14-3-3 Proteins regulate K 5.1 surface expression on T lymphocytes.

K 5.1 channels (also called TASK-2 or Kcnk5) have already been shown to be relevant in the pathophysiology of autoimmune disease because they are known to be upregulated on peripheral and central T lymphocytes of multiple sclerosis (MS) patients. Moreover, overexpression of K 5.

Pathogenesis of Helicobacter pylori infection.

Helicobacter pylori is estimated to infect more than half of the worlds human population and represents a major risk factor for chronic gastritis, peptic ulcer disease, MALT lymphoma, and gastric adenocarcinoma. H. pylori infection and clinical consequences are controlled by highly complex interactions between the host, colonizing bacteria, and environmental parameters.

Mechanism of caspase-2 activation upon DNA damage.

The mechanism of caspase-2 activation in response to DNA damage was studied using human ovarian cancer cells Caov-4 treated with chemotherapeutic agent cisplatin. It was shown that mutations of the three cleavage sites of caspase-2 do not affect the assembly of the macromolecular complex of caspase-2 and its activation, but, conversely, stabilize this complex, most likely, via the inhibition of the dissociation of the active caspase-2.

Proteome rearrangements after auditory learning: high-resolution profiling of synapse-enriched protein fractions from mouse brain.

Learning and memory processes are accompanied by rearrangements of synaptic protein networks. While various studies have demonstrated the regulation of individual synaptic proteins during these processes, much less is known about the complex regulation of synaptic proteomes. Recently, we reported that auditory discrimination learning in mice is associated with a relative down-regulation of proteins involved in the structural organization of synapses in various brain regions.

Chronic Toxoplasma gondii infection enhances β-amyloid phagocytosis and clearance by recruited monocytes.

Introduction: Alzheimer's disease (AD) is associated with the accumulation of β-amyloid (Aβ) as senile plaques in the brain, thus leading to neurodegeneration and cognitive impairment. Plaque formation depends not merely on the amount of generated Aβ peptides, but more importantly on their effective removal. Chronic infections with neurotropic pathogens, most prominently the parasite Toxoplasma (T.

New Insights Into the Mechanism of COP9 Signalosome-Cullin-RING Ubiquitin-Ligase Pathway Deregulation in Urological Cancers.

Urological cancers are a very common type of cancer worldwide and have alarming high incidence and mortality rates, especially in kidney cancers, illustrate the urgent need for new therapeutic targets. Recent publications point to a deregulated COP9 signalosome (CSN)-cullin-RING ubiquitin-ligase (CRL) pathway which is here considered and investigated as potential target in urological cancers with strong focus on renal cell carcinomas (RCC). The CSN forms supercomplexes with CRLs in order to preserve protein homeostasis and was found deregulated in several cancer types.

Receptor-Interacting Protein Kinase-2 Inhibition by CYLD Impairs Antibacterial Immune Responses in Macrophages.

Upon infection with intracellular bacteria, nucleotide oligomerization domain protein 2 recognizes bacterial muramyl dipeptide and binds, subsequently, to receptor-interacting serine/threonine kinase 2 (RIPK2), which activates immune responses via the nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB) and extracellular signal-regulated kinase (ERK) pathways. Activation of RIPK2 depends on its K63 ubiquitination by E3 ligases, whereas the deubiquitinating enzyme A20 counter regulates RIPK2 activity by cleaving K63-polyubiquitin chains from RIPK2. Here, we newly identify the deubiquitinating enzyme CYLD as a new inhibitor of RIPK2.

Molecular architecture of the DED chains at the DISC: regulation of procaspase-8 activation by short DED proteins c-FLIP and procaspase-8 prodomain.

The CD95/Fas/APO-1 death-inducing signaling complex (DISC), comprising CD95, FADD, procaspase-8, procaspase-10, and c-FLIP, has a key role in apoptosis induction. Recently, it was demonstrated that procaspase-8 activation is driven by death effector domain (DED) chains at the DISC. Here, we analyzed the molecular architecture of the chains and the role of the short DED proteins in regulating procaspase-8 activation in the chain model.

p97/VCP promotes Cullin-RING-ubiquitin-ligase/proteasome-dependent degradation of IκBα and the preceding liberation of RelA from ubiquitinated IκBα.

