scholarly journals Vaccinia-Related Kinase 2 Controls the Stability of the Eukaryotic Chaperonin TRiC/CCT by Inhibiting the Deubiquitinating Enzyme USP25

2015 ◽  
Vol 35 (10) ◽  
pp. 1754-1762 ◽  
Author(s):  
Sangjune Kim ◽  
Dohyun Lee ◽  
Juhyun Lee ◽  
Haengjin Song ◽  
Hyo-Jin Kim ◽  
...  
Keyword(s):  
Protein Aggregation ◽  
Ubiquitin Proteasome System ◽  
Mutant Protein ◽  
Critical Pathway ◽  
Interacting Protein ◽  
Protein Levels ◽  
Functional Regulation ◽  
The Stability ◽  
And Function ◽  
Polyglutamine Protein

Molecular chaperones monitor the proper folding of misfolded proteins and function as the first line of defense against mutant protein aggregation in neurodegenerative diseases. The eukaryotic chaperonin TRiC is a potent suppressor of mutant protein aggregation and toxicity in early stages of disease progression. Elucidation of TRiC functional regulation will enable us to better understand the pathological mechanisms of neurodegeneration. We have previously shown that vaccinia-related kinase 2 (VRK2) downregulates TRiC protein levels through the ubiquitin-proteasome system by recruiting the E3 ligase COP1. However, although VRK2 activity was necessary in TRiC downregulation, the phosphorylated substrate was not determined. Here, we report that USP25 is a novel TRiC interacting protein that is also phosphorylated by VRK2. USP25 catalyzed deubiquitination of the TRiC protein and stabilized the chaperonin, thereby reducing accumulation of misfolded polyglutamine protein aggregates. Notably, USP25 deubiquitinating activity was suppressed when VRK2 phosphorylated the Thr680, Thr727, and Ser745residues. Impaired USP25 deubiquitinating activity after VRK2-mediated phosphorylation may be a critical pathway in TRiC protein destabilization.

scholarly journals DBC1 (Deleted in Breast Cancer 1) modulates the stability and function of the nuclear receptor Rev-erbα

2013 ◽  
Vol 451 (3) ◽  
pp. 453-461 ◽  
Author(s):  
Claudia C. S. Chini ◽  
Carlos Escande ◽  
Veronica Nin ◽  
Eduardo N. Chini
Keyword(s):  
Breast Cancer ◽  
Nuclear Receptor ◽  
Clock Genes ◽  
Mrna Levels ◽  
Protein Levels ◽  
The Stability ◽  
And Function ◽  
Interfering Rna ◽  
In Cells

The nuclear receptor Rev-erbα has been implicated as a major regulator of the circadian clock and integrates circadian rhythm and metabolism. Rev-erbα controls circadian oscillations of several clock genes and Rev-erbα protein degradation is important for maintenance of the circadian oscillations and also for adipocyte differentiation. Elucidating the mechanisms that regulate Rev-erbα stability is essential for our understanding of these processes. In the present paper, we report that the protein DBC1 (Deleted in Breast Cancer 1) is a novel regulator of Rev-erbα. Rev-erbα and DBC1 interact in cells and in vivo, and DBC1 modulates the Rev-erbα repressor function. Depletion of DBC1 by siRNA (small interfering RNA) in cells or in DBC1-KO (knockout) mice produced a marked decrease in Rev-erbα protein levels, but not in mRNA levels. In contrast, DBC1 overexpression significantly enhanced Rev-erbα protein stability by preventing its ubiquitination and degradation. The regulation of Rev-erbα protein levels and function by DBC1 depends on both the N-terminal and C-terminal domains of DBC1. More importantly, in cells depleted of DBC1, there was a dramatic decrease in circadian oscillations of both Rev-erbα and BMAL1. In summary, our data identify DBC1 as an important regulator of the circadian receptor Rev-erbα and proposes that Rev-erbα could be involved in mediating some of the physiological effects of DBC1.

scholarly journals Nedd4-dependent lysine-11-linked polyubiquitination of the tumour suppressor Beclin 1

2011 ◽  
Vol 441 (1) ◽  
pp. 399-406 ◽  
Author(s):  
Harald W. Platta ◽  
Hilde Abrahamsen ◽  
Sigrid B. Thoresen ◽  
Harald Stenmark
Keyword(s):  
Tumour Suppressor ◽  
Beclin 1 ◽  
Class Iii ◽  
Phosphatidylinositol 3 Kinase ◽  
Interacting Protein ◽  
Polyubiquitin Chains ◽  
Protein Levels ◽  
Regulatory Link ◽  
A Subunit ◽  
The Stability

