The MAP2/Tau family of microtubule-associated proteins

Microtubule-associated proteins (MAPs) of the MAP2/Tau family include the vertebrate proteins MAP2, MAP4, and Tau and homologs in other animals. All three vertebrate members of the family have alternative splice forms; all isoforms share a conserved carboxy-terminal domain containing microtubule-binding repeats, and an amino-terminal projection domain of varying size. MAP2 and Tau are found in neurons, whereas MAP4 is present in many other tissues but is generally absent from neurons. Members of the family are best known for their microtubule-stabilizing activity and for proposed roles regulating microtubule networks in the axons and dendrites of neurons. Contrary to this simple, traditional view, accumulating evidence suggests a much broader range of functions, such as binding to filamentous (F) actin, recruitment of signaling proteins, and regulation of microtubule-mediated transport. Tau is also implicated in Alzheimer's disease and other dementias. The ability of MAP2 to interact with both microtubules and F-actin might be critical for neuromorphogenic processes, such as neurite initiation, during which networks of microtubules and F-actin are reorganized in a coordinated manner. Various upstream kinases and interacting proteins have been identified that regulate the microtubule-stabilizing activity of MAP2/Tau family proteins

The MAP1 family of microtubule-associated proteins

MAP1-family proteins are classical microtubule-associated proteins (MAPs) that bind along the microtubule lattice. The founding members, MAP1A and MAP1B, are predominantly expressed in neurons, where they are thought to be important in the formation and development of axons and dendrites. Mammalian genomes usually contain three family members, MAP1A, MAP1B and a shorter, more recently identified gene called MAP1S. By contrast, only one family member, Futsch, is found in Drosophila. After their initial expression, the MAP1A and MAP1B polypeptides are cleaved into light and heavy chains, which are then assembled into mature complexes together with the separately encoded light chain 3 subunit (LC3). Both MAP1A and MAP1B are well known for their microtubule-stabilizing activity, but MAP1 proteins can also interact with other cellular components, including filamentous actin and signaling proteins. Furthermore, the activity of MAP1A and MAP1B is controlled by upstream signaling mechanisms, including the MAP kinase and glycogen synthase kinase-3 β pathways

Design and synthesis of Nrf2-derived hydrocarbon stapled peptides for the disruption of protein-DNA-interactions

Misregulation and mutations of the transcription factor Nrf2 are involved in the development of a variety of human diseases. In this study, we employed the technology of stapled peptides to address a protein-DNA-complex and designed a set of Nrf2-based derivatives. Varying the length and position of the hydrocarbon staple, we chose the best peptide for further evaluation in both fixed and living cells. Peptide 4 revealed significant enrichment within the nucleus compared to its linear counterpart 5, indicating potent binding to DNA. Our studies suggest that these molecules offer an interesting strategy to target activated Nrf2 in cancer cells

NeuriteQuant: An open source toolkit for high content screens of neuronal Morphogenesis

<p>Abstract</p> <p>Background</p> <p>To date, some of the most useful and physiologically relevant neuronal cell culture systems, such as high density co-cultures of astrocytes and primary hippocampal neurons, or differentiated stem cell-derived cultures, are characterized by high cell density and partially overlapping cellular structures. Efficient analytical strategies are required to enable rapid, reliable, quantitative analysis of neuronal morphology in these valuable model systems.</p> <p>Results</p> <p>Here we present the development and validation of a novel bioinformatics pipeline called NeuriteQuant. This tool enables fully automated morphological analysis of large-scale image data from neuronal cultures or brain sections that display a high degree of complexity and overlap of neuronal outgrowths. It also provides an efficient web-based tool to review and evaluate the analysis process. In addition to its built-in functionality, NeuriteQuant can be readily extended based on the rich toolset offered by ImageJ and its associated community of developers. As proof of concept we performed automated screens for modulators of neuronal development in cultures of primary neurons and neuronally differentiated P19 stem cells, which demonstrated specific dose-dependent effects on neuronal morphology.</p> <p>Conclusions</p> <p>NeuriteQuant is a freely available open-source tool for the automated analysis and effective review of large-scale high-content screens. It is especially well suited to quantify the effect of experimental manipulations on physiologically relevant neuronal cultures or brain sections that display a high degree of complexity and overlap among neurites or other cellular structures.</p

An excitable Rho GTPase signaling network generates dynamic subcellular contraction patterns.

Rho GTPase-based signaling networks control cellular dynamics by coordinating protrusions and retractions in space and time. Here, we reveal a signaling network that generates pulses and propagating waves of cell contractions. These dynamic patterns emerge via self-organization from an activator-inhibitor network, in which the small GTPase Rho amplifies its activity by recruiting its activator, the guanine nucleotide exchange factor GEF-H1. Rho also inhibits itself by local recruitment of actomyosin and the associated RhoGAP Myo9b. This network structure enables spontaneous, self-limiting patterns of subcellular contractility that can explore mechanical cues in the extracellular environment. Indeed, actomyosin pulse frequency in cells is altered by matrix elasticity, showing that coupling of contractility pulses to environmental deformations modulates network dynamics. Thus, our study reveals a mechanism that integrates intracellular biochemical and extracellular mechanical signals into subcellular activity patterns to control cellular contractility dynamics

A Time Projection Chamber with GEM-Based Readout

For the International Large Detector concept at the planned International Linear Collider, the use of time projection chambers (TPC) with micro-pattern gas detector readout as the main tracking detector is investigated. In this paper, results from a prototype TPC, placed in a 1 T solenoidal field and read out with three independent GEM-based readout modules, are reported. The TPC was exposed to a 6 GeV electron beam at the DESY II synchrotron. The efficiency for reconstructing hits, the measurement of the drift velocity, the space point resolution and the control of field inhomogeneities are presented.Comment: 22 pages, 19 figure

