scholarly journals Functions of COP1/SPA E3 Ubiquitin Ligase Mediated by MpCRY in the Liverwort Marchantia Polymorpha under Blue Light

2021 ◽  
Vol 23 (1) ◽  
pp. 158
Author(s):  
Li Zhang ◽  
Tianhong Li ◽  
Shengzhong Su ◽  
Hao Peng ◽  
Sudi Li ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Blue Light ◽  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Land Plants ◽  
Marchantia Polymorpha ◽  
Regulatory Pathway ◽  
Knock Out

COP1/SPA1 complex in Arabidopsis inhibits photomorphogenesis through the ubiquitination of multiple photo-responsive transcription factors in darkness, but such inhibiting function of COP1/SPA1 complex would be suppressed by cryptochromes in blue light. Extensive studies have been conducted on these mechanisms in Arabidopsis whereas little attention has been focused on whether another branch of land plants bryophyte utilizes this blue-light regulatory pathway. To study this problem, we conducted a study in the liverwort Marchantia polymorpha and obtained a MpSPA knock-out mutant, in which Mpspa exhibits the phenotype of an increased percentage of individuals with asymmetrical thallus growth, similar to MpCRY knock-out mutant. We also verified interactions of MpSPA with MpCRY (in a blue light-independent way) and with MpCOP1. Concomitantly, both MpSPA and MpCOP1 could interact with MpHY5, and MpSPA can promote MpCOP1 to ubiquitinate MpHY5 but MpCRY does not regulate the ubiquitination of MpHY5 by MpCOP1/MpSPA complex. These data suggest that COP1/SPA ubiquitinating HY5 is conserved in Marchantia polymorpha, but dissimilar to CRY in Arabidopsis, MpCRY is not an inhibitor of this process under blue light.

Treatment of Lymphoid and Myeloid Malignancies by Immunomodulatory Drugs

2019 ◽  
Vol 19 (1) ◽  
pp. 51-78 ◽  
Author(s):  
Ota Fuchs
Keyword(s):  
Clinical Trials ◽  
Transcription Factors ◽  
Ubiquitin Ligase ◽  
Mononuclear Cells ◽  
E3 Ubiquitin Ligase ◽  
Lymphocytic Leukemia ◽  
Monocarboxylate Transporter ◽  
Immunomodulatory Drugs ◽  
Monocarboxylate Transporter 1 ◽  
Argonaute 2

Thalidomide and its derivatives (lenalidomide, pomalidomide, avadomide, iberdomide hydrochoride, CC-885 and CC-90009) form the family of immunomodulatory drugs (IMiDs). Lenalidomide (CC5013, Revlimid®) was approved by the US FDA and the EMA for the treatment of multiple myeloma (MM) patients, low or intermediate-1 risk transfusion-dependent myelodysplastic syndrome (MDS) with chromosome 5q deletion [del(5q)] and relapsed and/or refractory mantle cell lymphoma following bortezomib. Lenalidomide has also been studied in clinical trials and has shown promising activity in chronic lymphocytic leukemia (CLL) and non-Hodgkin lymphoma (NHL). Lenalidomide has anti-inflammatory effects and inhibits angiogenesis. Pomalidomide (CC4047, Imnovid® [EU], Pomalyst® [USA]) was approved for advanced MM insensitive to bortezomib and lenalidomide. Other IMiDs are in phases 1 and 2 of clinical trials. Cereblon (CRBN) seems to have an important role in IMiDs action in both lymphoid and myeloid hematological malignancies. Cereblon acts as the substrate receptor of a cullin-4 really interesting new gene (RING) E3 ubiquitin ligase CRL4CRBN. This E3 ubiquitin ligase in the absence of lenalidomide ubiquitinates CRBN itself and the other components of CRL4CRBN complex. Presence of lenalidomide changes specificity of CRL4CRBN which ubiquitinates two transcription factors, IKZF1 (Ikaros) and IKZF3 (Aiolos), and casein kinase 1α (CK1α) and marks them for degradation in proteasomes. Both these transcription factors (IKZF1 and IKZF3) stimulate proliferation of MM cells and inhibit T cells. Low CRBN level was connected with insensitivity of MM cells to lenalidomide. Lenalidomide decreases expression of protein argonaute-2, which binds to cereblon. Argonaute-2 seems to be an important drug target against IMiDs resistance in MM cells. Lenalidomide decreases also basigin and monocarboxylate transporter 1 in MM cells. MM cells with low expression of Ikaros, Aiolos and basigin are more sensitive to lenalidomide treatment. The CK1α gene (CSNK1A1) is located on 5q32 in commonly deleted region (CDR) in del(5q) MDS. Inhibition of CK1α sensitizes del(5q) MDS cells to lenalidomide. CK1α mediates also survival of malignant plasma cells in MM. Though, inhibition of CK1α is a potential novel therapy not only in del(5q) MDS but also in MM. High level of full length CRBN mRNA in mononuclear cells of bone marrow and of peripheral blood seems to be necessary for successful therapy of del(5q) MDS with lenalidomide. While transfusion independence (TI) after lenalidomide treatment is more than 60% in MDS patients with del(5q), only 25% TI and substantially shorter duration of response with occurrence of neutropenia and thrombocytopenia were achieved in lower risk MDS patients with normal karyotype treated with lenalidomide. Shortage of the biomarkers for lenalidomide response in these MDS patients is the main problem up to now.

