scholarly journals CENP-B dynamics at centromeres is regulated by a SUMOylation/ubiquitination and proteasomal-dependent degradation mechanism involving the SUMO-targeted ubiquitin E3 ligase RNF4

2018 ◽  
Author(s):  
Jhony El Maalouf ◽  
Pascale Texier ◽  
Indri Erliandri ◽  
Camille Cohen ◽  
Armelle Corpet ◽  
...  
Keyword(s):  
Dna Binding ◽  
Degradation Mechanism ◽  
E3 Ligase ◽  
Major Constituent ◽  
Post Translational Modification ◽  
Post Translational Modifications ◽  
Ubiquitin E3 Ligase ◽  
Satellite Repeats ◽  
Histone H3 Variant ◽  
Centromeric Protein

AbstractCentromeric protein B (CENP-B) is a major constituent of the centromere. It is a DNA binding protein that recognizes a specific 17-nt sequence present in the centromeric alphoid satellite repeats. CENP-B importance for centromere stability has only been revealed recently. In addition to its DNA binding properties, CENP-B interacts with the histone H3 variant CENP-A and CENP-C. These interactions confer a mechanical strength to the kinetochore that enables accurate sister chromatids segregation to avoid aneuploidy. Therefore, understanding the mechanisms that regulate CENP-B stability at the centromere is a major unresolved issue for the comprehension of centromere function. In this study, we demonstrate that lysine K402 of CENP-B is a substrate for SUMO post-translational modifications. We show that K402 regulates CENP-B stability at centromeres through a SUMOylation/ubiquitination and proteasomal-dependent degradation mechanism involving the SUMO-Targeted Ubiquitin E3 Ligase RNF4/SNURF. Our study describes SUMOylation of CENP-B as a major post-translational modification involved in centromere dynamics.

scholarly journals Structural Diversity of Ubiquitin E3 Ligase

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6682
Author(s):  
Sachiko Toma-Fukai ◽  
Toshiyuki Shimizu
Keyword(s):  
E3 Ligase ◽  
Structural Diversity ◽  
Biological Processes ◽  
Post Translational Modification ◽  
Post Translational Modifications ◽  
E3 Ligases ◽  
Cellular Processes ◽  
Ubiquitin E3 Ligase ◽  
Ubiquitin Ligase E3 ◽  
Ubiquitin Conjugating Enzyme

The post-translational modification of proteins regulates many biological processes. Their dysfunction relates to diseases. Ubiquitination is one of the post-translational modifications that target lysine residue and regulate many cellular processes. Three enzymes are required for achieving the ubiquitination reaction: ubiquitin-activating enzyme (E1), ubiquitin-conjugating enzyme (E2), and ubiquitin ligase (E3). E3s play a pivotal role in selecting substrates. Many structural studies have been conducted to reveal the molecular mechanism of the ubiquitination reaction. Recently, the structure of PCAF_N, a newly categorized E3 ligase, was reported. We present a review of the recent progress toward the structural understanding of E3 ligases.

Hls5, a Novel Ubiquitin E3 Ligase, Modulates Levels of Sumoylated GATA-1.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 253-253 ◽  
Author(s):  
Louise Natalie Winteringham ◽  
Raelene Endersby ◽  
Jennifer Beaumont ◽  
Jean-Philippe Lalonde ◽  
Merlin Crossley ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Dna Binding ◽  
Coiled Coil ◽  
Ring Finger ◽  
E3 Ligase ◽  
Proteasomal Degradation ◽  
Post Translational Modifications ◽  
E3 Ligases ◽  
Lineage Switch ◽  
Ubiquitin E3 Ligase

