scholarly journals The Role of Selective Protein Degradation in the Regulation of Iron and Sulfur Homeostasis in Plants

2020 ◽  
Vol 21 (8) ◽  
pp. 2771 ◽  
Author(s):  
Anna Wawrzyńska ◽  
Agnieszka Sirko
Keyword(s):  
Protein Degradation ◽  
Plant Development ◽  
Sulfur Metabolism ◽  
High Energy ◽  
26S Proteasome ◽  
Control Mechanisms ◽  
Wide Range ◽  
Ubiquitin Conjugation ◽  
Cellular Components

Plants are able to synthesize all essential metabolites from minerals, water, and light to complete their life cycle. This plasticity comes at a high energy cost, and therefore, plants need to tightly allocate resources in order to control their economy. Being sessile, plants can only adapt to fluctuating environmental conditions, relying on quality control mechanisms. The remodeling of cellular components plays a crucial role, not only in response to stress, but also in normal plant development. Dynamic protein turnover is ensured through regulated protein synthesis and degradation processes. To effectively target a wide range of proteins for degradation, plants utilize two mechanistically-distinct, but largely complementary systems: the 26S proteasome and the autophagy. As both proteasomal- and autophagy-mediated protein degradation use ubiquitin as an essential signal of substrate recognition, they share ubiquitin conjugation machinery and downstream ubiquitin recognition modules. Recent progress has been made in understanding the cellular homeostasis of iron and sulfur metabolisms individually, and growing evidence indicates that complex crosstalk exists between iron and sulfur networks. In this review, we highlight the latest publications elucidating the role of selective protein degradation in the control of iron and sulfur metabolism during plant development, as well as environmental stresses.

scholarly journals CCR4-NOT complex nuclease Caf1 is a novel shuttle factor involved in the degradation of ubiquitin-modified proteins by 26S proteasome

2020 ◽  
Author(s):  
Ganapathi Kandasamy ◽  
Ashis Kumar Pradhan ◽  
R Palanimurugan
Keyword(s):  
Protein Degradation ◽  
Translational Control ◽  
Ubiquitin Proteasome System ◽  
26S Proteasome ◽  
Control Mechanisms ◽  
Gene Expressions ◽  
Proteolytic Pathway ◽  
Ubiquitin Ligase E3 ◽  
Ubiquitin Proteasome ◽  
Modified Proteins

AbstractProtein degradation by ubiquitin proteasome system (UPS) is the major selective proteolytic pathway responsible for the degradation of short lived proteins ranging from regulatory proteins to abnormal proteins. Many diseases are associated with abnormal protein degradation; occasionally such dysregulated protein degradation is compensated by various transcriptional and translational control mechanisms in the cell. Among those pathways CCR4-NOT protein complex is responsible for transcriptional and transitional control of various gene expressions. Furthermore, CCR4-NOT complex also has a RING type ubiquitin ligase (E3) which is required for the degradation of several proteins. Here we report a novel function that the CCR4-NOT complex 3’-5’ exonuclease Caf1 is involved in ubiquitindependent degradation of short lived proteins by the 26S proteasome in yeast Saccharomyces cerevisiae. caf1 deletion results in stabilization of R-Ura3 (N-end rule) and Ub-V76-Ura3 (Ubiquitin fusion degradation) substrates from proteasomal degradation. Additionally, caf1 deletion accumulates ubiquitin-modified Ub-V76-Ura3 proteins and Caf1 binds to poly-ubiquitin conjugates and linear tetra ubiquitin chains. Surprisingly, Caf1 interacts with 19S regulatory particle complex of the 26S proteasome. Therefore, we conclude that Caf1 has an exciting novel function as an ubiquitin shuttle factor in which Caf1 targets ubiquitin-modified proteins to 26S proteasome for efficient degradation.

scholarly journals Evolution of flowers and inflorescences

Development ◽  
1994 ◽  
Vol 1994 (Supplement) ◽  
pp. 107-116 ◽  
Author(s):  
Enrico S. Coen ◽  
Jacqueline M. Nugent
Keyword(s):  
Plant Development ◽  
Branching Pattern ◽  
Inflorescence Architecture ◽  
Flower Symmetry ◽  
Wide Range ◽  
Inflorescence Structure ◽  
Key Genes ◽  
Flower Position ◽  
Inflorescence Type

