scholarly journals PICK1 inhibits the E3 ubiquitin ligase activity of Parkin and reduces its neuronal protective effect

2018 ◽  
Vol 115 (30) ◽  
pp. E7193-E7201 ◽  
Author(s):  
Jing He ◽  
Mengying Xia ◽  
Patrick K. K. Yeung ◽  
Jiahua Li ◽  
Zhifang Li ◽  
...  
Keyword(s):  
Protective Effect ◽  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Loss Of Function ◽  
Protective Function ◽  
Bar Domain ◽  
Protein Levels ◽  
Ubiquitin Ligase Activity ◽  
New Gene ◽  
Familial Parkinson’S Disease

Parkin functions as a multipurpose E3 ubiquitin ligase, and Parkin loss of function is associated with both sporadic and familial Parkinson’s disease (PD). We report that the Bin/Amphiphysin/Rvs (BAR) domain of protein interacting with PRKCA1 (PICK1) bound to the really interesting new gene 1 (RING1) domain of Parkin and potently inhibited the E3 ligase activity of Parkin by disrupting its interaction with UbcH7. Parkin translocated to damaged mitochondria and led to their degradation in neurons, whereas PICK1 robustly inhibited this process. PICK1 also impaired the protective function of Parkin against stresses in SH-SY5Y cells and neurons. The protein levels of several Parkin substrates were reduced in young PICK1-knockout mice, and these mice were resistant to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-mediated toxicity. Taken together, the results indicate that PICK1 is a potent inhibitor of Parkin, and the reduction of PICK1 enhances the protective effect of Parkin.

scholarly journals Inhibition of cIAP1 as a strategy for targeting c-MYC–driven oncogenic activity

2018 ◽  
Vol 115 (40) ◽  
pp. E9317-E9324 ◽  
Author(s):  
Haoyan Li ◽  
Yanjia Fang ◽  
Chunyi Niu ◽  
Hengyi Cao ◽  
Ting Mi ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
E3 Ligase ◽  
Pharmacological Agents ◽  
Protein Levels ◽  
Ubiquitin Ligase Activity ◽  
Molecule Inhibitor ◽  
Smac Mimetics ◽  
High Throughput Assay ◽  
In Cells

Protooncogenec-MYC, a master transcription factor, is a major driver of human tumorigenesis. Development of pharmacological agents for inhibiting c-MYC as an anticancer therapy has been a longstanding but elusive goal in the cancer field. E3 ubiquitin ligase cIAP1 has been shown to mediate the activation of c-MYC by destabilizing MAD1, a key antagonist of c-MYC. Here we developed a high-throughput assay for cIAP1 ubiquitination and identified D19, a small-molecule inhibitor of E3 ligase activity of cIAP1. We show that D19 binds to the RING domain of cIAP1 and inhibits the E3 ligase activity of cIAP1 by interfering with the dynamics of its interaction with E2. Blocking cIAP1 with D19 antagonizes c-MYC by stabilizing MAD1 protein in cells. Furthermore, we show that D19 and an improved analog (D19-14) promote c-MYC degradation and inhibit the oncogenic function of c-MYC in cells and xenograft animal models. In contrast, we show that activating E3 ubiquitin ligase activity of cIAP1 by Smac mimetics destabilizes MAD1, the antagonist of MYC, and increases the protein levels of c-MYC. Our study provides an interesting example using chemical biological approaches for determining distinct biological consequences from inhibiting vs. activating an E3 ubiquitin ligase and suggests a potential broad therapeutic strategy for targeting c-MYC in cancer treatment by pharmacologically modulating cIAP1 E3 ligase activity.

scholarly journals The E3 ubiquitin ligase RNF186 and RNF186 risk variants regulate innate receptor-induced outcomes

2021 ◽  
Vol 118 (32) ◽  
pp. e2013500118
Author(s):  
Kishu Ranjan ◽  
Matija Hedl ◽  
Clara Abraham
Keyword(s):  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Bacterial Clearance ◽  
Loss Of Function ◽  
Complex Molecules ◽  
Downstream Signaling ◽  
Signaling Complex ◽  
Risk Variants ◽  
Ubiquitin Ligase Activity ◽  
Inflammatory Bowel

