Die Begriffe Sozialraum, Sozialraumorientierung und Sozialraumanalyse sind in der Jugendarbeit sehr präsent und werden im deutschsprachigen Raum durchaus kontrovers und facettenreich diskutiert. Kritische Stimmen bringen sie mit der Ökonomisierung der Sozialen Arbeit, der Konsolidierung der kommunalen Haushalte und mit einem Rückgang des Staates zu Lasten der KlientInnen in Verbindung (vgl. Dahme/Wohlfahrt 2005:263–279). Gleichzeitig versprechen sie aber auch Modernität, Professionalität, Sicherheit bei knapper werdenden Ressourcen und werden daher als mögliche Qualifizierung der Sozialen Arbeit angesehen (vgl. Gilles 2006:166).

In the central nervous system, a constant microenvironment required for neuronal cell activity is maintained by the blood-brain barrier (BBB). The BBB is formed by the brain microvascular endothelial cells (BMEC), which are sealed by tight junctions (TJ). To identify genes that are differentially expressed in BMEC compared with peripheral endothelial cells, we constructed a subtractive cDNA library from porcine BMEC (pBMEC) and aortic endothelial cells (AOEC). Screening the library for differentially expressed genes yielded 26 BMEC-specific transcripts, such as solute carrier family 35 member F2 (SLC35F2), ADP-ribosylation factor-like 5B (ARL5B), TSC22 domain family member 1 (TSC22D1), integral membrane protein 2A (ITM2A), and epithelial membrane protein 1 (EMP1). In this study, we show that EMP1 transcript is enriched in pBMEC compared with brain tissue and that EMP1 protein colocalizes with the TJ protein occludin in mouse BMEC by coimmunoprecipitation and in rat brain vessels by immunohistochemistry. Epithelial membrane protein 1 expression was transiently induced in laser-capture microdissected rat brain vessels after a 20-min global cerebral ischemia, in parallel with the loss of occludin immunoreactivity. The study identifies EMP1 as a novel TJ-associated protein of the BBB and suggests its potential role in the regulation of the BBB function in cerebral ischemia.

Mammalian cationic amino acid transporters ( CAT) differ in their substrate affinity and sensitivity to trans-stimulation. The apparent K-m values for cationic amino acids and the sensitivity to trans-stimulation of CAT-1, -2B, and -3 are characteristic of system y(+). In contrast, CAT-2A exhibits a 10-fold lower substrate affinity and is largely independent of substrate at the trans-side of the membrane. CAT-2A and -2B demonstrate such divergent transport properties, even though their amino acid sequences differ only in a stretch of 42 amino acids. Here, we identify two amino acid residues within this 42-amino acid domain of the human CAT-2A protein that are responsible for the apparent low affinity of both the extracellular and intracellular substrate-binding sites. These residues are located in the fourth intracellular loop, suggesting that they are not part of the translocation pathway. Rather, they may be responsible for the low affinity conformation of the substrate-binding sites. The sensitivity to trans-stimulation is not determined by the same amino acid residues as the substrate affinity and must involve a more complex interaction between individual amino acid residues. In addition to the 42-amino acid domain, the adjacent transmembrane domain X seems to be involved in this function.

The article presents new ways of visualising problematic suburban developments. After reflecting on the dealing with peripheral growth in the US and Germany, possible future developments of space in an exemplary region are simulated by means of computer graphics. The advantage of this process lies in the number of different graphical results in one scenario after accessing the system. There is no firm development stipulated. Rather, different possible developments are shown.

Member 4 of human solute carrier family 7 (SLC7A4) exhibits significant sequence homology with the SLC7 subfamily of human cationic amino acid transporters (hCATs) [Sperandeo, Borsani, Incerti, Zollo, Rossi, Zuffardi, Castaldo, Taglialatela, Andria and Sebastio (1998) Genomics 49, 230-236]. It is therefore often referred to as hCAT-4 even though no convincing transport activity has been shown for this protein. We expressed SLC7A4 in Xenopus laevis oocytes, but could not detect any transport activity for cationic, neutral or anionic amino acids or for the polyamine putrescine. In addition, human glioblastoma cells stably overexpressing a fusion protein between SLC7A4 and the enhanced green fluorescent protein (EGFP) did not exhibit an increased transport activity for l-arginine. The lack of transport activity was not due to a lack of SLC7A4 protein expression in the plasma membrane, as in both cell types SLC7A4-EGFP exhibited a similar subcellular localization and level of protein expression as functional hCAT-EGFP proteins. The expression of SLC7A4 can be induced in NT2 teratocarcinoma cells by treatment with retinoic acid. However, also for this endogenously expressed SLC7A4, we could not detect any transport activity for l-arginine. Our data demonstrate that the expression of SLC7A4 in the plasma membrane is not sufficient to induce an amino acid transport activity in X. laevis oocytes or human cells. Therefore, SLC7A4 is either not an amino acid transporter or it needs additional (protein) factor(s) to be functional.

At least five distinct carrier proteins form the family of mammalian cationic amino acid transporters (CATs). We have cloned a cDNA containing the complete coding region of human CAT-3. hCAT-3 is glycosylated and localized to the plasma membrane. Transport studies in Xenopus laevis oocytes revealed that hCAT-3 is selective for cationic L-amino acids and exhibits a maximal transport activity similar to other CAT proteins. The apparent substrate affinity and sensitivity to trans-stimulation of hCAT-3 resembles most closely hCAT-2B. This is in contrast to rat and murine CAT-3 proteins that have been reported to display a very low activity and to be inhibited by neutral and anionic L-amino acids as well as D-arginine (Hosokawa, H., et al. (1997) J. Biol Chem. 272, 8717-8722; Ito, K., and Groudine, M. (1997) J. Biol. Chem. 272, 26780-26786). Also, in adult rat and mouse, CAT-3 has been found exclusively in central neurons. Human CAT-3 expression is not restricted to the brain, in fact, by far the highest expression was found in thymus. Also in other peripheral tissues, hCAT-3 expression was equal to or higher than in most brain regions, suggesting that hCAT-3 is not a neuron-specific transporter.

