Fabienne AILLET

Inbiomed · cancer

Protein ubiquitylation coordinates crucial cellular events in physiological and pathological conditions. A comparative analysis of the ubiquitin proteome from bortezomib (BTZ)-sensitive and BTZ-resistant mantle cell lymphoma (MCL) revealed an enrichment of the autophagy–lysosome system (ALS) in BTZ-resistant cells. Pharmacological inhibition of aut...

DNA damage activated by Adriamycin (ADR) promotes ubiquitin–proteasome system-mediated proteolysis by stimulating both the activity of ubiquitylating enzymes and the proteasome. In ADR-resistant breast cancer MCF7 (MCF7ADR) cells, protein ubiquitylation is significantly reduced compared to the parental MCF7 cells. Here, we used tandem ubiquitin-bin...

Tandem ubiquitin-binding entities (TUBEs) act as molecular traps to isolate polyubiquitylated proteins facilitating the study of this highly reversible posttranslational modification. We provide here sample preparation and adaptations required for TUBE-based enrichment of the ubiquitin proteome from tumor cell lines or primary cells. Our protocol i...

Analyzing protein ubiquitylation changes during physiological or pathological processes is challenging due to its high reversibility and dynamic turnover of modified targets. We have developed a protein microarray to assess endogenous ubiquitylation levels from cell cultures, employing Tandem Ubiquitin Binding Entities (TUBEs) with 3 or 4 UBA domai...

Biological of significance: In this work we analyze for the first time the interconnection between Plasmodium and human red blood cells ubiquitin-regulated proteins in the context of infection. We identified a number of human and Plasmodium proteins whose ubiquitylation pattern changes during the asexual infective stage. We demonstrate that ubiqui...

The ubiquitin proteasome system (UPS) is one of the main proteolytical pathways in eukaryotic cells and plays an essential role in key cellular processes such as cell cycle, stress response, signal transduction, and transcriptional regulation. Many components of this pathway have been implicated in diverse pathologies including cancer, neurodegener...

The Ubiquitin-Proteasome System (UPS) plays an important role in the setting of the cellular response to multiple stress signals. Although the primary function of ubiquitin was initially associated with proteolysis, it is now considered as a key regulator of protein function controlling, among other functions, signalling cascades, transcription, ap...

Accurate regulation of nuclear factor-jB (NF-jB) activity is crucial to prevent a variety of disorders including immune and inflammatory diseases. Active NF-jB promotes IjBa and A20 expression, important negative regulatory molecules that control the NF-jB response. In this study, using two-hybrid screening we identify the RING-type zinc-finger pro...

Accurate regulation of nuclear factor-κB (NF-κB) activity is crucial to prevent a variety of disorders including immune and inflammatory diseases. Active NF-κB promotes IκBα and A20 expression, important negative regulatory molecules that control the NF-κB response. In this study, using two-hybrid screening we identify the RING-type zinc-finger pro...

The tumor suppressor p53 regulates the expression of genes involved in cell cycle progression, senescence and apoptosis. Here, we investigated the effect of single point mutations in the oligomerization domain (OD) on tetramerization, transcription, ubiquitylation and stability of p53. As predicted by docking and molecular dynamics simulations, p53...

The tumor suppressor p53 regulates the expression of genes involved in cell cycle progression, senescence and apoptosis. Here, we investigated the effect of single point mutations in the oligomerization domain (OD) on tetramerization, transcription, ubiquitylation and stability of p53. As predicted by docking and molecular dynamics simulations, p53...

SUMO-modified proteins are recognized by SUMO interacting motifs (SIMs), thus triggering diverse cellular responses. Here SIMs were used to develop SUMO-traps to capture endogenous SUMOylated proteins. Our results show that these small peptides are transferable motifs that maintain their SUMO binding capacity when fused to the heterologous carrier...

Supplementary Information

The NF-kB pathway is regulated by SUMOylation at least at three levels: the inhibitory molecule IkBa, the IKK subunit c/ NEMO and the p52 precursor p100. Here we investigate the role of SUMO-2/3 in the degradation of IkBa and activation of NF-kB mediated by TNFa. We found that under conditions of deficient SUMOylation, an important delay in both TN...

Studying postubiquitylation events has always been a difficult task due to the labile nature of these posttranslational modifications. When utilized in tandem, ubiquitin-binding entities (TUBEs) not only increase up to thousand times the affinity for poly-ubiquitin chains but also protect ubiquitylated proteins from the action of the proteasome and...

TUBE-captured monoubiquitylated IκBα fails to be immunoprecipitated using specific IκBα antibodies. HEK293 cells were treated or not, 1 hour with 20 µM of MG-132 and lysed in a buffer containing 100 µg of TUBE-HR23A or GST proteins. After lysis, samples were centrifuged and clarified supernatant incubated for 2 hours in the presence of glutathione...

