scholarly journals Characterization of Brassica rapa RAP2.4-Related Proteins in Stress Response and as CUL3-Dependent E3 Ligase Substrates

Cells ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 336 ◽  
Author(s):  
Sutton Mooney ◽  
Raed Al-Saharin ◽  
Christina M. Choi ◽  
Kyle Tucker ◽  
Chase Beathard ◽  
...  
Keyword(s):  
Brassica Rapa ◽  
Stress Responses ◽  
Expression Patterns ◽  
Economic Value ◽  
E3 Ligase ◽  
26S Proteasome ◽  
Dependent Manner ◽  
E3 Ligases ◽  
Subsequent Degradation ◽  
Stress Dependent

The turnip Brassica rapa has important economic value and represents a good model system to study gene function in crop plants. ERF/AP2 transcription factors are a major group of proteins that are often involved in regulating stress-responses and developmental programs. Some ERF/AP2 proteins are targets of CULLIN3-based E3 ligases that use BTB/POZ-MATH proteins as substrate receptors. These receptors bind the transcription factor and facilitate their ubiquitylation and subsequent degradation via the 26S proteasome. Here, we show tissue and stress-dependent expression patterns for three Brassica rapa ERF/AP2 proteins that are closely related to Arabidopsis thaliana AtRAP2.4. Cloning of the Brassica genes showed that the corresponding proteins can assemble with a BPM protein and CULLIN3, and that they are instable in a 26S proteasome dependent manner. This work demonstrates the conserved nature of the ERF/AP2-CULLIN3-based E3 ligase interplay, and represents a first step to analyze their function in a commercially relevant crop plant.

scholarly journals MPSR1 is a cytoplasmic PQC E3 ligase for eliminating emergent misfolded proteins in Arabidopsis thaliana

2017 ◽  
Vol 114 (46) ◽  
pp. E10009-E10017 ◽  
Author(s):  
Jong Hum Kim ◽  
Seok Keun Cho ◽  
Tae Rin Oh ◽  
Moon Young Ryu ◽  
Seong Wook Yang ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Protein Quality ◽  
E3 Ligase ◽  
26S Proteasome ◽  
Misfolded Proteins ◽  
E3 Ligases ◽  
Proteotoxic Stress ◽  
Ring E3 Ligase ◽  
Initial Stage ◽  
Subsequent Degradation

Ubiquitin E3 ligases are crucial for eliminating misfolded proteins before they form cytotoxic aggregates that threaten cell fitness and survival. However, it remains unclear how emerging misfolded proteins in the cytoplasm can be selectively recognized and eliminated by E3 ligases in plants. We found that Misfolded Protein Sensing RING E3 ligase 1 (MPSR1) is an indispensable E3 ligase required for plant survival after protein-damaging stress. Under no stress, MPSR1 is prone to rapid degradation by the 26S proteasome, concealing its protein quality control (PQC) E3 ligase activity. Upon proteotoxic stress, MPSR1 directly senses incipient misfolded proteins and tethers ubiquitins for subsequent degradation. Furthermore, MPSR1 sustains the structural integrity of the proteasome complex at the initial stage of proteotoxic stress. Here, we suggest that the MPSR1 pathway is a constitutive mechanism for proteostasis under protein-damaging stress, as a front-line surveillance system in the cytoplasm.

scholarly journals Homeostatic scaling is driven by a translation-dependent degradation axis that recruits miRISC remodeling

PLoS Biology ◽  
2021 ◽  
Vol 19 (11) ◽  
pp. e3001432
Author(s):  
Balakumar Srinivasan ◽  
Sarbani Samaddar ◽  
Sivaram V. S. Mylavarapu ◽  
James P. Clement ◽  
Sourav Banerjee
Keyword(s):  
Ampa Receptors ◽  
E3 Ligase ◽  
26S Proteasome ◽  
Network Activity ◽  
Dependent Manner ◽  
Synaptic Homeostasis ◽  
Subsequent Degradation ◽  
The Individual ◽  
Translational Apparatus ◽  
Synthesis And Degradation