Beclin 1, a subunit of the class III phosphatidylinositol 3-kinase complex, is a tumour suppressor with a central role in endocytic trafficking, cytokinesis and the cross-regulation between autophagy and apoptosis. Interestingly, not only reduced expression but also overexpression of Beclin 1 is correlated with cancer development and metastasis. Thus it seems necessary for the cell to balance the protein levels of Beclin 1. In the present study we describe a regulatory link between Beclin 1 and the ubiquitin ligase Nedd4 (neural-precursor-cell-expressed developmentally down-regulated 4). We establish Nedd4 as a novel binding partner of Beclin 1 and demonstrate that Nedd4 polyubiquitinates Beclin 1 with Lys11- and Lys63-linked chains. Importantly, Nedd4 expression controls the stability of Beclin 1, and depletion of the Beclin 1-interacting protein VPS34 causes Nedd4-mediated proteasomal degradation of Beclin 1 via Lys11-linked polyubiquitin chains. Beclin 1 is thus the first tumour suppressor reported to be controlled by Lys11-linked polyubiquitination.

scholarly journals Polymerase delta-interacting protein 38 (PDIP38) modulates the stability and activity of the mitochondrial AAA+ protease CLPXP

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Philip R. Strack ◽  
Erica J. Brodie ◽  
Hanmiao Zhan ◽  
Verena J. Schuenemann ◽  
Liz J. Valente ◽  
...  
Keyword(s):  
Adaptor Protein ◽  
Subcellular Location ◽  
Binding Pocket ◽  
Dependent Manner ◽  
Interacting Protein ◽  
The Matrix ◽  
Bona Fide ◽  
The Stability ◽  
And Function ◽  
Zinc Binding Domain

Abstract Over a decade ago Polymerase δ interacting protein of 38 kDa (PDIP38) was proposed to play a role in DNA repair. Since this time, both the physiological function and subcellular location of PDIP38 has remained ambiguous and our present understanding of PDIP38 function has been hampered by a lack of detailed biochemical and structural studies. Here we show, that human PDIP38 is directed to the mitochondrion in a membrane potential dependent manner, where it resides in the matrix compartment, together with its partner protein CLPX. Our structural analysis revealed that PDIP38 is composed of two conserved domains separated by an α/β linker region. The N-terminal (YccV-like) domain of PDIP38 forms an SH3-like β-barrel, which interacts specifically with CLPX, via the adaptor docking loop within the N-terminal Zinc binding domain of CLPX. In contrast, the C-terminal (DUF525) domain forms an immunoglobin-like β-sandwich fold, which contains a highly conserved putative substrate binding pocket. Importantly, PDIP38 modulates the substrate specificity of CLPX and protects CLPX from LONM-mediated degradation, which stabilises the cellular levels of CLPX. Collectively, our findings shed new light on the mechanism and function of mitochondrial PDIP38, demonstrating that PDIP38 is a bona fide adaptor protein for the mitochondrial protease, CLPXP.

P5998The Phosphodiesterase 4D interacting protein averts volume overload - but not pressure overload-induced pathological myocardial remodeling

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
B A Mohamed ◽  
M Elkenani ◽  
J Jakubiczka-Smorag ◽  
M Bader ◽  
G Hasenfuss ◽  
...  
Keyword(s):  
Pressure Overload ◽  
Mortality Rates ◽  
Structure And Function ◽  
Cardiac Structure ◽  
Myocardial Remodeling ◽  
Interacting Protein ◽  
Protein Levels ◽  
Cardiac Structure And Function ◽  
And Function ◽  
Phosphodiesterase 4D