Cullin-RING-ubiquitin-ligase (CRL)-dependent ubiquitination of the nuclear factor kappa B (NF-κB) inhibitor IκBα and its subsequent degradation by the proteasome usually precede NF-κB/RelA nuclear activity. Through removal of the CRL-activating modification of their cullin subunit with the ubiquitin (Ub)-like modifier NEDD8, the COP9 signalosome (CSN) opposes CRL Ub-ligase activity. While RelA phosphorylation was observed to mediate NF-κB activation independent of Ub-proteasome-pathway (UPP)-dependent turnover of IκBα in some studies, a strict requirement of the p97/VCP ATPase for both, IκBα degradation and NF-κB activation, was reported in others.

Combinatorial treatment of CD95L and gemcitabine in pancreatic cancer cells induces apoptotic and RIP1-mediated necroptotic cell death network.

Combination therapy of cancer is based on the cumulative effects mediated by several drugs. Although molecular mechanisms of action of each particular drug are partially elucidated, understanding of the dynamic cross-talk between different cell death pathways at the quantitative level induced by combination therapy is still missing. Here, we exemplified this question for the death receptor (DR) networks in pancreatic cancer cells.

Role of the nucleus in apoptosis: signaling and execution.

Since their establishment in the early 1970s, the nuclear changes upon apoptosis induction, such as the condensation of chromatin, disassembly of nuclear scaffold proteins and degradation of DNA, were, and still are, considered as the essential steps and hallmarks of apoptosis. These are the characteristics of the execution phase of apoptotic cell death. In addition, accumulating data clearly show that some nuclear events can lead to the induction of apoptosis.

Morphological and Functional Alterations of Alveolar Macrophages in a Murine Model of Chronic Inflammatory Lung Disease.

Purpose: Chronic lung inflammation commonly induces a multitude of structural and functional adaptations within the lung tissue and airspaces. Yet the impact of a persistent inflammatory environment on alveolar macrophages is still incompletely understood. Here, we examined morphology and function of alveolar macrophages in a transgenic mouse model of chronic lung disease.

CAND1 exchange factor promotes Keap1 integration into cullin 3-RING ubiquitin ligase during adipogenesis.

Adipogenesis is governed by a plethora of regulatory proteins which are most commonly controlled by the ubiquitin proteasome system. Here, we show that the differentiation of LiSa-2 preadipocytes is associated with an increase of cullin-associated and neddylation-dissociated 1 (CAND1), COP9 signalosome (CSN), neddylated cullin 3 (Cul3) and the BTB protein Keap1. Silencing of CAND1 leads to a decrease and reduced integration of Keap1 into Cul3-RING ubiquitin ligases (CRL3) and to a retardation of adipogenesis.

Molecular mechanisms of the non-coenzyme action of thiamin in brain: biochemical, structural and pathway analysis.

Thiamin (vitamin B1) is a pharmacological agent boosting central metabolism through the action of the coenzyme thiamin diphosphate (ThDP). However, positive effects, including improved cognition, of high thiamin doses in neurodegeneration may be observed without increased ThDP or ThDP-dependent enzymes in brain. Here, we determine protein partners and metabolic pathways where thiamin acts beyond its coenzyme role.

Structural modeling of the N-terminal signal-receiving domain of IκBα.

The transcription factor nuclear factor-κB (NF-κB) exerts essential roles in many biological processes including cell growth, apoptosis and innate and adaptive immunity. The NF-κB inhibitor (IκBα) retains NF-κB in the cytoplasm and thus inhibits nuclear localization of NF-κB and its association with DNA. Recent protein crystal structures of the C-terminal part of IκBα in complex with NF-κB provided insights into the protein-protein interactions but could not reveal structural details about the N-terminal signal receiving domain (SRD).

Diversity of COP9 signalosome structures and functional consequences.

The COP9 signalosome (CSN) is a regulator of the ubiquitin (Ub) proteasome system (UPS). It interacts with hundreds of cullin-RING ubiquitin E3 ligases (CRLs) and regulates their activity by removing the Ub-like protein Nedd8 from cullins. In mammalian cells 7 different cullins exist which form CRLs with adaptor proteins and with a large number of substrate recognition subunits such as F-box and BTB proteins.