The immunohistochemical analysis of the distribution of 5-oxo-l-prolinase in porcine brain at the light microscopic level was performed with an antibody raised against the enzyme purified from pig kidney. The present study reveals the specific expression of 5-oxo-l-prolinase in brain capillaries with an average diameter of 4.1±0.9 μm, while larger blood vessels remain unstained. Porcine kidney and skeletal muscle show no endothelial-specific staining with the antibody. In some cases, the asymmetrical staining pattern in cross and longitudinal sections of brain microvessels indicate endothelial- but also pericyte-specific expression.

5-Oxo-L-prolinase (5-OPase) catalyses the hydrolysis of 5-oxo-L-proline to glutamate with concomitant stoichiometric cleavage of ATP to ADP, a reaction which is known to be part of the gamma-glutamyl cycle-an interrelated series of reactions involved in the synthesis and metabolism of glutathione. As recent studies indicate, this cyclic pathway plays a crucial role in the regulation of amino acid transport. Apparently, the intermediate product 5-oxo-L-proline functions as a second messenger molecule that upregulates the activity of certain amino acid transport systems. Thus, the degradation of 5-oxo-L-proline by 5-OPase leads to the downregulation of this stimulus. In this study, a new sensitive fluorimetric assay for 5-OPase activity was established which is based on the derivatization of glutamate with o-phthaldialdehyde in the presence of thiols and subsequent separation of the products by HPLC. The method is suitable for the screening of chromatography fractions as well as for the determination of the kinetic parameters Km and Vmax of purified 5-OPase. Additionally, it can be used for the measurement of enzyme activity in crude cell extracts and evaluation of tissue distribution.

5-0xo-L-prolinase (E.C. 3.5.2.9) was purified to homogeneity from porcine kidney. The molecular weight of one subunit was estimated to 135 kDa by SDS-PAGE. N-terrninal sequencing was not successful, leading to the conclusion that the enzyme is N-terminal blocked. Partial sequence data from a chymotryptic peptide showed strong similarities to the rat enzyme.

The gamma-glutamyl cycle is thought to play a significant role in the transport of amino acids between the blood and the cerebrospinal fluid. In the present study we investigated the expression of 5-oxo-L-prolinase, an enzyme of this pathway, in mouse brain and kidney by in situ hybridization using digoxygenin-labeled RNA probes. Expression of 5-OPase mRNA was found in epithelial cells of the proximal tubules in kidney as well as in the epithelium and vascular endothelial cells of the choroid plexus but not in periventricular capillaries.

Chapter 1 Types and Function of Proteins Sabine Wolf, Sabine Wolf Darmstadt, GermanySearch for more papers by this authorHans Günter Gassen, Hans Günter Gassen Darmstadt, GermanySearch for more papers by this author Sabine Wolf, Sabine Wolf Darmstadt, GermanySearch for more papers by this authorHans Günter Gassen, Hans Günter Gassen Darmstadt, GermanySearch for more papers by this author Book Editor(s):Prof. Dr. H.-J. Rehm, Prof. Dr. H.-J. Rehm Institut für Mikrobiologie, Universität Münster, Corrensstraße 3, D-4400 MünsterSearch for more papers by this authorDr. G. Reed, Dr. G. Reed 2131 N. Summit Ave., Apartment #304, Milwaukee, WI 53202-1347, USASearch for more papers by this author First published: 10 May 2001 https://doi.org/10.1002/9783527620999.ch1d AboutPDFPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShareShare a linkShare onFacebookTwitterLinked InRedditWechat Summary The prelims comprise: Introduction Protein Types Protein Function Conclusions Biotechnology Set, Second Edition RelatedInformation

The zymogen of bacterial transglutaminase was found during cultivation of Streptoverticillium mobaraense (DSMZ strain) using rabbit antibodies raised against the active enzyme. Ion-exchange chromatography at pH 5.0 yielded a highly purified pro-enzyme. Structure information was obtained by means of Edman degradation and analysis of PCR amplified nucleotide fragments. The data revealed an excess of negatively charged amino acids in the pro-region resulting in a decreased isoelectric point of the zymogen. Additionally, the new sequence gave rise to some modifications to the previously published hypothetical structure of prepro-transglutaminase derived from genomic DNA [Washizu, K., Ando, K., Koikeda, S., Hirose, S., Matsuura, A., Takagi, H., Motoki, M. & Takeuchi, K. (1994) Biosci. Biotechnol. Biochem. 58, 82-87]. Inactive transglutaminase, which carries an activation peptide of 45 amino acids, has a calculated molecular mass of 42445 Da. Its pro-region provides for both suppression of activity and increased thermostability. Furthermore, it could be shown that the micro-organism produces a protease which cleaves pro-transglutaminase at the C-side of Pro45. Rapid transformation of the mature enzyme also occurs by addition of other proteases. During conversion, 43 and 41 amino acid peptides are released by bovine trypsin and dispase from Bacillus polymyxa, respectively. The detection of endogenous substrates in the murein layer makes discussion of the physiological role of bacterial transglutaminases necessary.