Abstract Background Although volume- and pressure-overload (VO and PO, respectively) are hemodynamic stress, each results in distinct phenotypes. The Phosphodiesterase 4D interacting protein (PDE4DIP) is a protein involved in cardiac muscle contraction and suggested to play a role in cardiomyopathy. We previously identified Pde4dip transcript as being downregulated in VO but upregulated in PO. Objective We wanted to address whether Pde4dip deletion would alter the progression of pathological myocardial remodeling and heart failure (HF) following hemodynamic stress. Methods Pde4dip knockout (Pde4dip-KO) and age- and sex-matched wild-type (WT) mice were exposed to aortocaval shunt-triggered VO or transthoracic aortic constriction (TAC)-induced PO. Mortality rates were assessed and the cardiac structure and function were determined by serial echocardiography. Results The PDE4DIP protein levels decreased significantly in volume-overloaded hearts. However, pressure-overloaded hearts did not alter PDE4DIP protein levels, suggesting different posttranscriptional modifications that might affect the PDE4DIP protein expression in VO versus PO. The Pde4dip-KO Hearts were structurally and functionally normal in echocardiographic and morphometric analyses. However, Pde4dip deletion mildly attenuated the mortality rates in shunt-, but not in TAC-operated mice. A significant deterioration of left ventricle geometry and function was observed in volume-overloaded WT hearts at 12 weeks after shunt, but preserved cardiac function were noticed in shunt-operated Pde4dip-KO mice. On the other hand, TAC-operated WT and Pde4dip-KO mice exhibited a significant, but comparable deterioration of cardiac structure and function compared to sham mice. Conclusion Here we identified the PDE4DIP as an essential regulator of pathological myocardial remodeling following VO, but irrelevant to the development of cardiac dysfunction after TAC. Further investigations are warranted to dissect the possible mechanisms underlying the protective role of PDE4DIP deletion in the setting of VO. Acknowledgement/Funding This work was supported by DFG (SFB1002 project D04 to KT and D01 to GH; IRTG1816 to ME); BAM was funded by DSHF

scholarly journals The WD40-repeat protein WDR-48 promotes the stability of the deubiquitinating enzyme USP-46 by inhibiting its ubiquitination and degradation

2020 ◽  
Vol 295 (33) ◽  
pp. 11776-11788
Author(s):  
Molly Hodul ◽  
Rakesh Ganji ◽  
Caroline L. Dahlberg ◽  
Malavika Raman ◽  
Peter Juo
Keyword(s):  
Mammalian Cells ◽  
Deubiquitinating Enzymes ◽  
Post Translational Modification ◽  
Wd40 Repeat ◽  
C Elegans ◽  
Protein Levels ◽  
Specific Protease ◽  
The Stability ◽  
And Function

Ubiquitination is a reversible post-translational modification that has emerged as a critical regulator of synapse development and function. However, the mechanisms that regulate the deubiquitinating enzymes (DUBs) responsible for the removal of ubiquitin from target proteins are poorly understood. We have previously shown that the DUB ubiquitin-specific protease 46 (USP-46) removes ubiquitin from the glutamate receptor GLR-1 and regulates its trafficking and degradation in Caenorhabditis elegans. We found that the WD40-repeat proteins WDR-20 and WDR-48 bind and stimulate the catalytic activity of USP-46. Here, we identified another mechanism by which WDR-48 regulates USP-46. We found that increased expression of WDR-48, but not WDR-20, promotes USP-46 abundance in mammalian cells in culture and in C. elegans neurons in vivo. Inhibition of the proteasome increased USP-46 abundance, and this effect was nonadditive with increased WDR-48 expression. We found that USP-46 is ubiquitinated and that expression of WDR-48 reduces the levels of ubiquitin–USP-46 conjugates and increases the t1/2 of USP-46. A point-mutated WDR-48 variant that disrupts binding to USP-46 was unable to promote USP-46 abundance in vivo. Finally, siRNA-mediated knockdown of wdr48 destabilizes USP46 in mammalian cells. Together, these results support a model in which WDR-48 binds and stabilizes USP-46 protein levels by preventing the ubiquitination and degradation of USP-46 in the proteasome. Given that a large number of USPs interact with WDR proteins, we propose that stabilization of DUBs by their interacting WDR proteins may be a conserved and widely used mechanism that controls DUB availability and function.

scholarly journals The WD40-repeat protein WDR-48 promotes the stability of the deubiquitinating enzyme USP-46 by inhibiting its ubiquitination and degradation

2019 ◽  
Author(s):  
Molly Hodul ◽  
Rakesh Ganji ◽  
Caroline L Dahlberg ◽  
Malavika Raman ◽  
Peter Juo
Keyword(s):  
Mammalian Cells ◽  
Deubiquitinating Enzyme ◽  
Deubiquitinating Enzymes ◽  
Post Translational Modification ◽  
Wd40 Repeat ◽  
C Elegans ◽  
Protein Levels ◽  
The Stability ◽  
And Function