scholarly journals Deep evolutionary origin of gamete-directed zygote activation by KNOX/BELL transcription factors in green plants

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Tetsuya Hisanaga ◽  
Shota Fujimoto ◽  
Yihui Cui ◽  
Katsutoshi Sato ◽  
Ryosuke Sano ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Transcription Factors ◽  
Chlamydomonas Reinhardtii ◽  
Plant Species ◽  
Land Plant ◽  
Land Plants ◽  
Marchantia Polymorpha ◽  
Mating Types ◽  
Meristem Maintenance

KNOX and BELL transcription factors regulate distinct steps of diploid development in plants. In the green alga Chlamydomonas reinhardtii, KNOX and BELL proteins are inherited by gametes of the opposite mating types and heterodimerize in zygotes to activate diploid development. By contrast, in land plants such as Physcomitrium patens and Arabidopsis thaliana, KNOX and BELL proteins function in meristem maintenance and organogenesis during the later stages of diploid development. However, whether the contrasting functions of KNOX and BELL were acquired independently in algae and land plants is currently unknown. Here, we show that in the basal land plant species Marchantia polymorpha, gamete-expressed KNOX and BELL are required to initiate zygotic development by promoting nuclear fusion in a manner strikingly similar to that in C. reinhardtii. Our results indicate that zygote activation is the ancestral role of KNOX/BELL transcription factors, which shifted toward meristem maintenance as land plants evolved.

scholarly journals A Novel Degron-mediated Degradation of the RTG Pathway Regulator, Mks1p, by SCFGrr1

2005 ◽  
Vol 16 (10) ◽  
pp. 4893-4904 ◽  
Author(s):  
Zhengchang Liu ◽  
Mário Spírek ◽  
Janet Thornton ◽  
Ronald A. Butow
Keyword(s):  
Transcription Factors ◽  
Ubiquitin Ligase ◽  
Positive Charge ◽  
E3 Ubiquitin Ligase ◽  
Retrograde Signaling ◽  
Yeast Cells ◽  
Leucine Rich Repeat ◽  
Negative Regulators ◽  
Acidic Domain ◽  
Lrr Domain

Yeast cells respond to mitochondrial dysfunction by altering the expression of a subset of nuclear genes, a process known as retrograde signaling (RS). RS terminates with two transcription factors, Rtg1p and Rtg3p. One positive regulator, Rtg2p, and four negative regulators, Lst8p, Mks1p, and the redundant 14-3-3 proteins, Bmh1p and Bmh2p, control RS upstream of Rtg1/3p. Mks1p is negatively regulated by binding to Rtg2p and positively regulated when bound to Bmh1/2p. Here we report that Grr1p, a component of the SCFGrr1 E3 ubiquitin ligase, modulates RS by affecting Mks1p levels. Grr1p polyubiquitinates Mks1p not bound to either Rtg2p or to Bmh1/2p, targeting it for degradation. An acidic domain region of Mks1p constitutes the portable Mks1p degron sequence. We have isolated dominant mutations in Grr1p leading to increased Mks1p degradation. These mutations result in a gain of positive charge on the concave surface of the leucine rich repeat (LRR) domain of Grr1p, the proposed substrate binding site. We propose that Mks1p is a central player of RS and is acted upon by multiple regulators of the pathway.

scholarly journals The Human Adenovirus Type 5 E4orf6/E1B55K E3 Ubiquitin Ligase Complex Can Mimic E1A Effects on E2F

mSphere ◽  
2015 ◽  
Vol 1 (1) ◽  
Author(s):  
Frédéric Dallaire ◽  
Sabrina Schreiner ◽  
G. Eric Blair ◽  
Thomas Dobner ◽  
Philip E. Branton ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Dna Synthesis ◽  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Viral Gene Expression ◽  
Adenovirus Vector ◽  
Human Adenovirus ◽  
Viral Gene ◽  
E2f Transcription Factors