Balancing microbial-induced cytokines and microbial clearance is critical at mucosal sites such as the intestine. How the inflammatory bowel disease (IBD)–associated gene RNF186 regulates this balance is unclear. We found that macrophages from IBD-risk rs6426833 carriers in the RNF186 region showed reduced cytokines to stimulation through multiple pattern recognition receptors (PRRs). Upon stimulation of PRRs, the E3-ubiquitin ligase RNF186 promoted ubiquitination of signaling complex molecules shared across PRRs and those unique to select PRRs. Furthermore, RNF186 was required for PRR-initiated signaling complex assembly and downstream signaling. RNF186, along with its intact E3-ubiquitin ligase activity, was required for optimal PRR-induced antimicrobial reactive oxygen species, reactive nitrogen species, and autophagy pathways and intracellular bacterial clearance in human macrophages and for bacterial clearance in intestinal myeloid cells. Cells transfected with the rare RNF186-A64T IBD-risk variant and macrophages from common rs6426833 RNF186 IBD-risk carriers demonstrated a reduction in these RNF186-dependent outcomes. These studies identify mechanisms through which RNF186 regulates innate immunity and show that RNF186 IBD-risk variants demonstrate a loss of function in PRR-initiated outcomes.

scholarly journals CHIP Is Associated with Parkin, a Gene Responsible for Familial Parkinson's Disease, and Enhances Its Ubiquitin Ligase Activity

2002 ◽  
Vol 10 (1) ◽  
pp. 55-67 ◽  
Author(s):  
Yuzuru Imai ◽  
Mariko Soda ◽  
Shigetsugu Hatakeyama ◽  
Takumi Akagi ◽  
Tsutomu Hashikawa ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Ubiquitin Ligase ◽  
Ubiquitin Ligase Activity ◽  
Familial Parkinson’S Disease

scholarly journals Id1 enhances RING1b E3 ubiquitin ligase activity through the Mel-18/Bmi-1 polycomb group complex

Oncogene ◽  
2010 ◽  
Vol 29 (43) ◽  
pp. 5818-5827 ◽  
Author(s):  
T Qian ◽  
J-Y Lee ◽  
J-H Park ◽  
H-J Kim ◽  
G Kong
Keyword(s):  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Polycomb Group ◽  
Ubiquitin Ligase Activity

Post-translational regulation of FLC is mediated by an E3 ubiquitin ligase activity of SINAT5 in Arabidopsis

Plant Science ◽  
2007 ◽  
Vol 173 (2) ◽  
pp. 269-275 ◽  
Author(s):  
Bong Soo Park ◽  
Wan Gyu Sang ◽  
Song Yion Yeu ◽  
Yang Do Choi ◽  
Nam-Chon Paek ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Translational Regulation ◽  
E3 Ubiquitin Ligase ◽  
Ubiquitin Ligase Activity

Abstract 18: Synoviolin, an E3 Ubiquitin Ligase, Modulates Cardiac Myocyte Size and Restores Heart Function in Hypertrophic Cardiomyopathy

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Shirin Doroudgar ◽  
Mirko Völkers ◽  
Donna J Thuerauf ◽  
Ashley Bumbar ◽  
Mohsin Khan ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Protein Misfolding ◽  
Cardiac Myocyte ◽  
Protein Quality ◽  
Heart Function ◽  
E3 Ubiquitin Ligase ◽  
Ubiquitin Ligases ◽  
Calcium Handling ◽  
Loss Of Function

