Margot Thome

Bio: Margot Thome is an academic researcher from University of Lausanne. The author has contributed to research in topics: Flip & Death effector domain. The author has an hindex of 7, co-authored 10 publications receiving 4081 citations.

Inhibition of death receptor signals by cellular FLIP

Abstract: The widely expressed protein Fas is a member of the tumour necrosis factor receptor family which can trigger apoptosis1 However, Fas surface expression does not necessarily render cells susceptible to Fas ligand-induced death signals1,2, indicating that inhibitors of the apoptosis-signalling pathway must exist Here we report the characterization of an inhibitor of apoptosis, designated FLIP (for FLICE-inhibitory protein), which is predominantly expressed in muscle and lymphoid tissues The short form, FLIPS, contains two death effector domains and is structurally related to the viral FLIP inhibitors of apoptosis3, whereas the long form, FLIPL, contains in addition a caspase-like domain in which the active-centre cysteine residue is substituted by a tyrosine residue FLIPS and FLIPL interact with the adaptor protein FADD4,5 and the protease FLICE6,7, and potently inhibit apoptosis induced by all known human death receptors1 FLIPL is expressed during the early stage of T-cell activation, but disappears when T cells become susceptible to Fas ligand-mediated apoptosis High levels of FLIPL protein are also detectable in melanoma cell lines and malignant melanoma tumours Thus FLIP may be implicated in tissue homeostasis as an important regulator of apoptosis

Regulation of lymphocyte proliferation and death by FLIP.

Abstract: Lymphocyte homeostasis is a balance between lymphocyte proliferation and lymphocyte death Tight control of apoptosis is essential for immune function, because its altered regulation can result in cancer and autoimmunity Signals from members of the tumour-necrosis-factor receptor (TNF-R) family, such as Fas and TNF-R1, activate the caspase cascade and result in lymphocyte death by apoptosis Anti-apoptotic proteins, such as FLIP (also known as FLICE/caspase-8 inhibitory protein) have recently been identified FLIP expression is tightly regulated in T cells and might be involved in the control of both T-cell activation and death Abnormal expression of FLIP might have a role not only in autoimmune diseases, but also in tumour development and cardiovascular disorders

Multifunctional roles for MALT1 in T-cell activation.

Abstract: Recent research on MALT1 (mucosa-associated-lymphoid-tissue lymphoma-translocation gene 1), a protein essential for nuclear factor-κB (NF-κB) activation, has uncovered new mechanisms by which MALT1 can orchestrate intracellular signalling events. Here, Margot Thome highlights recent progress which characterizes how the protease and scaffolding functions of MALT1 modulate T-cell activation. The activation of T cells is vital to the successful elimination of pathogens, but can also have a deleterious role in autoimmunity and transplant rejection. Various signalling pathways are triggered by the T-cell receptor; these have key roles in the control of the T-cell response and represent interesting targets for therapeutic immunomodulation. Recent findings define MALT1 (mucosa-associated-lymphoid-tissue lymphoma-translocation gene 1) as a protein with proteolytic activity that controls T-cell activation by regulating key molecules in T-cell-receptor-induced signalling pathways.

Distinct types of diffuse large B-cell lymphoma identified by gene expression profiling

Abstract: 12 Pathology and Microbiology, and 13 Diffuse large B-cell lymphoma (DLBCL), the most common subtype of non-Hodgkin's lymphoma, is clinically heterogeneous: 40% of patients respond well to current therapy and have prolonged survival, whereas the remainder succumb to the disease. We proposed that this variability in natural history reflects unrecognized molecular heterogeneity in the tumours. Using DNA microarrays, we have conducted a systematic characterization of gene expression in B-cell malignancies. Here we show that there is diversity in gene expression among the tumours of DLBCL patients, apparently reflecting the variation in tumour proliferation rate, host response and differentiation state of the tumour. We identified two molecularly distinct forms of DLBCL which had gene expression patterns indicative of different stages of B-cell differentiation. One type expressed genes characteristic of germinal centre B cells ('germinal centre B-like DLBCL'); the second type expressed genes normally induced during in vitro activation of peripheral blood B cells ('activated B-like DLBCL'). Patients with germinal centre B-like DLBCL had a significantly better overall survival than those with activated B-like DLBCL. The molecular classification of tumours on the basis of gene expression can thus identify previously undetected and clinically significant subtypes of cancer.

The biochemistry of apoptosis

Abstract: Apoptosis - the regulated destruction of a cell - is a complicated process. The decision to die cannot be taken lightly, and the activity of many genes influence a cell's likelihood of activating its self-destruction programme. Once the decision is taken, proper execution of the apoptotic programme requires the coordinated activation and execution of multiple subprogrammes. Here I review the basic components of the death machinery, describe how they interact to regulate apoptosis in a coordinated manner, and discuss the main pathways that are used to activate cell death.

Caspases: Enemies Within

Abstract: Apoptosis, an evolutionarily conserved form of cell suicide, requires specialized machinery. The central component of this machinery is a proteolytic system involving a family of proteases called caspases. These enzymes participate in a cascade that is triggered in response to proapoptotic signals and culminates in cleavage of a set of proteins, resulting in disassembly of the cell. Understanding caspase regulation is intimately linked to the ability to rationally manipulate apoptosis for therapeutic gain.

Death receptors: signaling and modulation

Abstract: Apoptosis is a cell suicide mechanism that enables metazoans to control cell number in tissues and to eliminate individual cells that threaten the animal's survival. Certain cells have unique sensors, termed death receptors, on their surface. Death receptors detect the presence of extracellular death signals and, in response, they rapidly ignite the cell's intrinsic apoptosis machinery.

Proliferation, cell cycle and apoptosis in cancer

Abstract: Beneath the complexity and idiopathy of every cancer lies a limited number of 'mission critical' events that have propelled the tumour cell and its progeny into uncontrolled expansion and invasion One of these is deregulated cell proliferation, which, together with the obligate compensatory suppression of apoptosis needed to support it, provides a minimal 'platform' necessary to support further neoplastic progression Adroit targeting of these critical events should have potent and specific therapeutic consequences