Plant development depends on the activity of meristems which continually reiterate a common plan. Permutations around this plan can give rise to a wide range of morphologies. To understand the mechanisms underlying this variation, the effects of parallel mutations in key developmental genes are being studied in different species. In Antirrhinum, three of these key genes are: (1) floricaula (flo) a gene required for the production of flowers (2) centroradialis (cen), a gene controlling flower position (3) cycloidea (cyc), a gene controlling flower symmetry. Several plant species, exhibiting a range of inflorescence types and floral symmetries are being analysed in detail. Comparative genetic and molecular analysis shows that inflorescence architecture depends on two underlying parameters: a basic inflorescence branching pattern and the positioning of flowers. The flo and cen genes play a key role in the positioning of flowers, and variation in the site and timing of expression of these genes, may account for many of the different inflorescence types. The evolution of inflorescence structure may also have influenced the evolution of floral asymmetry, as illustrated by the cen mutation which changes both inflorescence type and the symmetry of some flowers. Conflicting theories about the origins of irregular flowers and how they have coevolved with inflorescence architecture can be directly assessed by examining the role of cyc- and cen-like genes in species displaying various floral symmetries and inflorescence types.

Modeling of Size Effects in Diffusion Driven Processes at Nanoscale - Large Atomic and Mesoscale Methods

2017 ◽  
Vol 12 ◽  
pp. 38-73
Author(s):  
Tomasz Wejrzanowski ◽  
Krzysztof Jan Kurzydlowski
Keyword(s):  
Molecular Dynamics ◽  
Monte Carlo ◽  
Free Surface ◽  
Size Effects ◽  
Experimental Studies ◽  
High Energy ◽  
Intergranular Phase ◽  
Wide Range ◽  
Microstructure Effect

The results of the studies presented here are devoted to understanding of microstructure effect on the processes and properties driven by diffusion. The role of various interfaces (intergranular, phase, free surface), as the high-energy defects, is underlined and investigated with special attention. The methodology relevant to analyses of the microstructural processes is first briefly presented. The capability and limitations of classical molecular dynamics, mesoscale Monte Carlo and cellular automaton techniques are described. Two examples of the diffusion driven processes analyzed at various length and time scale are shown: namely, grain growth in nanometallic materials and melting of thin embedded films. The modeling results are also accompanied with experimental studies. Thanks to application of numerical methods, models of relevant processes were proposed, which enabled to provide quantitative relationships between microstructure and the process kinetics. Such relationships can be later used for design of optimized materials for wide range of applications.

The Ubiquitin-Proteasome Pathway and Its Role in Cancer

2005 ◽  
Vol 23 (21) ◽  
pp. 4776-4789 ◽  
Author(s):  
Aparna Mani ◽  
Edward P. Gelmann
Keyword(s):  
Cell Cycle ◽  
Protein Degradation ◽  
Ubiquitin Ligase ◽  
De Novo ◽  
Cell Cancer ◽  
26S Proteasome ◽  
Great Promise ◽  
Major Pathway ◽  
Cellular Processes ◽  
Wide Range

Critical cellular processes are regulated, in part, by maintaining the appropriate intracellular levels of proteins. Whereas de novo protein synthesis is a comparatively slow process, proteins are rapidly degraded at a rate compatible with the control of cell cycle transitions and cell death induction. A major pathway for protein degradation is initiated by the addition of multiple 76–amino acid ubiquitin monomers via a three-step process of ubiquitin activation and substrate recognition. Polyubiquitination targets proteins for recognition and processing by the 26S proteasome, a cylindrical organelle that recognizes ubiquitinated proteins, degrades the proteins, and recycles ubiquitin. The critical roles played by ubiquitin-mediated protein turnover in cell cycle regulation makes this process a target for oncogenic mutations. Oncogenes of several common malignancies, for example colon and renal cell cancer, code for ubiquitin ligase components. Cervical oncogenesis by human papillomavirus is also mediated by alteration of ubiquitin ligase pathways. Protein degradation pathways are also targets for cancer therapy, as shown by the successful introduction of bortezomib, an inhibitor of the 26S proteasome. Further work in this area holds great promise toward our understanding and treatment of a wide range of cancers.