The endoplasmic reticulum (ER) is essential for protein homeostasis, or proteostasis, which governs the balance of the proteome. In addition to secreted and membrane proteins, proteins bound for many other cellular locations are also made on ER-bound ribosomes, emphasizing the importance of protein quality and quantity control in the ER. Unlike cytosolic E3 ubiquitin ligases studied in the heart, synoviolin/Hrd1, which has not been studied in the heart, is an ER transmembrane E3 ubiquitin ligase, which we found to be upregulated upon protein misfolding in cardiac myocytes. Given the strategic location of synoviolin in the ER membrane, we addressed the hypothesis that synoviolin is critical for regulating the balance of the proteome, and accordingly, myocyte size. We showed that in vitro, adenovirus-mediated overexpression of synoviolin decreased cardiac myocyte size and protein synthesis, but unlike atrophy-related ubiquitin ligases, synoviolin did not increase global protein degradation. Furthermore, targeted gene therapy using adeno-associated virus 9 (AAV9) showed that overexpression of synoviolin in the left ventricle attenuated maladaptive cardiac hypertrophy and preserved cardiac function in mice subjected to trans-aortic constriction (AAV9-control TAC = 22.5 ± 6.2% decrease in EF vs. AAV9-synoviolin TAC at 6 weeks post TAC; P<0.001), and decreased mTOR activity. Since calcium is a major regulator of cardiac myocyte size, we examined the effects of synoviolin gain- or loss-of-function, using AAV9-synoviolin, or an miRNA designed to knock down synoviolin, respectively. While synoviolin gain-of-function did not affect calcium handling in isolated adult myocytes, synoviolin loss-of-function increased calcium transient amplitude (P<0.01), prolonged spark duration (P<0.001), and increased spark width (P<0.001). Spark frequency and amplitude were unaltered upon synoviolin gain- or loss-of-function. Whereas SR calcium load was unaltered by synoviolin loss-of-function, SERCA-mediated calcium removal was reduced (P<0.05). In conclusion, our studies suggest that in the heart, synoviolin is 1) a critical component of proteostasis, 2) a novel determinant of cardiac myocyte size, and 3) necessary for proper calcium handling.

Functions of RMR proteins in intracellular trafficking in the moss "Physcomitrium patens" Mitten (previously "Physcomitrella patens")

2021 ◽  
Author(s):  
◽  
Carla Coppola
Keyword(s):  
Ubiquitin Ligase ◽  
Physcomitrella Patens ◽  
Fluorescent Protein ◽  
Storage Proteins ◽  
Higher Plants ◽  
E3 Ubiquitin Ligase ◽  
E3 Ligases ◽  
Ubiquitin Ligase Activity ◽  
Vacuolar Transport

In this study, I focused on a new family of receptors, called RMRs (Receptor-like Membrane RING-H2) and I tried to investigate their role in the moss Physcomitrium patens Mitten (previously Physcomitrella patens). There is some evidence that in Angiosperms, RMRs are vacuolar receptors for the neutral/storage vacuole that is a compartment where storage proteins and metabolites are accumulated during seeds development or in somatic tissues. It is distinguished from lytic vacuole which has the same functions as animal lysosomes. The five PpRMR genes have been knocked-out, yielding viable material without visible phenotype (Ayachi, 2012). A trafficking phenotype was described by Fahr (2017) who generated the construct Citrine-Cardosin (Ci-Card) composed of the fluorescent protein Citrine fused to the C-terminal vacuolar sorting determinant (ctVSD) from cardosin A (cardosin is addressed to the vacuole in higher plants —Pereira et al., 2013). The fusion protein was delivered to the central vacuole of PpWT but mistargeted in PpRMR-KO lines, indicating that the targeting of this protein to the vacuole depends on PpRMRs. The introduction of this thesis presents the plant endomembrane system, with particular attention to vacuolar transport and ubiquitylation. In the second chapter, I show the techniques used to attempt to detect PpRMRs by Western Blot: our failure may be due to a rapid degradation of these proteins, which could prevent their detection. In the third chapter, I focused on PpRMR2 involvement in ubiquitylation. We hypothesize that PpRMRs are E3 ligases because they are members of the PA-TM-RING protein family. Most of these proteins have an E3 ubiquitin ligase activity in animals (Seroogy et al., 2004; Borchers et al., 2002), for this reason, we think that plant PpRMRs could have this function as well, which could contribute to vacuolar targeting. Indeed, I could confirm that PpRMR2 has an E3 ubiquitin ligase activity. PpRMRs substrates are still unknown in moss thus we have analysed putative candidates supposing that they could be ubiquitylated by PpRMRs. We have tested this hypothesis through in vitro ubiquitylation assays, obtaining ambiguous results. In the fourth chapter, I show preliminary results about the visible phenotype of PpRMR-KO mutants: PpWT and PpRMR-KO lines displayed phenotypic differences in leafy gametophores, which were accentuated upon salt stress exposure. Lastly, I transformed the transgenic lines PpWT/Ci-Card and Pp5KO/Ci-Card with mutated versions of PpRMR2 and analysed their effect on vacuolar transport by confocal microscopy. For most of the constructions tested, the trafficking was perturbed in both lines. Only PpWT/Ci-Card expressing PpRMR2ΔSer (lacking the Serine-Rich motif) displayed a typical vacuolar pattern.