Abstract Abstract 253 Hemopoietic lineage commitment is controlled, in part, by transcription factors that regulate specific genes required for the formation of mature blood cells. Differentiation along particular hemopoietic lineages is dependant not only on the presence of particular transcription factors, but also on appropriate concentrations - altering transcription factor levels can force cells into different hemopoietic pathways. Transcription factors undergo numerous post-translational modifications and are controlled spatially via sub-cellular localisation. De-regulation of transcription factors can result in leukemias, or other blood disorders. GATA-1 is an example of a key lineage-determining gene, essential for erythropoiesis. Increasing GATA-1 levels promotes maturation along the erythroid pathway, whereas reducing GATA-1 concentrations favours myelopoiesis. GATA-1 regulation occurs at multiple levels including transcription, translation and post-translational modifications such as phosphorylation, acetylation, ubiquitination and sumoylation. Although GATA-1 ubiquitination modifies the protein for proteasomal degradation, the effect of adding small ubiquitin-like modier (Sumo) to GATA-1 is unclear. Several examples of hemopoietic differentiation plasticity have been observed. We reported a lineage switch by erythroleukemic J2E cells which spontaneously developed a monoblastoid phenotype. Two genes (Hls5 and Hls7/Mlf1) were isolated from this lineage switch with potential lineage-determining features. Hls5 is a member of the RBCC (Ring finger, B-box, Coiled-coil) family of proteins, which includes PML. Ectopic expression of Hls5 impedes erythroid differentiation by reducing GATA-1 levels, and suppressing hemoglobin synthesis. Significantly, Hls5 relocates from the cytoplasm to associate with GATA-1 in the nucleus, where it interferes with DNA binding and transactivation of GATA-1. Several members of the RBCC family are ubiquitin E3 ligases, catalysing the final step in the ubiquitination process - these molecules play a vital role in regulating the levels of target proteins. Here we show that Hls5 is a bona fide ubiquitin E3 ligase, in partnership with several ubiquitin E2 enzymes. The Ring finger is critical for Hls5 ligase activity as mutation of key residues within the Ring finger ablates catalytic activity. Interestingly, a yeast 2 hybrid screen for Hls5 interactors identified Ubc9 and Pias1, which act as E2 and E3 enzymes in the sumoylation cascade. Co-immunoprecipitation, BRET and co-localization experiments confirmed the Hls5 association with Ubc9 and Pias1. Moreover, Hls5 binds Sumo-1 (but not Sumo-2 or 3), and co-localizes with Sumo-1 in discrete nuclear bodies. Thus, Hls5 interacts with several components of the intracellular sumoylation machinery. Hls5 can also reduce sumoylated proteins globally, indicating it may target these modified proteins for degradation. Recently, a new family of ubiquitin E3 ligases has been described which specifically mark sumoylated proteins for degradation. These Sumo-targeted ubiquitin ligases (STUbL) are found primarily in yeast, and only one mammalian STUbL has been identified. We postulated that Hls5 may be a STUbL, capable of regulating sumoylated GATA-1. Our data demonstrate that while Hls5 is able to bind GATA-1 via the B-box and Coiled-coil domains, it preferentially associates with sumoylated GATA-1 through a canonical Sumo interacting motif (SIM). This results in increased GATA-1 ubiquitination and, as a consequence, levels of sumoylated GATA-1 are reduced substantially. Since mutation of the lysine necessary for Sumo attachment does not affect GATA-1 transactivation, sumoylation may act as a prelude to ubiquitination and protein turn-over. We propose, therefore, that GATA-1 mediates transcription of target genes, and is subsequently sumoylated by Pias1 and Ubc9 – addition of Sumo moieties to GATA-1 enhance binding to Hls5, which in turn impedes GATA-1 DNA binding, and promotes ubiquitination for proteasomal degradation. This model is consistent with decreased levels of GATA-1 in erythroid cells ectopically expressing Hls5, and with the original isolation of Hls5 as a potential lineage-determining gene involved with the erythroid to monoblastoid lineage switch. Thus, Hls5 is a novel STUbL which plays a role in hemopoietic lineage commitment by modulating GATA-1 activity and content. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Linear ubiquitin chains: enzymes, mechanisms and biology

Open Biology ◽  
2017 ◽  
Vol 7 (4) ◽  
pp. 170026 ◽  
Author(s):  
Katrin Rittinger ◽  
Fumiyo Ikeda
Keyword(s):  
Cellular Response ◽  
Apoptotic Cell ◽  
Gene Mutations ◽  
E3 Ligase ◽  
Biological Functions ◽  
Post Translational Modification ◽  
Ubiquitin Chain ◽  
Polyubiquitin Chains ◽  
Ubiquitin E3 Ligase ◽  
Ubiquitin Receptors

