Role of SUMO-1–modified PML in nuclear body formation

Blood ◽  
2000 ◽  
Vol 95 (9) ◽  
pp. 2748-2752 ◽  
Author(s):  
Sue Zhong ◽  
Stefan Müller ◽  
Simona Ronchetti ◽  
Paul S. Freemont ◽  
Anne Dejean ◽  
...  

The tumor-suppressive promyelocytic leukemia (PML) protein of acute promyelocytic leukemia (APL) has served as one of the defining components of a class of distinctive nuclear bodies (NBs). PML is delocalized from NBs in APL cells and is degraded in cells infected by several viruses. In these cells, NBs are disrupted, leading to the aberrant localization of NB proteins. These results have suggested a critical role for the NB in immune response and tumor suppression and raised the question of whether PML is crucial for the formation or stability of NB. In addition, PML is, among other proteins, covalently modified by SUMO-1. However, the functional relevance of this modification is unclear. Here, we show in primary PML−/− cells of various histologic origins, that in the absence of PML, several NB proteins such as Sp100, CBP, ISG20, Daxx, and SUMO-1 fail to accumulate in the NB and acquire aberrant localization patterns. Transfection of PML in PML−/−cells causes the relocalization of NB proteins. By contrast, a PML mutant that can no longer be modified by SUMO-1 fails to do so and displays an aberrant nuclear localization pattern. Therefore, PML is required for the proper formation of the NB. Conjugation to SUMO-1 is a prerequisite for PML to exert this function. These data shed new light on both the mechanisms underlying the formation of the NBs and the pathogenesis of APL.

2002 ◽  
Vol 80 (3) ◽  
pp. 301-310 ◽  
Author(s):  
Christopher H Eskiw ◽  
David P Bazett-Jones

The promyelocytic leukemia (PML) nuclear body is one of many subnuclear domains in the eukaryotic cell nucleus. It has received much attention in the past few years because it accumulates the promyelocytic leukemia protein called PML. This protein is implicated in many nuclear events and is found as a fusion with the retinoic acid receptor RARα in leukemic cells. The importance of PML bodies in cell differentiation and growth is implicated in acute promyelocitic leukemia cells, which do not contain PML bodies. Treatment of patients with drugs that reverse the disease phenotype also causes PML bodies to reform. In this review, we discuss the structure, composition, and dynamics that may provide insights into the function of PML bodies. We also discuss the repsonse of PML bodies to cellular stresses, such as virus infection and heat shock. We interpret the changes that occur as evidence for a role of these structures in gene transcription. We also examine the role of the posttranslational modification, SUMO-1 addition, in directing proteins to this nuclear body. Characterization of the mobility of PML body associated proteins further supports a role in specific nuclear events, rather than the bodies resulting from random accumulations of proteins.Key words: promyelocytic leukemia, nucleus, transcription, nuclear bodies.


Sociology ◽  
2016 ◽  
Vol 51 (5) ◽  
pp. 1011-1033 ◽  
Author(s):  
James Laurence

Extensive research has demonstrated that neighbourhood ethnic diversity is negatively associated with intra-neighbourhood social capital. This study explores the role of segregation and integration in this relationship. To do so it applies three-level hierarchical linear models to two sets of data from across Great Britain and within London, and examines how segregation across the wider-community in which a neighbourhood is nested impacts trust amongst neighbours. This study replicates the increasingly ubiquitous finding that neighbourhood diversity is negatively associated with neighbour-trust. However, we demonstrate that this relationship is highly dependent on the level of segregation across the wider-community in which a neighbourhood is nested. Increasing neighbourhood diversity only negatively impacts neighbour-trust when nested in more segregated wider-communities. Individuals living in diverse neighbourhoods nested within integrated wider-communities experience no trust-penalty. These findings show that segregation plays a critical role in the neighbourhood diversity/trust relationship, and that its absence from the literature biases our understanding of how ethnic diversity affects social cohesion.


2020 ◽  
Vol 31 (18) ◽  
pp. 2048-2056 ◽  
Author(s):  
Huaiying Zhang ◽  
Rongwei Zhao ◽  
Jason Tones ◽  
Michel Liu ◽  
Robert L. Dilley ◽  
...  