ABSTRACT During the course of work on the adenovirus E3 ubiquitin ligase formed by the viral E4orf6 and E1B55K proteins, we found, very surprisingly, that expression of these species was sufficient to permit low levels of replication of an adenovirus vector lacking E1A, the central regulator of infection. E1A products uncouple E2F transcription factors from Rb repression complexes, thus stimulating viral gene expression and cell and viral DNA synthesis. We found that the E4orf6/E1B55K ligase mimics these functions. This finding is of significance because it represents an entirely new function for the ligase in regulating adenovirus replication. The human adenovirus E4orf6/E1B55K E3 ubiquitin ligase is well known to promote viral replication by degrading an increasing number of cellular proteins that inhibit the efficient production of viral progeny. We report here a new function of the adenovirus 5 (Ad5) viral ligase complex that, although at lower levels, mimics effects of E1A products on E2F transcription factors. When expressed in the absence of E1A, the E4orf6 protein in complex with E1B55K binds E2F, disrupts E2F/retinoblastoma protein (Rb) complexes, and induces hyperphosphorylation of Rb, leading to induction of viral and cellular DNA synthesis as well as stimulation of early and late viral gene expression and production of viral progeny of E1/E3-defective adenovirus vectors. These new and previously undescribed functions of the E4orf6/E1B55K E3 ubiquitin ligase could play an important role in promoting the replication of wild-type viruses. IMPORTANCE During the course of work on the adenovirus E3 ubiquitin ligase formed by the viral E4orf6 and E1B55K proteins, we found, very surprisingly, that expression of these species was sufficient to permit low levels of replication of an adenovirus vector lacking E1A, the central regulator of infection. E1A products uncouple E2F transcription factors from Rb repression complexes, thus stimulating viral gene expression and cell and viral DNA synthesis. We found that the E4orf6/E1B55K ligase mimics these functions. This finding is of significance because it represents an entirely new function for the ligase in regulating adenovirus replication.

scholarly journals Deep evolutionary origin of gamete-directed zygote activation by KNOX/BELL transcription factors in green plants

2020 ◽  
Author(s):  
Tetsuya Hisanaga ◽  
Shota Fujimoto ◽  
Yihui Cui ◽  
Katsutoshi Sato ◽  
Ryosuke Sano ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Chlamydomonas Reinhardtii ◽  
Plant Species ◽  
Green Alga ◽  
Land Plant ◽  
Land Plants ◽  
Marchantia Polymorpha ◽  
Mating Types ◽  
Meristem Maintenance

AbstractKNOX and BELL transcription factors regulate distinct steps of diploid development in the green lineages. In the green alga Chlamydomonas reinhardtii, KNOX and BELL proteins are inherited by gametes of the opposite mating types, and heterodimerize in zygotes to activate diploid development. By contrast, in land plants such as Physcomitrella and Arabidopsis, KNOX and BELL proteins function in meristem maintenance and organogenesis during the later stages of diploid development. However, whether the contrasting functions of KNOX and BELL were acquired independently in algae and land plants is currently unknown. Here we show that in the basal land plant species Marchantia polymorpha, gamete-expressed KNOX and BELL are required to initiate zygotic development by promoting nuclear fusion in a manner strikingly similar to that of C. reinhardtii. Our results indicate that zygote activation is the ancestral role of KNOX/BELL transcription factors, which shifted toward meristem maintenance as land plants evolved.

scholarly journals Major components in the KARRIKIN INSENSITIVE2-ligand signaling pathway are conserved in the liverwort, Marchantia polymorpha

2020 ◽  
Author(s):  
Yohei Mizuno ◽  
Aino Komatsu ◽  
Shota Shimazaki ◽  
Xiaonan Xie ◽  
Kimitsune Ishizaki ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Ubiquitin Ligase ◽  
Common Ancestor ◽  
Marchantia Polymorpha ◽  
Wild Type ◽  
Knock Out ◽  
Ubiquitin Ligase Complex ◽  
The Common ◽  
F Box Protein ◽  
And Control