Homeostatic scaling in neurons has been attributed to the individual contribution of either translation or degradation; however, there remains limited insight toward understanding how the interplay between the two processes effectuates synaptic homeostasis. Here, we report that a codependence between protein synthesis and degradation mechanisms drives synaptic homeostasis, whereas abrogation of either prevents it. Coordination between the two processes is achieved through the formation of a tripartite complex between translation regulators, the 26S proteasome, and the miRNA-induced silencing complex (miRISC) components such as Argonaute, MOV10, and Trim32 on actively translating transcripts or polysomes. The components of this ternary complex directly interact with each other in an RNA-dependent manner. Disruption of polysomes abolishes this ternary interaction, suggesting that translating RNAs facilitate the combinatorial action of the proteasome and the translational apparatus. We identify that synaptic downscaling involves miRISC remodeling, which entails the mTORC1-dependent translation of Trim32, an E3 ligase, and the subsequent degradation of its target, MOV10 via the phosphorylation of p70 S6 kinase. We find that the E3 ligase Trim32 specifically polyubiquitinates MOV10 for its degradation during synaptic downscaling. MOV10 degradation alone is sufficient to invoke downscaling by enhancing Arc translation through its 3′ UTR and causing the subsequent removal of postsynaptic AMPA receptors. Synaptic scaling was occluded when we depleted Trim32 and overexpressed MOV10 in neurons, suggesting that the Trim32-MOV10 axis is necessary for synaptic downscaling. We propose a mechanism that exploits a translation-driven protein degradation paradigm to invoke miRISC remodeling and induce homeostatic scaling during chronic network activity.

Reciprocal antagonistic regulation of E3 ligases controls ACC synthase stability and responses to stress

2021 ◽  
Vol 118 (34) ◽  
pp. e2011900118
Author(s):  
Han Yong Lee ◽  
Hye Lin Park ◽  
Chanung Park ◽  
Yi-Chun Chen ◽  
Gyeong Mee Yoon
Keyword(s):  
Stress Responses ◽  
Molecular Mechanisms ◽  
E3 Ligase ◽  
Acc Synthase ◽  
Ethylene Biosynthesis ◽  
Cellular Protein ◽  
Dependent Manner ◽  
E3 Ligases ◽  
Seven In Absentia ◽  
Rate Limiting

Ethylene influences plant growth, development, and stress responses via crosstalk with other phytohormones; however, the underlying molecular mechanisms are still unclear. Here, we describe a mechanistic link between the brassinosteroid (BR) and ethylene biosynthesis, which regulates cellular protein homeostasis and stress responses. We demonstrate that as a scaffold, 1-aminocyclopropane-1-carboxylic acid (ACC) synthases (ACS), a rate-limiting enzyme in ethylene biosynthesis, promote the interaction between Seven-in-Absentia of Arabidopsis (SINAT), a RING-domain containing E3 ligase involved in stress response, and ETHYLENE OVERPRODUCER 1 (ETO1) and ETO1-like (EOL) proteins, the E3 ligase adaptors that target a subset of ACS isoforms. Each E3 ligase promotes the degradation of the other, and this reciprocally antagonistic interaction affects the protein stability of ACS. Furthermore, 14–3-3, a phosphoprotein-binding protein, interacts with SINAT in a BR-dependent manner, thus activating reciprocal degradation. Disrupted reciprocal degradation between the E3 ligases compromises the survival of plants in carbon-deficient conditions. Our study reveals a mechanism by which plants respond to stress by modulating the homeostasis of ACS and its cognate E3 ligases.

scholarly journals Comprehensive Analysis of the Histone Deacetylase Gene Family in Chinese Cabbage (Brassica rapa): From Evolution and Expression Pattern to Functional Analysis of BraHDA3

Agriculture ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 244
Author(s):  
Seung Hee Eom ◽  
Tae Kyung Hyun
Keyword(s):  
Functional Analysis ◽  
Brassica Rapa ◽  
Chinese Cabbage ◽  
Stress Responses ◽  
Histone Deacetylases ◽  
Expression Patterns ◽  
Evolutionary Relationship ◽  
Gene Families ◽  
Physiological Processes ◽  
Lysine Residues