The Role of Nitrate in the Osmotic and Nutritional Control of Plant Development

1997 ◽  
Vol 24 (2) ◽  
pp. 103 ◽  
Author(s):  
G. I. McIntyre
Keyword(s):  
Plant Development ◽  
Osmotic Effect ◽  
Nutritional Effect ◽  
Developmental Effects ◽  
Wide Range ◽  
Physiological Explanation ◽  
Developmental Responses ◽  
Reduced Forms ◽  
Established Role

I postulate that certain of the effects of nitrate on plant development are mediated by the combination of an osmotic effect on water uptake and a nutritional effect on protein synthesis. This hypothesis is discussed with reference to effects on seed germination, apical dominance, lateral root initiation, flowering and leaf senescence. The postulated osmotic effect of nitrate is consistent with the well-established role of both nitrate and reduced forms of N as major osmotica in plant cells, and also with the similarity and interaction between developmental effects of nitrate and water. Evidence of the nutritional component of developmental effects of nitrate is provided by a comparison of responses induced by nitrate and by other osmotica of less nutritional significance. Carbohydrate has also been reported to influence development by a combination of osmotic and nutritional effects. The proposed hypothesis is a unifying concept which provides a similar physiological explanation for a wide range of diverse developmental responses that are usually attributed to the effect or interaction of different hormonal factors.

scholarly journals Direct Conjugation of NEDD8 to the N-Terminus of a Model Protein Can Induce Degradation

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 854
Author(s):  
Kartikeya Vijayasimha ◽  
Marilyn Vo Tran ◽  
Amy L. Leestemaker-Palmer ◽  
Brian P. Dolan
Keyword(s):  
Protein Degradation ◽  
Model System ◽  
Precursor Cell ◽  
Neural Precursor Cell ◽  
Conjugation System ◽  
Covalent Linkage ◽  
N Terminus ◽  
Model Protein ◽  
Ubiquitin Conjugation

While the role of ubiquitin in protein degradation is well established, the role of other ubiquitin-like proteins (UBLs) in protein degradation is less clear. Neural precursor cell expressed developmentally down-regulated protein 8 (NEDD8) is the UBL with the highest level of amino acids identified when compared to ubiquitin. Here we tested if the N-terminal addition of NEDD8 to a protein of interest could lead to degradation. Mutation of critical glycine residues required for normal NEDD8 processing resulted in a non-cleavable fusion protein that was rapidly degraded within the cells by both the proteasome and autophagy. Both degradation pathways were dependent on a functional ubiquitin-conjugation system as treatment with MLN7243 increased levels of non-cleavable NEDD8-GFP. The degradation of non-cleavable, N-terminal NEDD8-GFP was not due to a failure of GFP folding as different NEDD8-GFP constructs with differing abilities to fold and fluoresce were similarly degraded. Though the fusion of NEDD8 to a protein resulted in degradation, treatment of cells with MLN4924, an inhibitor of the E1 activating enzyme for NEDD8, failed to prevent degradation of other destabilized substrates. Taken together these data suggest that under certain conditions, such as the model system described here, the covalent linkage of NEDD8 to a protein substrate may result in the target proteins degradation.

A role of Arabidopsis COP9 signalosome in multifaceted developmental processes revealed by the characterization of its subunit 3

Development ◽  
2001 ◽  
Vol 128 (21) ◽  
pp. 4277-4288 ◽  
Author(s):  
Zhaohua Peng ◽  
Giovanna Serino ◽  
Xing-Wang Deng
Keyword(s):  
Protein Degradation ◽  
26S Proteasome ◽  
Cop9 Signalosome ◽  
Developmental Processes ◽  
Developmental Defects ◽  
E3 Ligases ◽  
Ubiquitinated Proteins ◽  
Transgenic Lines ◽  
Ubiquitin Proteasome

The COP9 signalosome is a highly conserved eight-subunit protein complex initially defined as a repressor of photomorphogenic development in Arabidopsis. It has recently been suggested that the COP9 signalosome directly interacts and regulates SCF type E3 ligases, implying a key role in ubiquitin-proteasome mediated protein degradation. We report that Arabidopsis FUS11 gene encodes the subunit 3 of the COP9 signalosome (CSN3). The fus11 mutant is defective in the COP9 signalosome and accumulates significant amount of multi-ubiquitinated proteins. The same mutant is specifically impaired in the 26S proteasome-mediated degradation of HY5 but not PHYA, indicating a selective involvement in protein degradation. Reduction-of-function transgenic lines of CSN3 produced through gene co-suppression also accumulate multi-ubiquitinated proteins and exhibit diverse developmental defects. This result substantiates a hypothesis that the COP9 signalosome is involved in multifaceted developmental processes through regulating proteasome-mediated protein degradation.

