ability of insulin to limit protein degradation was severely blunted 48 h after infection. On day 6 after infection, insulin inhibited proteolysis to a greater extent than on day 2. PTX suppressed the increase in plasma concentrations of tumor necrosis factor more than 600-fold after injection of bacteria, and partially prevented the inhibition of protein synthesis and stimulation of protein degradation during sepsis. Moreover, PTX administration maintained the responsiveness of protein degradation to insulin during sepsis. Thus cytokines may influence skeletal muscle protein metabolism during sepsis, both indirectly through inhibition of the effects of insulin on proteolysis, and directly on the protein synthesis and degradation machinery.

Skeletal muscle protein synthesis and degradation in vitro: effects of temperature

1985 ◽  
Vol 249 (5) ◽  
pp. C464-C470 ◽  
Author(s):  
D. A. Essig ◽  
S. S. Segal ◽  
T. P. White
Keyword(s):  
Protein Synthesis ◽  
Specific Activity ◽  
Muscle Protein ◽  
Peripheral Region ◽  
Core Region ◽  
Tension Development ◽  
The Core ◽  
Protein Synthesis And Degradation ◽  
Synthesis And Degradation

We compared the structure, function, protein synthesis, and degradation of 70- to 95-mg rat soleus muscles during 120 min of incubation at 20 and 37 degrees C. At 37 degrees C, muscles were characterized by a damaged central core region and a decline of isometric tension development during incubation. Protein synthesis in the core region at 37 degrees C was depressed relative to the peripheral region. At 20 degrees C, developed tension remained constant during incubation, and synthesis rates in the core region were not different from the peripheral region. Compared with fresh muscle, ATP concentration after incubation was not affected by temperature. After equilibration of phenylalanine specific activity between extracellular and intracellular spaces (60 min at 20 degrees C; 30 min at 37 degrees C), rates of protein synthesis at 20 [0.048 nmol tyrosine (Tyr) X mg wet mass-1 X 2 h-1] and 37 degrees C (0.160 nmol Tyr X mg wet mass-1 X 2 h-1) were linear up to 180 and 120 min, respectively. Rates of protein degradation at 20 (0.076 nmol Tyr X mg wet mass-1 X 2 h-1) and 37 degrees C (0.248 nmol Tyr X mg wet mass-1 X 2 h-1) measured after 60 min were linear up to 180 and 120 min, respectively. Incubation at 20 degrees C offers an approach to study 70- to 95-mg muscles in vitro without compromising structure and function.

scholarly journals The effect of glutamine on protein turnover in chick skeletal muscle in vitro

1990 ◽  
Vol 265 (2) ◽  
pp. 593-598 ◽  
Author(s):  
G Wu ◽  
J R Thompson
Keyword(s):  
Protein Synthesis ◽  
Skeletal Muscles ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Plasma Concentrations ◽  
Glutamine Concentration ◽  
Protein Synthesis And Degradation ◽  
Synthesis And Degradation

The effect of glutamine on the rates of protein synthesis and degradation was studied in isolated chick extensor digitorum communis muscles incubated in the presence of plasma concentrations of amino acids. Addition of 0.5-15 mM-glutamine increases (P less than 0.01) intracellular glutamine concentrations by 31-670%. There is a positive relationship (r = 0.975, P less than 0.01) between intracellular glutamine concentration and the rate of muscle protein synthesis measured by the incorporation of [3H]phenylalanine. The stimulating effect of 15 mM-glutamine on protein synthesis was decreased from 58 to 19% in muscles incubated in the absence of tyrosine. The rates of protein degradation, estimated from [3H]phenylalanine release from muscle proteins prelabelled in vivo, decreased (P less than 0.05) by 15-30% in the presence of 4-15 mM-glutamine when compared with muscles incubated in the presence of physiological concentrations of glutamine (0.5-1 mM). Glutamine concentrations ranging from 2 to 15 mM appear to have an overall anabolic effect on chick skeletal muscles incubated in vitro.

Sign in / Sign up

Export Citation Format

Share Document