Ubiquitination is a versatile post-translational modification that regulates a multitude of cellular processes. Its versatility is based on the ability of ubiquitin to form multiple types of polyubiquitin chains, which are recognized by specific ubiquitin receptors to induce the required cellular response. Linear ubiquitin chains are linked through Met 1 and have been established as important players of inflammatory signalling and apoptotic cell death. These chains are generated by a ubiquitin E3 ligase complex called the linear ubiquitin chain assembly complex (LUBAC) that is thus far the only E3 ligase capable of forming linear ubiquitin chains. The complex consists of three subunits, HOIP, HOIL-1L and SHARPIN, each of which have specific roles in the observed biological functions of LUBAC. Furthermore, LUBAC has been found to be associated with OTULIN and CYLD, deubiquitinases that disassemble linear chains and counterbalance the E3 ligase activity of LUBAC. Gene mutations in HOIP, HOIL-1L and OTULIN are found in human patients who suffer from autoimmune diseases, and HOIL-1L mutations are also found in myopathy patients. In this paper, we discuss the mechanisms of linear ubiquitin chain generation and disassembly by their respective enzymes and review our current understanding of their biological functions and association with human diseases.

scholarly journals Nedd4 E3 ligase and beta-arrestins regulate ubiquitination, trafficking, and stability of the mGlu7 receptor

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Sanghyeon Lee ◽  
Sunha Park ◽  
Hyojin Lee ◽  
Seulki Han ◽  
Jae-man Song ◽  
...  
Keyword(s):  
Metabotropic Glutamate Receptor ◽  
E3 Ligase ◽  
Ubiquitin Proteasome System ◽  
Surface Expression ◽  
Degradation Pathway ◽  
Mapk Signaling ◽  
Post Translational Modification ◽  
Excitatory Neurotransmitter ◽  
Ubiquitin E3 Ligase ◽  
And Function

The metabotropic glutamate receptor 7 (mGlu7) is a class C G protein-coupled receptor that modulates excitatory neurotransmitter release at the presynaptic active zone. Although post-translational modification of cellular proteins with ubiquitin is a key molecular mechanism governing protein degradation and function, mGlu7 ubiquitination and its functional consequences have not been elucidated yet. Here, we report that Nedd4 ubiquitin E3 ligase and β-arrestins regulate ubiquitination of mGlu7 in heterologous cells and rat neurons. Upon agonist stimulation, β-arrestins recruit Nedd4 to mGlu7 and facilitate Nedd4-mediated ubiquitination of mGlu7. Nedd4 and β-arrestins regulate constitutive and agonist-induced endocytosis of mGlu7 and are required for mGlu7-dependent MAPK signaling in neurons. In addition, Nedd4-mediated ubiquitination results in the degradation of mGlu7 by both the ubiquitin-proteasome system and the lysosomal degradation pathway. These findings provide a model in which Nedd4 and β-arrestin act together as a complex to regulate mGlu7 surface expression and function at presynaptic terminals.

scholarly journals Post-translational modifications of Drosophila melanogaster HOX protein, Sex combs reduced

2019 ◽  
Author(s):  
Anirban Banerjee ◽  
Anthony Percival-Smith
Keyword(s):  
Dna Binding ◽  
Post Translational Modification ◽  
Hox Proteins ◽  
Sex Combs Reduced ◽  
Post Translational Modifications ◽  
Dna Binding Sites ◽  
Sex Combs ◽  
Evolutionarily Conserved ◽  
The Individual ◽  
Hox Protein

AbstractHomeotic selector (HOX) transcription factors (TFs) regulate gene expression that determines the identity of Drosophila segments along the anterior-posterior (A-P) axis. The current challenge with HOX proteins is understanding how they achieve their functional specificity while sharing a highly conserved homeodomain (HD) that recognize the same DNA binding sites. One mechanism proposed to regulate HOX activity is differential post-translational modification (PTM). As a first step in investigating this hypothesis, the sites of PTM on a Sex combs reduced protein fused to a triple tag (SCRTT) extracted from developing embryos were identified by Tandem Mass Spectrometry (MS/MS). The PTMs identified include phosphorylation at S185, S201, T315, S316, T317 and T324, acetylation at K218, S223, S227, K309, K434 and K439, formylation at K218, K309, K325, K341, K369, K434 and K439, methylation at S19, S166, K168 and T364, carboxylation at D108, K298, W307, K309, E323, K325 and K369, and hydroxylation at P22, Y87, P107, D108, D111, P269, P306, R310, N321, K325, Y334, R366, P392 and Y398. Of the 44 modifications, 18 map to functionally important regions of SCR. Besides a highly conserved DNA-binding HD, HOX proteins also have functionally important, evolutionarily conserved small motifs, which may be Short Linear Motifs (SLiMs). SLiMs are proposed to be preferential sites of phosphorylation. Although 6 of 7 phosphosites map to regions of predicted SLiMs, we find no support for the hypothesis that the individual S, T and Y residues of predicted SLiMs are phosphorylated more frequently than S, T and Y residues outside of predicted SLiMs.

