Integrating Signals from the T-Cell Receptor and the Interleukin-2 Receptor

T cells orchestrate the adaptive immune response, making them targets for immunotherapy. Although immunosuppressive therapies prevent disease progression, they also leave patients susceptible to opportunistic infections. To identify novel drug targets, we established a logical model describing T-cell receptor (TCR) signaling. However, to have a model that is able to predict new therapeutic approaches, the current drug targets must be included. Therefore, as a next step we generated the interleukin-2 receptor (IL-2R) signaling network and developed a tool to merge logical models. For IL-2R signaling, we show that STAT activation is independent of both Src- and PI3-kinases, while ERK activation depends upon both kinases and additionally requires novel PKCs. In addition, our merged model correctly predicted TCR-induced STAT activation. The combined network also allows information transfer from one receptor to add detail to another, thereby predicting that LAT mediates JNK activation in IL-2R signaling. In summary, the merged model not only enables us to unravel potential cross-talk, but it also suggests new experimental designs and provides a critical step towards designing strategies to reprogram T cells

The bc 1 complexes of Rhodobacter sphaeroides and Rhodobacter capsulatus

Photosynthetic bacteria offer excellent experimental opportunities to explore both the structure and function of the ubiquinol-cytochrome c oxidoreductase ( bc 1 complex). In both Rhodobacter sphaeroides and Rhodobacter capsulatus , the bc 1 complex functions in both the aerobic respiratory chain and as an essential component of the photosynthetic electron transport chain. Because the bc 1 complex in these organisms can be functionally coupled to the photosynthetic reaction center, flash photolysis can be used to study electron flow through the enzyme and to examine the effects of various amino acid substitutions. During the past several years, numerous mutations have been generated in the cytochrome b subunit, in the Rieske iron-sulfur subunit, and in the cytochrome c 1 subunit. Both site-directed and random mutagenesis procedures have been utilized. Studies of these mutations have identified amino acid residues that are metal ligands, as well as those residues that are at or near either the quinol oxidase (Q o ) site or the quinol reductase (Q i ) site. The postulate that these two Q-sites are located on opposite sides of the membrane is supported by these studies. Current research is directed at exploring the details of the catalytic mechanism, the nature of the subunit interactions, and the assembly of this enzyme.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44795/1/10863_2004_Article_BF00762582.pd

Integrated Digital Receiver for the EPR Spectrometer

W pracy przedstawiono koncepcję zintegrowanego, cyfrowego odbiornika spektrometru EPR (elektronowego rezonansu paramagnetycznego), przeznaczoną do realizacji w technologii SoC na platformie Virtex-II Pro. Krótko opisano środowisko eksperymentu EPR, skupiając się na interesujących aspektach projektu, m.in. wykorzystaniu wbudowanego procesora. Zaprezentowano budowę całego systemu przetwarzania danych, składającego się z: interfejsu szybkiego przetwornika analogowo-cyfrowego, jednostki wstępnego przetwarzania (akumulacji) danych oraz wbudowanego procesora PowerPC 405, realizującego końcową obróbkę danych. Omówiono interesujące szczegóły konstrukcyjne interfejsu przetwornika, strukturę bloku wstępnej akumulacji danych, blok sterownika oraz podsystem sygnałów zegarowych. Przedstawiono także architekturę nadrzędnego systemu procesorowego, opartego na mikroprocesorze PowerPC. Opisano metodologię i wykorzystane narzędzia projektowe, jak również sposób weryfikacji układu i wyniki testów.The paper describes a design of an integrated digital receiver for the Electron Paramagnetic Resonance spectrometer. The design, based on a SoC technology, utilizes the PowerPC processor embedded in the Virtex-II Pro FPGA. Description shortly introduces an experimental environment (Fig. 1), focusing on interesting FPGA design issues. Two concepts of the device are presented. The first one was developed with the use of DSP (Fig. 2), and another includes an embedded microprocessor (Fig. 3). The design of FPGA includes a digital interface for fast, 800Msps analog-to-digital converter. Another important part of the design is a digital signal preprocessing unit, allowing fast, multiple data accumulation for separation weak signals from the noise. There are also given some details on construction of dual-ported accumulation buffers, accumulation controller and clocking system. Additionally the unit provides some means to control the remaining part of a measurement device as well as the pulse stimulation generator