scholarly journals E3 ubiquitin ligase MARCHF5 controls BAK apoptotic activity independently of BH3-only proteins

2022 ◽  
Author(s):  
Grant Dewson ◽  
Alan Shuai Huang ◽  
Hui San Chin ◽  
Boris Reljic ◽  
Tirta M Djajawi ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Apoptotic Cell ◽  
E3 Ubiquitin Ligase ◽  
Ubiquitin Ligase Activity ◽  
A Genome ◽  
Library Screen ◽  
Important Regulator ◽  
Apoptotic Activity ◽  
Bh3 Mimetic ◽  
Survival Proteins

Intrinsic apoptosis is principally governed by the BCL-2 family of proteins, but some non-BCL-2 proteins are also critical to control this process. To identify novel apoptosis regulators, we performed a genome-wide CRISPR-Cas9 library screen, and identified the mitochondrial E3 ubiquitin ligase MARCHF5/MITOL/RNF153 as an important regulator of BAK apoptotic function. Deleting MARCHF5 in diverse cell lines dependent on BAK conferred profound resistance to BH3-mimetic drugs. The loss of MARCHF5 or its E3 ubiquitin ligase activity surprisingly drove BAK to adopt an activated conformation, with resistance to BH3-mimetics afforded by the formation of inhibitory complexes with pro-survival proteins MCL-1 and BCL-XL. Importantly, these changes to BAK conformation and pro-survival association occurred independently of BH3-only proteins and influence on pro-survival proteins. This study identifies a new mechanism by which MARCHF5 regulates apoptotic cell death and provides new insight into how cancer cells respond to BH3-mimetic drugs. These data also highlight the emerging role of ubiquitin signalling in apoptosis that may be exploited therapeutically.

scholarly journals AtPPRT1, an E3 Ubiquitin Ligase, Enhances the Thermotolerance in Arabidopsis

Plants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1074
Author(s):  
Yu Liu ◽  
Shuya Xiao ◽  
Haoran Sun ◽  
Linsen Pei ◽  
Yingying Liu ◽  
...  
Keyword(s):  
Heat Stress ◽  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Degradation Pathway ◽  
Vital Role ◽  
Loss Of Function ◽  
Positive Role ◽  
Heat Stress Response ◽  
Acquired Thermotolerance ◽  
Ubiquitin E3 Ligase

E3 ubiquitin ligase plays a vital role in the ubiquitin-mediated heat-related protein degradation pathway. Herein, we report that the expression of AtPPRT1, a C3HC4 zinc-finger ubiquitin E3 ligase gene, was induced by heat stress, and the β-glucuronidase (GUS) gene driven by the AtPPRT1 promoter has shown increased activity after basal and acquired thermotolerance. To further explore the function of AtPPRT1 in heat stress response (HSR), we used the atpprt1 mutant and AtPPRT1-overexpressing lines (OE2 and OE10) to expose in heat shock. In this study, the atpprt1 mutant had a lower germination and survival rate than those of Col-0 when suffered from the heat stress, whereas OEs enhanced basal and acquired thermotolerance in Arabidopsis seedlings. When compared to Col-0 and OEs, loss-of-function in AtPPRT1 resulted in lower chlorophyll retention and higher content of reactive oxygen species (ROS) after heat treatment. Moreover, the transcript levels of AtPPRT1 and several heat-related genes (AtZAT12, AtHSP21 and AtHSFA7a) were upregulated to greater extents in OEs and lower extents in atpprt1 compared to Col-0 after heat treated. Hence, we suggest that AtPPRT1 may act as a positive role in regulating the high temperature by mediating the degradation of unknown target proteins.

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