scholarly journals Nedd4 E3 ligase and beta-arrestins regulate ubiquitination, trafficking, and stability of the mGlu7 receptor

2019 ◽  
Author(s):  
Sanghyeon Lee ◽  
Sunha Park ◽  
Hyojin Lee ◽  
Seulki Han ◽  
Jae-man Song ◽  
...  
Keyword(s):  
Metabotropic Glutamate Receptor ◽  
E3 Ligase ◽  
Surface Expression ◽  
Mapk Signaling ◽  
Post Translational Modification ◽  
Excitatory Neurotransmitter ◽  
Metabotropic Glutamate ◽  
Ubiquitin E3 Ligase ◽  
Beta Arrestins ◽  
And Function

AbstractThe metabotropic glutamate receptor 7 (mGlu7) is a class C G protein-coupled receptor (GPCR) that modulates excitatory neurotransmitter release at the presynaptic active zone. Although post-translational modification of cellular proteins with ubiquitin is a key molecular mechanism governing protein degradation and function, mGlu7 ubiquitination and its functional consequences have not been elucidated yet. Here, we report that Nedd4 ubiquitin E3 ligase and β-arrestins regulate ubiquitination of mGlu7 in heterologous cells and neurons. Upon agonist-stimulation, β-arrestins recruit Nedd4 to mGlu7 and facilitate Nedd4-mediated ubiquitination of mGlu7. Nedd4 and β-arrestins regulate constitutive and agonist-induced endocytosis of mGlu7 and are required for mGlu7-dependent MAPK signaling in neurons. In addition, Nedd4-mediated ubiquitination results in the degradation of mGlu7 by both the lysosomal and proteasomal degradation pathways. These findings provide a model in which Nedd4 and β-arrestin act together as a complex to regulate mGlu7 surface expression and function at the presynaptic terminals.

Dicarbonyl derived post-translational modifications: chemistry bridging biology and aging-related disease

2020 ◽  
Vol 64 (1) ◽  
pp. 97-110
Author(s):  
Christian Sibbersen ◽  
Mogens Johannsen
Keyword(s):  
Mass Spectrometry ◽  
Future Research ◽  
Amino Acid Residues ◽  
Post Translational Modification ◽  
Dicarbonyl Compounds ◽  
Protein Targets ◽  
Post Translational Modifications ◽  
Reactive Protein ◽  
Glycation End Products ◽  
Direct Mass Spectrometry

Abstract In living systems, nucleophilic amino acid residues are prone to non-enzymatic post-translational modification by electrophiles. α-Dicarbonyl compounds are a special type of electrophiles that can react irreversibly with lysine, arginine, and cysteine residues via complex mechanisms to form post-translational modifications known as advanced glycation end-products (AGEs). Glyoxal, methylglyoxal, and 3-deoxyglucosone are the major endogenous dicarbonyls, with methylglyoxal being the most well-studied. There are several routes that lead to the formation of dicarbonyl compounds, most originating from glucose and glucose metabolism, such as the non-enzymatic decomposition of glycolytic intermediates and fructosyl amines. Although dicarbonyls are removed continuously mainly via the glyoxalase system, several conditions lead to an increase in dicarbonyl concentration and thereby AGE formation. AGEs have been implicated in diabetes and aging-related diseases, and for this reason the elucidation of their structure as well as protein targets is of great interest. Though the dicarbonyls and reactive protein side chains are of relatively simple nature, the structures of the adducts as well as their mechanism of formation are not that trivial. Furthermore, detection of sites of modification can be demanding and current best practices rely on either direct mass spectrometry or various methods of enrichment based on antibodies or click chemistry followed by mass spectrometry. Future research into the structure of these adducts and protein targets of dicarbonyl compounds may improve the understanding of how the mechanisms of diabetes and aging-related physiological damage occur.

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