Quantification of apoptosis and necroptosis at the single cell level by a combination of Imaging Flow Cytometry with classical Annexin V/propidium iodide staining.

Precisely identifying the type of programmed cell death is one of the key questions in contemporary biomedical research. We developed a straightforward approach allowing quantitative discrimination between two types of cell death on the single cell level: apoptosis and necroptosis. This method uses the combination of imaging flow cytometry with classical Annexin V/propidium iodide staining, which allows for the ascertainment of typical features of dying cells: exposure of the phospholipid phosphatidylserine and the loss of membrane integrity.

Quantification of CD95-induced apoptosis and NF-κB activation at the single cell level.

CD95/Fas/APO-1 is a member of the death receptor (DR) family. Stimulation of CD95 leads to the induction of apoptosis as well as to NF-κB signaling. Crosstalk between these two pathways plays a central role in cell fate.

Differential effects of dopamine signalling on long-term memory formation and consolidation in rodent brain.

Background: Using auditory discrimination learning in gerbils, we have previously shown that activation of auditory-cortical D1/D5 dopamine receptors facilitates mTOR-mediated, protein synthesis-dependent mechanisms of memory consolidation and anterograde memory formation. To understand molecular mechanisms of this facilitatory effect, we tested the impact of local pharmacological activation of different D1/D5 dopamine receptor signalling modes in the auditory cortex. To this end, protein patterns in soluble and synaptic protein-enriched fractions from cortical, hippocampal and striatal brain regions of ligand- and vehicle-treated gerbils were analysed by 2D gel electrophoresis and mass spectrometry 24 h after intervention.

DNA-dependent protein kinase (DNA-PK) permits vascular smooth muscle cell proliferation through phosphorylation of the orphan nuclear receptor NOR1.

Aims: Being central part of the DNA repair machinery, DNA-dependent protein kinase (DNA-PK) seems to be involved in other signalling processes, as well. NOR1 is a member of the NR4A subfamily of nuclear receptors, which plays a central role in vascular smooth muscle cell (SMC) proliferation and in vascular proliferative processes. We determined putative phosphorylation sites of NDA-PK in NOR1 and hypothesized that the enzyme is able to modulate NOR1 signalling and, this way, proliferation of SMC.

Protective dendritic cell responses against listeriosis induced by the short form of the deubiquitinating enzyme CYLD are inhibited by full-length CYLD.

The deubiquitinating enzyme CYLD is an important tumor suppressor and inhibitor of immune responses. In contrast to full-length CYLD, the immunological function of the naturally occurring short splice variant of CYLD (sCYLD) is insufficiently described. Previously, we showed that DCs, which lack full-length CYLD but express sCYLD, exhibit augmented NF-κB and DC activation.

CSN-associated USP48 confers stability to nuclear NF-κB/RelA by trimming K48-linked Ub-chains.

Diligent balance of nuclear factor kappa B (NF-κB) activity is essential owing to NF-κB's decisive role in cellular processes including inflammation, immunity and cell survival. Ubiquitin/proteasome-system (UPS)-dependent degradation of activated NF-κB/RelA involves the cullin-RING-ubiquitin-ligase (CRL) ECS(SOCS1). The COP9 signalosome (CSN) controls ubiquitin (Ub) ligation by CRLs through the removal of the CRL-activating Ub-like modifier NEDD8 from their cullin subunits and through deubiquitinase (DUB) activity of associated DUBs.

Cell death controlling complexes and their potential therapeutic role.

Programmed cell death plays a central role in the regulation of homeostasis and development of multicellular organisms. Deregulation of programmed cell death is connected to a number of disorders, including cancer and autoimmune diseases. Initiation of cell death occurs in the multiprotein complexes or high molecular weight platforms.

Helicobacter pylori promotes eukaryotic protein translation by activating phosphatidylinositol 3 kinase/mTOR.

The innate immune response elicited by Helicobacter pylori in the human gastric mucosa involves a range of cellular signalling pathways, including those implicated in metabolism regulation. In this study, we analysed H. pylori-induced PI3K/Akt/mTOR signalling, which regulates glycolysis and protein synthesis and associates thereby with cellular energy- and nutrients-consuming processes such as growth and proliferation.