A chemical dimerization approach is developed to induce phase separation of APB nuclear bodies involved in telomere elongation in alternative lengthening of telomeres (ALT) cancer cells. It reveals that ALT telomere-associated promyelocytic leukemia nuclear body (APB) fusion leads to telomere clustering to provide templates for homology-directed telomere synthesis, an ability that is decoupled from APB function in enriching DNA repair factors.


2017 ◽  
Vol 130 (20) ◽  
pp. 3496-3506 ◽  
Author(s):  
Chuang Li ◽  
Qiongfang Peng ◽  
Xiao Wan ◽  
Haili Sun ◽  
Jun Tang

2018 ◽  
Vol 46 (1) ◽  
pp. 418-430 ◽  
Author(s):  
Deneshia J. McIntosh ◽  
Treniqka S. Walters ◽  
Ifeanyi J. Arinze ◽  
Jamaine Davis

Background/Aims: The transcription factor Nrf2 is a master regulator of the antioxidant defense system, protecting cells from oxidative damage. We previously reported that the SUMO-targeted E3 ubiquitin ligase (STUbL), RING finger protein 4 (RNF4) accelerated the degradation rate of Nrf2 in promyelocytic leukemia-nuclear body (PML-NB)-enriched fractions and decreased Nrf2-mediated gene transcription. The mechanisms that regulate Nrf2 nuclear levels are poorly understood. In this study, we aim to explore the role of the second mammalian STUbL, Arkadia/RNF111 on Nrf2. Methods: Arkadia mediated ubiquitination was detected using co-immunoprecipitation assays in which whole cell lysates were immunoprecipated with anti-Nrf2 antibody and Western blotted with anti-hemagglutinin (HA) antibody or anti-Lys-48 ubiquitin-specific antibody. The half-life of Nrf2 was detected in whole cell lysates and promyelocytic leukemia-nuclear body enriched fractions by cycloheximide-chase. Reporter gene assays were performed using the antioxidant response element (ARE)-containing promoter Heme oxygenase-1 (HO-1). Results: We show that Arkadia/RNF111 is able to ubiquitinate Nrf2 resulting in the stabilization of Nrf2. This stabilization was mediated through Lys-48 ubiquitin chains, contrary to traditionally degradative role of Lys-48 ubiquitination, suggesting that Lys-48 ubiquitination of Nrf2 protects Nrf2 from degradation thereby allowing Nrf2-dependent gene transcription. Conclusion: Collectively, these findings highlight a novel mechanism to positively regulate nuclear Nrf2 levels in response to oxidative stress through Arkadia-mediated K48-linked ubiquitination of Nrf2.


Biology ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 65
Author(s):  
Goncalo Barreto ◽  
Mikko Manninen ◽  
Kari K. Eklund

Osteoarthritis (OA) has long been viewed as a degenerative disease of cartilage, but accumulating evidence indicates that inflammation has a critical role in its pathogenesis. In particular, chondrocyte-mediated inflammatory responses triggered by the activation of innate immune receptors by alarmins (also known as danger signals) are thought to be involved. Thus, toll-like receptors (TLRs) and their signaling pathways are of particular interest. Recent reports suggest that among the TLR-induced innate immune responses, apoptosis is one of the critical events. Apoptosis is of particular importance, given that chondrocyte death is a dominant feature in OA. This review focuses on the role of TLR signaling in chondrocytes and the role of TLR activation in chondrocyte apoptosis. The functional relevance of TLR and TLR-triggered apoptosis in OA are discussed as well as their relevance as candidates for novel disease-modifying OA drugs (DMOADs).


2006 ◽  
Vol 175 (1) ◽  
pp. 55-66 ◽  
Author(s):  
Graham Dellaire ◽  
Reagan W. Ching ◽  
Kashif Ahmed ◽  
Farid Jalali ◽  
Kenneth C.K. Tse ◽  
...  

The promyelocytic leukemia (PML) nuclear body (NB) is a dynamic subnuclear compartment that is implicated in tumor suppression, as well as in the transcription, replication, and repair of DNA. PML NB number can change during the cell cycle, increasing in S phase and in response to cellular stress, including DNA damage. Although topological changes in chromatin after DNA damage may affect the integrity of PML NBs, the molecular or structural basis for an increase in PML NB number has not been elucidated. We demonstrate that after DNA double-strand break induction, the increase in PML NB number is based on a biophysical process, as well as ongoing cell cycle progression and DNA repair. PML NBs increase in number by a supramolecular fission mechanism similar to that observed in S-phase cells, and which is delayed or inhibited by the loss of function of NBS1, ATM, Chk2, and ATR kinase. Therefore, an increase in PML NB number is an intrinsic element of the cellular response to DNA damage.


