@article{JunemannWinterhoffNordholzetal.2013, author = {Junemann, Alexander and Winterhoff, Moritz and Nordholz, Benjamin and Rottner, Klemens and Eichinger, Ludwig and Gr{\"a}f, Ralph and Faix, Jan}, title = {ForC lacks canonical formin activity but bundles actin filaments and is required for multicellular development of Dictyostelium cells}, series = {European journal of cell biology}, volume = {92}, journal = {European journal of cell biology}, number = {6-7}, publisher = {Elsevier}, address = {Jena}, issn = {0171-9335}, doi = {10.1016/j.ejcb.2013.07.001}, pages = {201 -- 212}, year = {2013}, abstract = {Diaphanous-related formins (DRFs) drive the nucleation and elongation of linear actin filaments downstream of Rho GTPase signalling pathways. Dictyostelium formin C (ForC) resembles a DRF, except that it lacks a genuine formin homology domain 1 (FH1), raising the questions whether or not ForC can nucleate and elongate actin filaments. We found that a recombinant ForC-FH2 fragment does not nucleate actin polymerization, but moderately decreases the rate of spontaneous actin assembly and disassembly, although the barbed-end elongation rate in the presence of the formin was not markedly changed. However, the protein bound to and crosslinked actin filaments into loose bundles of mixed polarity. Furthermore, ForC is an important regulator of morphogenesis since ForC-null cells are severely impaired in development resulting in the formation of aberrant fruiting bodies. Immunoblotting revealed that ForC is absent during growth, but becomes detectable at the onset of early aggregation when cells chemotactically stream together to form a multicellular organism, and peaks around the culmination stage. Fluorescence microscopy of cells ectopically expressing a GFP-tagged, N-terminal ForC fragment showed its prominent accumulation in the leading edge, suggesting that ForC may play a role in cell migration. In agreement with its expression profile, no defects were observed in random migration of vegetative mutant cells. Notably, chemotaxis of starved cells towards a source of cAMP was severely impaired as opposed to control. This was, however, largely due to a marked developmental delay of the mutant, as evidenced by the expression profile of the early developmental marker csA. In line with this, chemotaxis was almost restored to wild type levels after prolonged starvation. Finally, we observed a complete failure of phototaxis due to abolished slug formation and a massive reduction of spores consistent with forC promoter-driven expression of beta-galactosidase in prespore cells. Together, these findings demonstrate ForC to be critically involved in signalling of the cytoskeleton during various stages of development.}, language = {en} } @article{LaurenzanaCencettiSerratietal.2015, author = {Laurenzana, Anna and Cencetti, Francesca and Serrati, Simona and Bruno, Gennaro and Japtok, Lukasz and Bianchini, Francesca and Torre, Eugenio and Fibbi, Gabriella and Del Rosso, Mario and Bruni, Paola and Donati, Chiara}, title = {Endothelial sphingosine kinase/SPNS2 axis is critical for vessel-like formation by human mesoangioblasts}, series = {Journal of molecular medicine}, volume = {93}, journal = {Journal of molecular medicine}, number = {10}, publisher = {Springer}, address = {New York}, issn = {0946-2716}, doi = {10.1007/s00109-015-1292-0}, pages = {1145 -- 1157}, year = {2015}, abstract = {The interaction between endothelial cells and pericytes is crucial for the stabilization of newly formed vessels in angiogenesis. The comprehension of the mechanisms regulating peiicyte recruitment might open therapeutical perspectives on vascular-related pathologies. Sphingosine 1phosphate (SIP) is a bioactive sphingolipid that derives from sphingomyelin catabolism and regulates biological functions in cell survival, proliferation, and differentiation. In this study, we aimed to identify the role of SIP axis in the intercellular communication between human mesenchymal progenitor mesoangioblasts (MAB) and endothelial cells (human microvascular endothelial cells (HMVEC)) in the formation of capillary-like structures. We demonstrated that the SIP biosynthetic pathway brought about by sphingosine kinases (SK) SKI and SK2 as well as spinster homolog 2 (SPNS2) transporter in H-MVEC is crucial for MAB migration measured by Boyden chambers and for the formation and stabilization of capillary-like structures in a 3D Matrigel culture. Moreover, the conditioned medium (CM) harvested from HMVEC, where SKI, 5K2, and SPNS2 were down-regulated, exerted a significantly diminished effect on MAB capillary morphogenesis and migration. Notably, we demonstrated that S I Pi and Si p3 receptors were positively involved in CM-induced capillary-like formation and migration, while S I P2 exerted a negative role on CM-induced migratory action of MAB. Finally, SK inhibition as well as MAB SlPi and S1P3 down-regulation impaired HMVEC-MAB cross-talk significantly reducing in vivo angiogenesis evaluated by Matrigel plug assay. These findings individuate novel targets for the employment of MAB in vascular-related pathologic conditions.}, language = {en} } @misc{WozniakSicard2018, author = {Wozniak, Natalia Joanna and Sicard, Adrien}, title = {Evolvability of flower geometry}, series = {Seminars in cell \& developmental biology}, volume = {79}, journal = {Seminars in cell \& developmental biology}, publisher = {Elsevier}, address = {London}, issn = {1084-9521}, doi = {10.1016/j.semcdb.2017.09.028}, pages = {3 -- 15}, year = {2018}, abstract = {Flowers represent a key innovation during plant evolution. Driven by reproductive optimization, evolution of flower morphology has been central in boosting species diversification. In most cases, this has happened through specialized interactions with animal pollinators and subsequent reduction of gene flow between specialized morphs. While radiation has led to an enormous variability in flower forms and sizes, recurrent evolutionary patterns can be observed. Here, we discuss the targets of selection involved in major trends of pollinator-driven flower evolution. We review recent findings on their adaptive values, developmental grounds and genetic bases, in an attempt to better understand the repeated nature of pollinator-driven flower evolution. This analysis highlights how structural innovation can provide flexibility in phenotypic evolution, adaptation and speciation. (C) 2017 Elsevier Ltd. All rights reserved.}, language = {en} }