Iron-Sulfur Flavoprotein (Isf) from Methanosarcina thermophila Is the Prototype of a Widely Distributed Family

A total of 35 homologs of the iron-sulfur flavoprotein (Isf) from Methanosarcina thermophila were identified in databases. All three domains were represented, and multiple homologs were present in several species. An unusually compact cysteine motif ligating the 4Fe-4S cluster in Isf is conserved in all of the homologs except two, in which either an aspartate or a histidine has replaced the second cysteine in the motif. A phylogenetic analysis of Isf homologs identified four subgroups, two of which were supported by bootstrap data. Three homologs from metabolically and phylogenetically diverse species in the Bacteria and Archaea domains (Af3 from Archaeoglobus fulgidus, Cd1 from Clostridium difficile, and Mj2 from Methanococcus jannaschii) were overproduced in Escherichia coli. Each homolog purified as a homodimer, and the UV-visible absorption spectra were nearly identical to that of Isf. After reconstitution with iron, sulfide, and flavin mononucleotide (FMN) the homologs contained six to eight nonheme iron atoms and 1.6 to 1.7 FMN molecules per dimer, suggesting that two 4Fe-4S or 3Fe-4S clusters and two FMN cofactors were bound to each dimer, which is consistent with Isf data. Homologs Af3 and Mj2 were reduced by CO in reactions catalyzed by cell extract of acetate-grown M. thermophila, but Cd1 was not. Homologs Af3 and Mj2 were reduced by CO in reactions catalyzed by A. fulgidus and M. jannaschii cell extracts. Cell extract of Clostridium thermoaceticum catalyzed CO reduction of Cd1. Our database sequence analyses and biochemical characterizations indicate that Isf is the prototype of a family of iron-sulfur flavoproteins that occur in members of all three domains

Alterations in NO- and PGI2- dependent function in aorta in the orthotopic murine model of metastatic 4T1 breast cancer: relationship with pulmonary endothelial dysfunction and systemic inflammation

Abstract Background Patients with cancer develop endothelial dysfunction and subsequently display a higher risk of cardiovascular events. The aim of the present work was to examine changes in nitric oxide (NO)- and prostacyclin (PGI2)-dependent endothelial function in the systemic conduit artery (aorta), in relation to the formation of lung metastases and to local and systemic inflammation in a murine orthotopic model of metastatic breast cancer. Methods BALB/c female mice were orthotopically inoculated with 4T1 breast cancer cells. Development of lung metastases, lung inflammation, changes in blood count, systemic inflammatory response (e.g. SAA, SAP and IL-6), as well as changes in NO- and PGI2-dependent endothelial function in the aorta, were examined 2, 4, 5 and 6 weeks following cancer cell transplantation. Results As early as 2 weeks following transplantation of breast cancer cells, in the early metastatic stage, lungs displayed histopathological signs of inflammation, NO production was impaired and nitrosylhemoglobin concentration in plasma was decreased. After 4 to 6 weeks, along with metastatic development, progressive leukocytosis and systemic inflammation (as seen through increased SAA, SAP, haptoglobin and IL-6 plasma concentrations) were observed. Six weeks following cancer cell inoculation, but not earlier, endothelial dysfunction in aorta was detected; this involved a decrease in basal NO production and a decrease in NO-dependent vasodilatation, that was associated with a compensatory increase in cyclooxygenase-2 (COX-2)- derived PGI2 production. Conclusions In 4 T1 metastatic breast cancer in mice early pulmonary metastasis was correlated with lung inflammation, with an early decrease in pulmonary as well as systemic NO availability. Late metastasis was associated with robust, cancer-related, systemic inflammation and impairment of NO-dependent endothelial function in the aorta that was associated with compensatory upregulation of the COX-2-derived PGI2 pathway