ABSTRACTUbiquitination is a reversible post-translational modification that has emerged as a critical regulator of synapse development and function. However, mechanisms that regulate the deubiquitinating enzymes (DUBs) that are responsible for the removal of ubiquitin from target proteins are poorly understood. We previously showed that the DUB USP-46 removes ubiquitin from the glutamate receptor GLR-1 and regulates it trafficking and degradation in C. elegans. We found that WD40-repeat proteins WDR-20 and WDR-48 bind and stimulate the catalytic activity of USP-46. Here, we identify another mechanism by which WDR-48 regulates USP-46. We found that increased expression of WDR-48, but not WDR-20, promotes USP-46 abundance in mammalian cells in culture and in C. elegans neurons in vivo. Inhibition of the proteasome promotes the abundance of USP-46, and this effect is non-additive with increased expression of WDR-48. We found that USP-46 is ubiquitinated, and expression of WDR-48 reduces the levels of ubiquitin-USP-46 conjugates and increases the half-life of USP-46. A point mutant version of WDR-48 that disrupts binding to USP-46 is unable to promote USP-46 abundance in vivo. Together, these data support a model in which WDR-48 binds and stabilizes USP-46 protein levels by preventing the ubiquitination and degradation of USP-46 in the proteasome. Given that a large number of USPs interact with WDR proteins, we propose that stabilization of DUBs by their interacting WDR proteins may be a conserved and widely used mechanism to control DUB availability and function.

scholarly journals APC/CFZR-1 Controls SAS-5 Levels to Regulate Centrosome Duplication in Caenorhabditis elegans

2017 ◽  
Author(s):  
Jeffrey C. Medley ◽  
Lauren E. DeMeyer ◽  
Megan M. Kabara ◽  
Mi Hye Song
Keyword(s):  
Cell Division ◽  
Caenorhabditis Elegans ◽  
Ubiquitin Proteasome System ◽  
Mitotic Cell ◽  
Early Embryo ◽  
Negative Regulator ◽  
Centrosome Duplication ◽  
Microtubule Organizing Center ◽  
Protein Levels ◽  
And Function

ABSTRACTAs the primary microtubule-organizing center, centrosomes play a key role in establishing mitotic bipolar spindles that secure correct transmission of genomic content. For the fidelity of cell division, centrosome number must be strictly controlled by duplicating only once per cell cycle. Proper levels of centrosome proteins are shown to be critical for normal centrosome number and function. Overexpressing core centrosome factors leads to extra centrosomes, while depleting these factors results in centrosome duplication failure. In this regard, protein turnover by the ubiquitin-proteasome system provides a vital mechanism for the regulation of centrosome protein levels. Here, we report that FZR-1, the Caenorhabditis elegans homolog of Cdh1/Hct1/Fzr, a co-activator of the anaphase promoting complex/cyclosome (APC/C), an E3 ubiquitin ligase, functions as a negative regulator of centrosome duplication in the Caenorhabditis elegans embryo. During mitotic cell division in the early embryo, FZR-1 is associated with centrosomes and enriched at nuclei. Loss of fzr-1 function restores centrosome duplication and embryonic viability to the hypomorphic zyg-1(it25) mutant, in part, through elevated levels of SAS-5 at centrosomes. Our data suggest that the APC/CFZR-1 regulates SAS-5 levels by directly recognizing the conserved KEN-box motif, contributing to proper centrosome duplication. Together, our work shows that FZR-1 plays a conserved role in regulating centrosome duplication in Caenorhabditis elegans.

scholarly journals Dimerization of CUL7 and PARC Is Not Required for All CUL7 Functions and Mouse Development

2005 ◽  
Vol 25 (13) ◽  
pp. 5579-5589 ◽  
Author(s):  
Jeffrey R. Skaar ◽  
Takehiro Arai ◽  
James A. DeCaprio
Keyword(s):  
Knockout Mice ◽  
Cytoplasmic Protein ◽  
Mouse Development ◽  
Interacting Protein ◽  
Targeted Deletion ◽  
Neonatal Lethality ◽  
The Stability ◽  
And Function

ABSTRACT CUL7, a recently identified member of the cullin family of E3 ubiquitin ligases, forms a unique SCF-like complex and is required for mouse embryonic development. To further investigate CUL7 function, we sought to identify CUL7 binding proteins. The p53-associated, parkin-like cytoplasmic protein (PARC), a homolog of CUL7, was identified as a CUL7-interacting protein by mass spectrometry. The heterodimerization of PARC and CUL7, as well as homodimerization of PARC and CUL7, was confirmed in vivo. To determine the biological role of PARC by itself and in conjunction with CUL7, a targeted deletion of Parc was created in the mouse. In contrast to the neonatal lethality of the Cul7 knockout mice, Parc knockout mice were born at the expected Mendelian ratios and exhibited no apparent phenotype. Additionally, Parc deletion did not appear to affect the stability or function of p53. These results suggest that PARC and CUL7 form an endogenous complex and that PARC and CUL7 functions are at least partially nonoverlapping. In addition, although PARC and p53 form a complex, the absence of effect of Parc deletion on p53 stability, localization, and function suggests that p53 binding to PARC may serve to control PARC function.