Histone deacetylases (HDACs) are known as erasers that remove acetyl groups from lysine residues in histones. Although plant HDACs play essential roles in physiological processes, including various stress responses, our knowledge concerning HDAC gene families and their evolutionary relationship remains limited. In Brassica rapa genome, we identified 20 HDAC genes, which are divided into three major groups: RPD3/HDA1, HD2, and SIR2 families. In addition, seven pairs of segmental duplicated paralogs and one pair of tandem duplicated paralogs were identified in the B. rapa HDAC (BraHDAC) family, indicating that segmental duplication is predominant for the expansion of the BraHDAC genes. The expression patterns of paralogous gene pairs suggest a divergence in the function of BraHDACs under various stress conditions. Furthermore, we suggested that BraHDA3 (homologous of Arabidopsis HDA14) encodes the functional HDAC enzyme, which can be inhibited by Class I/II HDAC inhibitor SAHA. As a first step toward understanding the epigenetic responses to environmental stresses in Chinese cabbage, our results provide a solid foundation for functional analysis of the BraHDAC family.

scholarly journals SUMO3 modification by PIAS1 modulates androgen receptor cellular distribution and stability

2019 ◽  
Vol 17 (1) ◽  
Author(s):  
Nanyang Yang ◽  
Sitong Liu ◽  
Tian Qin ◽  
Xintong Liu ◽  
Nobumoto Watanabe ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Nuclear Export ◽  
Intracellular Localization ◽  
E3 Ligase ◽  
Binary Complex ◽  
Cellular Distribution ◽  
Castration Resistant Prostate Cancer ◽  
E3 Ligases ◽  
Subsequent Degradation

Abstract Background Abnormal reactivation of androgen receptor (AR) signaling in castration-resistant prostate cancer (CRPC) mainly results from overexpression and down-regulation of AR. Sumoylation of AR can influence its function. However, regulation of AR sumoylation by SUMO E3 ligases PIASs to modify AR distribution and stability are not well understood. Methods We assessed the potential effect of SUMO3 modification on AR intracellular localization by immunostaining in AR-negative prostate cancer DU145 cells, and detected the effect of PIAS1/SUMO3 overexpression on AR sumoylation related degradation. Then we characterized AR sumoylation sites involved modified by SUMO3, and the key residue of PIAS1 involved in itself sumoylation and further mediated AR sumoylation (sumo3-conjugated), translocation and degradation. Finally we detected the recognition of PIAS1 (sumoylation ligase) to MDM2, a ubiquin ligase mediated AR degradation. Results We demonstrate that SUMO E3 ligase PIAS1, along with SUMO3, mediates AR cytosolic translocation and subsequent degradation via a ubiquitin-proteasome pathway. Although AR sumoylation occurs prior to ubiquitination, the SUMO-acceptor lysine 386 on AR, together with ubiquitin-acceptor lysine 845, contribute to PIAS1/SUMO3-induced AR nuclear export, ubiquitination and subsequent degradation. Moreover, PIAS1 itself is modified by SUMO3 overexpression, and mutation of SUMO-acceptor lysine 117 on PIAS1 can impair AR cytoplasmic distribution, demonstrating the essential role of sumoylated PIAS1 in AR translocation. We further determine that sumoylated PIAS1 interacts with AR lysine 386 and 845 to form a binary complex. Consistent with the effect on AR distribution, SUMO3 modification of PIAS1 is also required for AR ubiquitination and degradation by recruiting ubiquitin E3 ligase MDM2. Conclusion Taken together, SUMO3 modification of PIAS1 modulates AR cellular distribution and stability. Our study provided the evidence the crosstalk between AR sumoylation and ubquitination mediated by PIAS1 and SUMO3.

scholarly journals Novel Approach for Characterizing Ubiquitin E3 Ligase Function