scholarly journals Modifications of Human Subcutaneous ADMSC after PPARγActivation and Cold Exposition

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Diana Vargas ◽  
Wendy Rosales ◽  
Fernando Lizcano
Keyword(s):  
Stem Cells ◽  
Energy Expenditure ◽  
Metabolic Disorders ◽  
Subcutaneous Tissue ◽  
High Energy ◽  
Mature Adipocyte ◽  
Partial Agonists ◽  
Wide Range ◽  
A Cell

Mesenchymal stem cells are a diverse population of cells with a wide range of potential therapeutic applications. In particular, cells from adipose tissue have the distinction of being easily accessible and contain a lot of stem cells. ADMSCs can be induced to mature adipocyte and activate the energy expenditure upon treatment with total PPARγagonists. Additionally these cells may respond to cold by activating the thermogenic program. In the present study, we determined the effect of partial agonism of PPARγand temperature reduction on phenotype and metabolic activity of ADMSCs from human adipose subcutaneous tissue. We found that adipocytes differentiated with total and partial agonists of PPARγand exposed to 31°C are able to respond to cold significantly increasing the expression of thermogenic proteins such as UCP1, PGC1α, and CITED1, a marker of beige phenotype. Additionally, we found that adipocyte cells subjected to cold had a reduction in triglycerides and increased adiponectin levels. These data confirm the promising role of ADMSCs as a treatment for metabolic disorders since it is possible to induce them to mature adipocytes and modulate their phenotype toward a cell with high-energy expenditure and metabolic beneficial effect.

scholarly journals Important Role of Autophagy in Regulation of Metabolic Processes in Health, Disease and Aging

2014 ◽  
pp. 409-420 ◽  
Author(s):  
Z. PAPÁČKOVÁ ◽  
M. CAHOVÁ
Keyword(s):  
Metabolic Disorders ◽  
Storage Disease ◽  
External Environment ◽  
Nutrient Deprivation ◽  
Lysosomal Storage ◽  
Physiological Processes ◽  
Wide Range ◽  
Normal Human ◽  
Cellular Components

Autophagy is the basic catabolic mechanism that involves degradation of dysfunctional cellular components through the action of lysosome as well as supplying energy and compounds for the synthesis of essential biomacromolecules. This process enables cells to survive stress from the external environment like nutrient deprivation. Autophagy is important in the breakdown of proteins, carbohydrates and lipids as well. Furthermore, recent studies have shown that autophagy is critical in wide range of normal human physiological processes, and defective autophagy is associated with diverse diseases, including lysosomal storage disease, myopathies, neurodegeneration and various metabolic disorders. This review summarizes the most up-to-date findings on what role autophagy plays in metabolism.

Galactose induction of the GAL1 gene requires conditional degradation of the Mig2 repressor

2011 ◽  
Vol 435 (3) ◽  
pp. 641-649 ◽  
Author(s):  
Mei Kee Lim ◽  
Wee Leng Siew ◽  
Jin Zhao ◽  
Ywee Chieh Tay ◽  
Edwin Ang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Degradation ◽  
Chromatin Immunoprecipitation ◽  
26S Proteasome ◽  
Expression Studies ◽  
Gal1 Promoter ◽  
Gene Expression Studies ◽  
F Box Protein ◽  
Gal1 Gene

Skp1 an essential component of the SCF (Skp1/cullin/F-box) E3 ubiquitin ligases, which target proteins for degradation by the 26S proteasome. We generated a skp1dM mutant strain that is defective for galactose induction of the GAL1 gene and we have found that galactose-induced protein degradation of the repressor Mig2 is defective in this strain. Mig2 degradation was also abolished in cells lacking the protein kinase Snf1 and the F-box protein Das1, suggesting that Snf1 triggers galactose-induced protein degradation of Mig2 by SCFDas1. Chromatin immunoprecipitation showed that Mig2 associates with the GAL1 promoter upon the galactose-induced exit of Mig1 in skp1dM cells, but not in wild-type cells, suggesting that the conditional degradation of Mig2 is required to prevent it from binding to the GAL1 promoter under inducing conditions. A galactose-stable deletion derivative of Mig2 caused a strong Mig (multi-copy inhibition of GAL gene expression) phenotype, confirming that galactose induction of the GAL1 gene requires the degradation of the repressor Mig2. Our results shed new light on the conflicting reports about the functional role of the degradation of transcriptional activators and indicate that gene expression studies interfering with proteasome degradation should take the stabilization of potential repressors into account.

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