scholarly journals The Chaperone-Like Protein HYPK Acts Together with NatA in Cotranslational N-Terminal Acetylation and Prevention of Huntingtin Aggregation

2010 ◽  
Vol 30 (8) ◽  
pp. 1898-1909 ◽  
Author(s):  
Thomas Arnesen ◽  
Kristian K. Starheim ◽  
Petra Van Damme ◽  
Rune Evjenth ◽  
Huyen Dinh ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Protein Translation ◽  
Physical Interaction ◽  
Interacting Protein ◽  
Protein Levels ◽  
Substrate Protein ◽  
Cycle Arrest ◽  
The Stability ◽  
Green Fluorescent

ABSTRACT The human NatA protein Nα-terminal-acetyltransferase complex is responsible for cotranslational N-terminal acetylation of proteins with Ser, Ala, Thr, Gly, and Val N termini. The NatA complex is composed of the catalytic subunit hNaa10p (hArd1) and the auxiliary subunit hNaa15p (hNat1/NATH). Using immunoprecipitation coupled with mass spectrometry, we identified endogenous HYPK, a Huntingtin (Htt)-interacting protein, as a novel stable interactor of NatA. HYPK has chaperone-like properties preventing Htt aggregation. HYPK, hNaa10p, and hNaa15p were associated with polysome fractions, indicating a function of HYPK associated with the NatA complex during protein translation. Knockdown of both hNAA10 and hNAA15 decreased HYPK protein levels, possibly indicating that NatA is required for the stability of HYPK. The biological importance of HYPK was evident from HYPK-knockdown HeLa cells displaying apoptosis and cell cycle arrest in the G0/G1 phase. Knockdown of HYPK or hNAA10 resulted in increased aggregation of an Htt-enhanced green fluorescent protein (Htt-EGFP) fusion with expanded polyglutamine stretches, suggesting that both HYPK and NatA prevent Htt aggregation. Furthermore, we demonstrated that HYPK is required for N-terminal acetylation of the known in vivo NatA substrate protein PCNP. Taken together, the data indicate that the physical interaction between HYPK and NatA seems to be of functional importance both for Htt aggregation and for N-terminal acetylation.

scholarly journals OTU Domain-containing Ubiquitin Aldehyde-binding Protein 1 (OTUB1) Deubiquitinates Estrogen Receptor (ER) α and Affects ERα Transcriptional Activity

2009 ◽  
Vol 284 (24) ◽  
pp. 16135-16145 ◽  
Author(s):  
Vladimir Stanišić ◽  
Anna Malovannaya ◽  
Jun Qin ◽  
David M. Lonard ◽  
Bert W. O'Malley
Keyword(s):  
Estrogen Receptor ◽  
Transcriptional Activity ◽  
Binding Protein ◽  
Ubiquitin Proteasome System ◽  
Mass Spectrometry Analysis ◽  
Interacting Protein ◽  
Spectrometry Analysis ◽  
Protein Levels ◽  
Ubiquitin Proteasome

Estrogen receptor (ER) α is an essential component in human physiology and is a key factor involved in the development of breast and endometrial cancers. ERα protein levels and transcriptional activity are tightly controlled by the ubiquitin proteasome system. Deubiquitinating enzymes, a class of proteases capable of removing ubiquitin from proteins, are increasingly being seen as key modulators of the ubiquitin proteasome system, regulating protein stability and other functions by countering the actions of ubiquitin ligases. Using mass spectrometry analysis of an ERα protein complex, we identified OTU domain-containing ubiquitin aldehyde-binding protein 1 (OTUB1) as a novel ERα-interacting protein capable of deubiquitinating ERα in cells and in vitro. We show that OTUB1 negatively regulates transcription mediated by ERα in transient reporter gene assays and transcription mediated by endogenous ERα in Ishikawa endometrial cancer cells. We also show that OTUB1 regulates the availability and functional activity of ERα in Ishikawa cells by affecting the transcription of the ERα gene and by stabilizing the ERα protein in the chromatin.

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