Immunoprecipitation using IκBα antibodies fail to pull down monoubiquitylated IκBα. HEK293 cells were treated or not for 1 hour with 20 µM of MG-132, lysed in the properly lysis buffer for 20 minutes, centrifuged and the supernatant was incubated with cross-linked anti- IκBα (10B) antibody for 2 hours. After incubation the samples were centrifuged,...

IκBαWT and ubiquitin-IκBα fusion were expressed in HEK293 cells, and processed for immunostaining with anti-SV5 or anti-HA antibodies. (TIF)

The NF-κB pathway is regulated by multiple post-translational modifications including phosphorylation, ubiquitylation and SUMOylation. Many of these modifications act on the natural inhibitor IκBα modulating its capacity to control signal-mediated NF-κB activity. While the canonical pathway involving the phosphorylation and polyubiquitylation of Iκ...

In normal cells p53 is maintained at low level through the action of the ubiquitin-proteasome system. As a consequence of p53 transcriptional activity, various regulators of this tumor suppressor are produced, forming a negative feedback loop tightly controlling p53 stability. One of the most prominent is the ubiquitin-ligase Mdm2. Here, we have us...

Ubiquitylation provides a rapid alternative to control the activity of crucial cellular factors through the remodelling of a target protein. Diverse ubiquitin chains are recognized by domains with affinity for UBDs (ubiquitin-binding domains) present in receptor/effector proteins. Interestingly, some proteins contain more than one UBD and the prese...

Post-translational modification with ubiquitin is one of the most important mechanisms in the regulation of protein stability and function. However, the high reversibility of this modification is the main obstacle for the isolation and characterization of ubiquitylated proteins. To overcome this problem, we have developed tandem-repeated ubiquitin-...

We have integrated gene expression profiling of liver biopsies of NASH patients with liver samples of a mouse model of steatohepatitis (MAT1A-KO) to identify a gene-pathway associated with NASH. Affymetrix U133 Plus 2.0 microarrays were used to evaluate nine patients with NASH, six patients with steatosis, and six control subjects; Affymetrix MOE43...

Macrophages play a major role in HIV-1 persistence. In the present paper, we demonstrate that the absence of apoptosis in HIV-1-infected primary human monocyte-differentiated macrophages (MDM) correlates with an increase in anti-apoptotic (Bcl-2 and Bcl-x(L)) and a decrease in pro-apoptotic (Bax and Bad) proteins. This is associated with macrophage...

The transcription factor NF-kappaB is a key modulator of apoptosis in a variety of cell types, but to date this specific function of NF-kappaB has not been demonstrated in epithelia. Here, we describe the activation of NF-kappaB during post-lactational involution of the mouse mammary gland, a period of extensive apoptosis of luminal epithelial cell...

The NF-kappaB/Rel family of transcription factors regulates a wide variety of genes whose products play a fundamental role in inflammatory and immune responses. The implication of NF-kappaB/Rel proteins and their IkappaB regulatory subunits in the control of cellular growth and oncogenesis, was suggested by the induction of fatal lymphomas in birds...

This work aims at characterizing the interplay between human immunodeficiency virus type 1 (HIV-1) and the antiapoptotic cellular protein Bcl-2 responsible for a persistent infection in lymphoblastoid T (J.Jhan) or monocytic (U937) cells. We report that the kinetics of Bcl-2 protein level during the establishment of a chronic infection is biphasic,...

In the human lymphoblastoid T cell line JJhan-5.1, stably transfected with a human immunodeficiency virus-1 long terminal repeat luciferase vector, the level of luciferase activity is dependent on activation of the nuclear factor kappaB (NF-kappaB) transcription factor. Tumor necrosis factor-induced luciferase activity was not modified in JJhan-5.1...

Antioxidant molecules have been suggested to be of therapeutic value in the treatment of HIV-infected patients. To evaluate this possibility, we examined in vitro the effects of two types of antioxidant molecules in terms of inhibition of HIV replication in monocytes, one of the main reservoirs of HIV, and also in terms of modulation of the immune...

We used BHA, a phenolic, lipid-soluble, chain-breaking antioxidant to show that peroxyl radical scavenging blocks NF-1(B activation and HIV1 enhancer activity in PMA- or TNF-stimulated lymphoblastoid T (J.Jhan) and monocytic (U937) cell lines. The anti-oxidative effect of BHA was accompanied by an increase in thiol, but not glutathione, content in...

We have tested the hypothesis that cellular activation events occurring in T lymphocytes and monocytes and mediated through translocation of the transcription factor NF-kappa B are dependent upon the constitutive redox status of these cells. We used phenolic, lipid-soluble, chain-breaking antioxidants (butylated hydroxyanisole (BHA), nordihydroquai...