2010 ◽  
Vol 21 (23) ◽  
pp. 4227-4239 ◽  
Author(s):  
Marie-Claude Geoffroy ◽  
Ellis G. Jaffray ◽  
Katherine J. Walker ◽  
Ronald T. Hay

In acute promyelocytic leukemia (APL), the promyelocytic leukemia (PML) protein is fused to the retinoic acid receptor alpha (RAR). Arsenic is an effective treatment for this disease as it induces SUMO-dependent ubiquitin-mediated proteasomal degradation of the PML-RAR fusion protein. Here we analyze the nuclear trafficking dynamics of PML and its SUMO-dependent ubiquitin E3 ligase, RNF4 in response to arsenic. After administration of arsenic, PML immediately transits into nuclear bodies where it undergoes SUMO modification. This initial recruitment of PML into nuclear bodies is not dependent on RNF4, but RNF4 quickly follows PML into the nuclear bodies where it is responsible for ubiquitylation of SUMO-modified PML and its degradation by the proteasome. While arsenic restricts the mobility of PML, FRAP analysis indicates that RNF4 continues to rapidly shuttle into PML nuclear bodies in a SUMO-dependent manner. Under these conditions FRET studies indicate that RNF4 interacts with SUMO in PML bodies but not directly with PML. These studies indicate that arsenic induces the rapid reorganization of the cell nucleus by SUMO modification of nuclear body-associated PML and uptake of the ubiquitin E3 ligase RNF4 leading to the ubiquitin-mediated degradation of PML.


2009 ◽  
Vol 20 (22) ◽  
pp. 4804-4815 ◽  
Author(s):  
Anneke K. Brouwer ◽  
Joost Schimmel ◽  
Joop C.A.G. Wiegant ◽  
Alfred C.O. Vertegaal ◽  
Hans J. Tanke ◽  
...  

The cell nucleus harbors a variety of different bodies that vary in number, composition, and size. Although these bodies coordinate important nuclear processes, little is known about how they are formed. Among the most intensively studied bodies in recent years is the PML body. These bodies have been implicated in gene regulation and other cellular processes and are disrupted in cells from patients suffering from acute promyelocytic leukemia. Using live cell imaging microscopy and immunofluorescence, we show in several cell types that PML bodies are formed at telomeric DNA during interphase. Recent studies revealed that both SUMO modification sites and SUMO interaction motifs in the promyelocytic leukemia (PML) protein are required for PML body formation. We show that SMC5, a component of the SUMO ligase MMS21-containing SMC5/6 complex, localizes temporarily at telomeric DNA during PML body formation, suggesting a possible role for SUMO in the formation of PML bodies at telomeric DNA. Our data identify a novel role of telomeric DNA during PML body formation.


2000 ◽  
Vol 191 (4) ◽  
pp. 631-640 ◽  
Author(s):  
Sue Zhong ◽  
Paolo Salomoni ◽  
Simona Ronchetti ◽  
Ailan Guo ◽  
Davide Ruggero ◽  
...  

The promyelocytic leukemia protein (PML) gene of acute promyelocytic leukemia (APL) encodes a cell growth and tumor suppressor essential for multiple apoptotic signals. Daxx was identified as a molecule important for the cytoplasmic transduction of the Fas proapoptotic stimulus. Here, we show that upon mitogenic activation of mature splenic lymphocytes, Daxx is dramatically upregulated and accumulates in the PML nuclear body (NB) where PML and Daxx physically interact. In the absence of PML, Daxx acquires a dispersed nuclear pattern, and activation-induced cell death of splenocytes is profoundly impaired. PML inactivation results in the complete abrogation of the Daxx proapoptotic ability. In APL cells, Daxx is delocalized from the NB. Upon retinoic acid treatment, which induces disease remission in APL, Daxx relocalizes to the PML NBs. These results indicate that PML and Daxx cooperate in a novel NB-dependent pathway for apoptosis and shed new light in the role of PML in tumor suppression.


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