scholarly journals Nuclear Functions of TOR: Impact on Transcription and the Epigenome

Genes ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 641 ◽  
Author(s):  
R. Nicholas Laribee ◽  
Ronit Weisman

The target of rapamycin (TOR) protein kinase is at the core of growth factor- and nutrient-dependent signaling pathways that are well-known for their regulation of metabolism, growth, and proliferation. However, TOR is also involved in the regulation of gene expression, genomic and epigenomic stability. TOR affects nuclear functions indirectly through its activity in the cytoplasm, but also directly through active nuclear TOR pools. The mechanisms by which TOR regulates its nuclear functions are less well-understood compared with its cytoplasmic activities. TOR is an important pharmacological target for several diseases, including cancer, metabolic and neurological disorders. Thus, studies of the nuclear functions of TOR are important for our understanding of basic biological processes, as well as for clinical implications.

2019 ◽  
Vol 23 (15) ◽  
pp. 1663-1670 ◽  
Author(s):  
Chunyan Ao ◽  
Shunshan Jin ◽  
Yuan Lin ◽  
Quan Zou

Protein methylation is an important and reversible post-translational modification that regulates many biological processes in cells. It occurs mainly on lysine and arginine residues and involves many important biological processes, including transcriptional activity, signal transduction, and the regulation of gene expression. Protein methylation and its regulatory enzymes are related to a variety of human diseases, so improved identification of methylation sites is useful for designing drugs for a variety of related diseases. In this review, we systematically summarize and analyze the tools used for the prediction of protein methylation sites on arginine and lysine residues over the last decade.


2021 ◽  
Vol 22 (2) ◽  
pp. 522
Author(s):  
Noreen Falak ◽  
Qari Muhammad Imran ◽  
Adil Hussain ◽  
Byung-Wook Yun

Plants are in continuous conflict with the environmental constraints and their sessile nature demands a fine-tuned, well-designed defense mechanism that can cope with a multitude of biotic and abiotic assaults. Therefore, plants have developed innate immunity, R-gene-mediated resistance, and systemic acquired resistance to ensure their survival. Transcription factors (TFs) are among the most important genetic components for the regulation of gene expression and several other biological processes. They bind to specific sequences in the DNA called transcription factor binding sites (TFBSs) that are present in the regulatory regions of genes. Depending on the environmental conditions, TFs can either enhance or suppress transcriptional processes. In the last couple of decades, nitric oxide (NO) emerged as a crucial molecule for signaling and regulating biological processes. Here, we have overviewed the plant defense system, the role of TFs in mediating the defense response, and that how NO can manipulate transcriptional changes including direct post-translational modifications of TFs. We also propose that NO might regulate gene expression by regulating the recruitment of RNA polymerase during transcription.


1996 ◽  
Vol 271 (2) ◽  
pp. E253-E260 ◽  
Author(s):  
C. E. Torgan ◽  
W. E. Kraus

Skeletal muscle exhibits a wide range in functional phenotype in response to changes in physiological demands. We have observed that, in response to changes in work patterns, alterations in gene expression of some proteins coincide with changes in adenylyl cyclase (AC) activity [Kraus, W.E., J.P. Longabaugh, and S. B. Liggett. Am. J. Physiol 263 (Endocrinol. Metab. 26): E266-E230, 1992]. We now examine AC isoform transcript prevalence in various rabbit skeletal muscles and in response to changing work demands. Using reverse transcriptase-polymerase chain reaction, we detected type II AC isoform transcripts in rabbit skeletal muscle. Ribonuclease protection analyses revealed that expression of the type II isoform significantly correlated with the percentage of fast-twitch type IIb/IId fibers (r2 = 0.765, P < 0.01). When a fast-twitch muscle was converted to a slow-twitch muscle via chronic electrical pacing, expression of type II AC mRNA significantly decreased. This response occurred 3 days after the onset of stimulation (78% decrease) and was still present after 21 days of stimulation (76% decrease). As type II AC is relatively insensitive to calcium regulation while sensitive to protein kinase C (PKC) signaling, these data provide further impetus for investigations of protein kinase A and PKC cross-talk signaling mechanisms in the regulation of gene expression.