Research and Design of a Routing Protocol in Large-Scale Wireless Sensor Networks

无线传感器网络，作为全球未来十大技术之一，集成了传感器技术、嵌入式计算技术、分布式信息处理和自组织网技术，可实时感知、采集、处理、传输网络分布区域内的各种信息数据，在军事国防、生物医疗、环境监测、抢险救灾、防恐反恐、危险区域远程控制等领域具有十分广阔的应用前景。 本文研究分析了无线传感器网络的已有路由协议，并针对大规模的无线传感器网络设计了一种树状路由协议，它根据节点地址信息来形成路由，从而简化了复杂繁冗的路由表查找和维护，节省了不必要的开销，提高了路由效率，实现了快速有效的数据传输。 为支持此路由协议本文提出了一种自适应动态地址分配算——ADAR（AdaptiveDynamicAddre...As one of the ten high technologies in the future, wireless sensor network, which is the integration of micro-sensors, embedded computing, modern network and Ad Hoc technologies, can apperceive, collect, process and transmit various information data within the region. It can be used in military defense, biomedical, environmental monitoring, disaster relief, counter-terrorism, remote control of haz...学位：工学硕士院系专业：信息科学与技术学院通信工程系_通信与信息系统学号：2332007115216

Identifizierung und Charakterisierung von Interaktionspartnern des Na + -Phosphat-Kotransporters Typ II

Der Na+/Phosphat Kotransporter NaPi-IIa spielt eine wichtige Rolle in der Phosphathomöostase von Vertebraten. Insbesondere die stark polarisierte Sortierung des Proteins zur luminalen Membran, als auch die Regulation des Proteins durch verschiedene Stimuli erfordert spezifische Interaktionen mit Adapterproteinen. Ziel der Arbeit war die Identifizierung und molekulare Charakterisierung eines Bindungspartners von NaPi-IIa. Mit Hilfe eines Two-Hybrid Screens gelang es, die PDZ-Domäne des Proteins C160 aufgrund einer Wechselwirkung mit dem C-Terminus des Na+/Phosphat Kotransportsystems NaPi-IIa der Maus zu identifizieren. PDZ-Domänen erkennen unter anderem ein C-terminales Motiv mit der allgemeinen Konsensussequenz S/T-X-V/L/I-COOH. Dieses Motiv ist auch in den C-terminalen Aminosäuren des Na+/Phosphat Kotransporters vorhanden (T-R-L-COOH). Die Interaktion dieser Domäne mit dem NaPi-IIa C-Terminus wurde in vitro durch einen "Blot-Overlay" mit aufgereinigten Fusionsproteinen bestätigt. Um weitere Untersuchungen durchführen zu können, wurde der komplette Klon isoliert. Dieser umfaßt 4.3 kb und kodiert für ein Protein mit einem Molekulargewicht von 77 kD. Zur immunhistochemischen Lokalisation von C160 wurden Nierenzellkulturen (OK-Zellen) untersucht, welche C160 und NaPi-IIa überexprimieren. Mit Hilfe von zwei unterschiedlichen fluoreszenzmarkierten sekundären Antikörpern konnten beide Proteine in der Bürstensaummembran dieser Zellen kolokalisiert werden. C160 gehört zu der Adapter-Proteinfamile Shank. Zwei Isoformen dieser Proteinfamilie wurden untersucht: Shank 2 und das im Lauf der Arbeit klonierte und in Shank3b umbenannte C160. Im intakten Organ ist eine Wechselwirkung von Shank3b/C160 mit NaPi-IIa unwahrscheinlich. Shank3b/C160 ist nach immunhistochemischen Untersuchungen an Mäusenierenschnitten in einem anderen Zelltyp als NaPi-IIa exprimiert. Shank3b/C160 wurde ausschließlich in dendritischen Zellen und Lymphocyten detektiert, auch in Rattenniere, Rattenleber und Rattenthymus. Da die Isoform Shank2 ein vielversprechender Kandidat für eine physiologisch relevante Interaktion mit NaPi-IIa ist, wurde dieses Protein immunhistochemisch in der Mäuseniere lokalisiert. Hierdurch konnte klar gezeigt werden, daß Shank2 und NaPi-IIa in der Bürstensaummembran von proximalen Tubuluszellen der Niere kolokalisiert sind. Durch Western-Blots mit der Bürstensaummembranfraktion der Mäuseniere wurde dieser Befund bestätigt. Für eine funktionelle Einordnung von Shank2 in das komplexe Netzwerk von Interaktionen in der Regulation von NaPi-IIa sind jedoch zu wenig Informationen vorhanden. Eine Interaktion der beiden Proteine ist sehr wahrscheinlich, obwohl sie in vivo noch nicht auf molekularer Ebene bewiesen wurde. Beide Proteine werden jedoch zur luminalen Membran von proximalen Tubuluszellen sortiert. Zur Beschreibung der dynamischen Vorgänge in der spezifischen Regulation von NaPi-IIa sind jedoch sicherlich weitere Interaktionspartner nötig, welche noch identifiziert werden müssen

Neurite outgrowth: a flick of the wrist

A new study has shown that, near the tip of a growing axon, dephosphorylation of the microtubule-associated protein Doublecortin is controlled by protein phosphatase 1 and its regulator spinophilin. This results in spatially regulated microtubule bundling within the axon and more efficient axon outgrowth