2010 ◽  
Vol 15 (10) ◽  
pp. 1220-1228 ◽  
Author(s):  
Jeffrey G. Marblestone ◽  
K. G. Suresh Kumar ◽  
Michael J. Eddins ◽  
Craig A. Leach ◽  
David E. Sterner ◽  
...  
Keyword(s):  
Drug Discovery ◽  
High Throughput Screening ◽  
E3 Ligase ◽  
Cost Effective ◽  
Ubiquitin Proteasome System ◽  
Dependent Manner ◽  
Ubiquitin Chain ◽  
E3 Ligases ◽  
Effective Manner ◽  
Wide Range

The ubiquitin-proteasome system is central to the regulation of numerous cellular events, and dysregulation may lead to disease pathogenesis. E3 ubiquitin ligases typically function in concert with E1 and E2 enzymes to recruit specific substrates, thereby coordinating their ubiquitylation and subsequent proteasomal degradation or cellular activity. E3 ligases have been implicated in a wide range of pathologies, and monitoring their activity in a rapid and cost-effective manner would be advantageous in drug discovery. The relative lack of high-throughput screening (HTS)–compliant E3 ligase assays has significantly hindered the discovery of E3 inhibitors. Herein, the authors describe a novel HTS-compliant E3 ligase assay platform that takes advantage of a ubiquitin binding domain’s inherent affinity for polyubiquitin chains, permitting the analysis of ubiquitin chain formation in an E3 ligase-dependent manner. This assay has been used successfully with members of both the RING and HECT families, demonstrating the platform’s broad utility for analyzing a wide range of E3 ligases. The utility of the assay platform is demonstrated by the identification of inhibitors of the E3 ligase CARP2. As the number of E3 ligases associated with various disease states increases, the ability to quantitate the activity of these enzymes in an expeditious manner becomes imperative in drug discovery.

scholarly journals The ARRE RING-Type E3 Ubiquitin Ligase Negatively Regulates Cuticular Wax Biosynthesis in Arabidopsis thaliana by Controlling ECERIFERUM1 and ECERIFERUM3 Protein Levels

2021 ◽  
Vol 12 ◽  
Author(s):  
Shuang Liu ◽  
Meixuezi Tong ◽  
Lifang Zhao ◽  
Xin Li ◽  
Ljerka Kunst
Keyword(s):  
Ubiquitin Ligase ◽  
Uv Light ◽  
E3 Ubiquitin Ligase ◽  
E3 Ligase ◽  
Cuticular Wax ◽  
26S Proteasome ◽  
Covalent Attachment ◽  
Wax Deposition ◽  
E3 Ligases ◽  
Ring Type

The outer epidermal cell walls of plant shoots are covered with a cuticle, a continuous lipid structure that provides protection from desiccation, UV light, pathogens, and insects. The cuticle is mostly composed of cutin and cuticular wax. Cuticular wax synthesis is synchronized with surface area expansion during plant development and is associated with plant responses to biotic and abiotic stresses. Cuticular wax deposition is tightly regulated by well-established transcriptional and post-transcriptional regulatory mechanisms, as well as post-translationally via the ubiquitin-26S proteasome system (UPS). The UPS is highly conserved in eukaryotes and involves the covalent attachment of polyubiquitin chains to the target protein by an E3 ligase, followed by the degradation of the modified protein by the 26S proteasome. A large number of E3 ligases are encoded in the Arabidopsis genome, but only a few have been implicated in the regulation of cuticular wax deposition. In this study, we have conducted an E3 ligase reverse genetic screen and identified a novel RING-type E3 ubiquitin ligase, AtARRE, which negatively regulates wax biosynthesis in Arabidopsis. Arabidopsis plants overexpressing AtARRE exhibit glossy stems and siliques, reduced fertility and fusion between aerial organs. Wax load and wax compositional analyses of AtARRE overexpressors showed that the alkane-forming branch of the wax biosynthetic pathway is affected. Co-expression of AtARRE and candidate target proteins involved in alkane formation in both Nicotiana benthamiana and stable Arabidopsis transgenic lines demonstrated that AtARRE controls the levels of wax biosynthetic enzymes ECERIFERUM1 (CER1) and ECERIFERUM3 (CER3). CER1 has also been confirmed to be a ubiquitination substrate of the AtARRE E3 ligase by an in vivo ubiquitination assay using a reconstituted Escherichia coli system. The AtARRE gene is expressed throughout the plant, with the highest expression detected in fully expanded rosette leaves and oldest stem internodes. AtARRE gene expression can also be induced by exposure to pathogens. These findings reveal that wax biosynthesis in mature plant tissues and in response to pathogen infection is controlled post-translationally.