1999 ◽  
Vol 276 (6) ◽  
pp. G1363-G1372 ◽  
Author(s):  
Vinzenz M. Stepan ◽  
Chris J. Dickinson ◽  
John del Valle ◽  
Masashi Matsushima ◽  
Andrea Todisco

Gastrin (G17) has a CCKBreceptor-mediated growth-promoting effect on the AR42J rat acinar cell line that is linked to induction of both mitogen-activated protein kinase (MAPK) and c- fos gene expression. We investigated the mechanisms that regulate the growth factor action of G17 on the rat pituitary adenoma cell line GH3. Both AR42J and GH3cells displayed equal levels of CCKBreceptor expression and similar binding kinetics of125I-labeled G17. G17 stimulation of cell proliferation was identical in both cell lines. G17 stimulation of GH3cell proliferation was completely blocked by the CCKBreceptor antagonist D2 but not by the MEK inhibitor PD-98059 or the protein kinase C inhibitor GF-109203X, which completely inhibited G17 induction of AR42J cell proliferation. G17 induced a c- fos SRE-luciferase reporter gene plasmid more than fourfold in the AR42J cells, whereas it had no effect in the GH3cells. In contrast to what we observed in the AR42J cells, G17 failed to stimulate MAPK activation and Shc tyrosyl phosphorylation and association with the adapter protein Grb2. Epidermal growth factor induced the MAPK pathway in the GH3cells, demonstrating the integrity of this signaling system. G17 induced Ca2+mobilization in both the GH3and AR42J cells. The calmodulin inhibitor N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide inhibited AR42J cell proliferation by 20%, whereas it completely blocked G17 induction of GH3cell growth. The Ca2+ionophore ionomycin stimulated GH3cell proliferation to a level similar to that observed in response to G17, but it had no effect on AR42J cell proliferation. Thus there are cell type specific differences in the requirement of the MAPK pathway for the growth factor action of G17. Whereas in the AR42J cells G17 stimulates cell growth through activation of MAPK and c- fos gene expression, in the GH3cells, G17 fails to activate MAPK, and it induces cell proliferation through Ca2+-dependent signaling pathways. Furthermore, induction of Ca2+mobilization in the AR42J cells appears not to be sufficient to sustain cell proliferation.


2021 ◽  
Author(s):  
Sara Artigas-Jerónimo ◽  
Margarita Villar ◽  
Agustín Estrada-Peña ◽  
Adrián Velázquez-Campoy ◽  
Pilar Alberdi ◽  
...  

The Akirin family of transcription cofactors are involved throughout the metazoan in the regulation of different biological processes such as immunity, interdigital regression, muscle and neural development. Akirin do not have catalytic or DNA-binding capability and exert its regulatory function primarily through interacting proteins such as transcription factors, chromatin remodelers, and RNA-associated proteins. In this study, we focused on the human Akirin2 regulome and interactome in neutrophil-like model human Caucasian promyelocytic leukemia HL60 cells. Our hypothesis is that metazoan evolved to have Akirin2 functional complements and different Akirin2-mediated mechanisms for the regulation of gene expression. To address this hypothesis, experiments were conducted using transcriptomics, proteomics and systems biology approaches in akirin2 knockdown and wildtype HL60 cells to characterize Akirin2 gene/protein targets, functional complements and to provide evidence of different mechanisms that may be involved in Akirin2-mediated regulation of gene expression. The results revealed Akirin2 gene/protein targets in multiple biological processes with higher representation of immunity and identified immune response genes as candidate Akirin2 functional complements. In addition to linking chromatin remodelers with transcriptional activation, Akirin2 also interacts with histone H3.1 for regulation of gene expression.


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