Mtss1 promotes cell-cell junction assembly and stability through the small GTPase Rac1

Cell-cell junctions are an integral part of epithelia and are often disrupted in cancer cells during epithelial-to-mesenchymal transition (EMT), which is a main driver of metastatic spread. We show here that Metastasis suppressor-1 (Mtss1; Missing in Metastasis, MIM), a member of the IMD-family of proteins, inhibits cell-cell junction disassembly in wound healing or HGF-induced scatter assays by enhancing cell-cell junction strength. Mtss1 not only makes cells more resistant to cell-cell junction disassembly, but also accelerates the kinetics of adherens junction assembly. Mtss1 drives enhanced junction formation specifically by elevating Rac-GTP. Lastly, we show that Mtss1 depletion reduces recruitment of F-actin at cell-cell junctions. We thus propose that Mtss1 promotes Rac1 activation and actin recruitment driving junction maintenance. We suggest that the observed loss of Mtss1 in cancers may compromise junction stability and thus promote EMT and metastasis

International Review and Advisory Committee

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Ultrasonic characterization of state and properties of Al-based metal matrix composites

In a comprehensive experimental study ultrasonic techniques are optimized and used to characterize the state and to evaluate the properties of Al-based Al2O3 fiber reinforced MMC-parts. It has been the objective to concentrate on those ultrasonic techniques which can be applied on real parts in order to demonstrate the ultrasonic potential in a quality assurance concept for MMC-mass products, like automotive pistons and con-rods. It is found that the ultrasonic backscattering to visualize the distribution of the reinforcing phase in surface layers as well as in the bulk of components is very informative although the results are of qualitative nature only. The evaluation of quantitative values of the local concentration on reinforcements as well as of the Young's and shear moduli are possible by measuring the ultrasonic velocities or time-of-flight. Information on the elastic anisotropy resp. isotropy is gained from measurements using linear polarized shear waves. The pulse distortion o f a longitudinal wave is found to be suitable to detect misalignments of continous fibers

Ultrasonic characterization of burrs in aluminium pressure castings

There are always burrs in hollow castings. They are caused by the joining of the different streams of molden alloy and they can be areas of poor mechanical properties. Up to now, burrs are checked destructively using samples cut from the head and tail of the pressure casted product. It is found that the ultrasonic backscattering is suitable to visualize the fine grained microstructure of the seam area of the burr and the surrounding coarse grained area with higher content of impurities. The direction dependency of ultrasonic time-of-flight is used to characterize the crystallographic texture in the burr region. The texture is found to be different in the burr and in the adjacent areas and this difference changes along the length of the pressed part. The combination of ultrasonic backscattering and time-of-flight measurements is seen as a very promising nondestructive approach to characterize the burr and to determine the length of the pressure casted product with well developed mechani cal propertie

Ultraschall-Laufzeitmessungen an Halbzeugen und Bauteilen - Nutzungsmöglichkeiten im QS-Element Qualiätsprüfungen

Die elastischen Materialeigenschaften, deren quantitative Werte ebenso wie die qualitative Information über deren Änderung z.B. mit dem Prüfort sind Qualitätsmerkmale. Aufgrund der bekannten Zusammenhänge zwischen den elastischen Eigenschaften und den Ausbreitungsgeschwindigkeiten von Ultraschallwellen lassen sich Ultraschallverfarhen zur Charakterisierung von Werkstoffzuständen und -eigenschaften im QS-Element Qualitätsprüfungen einsetzen. Die apparativen Voraussetzungen sind gegeben; die notwendigen Geräte und Systeme sind verfügbar. Anhand ausgewählter Anwendungsbeispiele wird das Potential der Laufzeitmessungen zur qualitativen und quantitativen Ermittlung von Qualitätsmerkmalen aufgezeigt

Brief calculus with applications

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