scholarly journals Engineered degradation of EYFP-tagged CENH3 via the 26S proteasome pathway in plants

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0247015
Author(s):  
Eberhard Sorge ◽  
Dmitri Demidov ◽  
Inna Lermontova ◽  
Andreas Houben ◽  
Udo Conrad
Keyword(s):  
E3 Ligase ◽  
Adaptor Protein ◽  
26S Proteasome ◽  
Adapter Protein ◽  
Loss Of Function ◽  
Modern Biology ◽  
Interaction Domain ◽  
E3 Ligases ◽  
Mammalian Cell Lines ◽  
Proteasome Pathway

Determining the function of proteins remains a key task of modern biology. Classical genetic approaches to knocking out protein function in plants still face limitations, such as the time-consuming nature of generating homozygous transgenic lines or the risk of non-viable loss-of-function phenotypes. We aimed to overcome these limitations by acting downstream of the protein level. Chimeric E3 ligases degrade proteins of interest in mammalian cell lines, Drosophila melanogaster embryos, and transgenic tobacco. We successfully recruited the 26S proteasome pathway to directly degrade a protein of interest located in plant nuclei. This success was achieved via replacement of the interaction domain of the E3 ligase adaptor protein SPOP (Speckle-type POZ adapter protein) with a specific anti-GFP nanobody (VHHGFP4). For proof of concept, the target protein CENH3 of A. thaliana fused to EYFP was subjected to nanobody-guided proteasomal degradation in planta. Our results show the potential of the modified E3-ligase adapter protein VHHGFP4-SPOP in this respect. We were able to point out its capability for nucleus-specific protein degradation in plants.

scholarly journals Evolution and Expression Divergence of E2 Gene Family under Multiple Abiotic and Phytohormones Stresses in Brassica rapa

2018 ◽  
Vol 2018 ◽  
pp. 1-18 ◽  
Author(s):  
Nadeem Khan ◽  
Chun-mei Hu ◽  
Waleed Amjad Khan ◽  
Emal Naseri ◽  
Han Ke ◽  
...  
Keyword(s):  
Expression Pattern ◽  
Brassica Rapa ◽  
Stress Responses ◽  
Expression Patterns ◽  
Resistance Mechanism ◽  
Interaction Network ◽  
Pcr Analysis ◽  
Network Analyses ◽  
Heat And Cold Stress ◽  
Ubiquitin Conjugating Enzymes

To understand ubiquitination mechanism, E2s (ubiquitin conjugating enzymes) have crucial part as they play a major role in regulating many biological processes in plants. Meanwhile, Brassica rapa is an important leafy vegetable crop and therefore its characterization along with the expression pattern of E2s under various stresses is imperative. In this study, a total of 83 genes were identified in B. rapa and were classified into four different classes based on domain information. Here, we analyzed phylogenetic relationships, collinear correlation, gene duplication, interacting network, and expression patterns of E2 genes in B. rapa. Furthermore, RT-PCR analysis for 8 multiple abiotic and hormone treatments (namely, ABA, GA, JA, BR, PEG, NaCl, and heat and cold stress) illustrated striking expression pattern under one or more treatments, speculating that these might be stress-responsive genes. The cis-elements and interaction network analyses implicate valuable clues of important function of E2 genes in development and multiple stress responses in B. rapa. This study will further facilitate functional analysis of E2s for improving stress resistance mechanism in B. rapa.

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