35 research outputs found
M phase phosphoprotein 1 is a human plus-end-directed kinesin-related protein required for cytokinesis.
International audienceThe human M phase phosphoprotein 1 (MPP1), previously identified through a screening of a subset of proteins specifically phosphorylated at the G2/M transition (Matsumoto-Taniura, N., Pirollet, F., Monroe, R., Gerace, L., and Westendorf, J. M. (1996) Mol. Biol. Cell 7, 1455-1469), is characterized as a plus-end-directed kinesin-related protein. Recombinant MPP1 exhibits in vitro microtubule-binding and microtubule-bundling properties as well as microtubule-stimulated ATPase activity. In gliding experiments using polarity-marked microtubules, MPP1 is a slow molecular motor that moves toward the microtubule plus-end at a 0.07 microm/s speed. In cycling cells, MPP1 localizes mainly to the nuclei in interphase. During mitosis, MPP1 is diffuse throughout the cytoplasm in metaphase and subsequently localizes to the midzone to further concentrate on the midbody. MPP1 suppression by RNA interference induces failure of cell division late in cytokinesis. We conclude that MPP1 is a new mitotic molecular motor required for completion of cytokinesis
Relaxation of Loaded ESCRT-III Spiral Springs Drives Membrane Deformation
International audienceESCRT-III is required for lipid membrane remodeling in many cellular processes, from abscission to viral budding and multi-vesicular body biogenesis. However, how ESCRT-III polymerization generates membrane curvature remains debated. Here, we show that Snf7, the main component of ESCRT-III, polymerizes into spirals at the surface of lipid bilayers. When covering the entire membrane surface, these spirals stopped growing when densely packed: they had a polygonal shape, suggesting that lateral compression could deform them. We reasoned that Snf7 spirals could function as spiral springs. By measuring the polymerization energy and the rigidity of Snf7 filaments, we showed that they were deformed while growing in a confined area. Furthermore, we observed that the elastic expansion of compressed Snf7 spirals generated an area difference between the two sides of the membrane and thus curvature. This spring-like activity underlies the driving force by which ESCRT-III could mediate membrane deformation and fission
The SIB Swiss Institute of Bioinformatics' resources: focus on curated databases
The SIB Swiss Institute of Bioinformatics (www.isb-sib.ch) provides world-class bioinformatics databases, software tools, services and training to the international life science community in academia and industry. These solutions allow life scientists to turn the exponentially growing amount of data into knowledge. Here, we provide an overview of SIB's resources and competence areas, with a strong focus on curated databases and SIB's most popular and widely used resources. In particular, SIB's Bioinformatics resource portal ExPASy features over 150 resources, including UniProtKB/Swiss-Prot, ENZYME, PROSITE, neXtProt, STRING, UniCarbKB, SugarBindDB, SwissRegulon, EPD, arrayMap, Bgee, SWISS-MODEL Repository, OMA, OrthoDB and other databases, which are briefly described in this article
LaserâAssisted Strain Engineering of Thin Elastomer Films to Form Variable Wavy Substrates for Cell Culture
International audienc
Visualization of the contact line during the water exit of flat plates
We investigate experimentally the time evolution of the wetted surface during the lifting of a body initially floating at the water surface. This phenomenon is referred to as the water exit problem. The water exit experiments were conducted with transparent (PMMA) mock-ups of two different shapes: a circular disc and a square flat plate. Two different lighting systems were used to diffuse light in the mock-up material: a central high-power LED light normal to the surface and an edge-lighting system featuring an array of LED lights. These setups make it possible to illuminate the contact line, which delimits the surface of contact between the mock-up and the water. The characteristic size of the mock-ups is about 20Â cm and the acceleration of the mock-up oscillates between 0 and 25Â m/s2. We show that the central light setup gives satisfactory results for the circular disc and that the edge lighting technique makes it possible to follow a contact line with a time-evolving complex shape (strong changes of convexity) up to 1000Â fps. The observations presented in the paper support the possibility of extending this promising technique to more general three-dimensional bodies with arbitrary motion (e.g., including pitch motion)
Etude expĂ©rimentale et numĂ©rique du phĂ©nomĂšne de sortie dâeau
We investigate the vertical water exit of a flat solid body initially in contact with a water surface. An original experimental technique based on light diffusion in a transparent mock-up is proposed for the tracking of the boundary of the surface of contact between the solid and the water. The feasability of the technique is shown by studying three bodies : a circular disc, an elliptic disc and a square plate. The results obtained for the circular disc are compared to results obtained with the CFD software ABAQUS and the analytical model of Korobkin (2013).Nous Ă©tudions la sortie dâeau verticale dâun corps plan initialement en contact avec une surface dâeau au repos. Une technique expĂ©rimentale originale basĂ©e sur la diffusion de lumiĂšre dans une maquette en matĂ©riau transparent est proposĂ©e pour suivre lâĂ©volution du contour de la surface de contact entre lâeau et le solide durant un essai de sortie dâeau.La faisabilitĂ© de cette technique est illustrĂ©e par lâĂ©tude de trois corps : un disque circulaire, un disque elliptique et une plaque carrĂ©e. Les rĂ©sultats obtenus pour le disque circulaire en termes de surface de contact sont comparĂ©s Ă des rĂ©sultats de simulations numĂ©riques rĂ©alisĂ©es avec le logiciel ABAQUS et Ă des rĂ©sultats issus du modĂšle analytique de sortie dâeau de Korobkin (2013)
Hydrophobic Interfacing of Fluorescent Membrane Probes: Original Data
Original data underlying the publication entitled "Hydrophobic Interfacing of Fluorescent Membrane Probes