AbstractKARRIKIN INSENSITIVE2 (KAI2) was first identified in Arabidopsis thaliana as a receptor of karrikin, a smoke-derived germination stimulant. KAI2 is also considered a receptor of an unidentified endogenous molecule called the KAI2-ligand (KL). Upon KAI2 activation, signals are transmitted through degradation of D53/SMXL proteins via ubiquitination by a Skp-Cullin-F-box (SCF) E3 ubiquitin ligase complex. All components in the KL signaling pathway exist in the liverwort Marchantia polymorpha, namely MpKAI2A and MpKAI2B, MpMAX2 encoding the F-box protein, and MpSMXL, indicating that the signaling pathway became functional in the common ancestor of bryophytes and seed plants. Genetic analysis using knock-out mutants of these KL signaling genes, produced using the CRISPR system, indicated that MpKAI2A, MpMAX2 and MpSMXL act in the same genetic pathway and control early gemma growth. Introduction of MpSMXLd53, in which a domain required for degradation is mutated, into wild-type plants caused phenotypes resembling those of the Mpkai2a and Mpmax2 mutants. In addition, Citrine fluorescence was detected in tobacco cells transiently transformed with the 35S:MpSMXL-Citrine gene construct and treated with MG132, a proteasome inhibitor. On the other hand, introduction of 35S:MpSMXLd53-Citrine conferred Citrine fluorescence without MG132 treatment. These findings imply that MpSMXL is subjected to degradation, and that degradation of MpSMXL is crucial for KL signaling in M. polymorpha. We also showed that MpSMXL is negatively regulated by KL signaling. Taken together, this study demonstrates that basic mechanisms in the KL signaling pathway are conserved in M. polymorpha.

scholarly journals Targeting oncoproteins with a positive selection assay for protein degraders

2021 ◽  
Vol 7 (6) ◽  
pp. eabd6263
Author(s):  
Vidyasagar Koduri ◽  
Leslie Duplaquet ◽  
Benjamin L. Lampson ◽  
Adam C. Wang ◽  
Amin H. Sabet ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Transcription Factor ◽  
Transcription Factors ◽  
Small Molecules ◽  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Signal To Noise ◽  
Independent Manner ◽  
Intracellular Proteins ◽  
Oncogenic Transcription Factor

Most intracellular proteins lack hydrophobic pockets suitable for altering their function with drug-like small molecules. Recent studies indicate that some undruggable proteins can be targeted by compounds that can degrade them. For example, thalidomide-like drugs (IMiDs) degrade the critical multiple myeloma transcription factors IKZF1 and IKZF3 by recruiting them to the cereblon E3 ubiquitin ligase. Current loss of signal (“down”) assays for identifying degraders often exhibit poor signal-to-noise ratios, narrow dynamic ranges, and false positives from compounds that nonspecifically suppress transcription or translation. Here, we describe a gain of signal (“up”) assay for degraders. In arrayed chemical screens, we identified novel IMiD-like IKZF1 degraders and Spautin-1, which, unlike the IMiDs, degrades IKZF1 in a cereblon-independent manner. In a pooled CRISPR-Cas9–based screen, we found that CDK2 regulates the abundance of the ASCL1 oncogenic transcription factor. This methodology should facilitate the identification of drugs that directly or indirectly degrade undruggable proteins.

scholarly journals E3 ubiquitin ligase RFWD2 controls lung branching through protein-level regulation of ETV transcription factors

2016 ◽  
Vol 113 (27) ◽  
pp. 7557-7562 ◽  
Author(s):  
Yan Zhang ◽  
Shigetoshi Yokoyama ◽  
John C. Herriges ◽  
Zhen Zhang ◽  
Randee E. Young ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Ubiquitin Ligase ◽  
Protein Level ◽  
E3 Ubiquitin Ligase ◽  
Transcript Level ◽  
Branching Morphogenesis ◽  
Normal Lung ◽  
Lung Epithelium ◽  
E3 Ligases ◽  
Lung Branching

The mammalian lung is an elaborate branching organ, and it forms following a highly stereotypical morphogenesis program. It is well established that precise control at the transcript level is a key genetic underpinning of lung branching. In comparison, little is known about how regulation at the protein level may play a role. Ring finger and WD domain 2 (RFWD2, also termed COP1) is an E3 ubiquitin ligase that modifies specific target proteins, priming their degradation via the ubiquitin proteasome system. RFWD2 is known to function in the adult in pathogenic processes such as tumorigenesis. Here, we show that prenatal inactivation of Rfwd2 gene in the lung epithelium led to a striking halt in branching morphogenesis shortly after secondary branch formation. This defect is accompanied by distalization of the lung epithelium while growth and cellular differentiation still occurred. In the mutant lung, two E26 transformation-specific (ETS) transcription factors essential for normal lung branching, ETS translocation variant 4 (ETV4) and ETV5, were up-regulated at the protein level, but not at the transcript level. Introduction of Etv loss-of-function alleles into the Rfwd2 mutant background attenuated the branching phenotype, suggesting that RFWD2 functions, at least in part, through degrading ETV proteins. Because a number of E3 ligases are known to target factors important for lung development, our findings provide a preview of protein-level regulatory network essential for lung branching morphogenesis.

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